Max M. Carter Dot Com
Comments and Questions / Forum
February 5, 2012
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[Mon Oct 24 23:22:32 2005] amblog...
Well Max... I just finished reading the story of "Cat Radio". It captivated me even though I knew of the outcome beforehand.Be an even more wonderful world I'm thinking, if every little girl were able to have the kind of bonding memories that Tegan has of having this sort of lightly illegal alliance (being in cahoots) with her Dad, sharing an interest – while, all the while, having fun!Enjoyed the read.Carlos
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[Sat Oct 29 11:44:26 2005] about....
Hi Max,I enjoyed reading about the AM transmitter project - the push-pull topology is what I used for mine except I used IRF620's and was about 10dB down on your for output power! I used fet driver chips with a transformer to force a square wave on the gates. I am curious about your use of the 2N2222 as the complimentary drive - was it really happily driving those big fat (1200pf or so input) fets at nearly 2megs!!??I am wondering if I ought to give it a go as I have a 9100b Optimod AM broadcast audio processor....it would be fun to join in the 160M phone nets using something like that!Kind Regards,Rash.
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[Sat Oct 29 22:56:23 2005] fmtx.....
I LIKE TO BUY YOUR 200 WATT AM TRANSMITTER AND I LIKE TO COMTACT WITH YOUJOEL
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[Mon Oct 31 09:18:16 2005] home.....
2+2=4the end.
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[Mon Oct 31 18:06:53 2005] home.....
Hi Max,
This is just a test.%%*
;-)
John
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[Tue Dec 6 20:53:01 2005] fmtx.....
I've worked quite a few years as an engineer in TV & FM broadcasting; as an announcer; as a public safety/lmr 2-way radio tech; as a telephone company datacomm tech; as a commercial satellite tech; as a catv headend/distribution tech; have built quite a few 200' Rohn-25 towers; am a "ham," design/install surround sound home theaters; catv systems, etc. Have long thought about building an FM stereo lpfm station; possibly a pirate; also want to build a digital tv cable system, among other things. THOROUGHLY enjoyed your website. Funny, my wife is nicknamed "Cattie," and my daughter, "Little Cat." You are obviously a wonderful family. Is a pre-etched & drilled pcb, and parts, available for the '96? With YOUR mods? I would LOVE to build one; would put it on the air right away. I would even allow regularly scheduled programming thru my broadband connection FROM YOU to continue some of your "catcasts!" I wish you and your sweet little daughter the best. You are most fortunate to have each other. God bless. Dean ;
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[Tue Dec 6 21:03:59 2005] twist....
This is from Dean...I have some lowband Motorola Micor & Mitrek 100-watt mobiles, some GE 100-watt mobiles, some Uniden 800 meg SMR trunking mobiles, and some low band GE stations; all of them complete and tested good condition. For sale/trade. Anything special you are looking for that I might could help locate for you out here in the oil fields of West Texas? soon to be General or Extra AND Commercial!
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[Sun Jan 15 20:50:53 2006] home.....
can you send me an FSK transmitter and Receiver. it would be a great help.. thanks
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[Sun Jan 22 23:22:41 2006] about....
Nice work! I was just wondering if you ventured out again into the broadcast spectrum with your AM rig. I've & ("we") have enjoyed "Holiday Pirating" since the 70's. But the money hungry commision has cluttered up the spectrum so much that "NOW" you can't find a clean spot to operate and be heard without using some muscle & creating a little splatter. Looks like we'll have to get retro and utilize some AM emmisions to continue the tradition. Just when that FM system was sounding so good too! I'm trying to stay away from Ch.6 audio 87.75. But 87.9 might be my only other option. Oh well! We've had fun so far! Just don't want to be limited to a net audio stream! Not very exciting! Good for friends out of the listening range, and maybe linking to a remote xmtr, but... Have fun! Comment?
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[Fri Feb 17 11:03:21 2006] amblog...
Hi Max! Long time, no chat. Found your website fascinating. Would love to talk. I live in the far northern corner of Washington State. I work (still) at a test lab .73, Jim .
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[Mon Apr 3 13:06:33 2006] fmtx.....
Nice set of well thought-out mods! I'm not sure why you used the composite as the point for checking your modulation level. I would have looked at the AUDIO rather than the whole thing. I understand the idea of taking the BB (TP4) signal (after all, it has the sum signal). However, the pilot will surely mess with your overall levels. Perhaps you can compensate with the threshold setting of the limiter.It might also be worth adding a diode clipper after the limiter - it's really brutal, and can sound horrible, but if correctly set will completely prevent overshoot modulationpeaks.
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[Fri Apr 7 00:13:15 2006] classe...
nice comment box
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[Fri Apr 7 07:17:48 2006] home.....
CAN U PLZ SEND ME CIRCUIT FOR MAKING A LONG RANGE FM TRANSMITTER LIKE YOURSAT
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[Fri May 12 21:34:44 2006] home.....
Hi Max,Good lookin' laser pics. I'm still trying to get the mini-movie to run. I don't know if it's the video or my computer that's the problem, but it's likely the computer.The white light video effect from the laser has to be clipping of the data read by the sensor. As in, "white is just really bright black."John
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[Sun May 28 20:18:45 2006] catradio.
Catradio was a great story (and a nice way for you and your daughter to share some time together,) good it wasn't in the crow-bar motel! Funny story, I had acartoon, to that effect hanging on mybedroon wall when the FCC paid me a visit, many many years ago, 1966'ish Ithink. 6c4 osillator driving 6l6, plate modulated with back to back CTC universal audio output transformer, Dynco hi-fi amp. Operated a "request" radio station, maybe 4 days. I lived inMilwaukee Wisconsin area, FCC heard me by a FCC monitoring station (across lake Michigan) in Michigan. I still have myofficial letter & a reel to reel tape of"crazy dave's" radio station. Regards &73's
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[Sun Jun 4 12:30:07 2006] catradio.
LOVE IT! JUST BE MORE CAREFUL NEXTTIME. It CAN be done for years withsufficient care. Best of luck es 73.
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[Sun Jun 11 05:25:47 2006] home.....
Hello from Atlanta!!!
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[Wed Jun 14 14:34:40 2006] gatrip...
These were great, thank you so much for sending them. You gave me a good idea of the ceremony etc. Love the aquarium shots. I too wonder if Mom helped build that boomer. I'll try to do this for you when we go to New Zealand....I've nothing from Fauna's graduation but will try to get her to send me some. Lucky you got to be sheltered while daughter was exposed. Just the opposite for us with daughter nicely sheltered from the rain and us staring at umbrellas. Aren't mortar boards funny hats. Love, Tracy
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[Wed Jun 14 14:41:05 2006] gatrip...
test
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[Thu Jun 15 13:10:58 2006] gatrip...
Hey,Everyone looks relaxed and content! You look like you had a great time.See you tomorrow!The gang at SFSThank you for sharing..............
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[Thu Jun 15 16:50:11 2006] gatrip...
Great pictures. Keep the site its excellent.Anna
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[Tue Jun 27 07:10:05 2006] classe...
HI!ABOUT MODULATION,CAN I USE PWM OR CLASS H MODULATOR?
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[Wed Jun 28 03:46:08 2006] classe...
HI!ABOUT MODULATION,CAN I USE THE PWM OR CLASS H MODULATOR?PLEASE SEND ME INFORMATION ABOUT THAT: thanks!
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[Tue Jul 4 04:16:55 2006] classe...
please I'm a nigeria undergraduate in one of nigeria universities,i'm PHILIP, i want to learn how to design a transmitter.can i learn from your company.
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[Sun Jul 30 10:04:08 2006] home.....
Hi!how is the rms power of 1710khz trans. and how is the pep?thanks!
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[Sun Jul 30 10:06:45 2006] home.....
Hi!how is the rms power of 1710khz trans. and how is the pep?thanks!Can i tune this transmitter 550-1800khz?
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[Fri Aug 25 14:54:37 2006] catradio.
Hi, That was a good story and enjoyed reading it. Glad to hear Cat Radio lives on. I operate an internet radio station at radionc.com as well as a LPFM from my location. The FM signal stays within the part 15 limits most of the time :o) I am legally licensed to play copyrighted music on both. My transmitter is a pci card adjustable type with a max of 1 watt but reaches several miles with my 1/4 wave antenna when at full power. The town I live in also has no FM station. The ones that do come in play stuff I (and most others my age) don't want to hear. I hope the laws will change for LPFM so that us smaller broadcasters can get licensed and reach our local communities with an alternative to the new age music. Take Care, Wildun ..
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[Fri Sep 29 22:10:41 2006] home.....
im looking for some tune up ? hop ups for my galaxy DX949 raido plese help me thanks thanks again
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[Wed Oct 18 08:59:29 2006] amblog...
How can I find a 60 watts AM transmitter for a community station?
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[Fri Oct 20 23:40:31 2006] amblog...
Hello! Interesting stories you have regarding your AM and FM low powered days. Do you ever fire up eith the 35 watt AM or the 14 watt FM transmitters anymore? I know a guy that is considering putting on a low powered AM station in Rome NY, about 20 miles from me. Should be interesting to say the least.Bob-
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[Sun Oct 22 04:28:16 2006] catradio.
Radio QRP - The Art of Low Power and Clandestine Operationshttp://www.geocities.com/Radio_QRP/We need your support! QRP is The Art of Low Power Radio where the challenge is to operate and/or build AM radio transmitters using a bare minimum of components, money and construction skill. Why work QRO with a factory set, when homebrew QRP works really well! We are searching for the ultimate design of a Grenade transmitter or Grenade Clone with a minimum of 5-10 watt output and is complete and working! Can anyone help us locate such a unit? We would appreciate any ideas on how to design this rig. Information in this subject would be appreciated! Thanks!
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[Thu Oct 26 20:36:31 2006] catradio.
you are the man, my mpx 96 started hissing and I lost all the schematics and stuff for it, its been so long since I built it I forgot what the adjustments were but found your page and was saved. I use mine to transmit out to the end of the driveway while plowing snow and working around the yard
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[Sat Oct 28 17:09:28 2006] fmtx.....
i have a radio station. my exciter is not producing sound out for broadcast. but the lights indicates that i am get the input. please help me. my station is off now. this is my e-mail.
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[Sat Nov 11 20:31:00 2006] home.....
Hi Max,I'd like to know what HTML command set to use to work on my pages. Can you refer me to the appropriate version?Tnx,John
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[Sat Dec 9 15:33:27 2006] amblog...
I am totally a hobbiest, not that dedicated to anything. I have been trolling the internet since the late 90's looking for a variety of low-tech transmitter designs. The designs fall into two categories: one transister 'bugs' that can be built for $5-$10 and big fancy pirate rigs that require lots of hard to find (expensive) parts. I heard that P.O.W.s made recievers with rusty rasorblades, graphite pencil lead, coils of wire on toliet tissue rolls and a tank commander's headphone. I wanted to design the transmitter equivalent of that. It's gotten a bit fancier than that. It's all made out of NTE replacement parts and "magnet wire" and little bits of cat4 untwisted braid. I'm too chicken to take it on the air, but I think it may have as much as four watts of something. Running it into three 150ohm 5watt resistors in paralell they get warm like a coffee mug warmer, and once I stuck it onto a 130 foot random wire thrown over the house, grounded it to a cold water pipe and stuck one of those 12 volt garden lightbulbs in series with the antenna and it lit right up. It was winking brighter in time with the music, then about ten seconds was all I could stand. I was (and still am) afraid that an rf version of "shot spotter" will triangulate to within 60 feet of my house. So, I have yet to see how well it modulates off of the dummy load. I guess by all rights it is a three stage transmitter in one box.
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[Wed Dec 13 13:23:58 2006] amblog...
Hi,How was the audio freq. response of your Globe with the "heavy Iron". Sound good on your 10 mile drive? I am currently working on that same setup with a Johnson Viking II. I take it that "Super Modulation" was not worth it. Im also on a quest for more info about that . The ARRL book doesnt have much information.Best Regards,
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[Sat Dec 16 00:04:03 2006] amblog...
The trouble with obtaining or building a quality am transmitter is that there are several "kits" out there (of which some are better than others) which seem pretty promising on paper but are a let-down once assembled. They either have poor audio quality or are so complex in design that it is near impossible to troubleshoot them when they "go astray." As for that globe transmitter conversion, that was a work of genius. Some of the terminology was hard for me to follow even though I have an AAS Electronics Tech degree from DeVry. I have been heavily involved in amateur radio since I was in high school. One guy named Phil had an interesting kit/plan posted online called the Li'l7 transmitter which is a basic one-tube design. It is easy enough to understand the fundimentals of such a simple circuit as this, given it uses a basic tank circuit and heartly oscillator. It did not look too different from a one or two transistor AM transmitter, but probably is a little more powerful being a tube rig and all. The only problem with the circuit is that it puts out entirely too little power (probalby about 100mw) to do much of anything with. I am in need of a little (not much) more complex circuit diagram, say a two or three tuber that will put out say a watt or two. At least this would be easier to assemble than any darn computer or PLL controlled AM transmitter would be, and it would definately outpreform say an SSTRAM or A Ramsey AM-25 in high power configuration. Any suggestions of schematics for a simple AM transmitter in the one to two watt range would be greatly appreciated. Do you have any idea of how to "beef up" or add a second stage to a Lil'7 for a bit more power? I would sure appreciate it. That kit that Antique Electronic Supply makes is little better than the Ramsey AM-1 as far as stability and audio is concerned. I hope I haven't talked your ear off, but I was totally fascinated to read about this project of yours!'73
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[Thu Jan 18 22:10:58 2007] fmtx.....
moo!
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[Fri Jan 26 01:14:43 2007] fmtx.....
I always have terrible trouble with comment-related plugins that require me to put some line in the comment loop; I can never seem to find the right spot. Can anyone tell me where I should put the php line in my comments loop? I haven not modified anything much, and I would be very grateful. Thanks!
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[Sat Jan 27 01:22:55 2007] fmtx.....
Bonjour! What a super websight! Very refreshing to peruse from where we live in Paris (France). I eat frogs and drink wine. Woold like more informatons on this. Best regards! Mikael.
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[Tue Jan 30 19:16:39 2007] fmtx.....
Superb! (I wrote something else and then I read below that I aint supposed ter. So I deleted it.)
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[Sun Feb 11 08:25:31 2007] home.....
Max, Wheres pretty Baby? SIGHH I see Laya but not Pretty Baby.
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[Sat Feb 24 11:50:00 2007] catradio.
Read the saga of CAT RADIO today. Very impressed, it embodies the spirit that keeps Free Radio ALIVE. I operate a SW 10 watt am station here in the UK, 6278khz BYCROSS RADIO (INTERNATIONAL). Striving to bring you something a little different in a spectrum of computor controlled channel blasters!
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[Wed Feb 28 06:02:03 2007] home.....
Good morning, Max. This thing is located on the north side of the air base in Anchorage:http://i94.photobucket.com/albums/l93/John_West_2006/Phasedarray.pngA Wullenwebber.John*******
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[Wed Feb 28 08:48:27 2007] home.....
Here ya go, Max:http://en.wikipedia.org/wiki/FLR-9John*******
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[Sat Mar 24 20:56:58 2007] catradio.
Fascinating story! At least in your instance there was a real owner. Not some jumbo corporation. Radio has gone to the dogs! Long live Cat Radio.:)
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[Wed Mar 28 17:35:52 2007] home.....
03/28/07Wow!I enjoyed the info about LASERS.Thank you,Ed
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[Wed Apr 18 02:08:00 2007] catradio.
Does the anybody really own the airwaves? Prove it
[62]
[Mon Apr 30 07:25:57 2007] lasermod.
Hi Max,A suggestion:It looks like you added an LC filter to notch out your local AM station. Since most hobbyists live in urban areas with multiple strong AM stations, you might want to go with a low pass filter to take out the entire AM band. That would make the circuit more immune to other RF gear as well.John*******
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[Tue May 1 18:09:33 2007] lasermod.
Hi Max,That sounds like a pretty simple alignment procedure to me.As an afterthought, almost everyone now has a PC and could use freebee audio software to act as a low freq scope. Add a divide by 10 chip for example and you could use to to set something like the FREQ adjust quite accurately. Or use a reference to a specific square wave level to set precise audio input levels. Lots of possibilities.John*******
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[Fri May 4 08:11:48 2007] home.....
Hi Max,You might want to mention to folks not to point the laser beam concentrator at the sun. Cook the detector real quick.John*******
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[Sun May 27 16:46:08 2007] lasermod.
Qool stuff!-Quahog
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[Sat Jun 9 09:33:14 2007] home.....
Hi Max,The Photo-Snooping circuit looks good, and removing it from the FM circuitry does clean things up a lot. Good idea.John*******
[171]
[Sun Jun 17 03:40:05 2007] lasermod.
Great photos! I'm rustling up a similar laser pointer serial data comms. setup, to be driven by a Picaxe micro (see Picaxe insights => www.picaxe.orcon.net.nz ). In fact a simpler approach to yours is at =>http://sci-toys.com/scitoys/scitoys/light/light.html#laser_communicatorHad you considered using a cheap telescope at the receive end?Regards- Stan
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[Sun Jun 24 10:14:35 2007] classe...
hi MAX i m alex from greece . I am an amateur in AM BAND. 1600KHZ. I have an am pll exciter about 30watt output.I Want to help me on a linear amplifier about 250-300watt. do you have any circuit about this??
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[Sun Jul 1 19:35:23 2007] classe...
This is an extremely well produceddocument, well done and thanks.I have not used a push pull pa beforebut intend to have a go, using yourdata.best regards Finbar
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[Wed Jul 18 08:09:45 2007] catradio.
congratulations, what a pity some people have little better to do than cause grief to others.I was a broadcast engineer some time back and on a Sunday morning we radiated test card(Television station) and a tape of the most boring music you ever heard. One sunday I took a load of records in and patched out the test tape direct to the transmitter (I thought!) after two hours of playing our own music to those on duty getting ready to open the station we got a call from the transmitter site saying how nice it was to have some decent music for a change!!!We got stuck with "performing rights" costs of about ten thousand dollars but pleaded that we were not radiating for entertainment but for station alignment so they dropped it! Thank God! We had been "pirating" with a power of 150 kilowatts!!! now thats some pirate station.Regards to your daughter and tell her to keep up the good work, books are wonderful things and sadly becoming obsolete.Kindest regards Clive
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[Thu Jul 26 14:58:27 2007] catradio.
i am a ham. i am also a pirate. i live in a small town in texas. i only go on the air a few times a year. i can transmitt up to 350 watts. it makes no sence why i enjoy the pirate life. i have made most of my equiptment.sounds like you have a great time. i guess we should be living in the 20's. too many rules and regs today.keep up the good way of life.
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[Mon Aug 13 04:06:12 2007] catradio.
From Bryan Sir Max:i am bryan , I am doing my thesis right now on pirate radio however, i got a hard time assembling the my this trasmitter ("islander" from braincambre500.freeservers.com)since got the hard time looking for parts in the Philippines, and not an electronic person.sir since you ceased from operation would you mind sir if you would donate your equipments to us here in the Philippines i am sure it would be of help in the opration of vegetable farming here since there are no station in the area. Sir ould you please help me the and my fellowmen. thank you.Bryan
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[Mon Aug 27 22:46:48 2007] classe...
Hi Max. My name is Agus. I m enjoying as a ham since 1979 when i was in middle school. I am intersesting in class e project and i found in the net your very clear project page. I m reproducing your schematic for 80 mtr band and it works at least i can produce RF. My problem is the power output is only 120 Watt.By knowing my problem i came back to see wheter i m overlooking something.Could you share your experience about my problem? Thanks for your help. Thanks Max 73s fer u es family.
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[Sun Sep 9 18:42:07 2007] amblog...
I am trying to find transmitting mica caps for modify Johnson KW Matchbox tuner for 160. Do you have a source for 2 each 350 pf. transmitting mica caps?
[201]
[Mon Sep 17 02:51:24 2007] amblog...
Hi Mr. Carter,Thank you for putting up a nicely done technical web page and for sharing your equipment-building experiences with the Net.Sincerely,Pat
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[Sat Sep 22 22:02:20 2007] lasermod.
I am looking for a receiver schematic to receive input from a laser beam for school. Do you have the schematic for the receiver you built for your project? If so can I get it? Thank youDavid
[273]
[Thu Nov 15 01:21:56 2007] fmtx.....
i am want PCB set modifications MPX96Thank you everymuch
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[Fri Nov 16 10:31:45 2007] catradio.
Brilliant. truely Brilliant. My name is Rob, and I was raided this year in the UK for operating a 10 watt Shortwave pirate station from my boarding house. We were on air tuesdays ,Thursdays and weekends for a year and a half untill 'The Knock'. At 15, i am Offcoms youngest SW pirate. Good job they didn't hear of the AM MW set that is still running at weekends...Cracking read, and all the best.
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[Thu Dec 27 15:55:59 2007] lasermod.
Hi Max.I enjoyed reading about Cat Radio and your various transmitter projects. It is nice to know that there are still some persons around who want to tinker with electronics and share their experience with others - even though you may buy almost every conceivable gadget on the earth on eBay for next to nothing.A. S.
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[Mon Jan 22 13:43:05 2007] class....
Question for you: When opening a program window (such as IE) the window often comes up in its non-maximized mode. Clicking the 'maximize' button or double-clicking the bar at the top of the window always maximizes the window, but after closing the window and reopening at a later time, it comes back up in the non-maximized mode again(!), making the maximize step necessary again! How do you get the window to remember to come back up maximized??
(This seems to be a "feature" of WinMe for sure - not sure about XP.)
[576]
[Mon Jan 22 13:44:44 2007] class....
Start with all windows closed. Open up one window (IE for example) and maximize it. Leave it open. Now, open up another window (It will open up NOT maximized). Maximize this one too. Now close both. Open up a new window and it'll open up maximized.
Another way to do it, although not really correct, is if you open up a window and it's not maximized, you can resize it (by putting your mouse on the corner of the windows and dragging) to it's maximized position. When you close it and open another window, it should come up to the size you resized it too.
Hope this helps!
[634]
[Mon Jan 7 16:30:44 2008] fmtx.....
Please send us the PCB design, and the complete part list of of the circuit
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[Mon Jan 7 20:36:44 2008] home.....
Good star story, Max.
John
*******
[62]
[Tue Jan 8 06:30:59 2008] viewcoms.
I will forward your request to my PCB design guy..
Max
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[Tue Jan 8 08:33:23 2008] max......
Thanks John!
(LED illuminated star here.)
Max
[155]
[Wed Jan 16 17:48:02 2008] classe...
Nice page. I just got done building a 50 watt AM transmitter a little while ago using a mosfet. I don't think the design counts as true class E but it puts out a clean good signal.
I find mosfets are the best way to build larger lower frequency transmitters today from longwave up to 3 or 4MHz.
If your interested here's my design..
(note it was kind of a makeshift rig and was my first ;)...
http://i92.photobucket.com/albums/l12/defectivemachine/AMTXfinal.jpg
Anywho check out our message board at..
http://darkliferadio.proboards100.com
[615]
[Tue Feb 5 23:49:12 2008] amblog...
my compliments for your story, it's like my story , i have many years ago a small radio in my village , but i must shut down for bad laws in italy .
massimo.gan@tele2.it
[193]
[Fri Feb 8 08:24:25 2008] viewcoms.
It sounds like Massimo and I have something in common.
Max
[79]
[Tue Mar 11 12:15:40 2008] home.....
Nice site. A good couple of hours entertainment. (Make yourself the PDM modulator! You'll love it!)
FFFR,
Andy
[154]
[Mon Mar 17 04:49:15 2008] viewcoms.
Thank you Andy,
Actually, I tried for several months to get the PDM to work.. without success. So I went back to using iron..
Max
[170]
[Mon Mar 24 21:29:26 2008] classe...
Lo felicito por su excelente descripci¨®n del amplificador Clase E de 200 vatios.
E realizado una sabana electr¨®nica en Excel, que me gustar¨ªa enviarle, donde desarrollo las sencillas formulas de Mark Mallory.
Entrando los valores del ejemplo de Mallory, da los valores esperados.
Entrando los valores de su amplificador, algunos no me coinciden y me gustar¨ªa conocer su opini¨®n al respecto.
La resistencia de carga en mis c¨¢lculos es de 22.2 ¦¸ y usted habla de 10 ¦¸ en su circuito
El condensador del tanque me da 2.433 pF y usted coloca 5.500 pF ( 0.0055 uF)
Me gustar¨ªa saber su correo para enviarle dicha sabana de Excel
Atentamente,
Herbert Botero B.
antecol@une.net.co
[828]
[Tue Mar 25 09:34:04 2008] viewcoms.
Thanks for the nice comment, Herbert.
I went back and recalculated the inductor and capacitor values for the 1.71 MHz class-e AM transmitter and discovered an error in the design instructions given in the web article. The confusion comes from the fact that the 1.71 MHz circuit is a push-pull design, whereas the Mallory circuit is single-ended. The error (my error) is in the P (power) term in the first equation (calculating for L). Since the power is shared by two tank circuits, the P term in the first equation should be 1/2 the output power. I did not make that clear.
I have re-written steps 1, 2 and 5 to clarify the design procedure. Please retry it - use 200 watts for P.
Here are the results of my calculations:
Calculated L = 1.07 uH
AL value (for T400-2 core, from table) = 185
Calculated turns (on T400-2 core) = 7.6 (rounded to 8)
Calculated C = 4829 pF (I used 5500; I happened to have ten 1100 pF mica caps on hand)
Calculated Z = 11 Ω (approx. 10)
I don't have contact information for Mark Mallory. If you like, you can send the spreadsheet file to me as an email attachment, or upload the file here.
Sorry for the confusion.
Regards,
Max
[13]
[Thu Mar 27 05:17:54 2008] viewcoms.
As a result of the above exchange, I put a CALCULATOR on the class-e equations page. Click: /classexmtr/classecalc.html
Max
[13]
[Sat Mar 29 00:10:12 2008] catrad...
Dear Max...I enjoyed reading of the escapades of Cat Radio! Your site is very interesting and your construction work looks superb.
I heard my first pirate back in 1969 (part of the Falling Star Network out of NYC)...although it has been quite a long time since I listened regularly, I have heard several hundred pirates in my day.
Last summer I was able to hear Radio Free Berkley from the car on a trip to northern California...what a nice find.
If you get a chance and have a tape of any of the broadcasts, I encourage you to post them here as .wav files.
Again, thanks for the interesting read...Bill Martin
[677]
[Tue Apr 1 05:21:10 2008] viewcoms.
Thanks for the nice comment, Bill! I'll consider your suggestion.
Max
[63]
[Wed Apr 9 22:23:04 2008] classe...
Hi! Enjoyed reading your 200W Class E article. How did you avoid saturating the core of the PA system transformer (or 115VAC-115VAC isolation transformer given that aboput 5A DC is passing through it? Thanks, Floyd K2DUV 2sailors@verizon.net
[259]
[Fri Apr 11 06:06:07 2008] viewcoms.
Thanks for the comment, Floyd. I had no problem with core saturation. There's a nice big ol' transformer in that PA amp. Lots of iron mitigates against the possibility of core saturation. I added a blurb in the article about it.
Max
[218]
[Thu May 1 08:29:22 2008] classe...
RF POWER LINEAR AMPLIFIER
[35]
[Fri May 2 07:53:29 2008] viewcoms.
You might want to get some protective eyewear, John. My understanding is that laser goggles are selected according to the wavelength of the laser you are using, i.e., so as to absorb in the wavelength range of that particular laser.
Max
[270]
[Fri May 2 08:46:05 2008] viewcoms.
Class-e definitely ain't linear!
Max
[61]
[Fri May 16 05:48:42 2008] amblog...
BLOCK DIAGRAM EN FUNCTIONS OF EACH BLOCK
[50]
[Thu Jun 5 14:08:53 2008] classe...
sir,
you are not giving audio in put stage clearly please give this through
email illiraj55@yahoo.com thanku for yours corcut idea
[158]
[Thu Jun 5 14:12:46 2008] classe...
give a simpul shmatric of am tramsmitter with long range i think you used mpspet hi watt with parell more than above and increase the range
of trannsmitter and watt also
[185]
[Fri Jun 6 07:22:23 2008] classe...
illiraj55@yahoo.com,
The [class-e AM transmitter] article shows the transmitter circuitry and gives some suggestions for interfacing a modulation amplifier. (The audio modulation power is supplied by the modulation amplifier.) As suggested by the article, many commonly available amplifiers, tube or solid-state, can be used - public address, home audio, car stereo, etc. The details of the modulation amplifier are beyond the scope of the article.
Max
[476]
[Fri Jun 6 08:36:06 2008] viewcoms.
I've never had very good luck paralleling MOSFETS. Must be doin' somethin' wrong..
Max
[112]
[Tue Jun 10 21:16:32 2008] home.....
Max,
I'm curious if you're the same Max Carter I served in the Air Force in Germany with. Ayers Kasern near Butzbach, Germany in the late 60's. I recall we were both into stereo's, built the "Brute 70" power amp. from scratch. Parts from Allied Radio & others. It does look like you in the pix. Let me know. You may respond to alucke@juno.com.........Al Luckey
[407]
[Thu Jun 12 05:48:44 2008] viewcoms.
Yeah, I'm the same guy, now 40 years older, retired and living in Wyoming (29 years). I still have that Brute 70, modified and repaired over the years but still going strong. I remained interested in electronics after leaving the service and have more or less made a living at it, plus doing a lot of hobby stuff.
Max
[341]
[Mon Jun 16 01:41:32 2008] home.....
Nice site. Enjoyed reading about your radio broadcasting. Thanks for sharing that and other projects.
Kind regards from 'Down-under'
[152]
[Mon Jun 16 16:29:13 2008] viewcoms.
Thanks 'Down-under'!
Max
[51]
[Tue Jun 17 14:30:08 2008] viewcoms.
give simpul hi watt long range transmitter you are not giving
smematric about 200w transmitte
give simpul ababul productto make
simpul
[160]
[Tue Jun 17 14:47:19 2008] viewcoms.
sorry sir,
parallel mospet means in rf out put stae we used pus pul type two mospet and increase this range through increase the pear of mospet like two pear & 3pear and increase volteg
like (ups or invertor) circut .and increase the range thanku for reading
and ancer me (112)
illiraj55
[335]
[Wed Jun 18 09:47:42 2008] viewcoms.
Here's a block diagram of the class-e AM transmitter (about the same as any other AM transmitter). Note that items marked "external" are not described (except in a general way) in the article:
Hope this is helpful.
Max
[243]
[Wed Jun 18 10:14:00 2008] viewcoms.
illiraj55,
Yeah, I know that in theory one can parallel MOSFETs to increase the power handling ability of the stage. I just have never had any luck doing it at the frequencies and modes (class-e) that I've tried..
Max
[259]
[Fri Jun 20 12:56:58 2008] home.....
sir
what is class e type transmitter and other a,b,c type transmitter
illiraj55
[131][-1][-1]
[Fri Jun 20 14:09:04 2008] viewcoms.
illiraj55,
Class A - output MOSFET (or other device, i.e., bipolar transistor or tube) conducts during 100% of the RF cycle time,
Class B - output device conducts 50% of the RF cycle time,
Class C - output device conducts less than 50% of the RF cycle time (typically about 45%),
Class E - output MOSFET acts as a switch, conducts only when the drain voltage is at 0. This is usually around 50% of the RF cycle time, but can vary depending on circuit parameters.
Look on the internet for further explanation of the various "classes". Wikipedia is usually pretty good.
Max
[685]
[Mon Jun 23 12:43:37 2008] viewcoms.
sir ,
still ihave adout 3.42 mhz carrier source means ?where i get this get idea details thanku for ancer me
illiraj55@yahoo.com
[184]
[Tue Jun 24 06:08:30 2008] viewcoms.
illiraj55,
Quoting the article: "...a signal generator, crystal oscillator, VFO or other source.." This would probably work:
Max
[181]
[Wed Jun 25 00:17:40 2008] viewcoms.
THANKU SIR
ILLIRAJ
[44]
[Thu Jun 26 12:06:58 2008] viewcoms.
max
i have a 500w/1kw transmitter circut can you give idea to make simpul this ai 1.9mb give your email add i give you this thanku
illiraj55@yahoo.com
[202]
[Thu Jun 26 13:17:29 2008] viewcoms.
Illiraj,
I emailed you regarding this. Check your email.
Or upload the file here.
Your choice.
Max
[148]
[Thu Jun 26 23:52:22 2008] classe...
RF POWER AMPLIFIER DRIVER
[35]
[Fri Jun 27 06:46:19 2008] viewcoms.
You might try phrasing your comment as a complete sentence..
Max
[88]
[Fri Jun 27 11:55:49 2008] viewcoms.
sir,
i sent this circut diagram through uplod option but it not give finish command after sending it will be heng up so if you are not receive than sent me e mail clearly my e mail illiraj55@yahoo.com and write (max) also then i understand uoy know there is more adv mels are comming and confus the peapul thanku sir
[342]
[Sat Jun 28 15:02:59 2008] max......
For what it's worth, here is a block diagram of the AM stereo transmitter Illiraj55 is referring to. About the only difference between a "regular" (mono) AM transmitter and a stereo one is the addition of the stereo processor/exciter. This one happens to be a C-QUAM exciter.
Note that the outputs of the processor/exciter consist of 1) a phase-modulated carrier at the transmitter's RF operating frequency and 2) a pulse width-modulated (PWM) AUDIO carrier, usually at around 100 kHz. The PWM stream is filtered in the modulator to remove the 100 kHz carrier and the two signals (RF carrier and now analog audio signal) are combined (multiplied) in the RF power amplifier to produce the composite stereo output signal. The composite signal is processed at the receiver to extract the original stereo audio signals.
I don't think AM stereo is used much anymore, at least in the US.
Hope this is helpful..
Max
[1005]
[Sun Jun 29 11:54:12 2008] viewcoms.
max
in our country radio transmitter is ilegal i heard that is in india . sir any idea to make transmitter in legal purpose houw can i get licance or any friquncy that is free for transmitting or hobby purpose any ligal sdvice if you know then give idea to solve my problame thanku sir
[306]
[Sun Jun 29 15:46:46 2008] max......
Illiraj55,
I don't know how to get a broadcasting license in India but, like many places, if you have the equipment, there is not much that prevents you from broadcasting WITHOUT a license.
(I didn't actually say that..)
My suggestion is to use FM. FM transmitters are generally simpler and cheaper, antennas much smaller, and coverage (transmitting range) is usually equal to or greater than AM for wattages less than 100 or so.
I don't know if low-powered FM transmitters are available in India, but they are available worldwide.
Type into Google terms like 'low-power FM', 'LPFM', 'pirate radio', 'FM transmitter', etc.
Hang around pirate radio forums like alt.radio.pirate or alt.pirate.radio:
groups.google.com/group/alt.radio.pirate/topics?hl=en&lnk=srg
groups.google.com/group/alt.pirate.radio/topics?hl=en&lnk=srg
Drop a question on there about where to get transmitting equipment.
Some sources that I know about are:
www.ramseyelectronics.com kits mostly; require soldering
www.northcountryradio.com kits; require soldering, adjustment skills, test equip
www.progressive-concepts.com ready-built mostly
There are many others.
Importation is a problem in some countries. I don't know about India.
It appears that the FM band in India extends from about 90 MHz to 108 MHz, about the same as everywhere else in the world. For a list of FM stations in India, see: www.asiawaves.net/india-fm-radio.htm Avoid frequencies on the list.
Max
[1739]
[Mon Jun 30 07:40:35 2008] amblog...
convercion cb radio to irf 530 final transistor
[63]
[Mon Jun 30 07:41:24 2008] amblog...
to radio cb
[27]
[Mon Jun 30 12:49:44 2008] viewcoms.
thanku max for your coparate i will quick come a anew topic thinku illiraj55
[87]
[Mon Jun 30 23:43:04 2008] fmtx.....
Keep up the good work! It's nice to see stuff like this on the net.
Greetings from a fellow pirate.
[125]
[Tue Jul 1 05:25:05 2008] viewcoms.
Thanks, Fellow Pirate.
Max
[49]
[Wed Jul 23 04:15:31 2008] viewcoms.
Hi Max..great story about CATradio. I run a small 5w pirate station and I too probably am 'pushing the limits' by broadcasting 8 hours a day or so! I am sure it is the local radio that will bust me if that ever happens. Luckily I live very far away from any FCC office..we'll see if that helps prevent 'the knock'...Your story will certinly guide me.
[372]
[Wed Jul 23 14:13:02 2008] viewcoms.
Thanks for the great comment!
Max
[56]
[Sun Aug 17 10:48:19 2008] classe...
-Can the unit run without load?
-We know what bifilar means but it is not seen in the pictures.
[114]
[Mon Aug 18 06:00:33 2008] viewcoms.
Yes, the transmitter can be operated without load. The output signal will be distorted. Why would you want to operate it without load?
Bifilar? The white and black conductors shown in the photo make up the transformer primary winding. Note that the conductors are parallel with one another and that each occupies the whole circumference of the torroid core. (The secondary, under the electrical tape, is not bifilar wound.)
Max
[429]
[Mon Aug 18 10:49:43 2008] amblog...
notify graphical representation
[41]
[Sat Aug 23 05:07:09 2008] viewcoms.
Without load incase of bad loadtuning or something. To know that the tx will survive. :-o
[101]
[Sat Aug 23 07:39:35 2008] viewcoms.
If minimal drive current (<200 mA) has been acheived and class-e operation has been verified with an oscilloscope during initial tune-up, mis-tuning the output filter will not cause excessive currents or high voltages on the drains of the output MOSFETs.
Arcing in the output filter capacitor or antenna tuning capacitor could be more troublesome. Be sure to use transmitting-type (high-voltage) capacitors in the output filter and antenna tuner to minimize the likelihood of arcing. Follow the guidelines given in the power supply section of the article to minimize the possibility of blowing the output transistors should arcing occur.
Max
[659]
[Fri Aug 29 16:04:35 2008] amblog...
Hay! (in LV)
Ja Jums gadījumā ir zināmi mērījumi par raidītāja izejošo jaudu, kā piem. Output 200 watt apraides zona km (brīvā un masīvā vidē).
[321]
[Sun Aug 31 05:47:10 2008] viewcoms.
Hello Latvia!
I think this is asking the transmitting range, or how much coverage area, the 200-watt transmitter provides.
The answer is 'it depends'. On a clear channel at night the range could be hundreds of kilometers. On a typical well occupied channel on the upper end of the medium-wave broadcast band in the daytime the range might be 50 km. At night maybe 25 km. Maybe more, maybe less.
A guy reported listening for the station one night in mid-winter at a range of about 2000 km. Nope, didn't hear it.
Max
[567]
[Tue Sep 2 14:31:22 2008] viewcoms.
Hi Max,
Great transmitter design (Class E 200w.)
I'd like to convert some of my LPB and Radio Systems transmitters or build new ones. I use them for carrier current operations in seniors retirement buildings. I head a not for profit group that provides senior citizens with radio listening they actually can enjoy!
Commercial broadcasters and advertisers no longer care about the baby boom generation.
worldsupercaster@yahoo.com
[468]
[Wed Sep 3 07:35:46 2008] viewcoms.
worldsupercaster,
Interesting that you mention radio for senior citizens. I deliver meals for the local Services for Seniors center. The idea had occurred to me to suggest a radio station for the housing area. (I was thinking LPFM rather than carrier current.) I thought better of it when I realized it would fall to me to implement the thing. Oh well..
Max
[394]
[Sat Nov 8 10:03:18 2008] lasermod.
hello friend.I congrulate you.I see which it useful circuit laser.I intrest laser communacation.wi-fi&laser internet. I will be very happy hear you.feed back.
haytek@bilgisayar.tv
[196]
[Tue Dec 2 14:54:26 2008] amblog...
HELLO, my name is Daniel
Live IN BRAZIL AND I also happen Electronics Technician.
And visit your site to worship the projects.
Congratulations on PROJECTS.
MY EMAIL It PU2UDK@GMAIL.COM
[230]
[Thu Dec 4 06:02:53 2008] viewcoms.
Thanks for the nice comment, Daniel.
Max
[63]
[Sat Dec 13 04:21:08 2008] classe...
This is just the info I have been looking for. Back to the bench and the junk box for now. 73's KQ2P
[113]
[Sat Dec 13 07:12:03 2008] viewcoms.
Glad you found the info useful, KQ2P.
Max
[88]
[Sat Dec 13 07:51:42 2008] home.....
Max:
Are you connected with Max Headroom,
Jim Carter or June Carter Cash family and Nashville?
jamesh
[188]
[Sun Dec 14 06:10:50 2008] viewcoms.
jamesh,
No.
Regards,
Max
[50]
[Mon Dec 29 23:44:32 2008] viewcoms.
Hi Max, I was navigating within your webpages for laser sound and when I accounted for it went more than 2 hours. You are quite a guy and let me tell you, you have quite a family, nice pets and live in a very nice place. You should be proud of what you achieved in life. Most guys want a lot of things in life, they forget how enjoyable life can be when you reach a point in life when you can do simple things and nobody has nothing to do with or rattle about it. You just get out and do it, enjoy yourself and feel proud of it.
Best wishes and Very Happy and Prosperous 2009.
Wagner (Orlando Florida).
[651]
[Tue Dec 30 06:14:36 2008] viewcoms.
Wow!
Thanks for the nice comment, Wagner!
Best Regards,
Max
[108]
[Fri Jan 2 22:28:49 2009] home.....
Hi Max,
This is really nice. Take a look.
http://ludens.cl/Electron/fmtx/fmtx.html
It reminds me of the way you do things, carefully and well. (And cheap!)
:)
John
*******
[249]
[Sat Jan 3 06:19:49 2009] viewcoms.
Hey, I like it! Looks great!
Thanks John,
Max
[86]
[Wed Mar 11 07:07:12 2009] viewcoms.
[John is referring to data derived from this test setup.]
No, I haven't tweaked it at all - since that one time 2-3 weeks ago. We're seeing its stand-alone performance. Latest reading (3/11) shows it drifting even higher into positive territory. Remember that the computation result is indicated in parts per 1011, quite expanded, in other words. My plan is to let it run for awhile to see the result. I've also decided to go ahead and compute a 30-day average, for what it's worth (after I figure out how to do that).
The osc does seem to react somewhat to changes in room temp. Those few days of exceptionally warm weather last week seemed to pull the osc lower in freq and now that its cold again (-1 degrees outside this morning, about 55 in this room overnight), its again drifting higher.
I'm thinking of knitting a cozy to put over the oscillator..
-Max
[888]
[Tue May 26 14:55:49 2009] viewcoms.
Hi Max,
John here. I use to run a lowfer beacon in Bonaire, GA. Call was JDH @ 184.5 KHz. I don't know if you ever listened for it. Kyle heard it in Minn.
Anyway, enjoyed your web page. Neat articles!
73
John
[266]
[Wed May 27 05:53:17 2009] viewcoms.
Hi John,
Nice to hear from you!
I never had very good luck hearing the eastern lowfers from here in Wyoming. I heard the west coast guys pretty regularly.
Thanks for the nice comment!
Max
[249]
[Fri Sep 25 22:36:26 2009] home.....
Hi Max,
Thanks for doing the Vref page. It looks great and says it all.
John
*******
P.S. Have ya bought a Harley yet? :)
[177]
[Sun Sep 27 22:17:03 2009] viewcoms.
Hi Max
Do you have any pcb for the 200w class E.
What kind of modulator can I use.
[103]
[Mon Sep 28 05:56:18 2009] viewcoms.
No PC board. The transmitter was built using point-to-point wiring on perforated proto board.
Series class D, etc, or linear audio power amplifier, as explained under the heading "modulation".
Max
[239]
[Wed Dec 9 23:46:54 2009] catrad...
hiks... it's so touching :)
[43]
[Mon Jan 11 15:55:27 2010] amblog...
what is your daytime range on 1710 KC?
My email is kc5dsw74ci@yahoo.com
[88]
[Tue Jan 12 09:07:06 2010] viewcoms.
I am contemplating on building a class E transmit/receiving station at home and am curious if you could tell me what your daytime range was with 200W? I plan to operate base to mobile on the bottom of the 160 meter band. Everyone usue 2 meters and I want to do it like they did before WW2. I know nightime range should be great, but what about groundwave in the daytime?
[394]
[Wed Jan 13 06:44:56 2010] viewcoms.
Hi kc5dsw74ci,
Yeah, that's the way they did it in pre-VHF FM days (I read).
The range of the 200W transmitter with the antenna shown in the article is comparable to a small local AM broadcast station. With a car radio it's about 10 miles noise-free, maybe 25 miles if you're willing to put up with some noise. Longer range might be achievable with a communications receiver at a quiet location.
Regards,
Max
[487]
[Mon Jul 12 13:28:27 2010] home.....
Hi Max
I was just looking at your project listings and it occurred to me that they don't really describe what they are about.
"Sewer-Pipe LED Projector" comes to mind.
You might consider renaming them for further clarity.
John
*******
[287]
[Thu Aug 12 19:58:32 2010] home.....
Hi Max
That was about a 17 degree temp drop in 30 minutes just before noon yesterday at your place. Impressive.
John
*******
[155]
[Sat Aug 14 00:51:48 2010] lasermod.
can we buy this modem
[31]
[Sat Aug 14 00:53:10 2010] viewcoms.
where can we get it? how much cost of this modem?
[63]
[Sat Aug 14 05:47:32 2010] viewcoms.
It's not available for purchase. Ya gotta build it.
Max
[65]
[Tue Aug 31 11:33:40 2010] viewcoms.
very interesting, found your site looking for a schematic for a VHF micor PA that is being modified for fm broadcast. We were trying to decide what to call the station, our cats were walking all over the equipment so we called it "98.1 the cat" My step son did a "meow" sound and I mixed a track as the station ID. You would have thought we knew about your station to hear the story.We were totally bootleg also. I out an ad on craigslist asking any potential DJs to make MP files and I would put them on the air. I got a tremendous response and one fella said"I looked up your station on the web and Im impressed, I would like to be a employee" so I looked up 98.1 the cat and found out it is a country station in new england(we are in virginia) I about died laughing at the situation!I was running 50 watts 40 feet off the ground and got about 10 miles of coverage.
steven.kleinnfg@gmail.com
[940]
[Sat Sep 18 21:48:11 2010] amblog...
nice circuits
[23]
[Mon Sep 27 01:38:59 2010] home.....
On your Laser pointer audio modulator circuit, what exactly is the function of the points labeled TP1 - TP7? I'm thinking they are test points. Any clarification would be much appreciated. Thanks in advance.
[223]
[Mon Sep 27 07:14:31 2010] viewcoms.
The test points labeled TP1-TP7 refer to points in the circuits where jumpers and a multimeter should be connected during the setup/alignment procedure called for in the "System Alignment" paragraphs near the bottom of the web article. The alignment is necessary in order to minimize audio distortion.
Max
[318]
[Fri Nov 26 15:54:56 2010] home.....
Hey Bro - Here's what I'd like for Xmas. Could you find "Highland Cathedral" played on bagpipes for me? Our local piper plays it in church for us and I just LOVE it....you will too if you've not already heard it. Love, T
[249]
[Sat Jan 15 07:03:10 2011] about....
Very Cool Max Carter :-)
[38]
[Sat Jan 22 11:58:34 2011] wwvb.....
Dear Sir,
Can you tell me what is the 10 MHz voltage output in the Lucent? Thanks.
Best Regards
Jose
e-Mail: gladius2000@gmail.com
[173]
[Tue Jan 25 06:15:05 2011] viewcoms.
Hello Jose,
The 10 MHz output level is 5 volts peak-to-peak - TTL logic level.
The unit also has a 15 MHz sinewave output. The level is approx 10 volts peak to peak when terminated in 50 ohms.
Hope this is helpful.
Regards,
Max
[298]
[Sat Feb 12 00:44:08 2011] lasermod.
can we able to detect laser ,as soon as the laser hits the circuit?
[82]
[Sat Feb 12 05:55:55 2011] lasermod.
See: http://www.maxmcarter.com/lasrstuf/lasermodulator.html
You might also be interested in this: http://www.maxmcarter.com/lasrstuf/photolistener.html
Max
[82]
[Mon Feb 21 21:58:29 2011] catrad...
This is too good! Sure wouldn't mind hearing a broadcast. a book reading on air would be great. Good luck!
[122]
[Fri May 13 11:08:27 2011] viewcoms.
can i convert a old motorola micro base radio into a 10 or 11 meter citizen band linear amplifiers,or junk it.ltobot@bellsouth.net
[143]
[Sat May 14 05:37:58 2011] viewcoms.
ltobot,
Probably not. I'd say junk it.
Max
[79]
[Tue Jun 7 14:21:30 2011] viewcoms.
Ah, brings back memories of my high school years of playing pirate radio (hombuilt AM 50 watt rig, then a Johnsom Ranger on 7.34MHz). A fun time was had by all. I never got the knock from the FCC, fortunately; probably lack of an efficient antenna back then.
Bud
[292]
[Thu Jun 9 05:34:16 2011] viewcoms.
Thanks for the nice comment, Bud.
Max
[60]
[Thu Jul 7 13:56:01 2011] lasermod.
Hi Max,
Kavan here. A trivial question: electrical signals can be AM, FM, PM modulated. Can a laser, be frequency modulated? I don't think so since the output frequency is fixed (unless we use an expensive external modulator). Lasers can only work with pulses and m-ary ASK...is that true or am I wrong?
thanks
kavan
[361]
[Fri Jul 8 06:09:43 2011] viewcoms.
Kavan,
I don't know for sure but I think you are generally correct. To directly phase or frequency modulate a laser you would need to vary (modulate) some physical aspect of the laser. Downstream phase modulators, as you mentioned, are available. These are based on optical delay lines.
Thanks for the question!
Max
[401]
[Tue Jul 26 02:25:48 2011] laser....
I've been thinking about building the listener and mounting it in the eyepiece holder of my 10" dobsonian reflector telescope. Do you think there is anything of interest to hear from space?
[205]
[Tue Jul 26 07:25:56 2011] viewcoms.
The photo sensor mounted on a 10" telescope should work great, but the phototransistor specified in the article is probably not optimal for resolving (listening to) objects in space. Resolving power is inversely proportional the size of the sensor (or individual pixel in the case of an image sensor) - the smaller the sensor (pixel), the greater the resolving power. The specified sensor should be able to "hear" the moon and Venus, but more distant objects might be a problem. When listening to light from a distant object, you may actually be hearing the light as modulated by the earth's atmosphere. But I really don't know. Give it a try!
Max
[611]
[Mon Aug 15 02:34:14 2011] lasermod.
where do i get all these components in MUMBAI??
[67]
[Mon Aug 15 05:12:25 2011] viewcoms.
I don't know specifically, but I suspect virtually any and all electronic components are available in Mumbai. Look for a place that sells electronic components, or you can always shop on line. Mouser Electronics is pretty good.
Max
[69]
[Sat Sep 17 22:27:23 2011] catrad...
I remember seeing her read in the basement I always thought it would be neat to own a radio station
[109]
[Thu Sep 29 20:42:26 2011] lasermod.
what can be a good replacement for the MOSFET driver??
[68]
[Fri Sep 30 06:08:12 2011] viewcoms.
There are lots of MOSFET drivers available. Google "mosfet driver" and look for a lowside mosfet driver with a peak output current around 1 amp or more with an internal resistance in the range of 10 ohms or less. Manufacturers include Maxim, International Rectifier, Haris Intersil and others. The Microchip TC1411 is available here:
http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en010647
and many other places.
Other laser drive schemes could be dreamed up. The negative drive scheme shown in the article was chosen because the cheap laser pointer used has the laser diode anode connected to the pointer case (positive ground). If this is not a concern, the driver could be something as simple as an open-collector NPN transistor. The mosfet driver, coupling capacitor and Schottky diodes (U4, C7, D1 and D2) would not be needed:
If you prefer having the case of the laser pointer grounded, the simplest approach in concept (though not necessarily simple in execution) would be to wire the entire laser modulator circuit as a positive-grounded system. The connection to the laser pointer would look like this:
Note the driver is a PNP transistor.
I added a blurb in the article about this. Thanks for the question.
Max
[13]
[Fri Oct 14 21:36:43 2011] catrad...
Ha.. Great story. Sooo- ya sang like a bird,eh?
I think the best part was your young daughters contribution. I todays world of video games and text messaging it would be great if more folks did this hands on science. But that is a dying thing with light pollution for home astronomers, electrical noise and digital hash ruining the spectrum for hams and radio hobiests etc.
Thanks again for sharing and for the web site. Next time set up in Canada! Industry Canada took two years to shut down a mega watt pirate in Toronto-even though they knew the adress and details! Infact the IC rules now have eliminated all requirment for them to find RFI interference to licensed operators etc. Theynrefuse to inforce unless it affects an emergency radio service such as police. Anything else and it carte Blanche . So come to Canada!
Hams are also affected- anything goes up hear. Operate without a license and no one cares because IC doesn't care.
Keep the site up!
Greg
VA3...
[1040]
[Sat Oct 15 05:24:03 2011] viewcoms.
Thanks for the comment, Greg.
For awhile there in the 1990s, the FCC in the States seemed to have the same attitude. That attitude changed as more pirates came on air and the powers that be (National Association of Broadcasters, among others) applied pressure. I'm not aware of the present situation.
Max
[413]
[Tue Dec 13 14:14:49 2011] lasermod.
can u give me idea the alternative for tc1411??
and how to measure the right transistor i use on "Alternate Laser Drive Options"??
[158]
[Wed Dec 14 08:40:27 2011] viewcoms.
Any small signal transistor with a current gain (beta) in the 100-200 range should work. 2N2222 (NPN) or 2N2907 (PNP) or similar.
There are lots of MOSFET drivers available. Google "mosfet driver" and look for a lowside mosfet driver with a peak output current around 1 amp or more with an internal resistance in the range of 10 ohms or less. Manufacturers include Maxim, International Rectifier, Haris Intersil and others. The Maxim MAX4420 should work. See: http://www.maxim-ic.com/datasheet/index.mvp/id/1486 Check the datasheet for the pinout.
Max
[533]
[Wed Dec 14 15:09:45 2011] home.....
Hi Max
I really like the Class E 200 Watt transmitter of yours. I noticed you did not include the output capacitance of the FETs. Does this cause any problems that you have found?
Thanks
Don
[217]
[Thu Dec 15 06:52:15 2011] viewcoms.
Hi Don,
No, I didn't have any problems related to FET output capacitance but I should have mentioned it in the article. It could be significant when the tank values calculation calls for a capacitance value below maybe 10x the MOSFETs' output capacitance. This could be the case when calculated tank impedance comes in "on the high side" - over 50-100 ohms or so, ie., when high power, high supply voltage and/or high frequency is called for. The FET output capacitance should be subtracted from the calculated value. The adjustable exciter provides for duty-cycle adjustment during tune-up. This compensates somewhat for variations in component values.
As mentioned in the article, the specified FETs probably won't work well in the circuit above 2-3 MHz.
Thanks for the comment.
Max
[810]
[Sun Dec 18 05:47:10 2011] viewcoms.
how i know which side is anode or cathode when i use a cheap laser pointer??
is it anode where positive (+) from battery connected??
thanks for reply
[189]
[Mon Dec 19 05:27:32 2011] viewcoms.
Yes. The anode connects to the positive terminal of the battery.
Max
[89]
[Wed Dec 21 04:05:47 2011] lasermod.
I try to build the detector,,
i found that resistor R2 is hot, and voltage in resistor R1, and A (+) is 0 volt.
are my detector is right?
or something wrong??
and when i tried to put speaker in output, i heard "hiss" sound..
[286]
[Wed Dec 21 06:11:34 2011] viewcoms.
Hard to say for sure. I'd say there's a wiring error or shorted component somewhere.
Another possibility is that the front end amplifier (Q1) is oscillating. This could be the case if the circuit was not constructed using the suggested double-sided circuit board . The stage gain is very high and the grounded backside of the board forms a shield. Try some shielding around the stage.
With no input signal, a loud hiss on the output is normal when the VOL control is set to maximum.
Max
[549]
[Wed Dec 21 06:21:50 2011] viewcoms.
if i want to use hot pointer case, how can i adjust the current regulator to 30MA?
what is the symbol (+) in hot pointer case? is it same as VDD?
[180]
[Wed Dec 21 06:31:09 2011] viewcoms.
so the receiver can not be built in single-sided circuit board? or i can use single side?
i just found out that voltage on r1 are depend on the photodiode, am i right?
i can not use double-sided circuit board because near me did not sell that, are the transmitter use the double side board to? can i use projectboard?
[351]
[Wed Dec 21 10:03:00 2011] viewcoms.
You've brought up an important point that I should have mentioned in the original article:
Yes, you can use proto-board to construct the circuits. The original boards were constructed that way. The receiver front-end amplifier and limiter-discriminator were shielded with copper foil as shown in the photos below. The shielding is necessary to to prevent the circuit from oscillating due to its very high gain. The grounded lower side of the double-sided board used on the suggested printed circuit board layout does the same.
The first photo shows the copper foil. The second shows the shielded front-end amplifier. The third shows the limiter-discriminator. [The limiter-discriminator ended up on a separate daughterboard. I ran out of room on the original board.]
Copper shielding foil. The foil is insulated on the back side. Though copper is best, any kind of metal would work nearly as well - aluminum, steel, etc. [For aluminum the ground connection(s) would need to be mechanical as aluminum is difficult to solder.] Be sure to insulate the shield.
Shielding below the front-end amplifier. I suggest you shield the entire board.
Limiter-discriminator daughterboard. Look closely and you can see the shielding on the back side of the board.
With no input signal, the output of the the receiver should be a steady hiss. It will sound very much like an FM radio not tuned to a station.
> i just found out that voltage on r1 are depend on the photodiode, am i right?
The photodiode is reverse-biased, so the voltage on the cathode should be very nearly the same as the positive supply voltage (+12 to 15 volts). Note: A photo-transistor will NOT work in the circuit. It will not be fast enough.
> if i want to use hot pointer case, how can i adjust the current regulator to 30MA?
> what is the symbol (+) in hot pointer case? is it same as VDD?
On the transmitter current regulator question: The output of the current regulator, instead of connecting to pins 1 and 8 of U4, would connect to the laser pointer case.
The + is the regulator output, 3 or 4 volts positive, depending on the setting of the regulator. Monitor the voltage across R21 and adjust for 30 mV.
[I should start a forum on the laser modulator-demodulator page to handle questions like this. Will be doing that Real Soon Now...]
Max
[1758]
[Thu Jan 5 07:24:01 2012] lasermod.
in the alignment step 4, 5, 6, and 7, where is the leads of a multimeter point to?
is it same as point 3 (when multimeter set to tp6 and tp7) ?
[175]
[Fri Jan 6 05:31:27 2012] viewcoms.
Yep.
Max
[29]
[Fri Jan 6 22:46:03 2012] home.....
Hi Max. Im Dave from Tasmania. Ive been enjoying your information on data logging with a picaxe. I notice that you have some information about haemoroids on your site. Vitamin P is the key. Its not a true vitamin but works with vitamin C to make it much more effective. Vitamin P helps the cells to have elasticity. Some berry fruits and the like contain it. If you get a multivitamin, vitamin P is called 'biflavonoids'. I suppose its easy to remember, "biflavonoids for haemoroids".
Regards Dave
[531]
[Sat Jan 7 05:27:26 2012] viewcoms.
Thanks for the information, Dave. I've never heard of vitamin P, but "bioflavonoids" rings a bell. It appears to be a controversial subject if the Wikipedia "talk" page is any indication. (en.wikipedia.org/wiki/Talk:Flavonoid)
I'm not troubled by hemorrhoids. I must be doing something right.
:)
Max
[327]
[Mon Jan 9 21:50:21 2012] viewcoms.
Have you done any work on an ethernet interface, similar to the open source Ronja project?
[116]
[Tue Jan 10 05:28:17 2012] viewcoms.
No, I have not. The laser pointer FM effort was in response to a friend's need to feed audio to a remote radio transmitter. Ronja looks interesting!
Max
[168]
[Tue Jan 10 18:50:24 2012] viewcoms.
I like your Sewer-Pipe LED Projector better than the Ronja one.
[85]
[Wed Jan 11 09:03:56 2012] viewcoms.
The Ronja system is obviously more sophisticated than our laser pointer/LED dabblings, but both suffer from the same limitations: attenuation of the light beam by precipitation and sensitivity to beam mis-alignment. There's probably not much that can be done about the first other than more power at the transmit end. The LED projector addresses the mis-alignment issue. The wider beam greatly simplifies alignment - at the sacrifice of range. Driving the LED harder than the pulsed 350 mA we used on our experiments - maybe up to a couple of amps pulsed - would make up for some of the lost range.
Thanks for the comment.
Max
[756]
[Tue Jan 24 13:43:25 2012] home.....
The Koil link on your page resulted in my Microsoft Security essentials antivirus intercepting a trojan. Thought you would want to know. I'm using Firefox 9.01
73 Chris W4NEQ.com
[204]
[Wed Jan 25 05:22:56 2012] viewcoms.
Thanks Chris,
KOIL link gone!
Max
[69]
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