Hello! for some reason the schematic page of my otherwise complete downloaded Ramsey AM-1 transmitter schematic is blank. everything else is there including layout. But no schematic. Does anyone have one? I built two of these three years ago, had problems with, and, chose to put them aside for a later time. I just came across them while cleaning and want to ressurrect them, and, add a crystal for stability (or a cheap DDVFO, etc...) I have the manuals..."somewhere"...??? :-) Thanks if you can help.
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Ramsey AM-1 schematic needed
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Older model CC Crane FM Xmtr quick mod works out nice!
Did the quick mods on my two Ebay aquired used CC Crane V1 FM Xmtrs: Turned VR2 all the way up, and gently snapped out the X1 crystal to go mono. They went from barely covering the inside of my apartment to covering about 80 feet outside! I seem to recall that the FCC regs talk about an understanding that part 15 is generally intended for a range of about 300 feet, and lacking a more sophisticated approach, I will be using that as my guide to stay out of trouble with them, so, I go for a walk with my Grundig G8 Traveller II, and enjoy the very signifigant improvement. I think I will easily obtain the 300 foot limit through antenna mods and will not need any more transmit circuit mods. Around here, a 300 foot bubble is a lot of households to broadcast to! Best regards to the community!
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Young kid builds impressive tiny FM transmitter
Stumbled across this well done video by some kid showing how to build a tiny FM transmitter that from his presented field test appears to rival the capabilities of my CCrane.
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Talking House (Enhanced Version Photos)
There has been a lot of discussion about V5 Talking House units. Not all are the same. I have included (hopefully) a link to view the photos I took. If you don't see these mods you do not have an enhanced version. Among things like adding and changing component values, you will see a netting capacitor near the crystal.
http://s1047.photobucket.com/user/wa4jm/Talking%20House/story
For $50 more you can get the enhanced version. Well worth it.
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Should I have my Transmitters in my bed room?
So somewhere else I was talking to someone about my transmitters and how I got them setup. I got them in my bedroom next to my window. I was told though to be careful of doing that because I might get affected by the RF radiation. So my question is should I move them and where to? I do have them running 24/7 playing music. The transmitters I use are the Talking House AM 5, and the C.Crane FM2.
Thanks :D
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Part 15 Transmitters in Oceanside Environments
Noted a discussion with our own RichPowers about this on another site.
I had a Decade MS-100 inside a weatherproof box on Bowen Island pretty close to the water, running 24/7. Absolutely no damage at all to the transmitter - I did note that the metal screws securing it to the box were rusted after 2 years.
I also put heat shrink tubing over the telescopic antenna that was sticking outside the box - it was like new when I removed it.
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SS-tran AMT 3000 PLL. (i give up)
so with these chips, i managed to make the tompolk PLL work with 13.8V. no such luck with the SStran 4 chip PLL on 5 volts. since i found that unsoldering components also ruins the PCB trace, im gonna just remove everything in the PLL and jumper in the tompolk PLL since that's a cheaper alternative to giving SStran $30 bucks for the privilege rectifying the fact that the original chips that came with this are junk apparently. no, i did not install any incorrect values. i've more than quintuple-checked all of that, and i've had this dead transmitter for literally a decade and have tried multiple times to get it going on the correct freq. it sucks that it's gonna be ugly, but that's still better than not working at all
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So Near but Too Far
All week a Radio Systems TR6000 Transmitter was on auction at eBay, and as second bidder my offer of $103.00 stood most of the week.
TR6000 is adjustable 0-10 Watts for TIS and carrier current, new models costing above $2,500.
This afternoon in the last hours the bids climbed into the multiple hundreds so I tuned out.
The version shown was an earlier model with controls on the flat wide surface, replaced more recently by a version with controls on the narrow end panel for conserving rack space.
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ELECTROMAGNETIC WARFARE
Would the Navy conduct electromagnetic warfare experiments on unwitting civilians in the United States?
After all, most people routinely debunk any harm from electromagnetic energy, despite knowing nothing about it.
But exposure to electromagnetic radiation causes a myriad of human health problems, including corneal damage, tubular degeneration of testicles, brain heating, sterility, altered penile function, death, cranial nerve disorders, seizures, convulsions, depression, insomnia, chest pain, and even sparking between dental fillings.
To explore the harmful affects of electromagnetic radiation experiments are underway.
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Decrypting Schematic Diagrams
The Part 15 FM transmitters pose a challenge for the ambitious engineer hoping to improve them with modifications.
A modification might be, for example, adding a switch to turn off the stereo generator.
Looking at five transmitters on hand, it's mostly the IC chips, the integrated circuits, which raise the greatest obstacle for the most part because some of them are unmarked and can't be traced to a data sheet which would aid in their reverse engineering.
It would also be nice to add a control to calibrate the stereo injection level, many transmitters are found to have stereo pilots or subcarriers set above professional levels.
I'll sit back while someone makes the meaningless claim that modifying some of these devices negates their certification. Then I'll come back and explain why that's a non-issue.
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The Case for 100 mW AM
Reprinted by self permission from thealpb(dot)com originally posted Jan. 2016
Some are naturally disappointed by the 1/10th Watt of power allowed for legal Part 15 radio transmission, or, by the same token, equally downcast about the 3-meter antenna limit.But my experience tells me the 100mW 3-meter figures were very intelligently calculated by the FCC as the right signal level to allow for compliance with 15.219.Consider these observations and tell me if you don't agree...About 6-feet from the metal window frame serving as the antenna for an AMT5000 transmitter is a Panasonic table radio tuned to that transmitter. The radio is very sensitive and extremely useful for DXing far away AM stations.But with the AMT5000 set at exactly 100mW, the antenna length measured to a precise 3-meters, the radio is over-saturated and the audio sounds like it's coming from under water.The FCC obviously calculated this delicate relationship, and with the further recognition that most Part 15 users are living near other households, any more power and Part 15 stations would be jamming their nearby neighbor's radios leading to a steep rise in complaints.On the other side of the coin the Part 15 rule for FM, 15.239, is set ridiculously low without any obvious rationation, virtually guaranteeing violation of anyone trying to make use of the FM band for low power operation.
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Margin of Error
While pondering Tim in Bovey's curious findings regarding "Certified" Part 15 FM transmitters, in which every transmitter measured was either over or under the specific field strength seen in 15.239.
Since then we have assumed that the whole system of certification is not being seriously adherred to by either the manufacturers, the FCC, or both.
Preachers have issued once-an-hour reminders that the operator of these transmitters is the one responsible for actual compliance with 15.239, despite having no means of ascertaining that compliance and no appeal to the FCC nor manufacturers for their slapdash results.
Something doesn't make sense with this picture. A lot of somethings don't make sense.
That's why an evolutionary thinker, good morning, tends to believe there's an untold part of the story. He thinks the certifying labs have a different set of parameters, not simply the 15.239 rule, giving a certain margin of error in recognition of the loose tolerances of consumer level electronics manufacturing.
Makes sense, but this is human business which isn't bound to making sense.
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Cable modem power supply puts noise over the air
Gents,I've had a horrendous ground loop making its way onto the air and narrowed it down to the power supply of the cable modem. This also occurred with the power supply of the DSL modem I used to have. Isolating the modem on a non grounded line does nothing. Trouble is, I need the modem for the internet stream.Have any of you had this problem? How did you rectify?
Thanks!
PinWiz (novice)
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my homemade PLL transmitter
| Attachment | Size |
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 PLLhorseman.jpg | 64.91 KB |
tompolk PLL design (with different resistors around the VCO)2n7000 mosfet output, can easily do 600mW of carrier with no sweat or heat, but the LM386 modulator is not havin that due to the draw and heat it generates. got it set to around 90mW so if it's not legal, it's close enough. im pretty sure that without scopes or anything, i can say that it's running in class E. would be interested in what everything looks like on a screen
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Ramsey AM-1
Recently a member mentioned improvements
that were made to his Ramsey AM-1. I
believe it had to do with the modulation scheme.
I have had an AM-1 for 20 years. Although it
is not the greatest thing in the world,
I think it is a fantastic unit for learning
about radio transmitters and Amplitude Modulation.
After my recent move, I found my AM-1.
After modifying it for crystal control, I wound a
gigantic loading coil on a bucket and got it to
go 1/2 mile. (This was years ago.)
I did a bunch of other things. I had crystals for
1590, 1670, and 1700 kHz.
It was a ton of fun.
It sat frozen under a bucket under a snow bank
for a whole winter. It was fed by audio and power
cables that went through the yard from the indoor
set-up.
I don't believe it did 100 percent modulation, which
of course was a problem, but I learned a great deal.
This was way before other transmitters, such as
the "Talking House," or AMT-3000 were available -
even before the Ramsey AM-25.
I am trying to put mine back on air just for fun.
(I have other AM transmitters, too.)
As mentioned, we moved a while back, and I don't
have a "workbench" yet.
Brooce, DOGRADIO and all sorts of other Part 15 experiments.
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New Idea Thread
I ran into MICRO1700 at a laundromat and we got to talking.
MICRO had an idea I've never thought of for Part 15 FM stations used as Studio-Transmitter-Links (STL), but otherwise do not want to attract too much attention in their signal range.
The secret: use in-between channels!
I tried it. It works. I moved from 89.5 to 89.6 and am now "off the dial" for anyone flipping to ordinary digital channels, but my digital radios are capable of tuning the in-betweens and of course analog receivers can do it.
The one thing that needs checking is that I want to move AWAY from any nearby stations and not TOWARD them.
Part 15 is fun all over again.
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InfoSpot Transmitter
Looks strangely familar. http://www.theradiosource.com/products/infospot.htm
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Stories of AM Deconstruction
KGO AM 810 is a 50 kW San Francisco news station... well, not any more. The entire news staff has been dismissed as times change.
KGO LAYS OFF NEWS STAFF
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Current FM Transmitters
Just gathering information. Other than the C. Crane FM Transmitter 2 and the Whole House 3.0, what are current, commonly available, actually certified FM transmitters out there these days?
Don't give me legacy transmitters, or old favorites, or things that are not presently available as current stock.
Further testing to satisfy my own curiosity coming up this spring.
TIB
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Two Programs from One Transmitter
While tuning around the shortwave dial as the sun went down I came across a clear signal that happened to be a religious program describing their various satellite channels that I guess were used to distribute their programs.
The preacher explained that they were sending two different programs over a stereo-pair of satellite channels, with one (mono) program on the left audio channel and a second (mono) program on the right audio channel.
So I got to wondering if that could be done with FM stereo...
Obviously on a mono portable receiver you'd hear both audio programs mixed together, but on a stereo receiver you could turn off the right speaker to hear the mono program on the left channel and vice versa.
What could go wrong with that?
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