Someone should Modernize the 1W AM Transmitter for Old Radios
 

I have a transmitter that I built from a kit a few years back. Takes analog input and broadcasts under the 1W limit.

I've been thinking that there might be more interest in preserving/restoring radios if it was easy to send programming from any media source. What if there was a small transmitter that not only had analog audio input, but would also accept digital audio, maybe even from a computer network, and had a Bluetooth receiver? Then people could listen to music or podcasts or whatever on their old sets without limitations.

Does anything like this exist? If not, how hard would it be to put it together?

Something like this?

https://www.ebay.com/itm/13509683048...Bk9SR_jJx4iBZA

jr

I've got an old Wild Planet Radio DJ toy transmitter. It works decently, but there's lots of info on hotrodding them and I plan to do so eventually. I recently came upon a 200 disc CD changer that may give me my program source (if I don't just set up a mp3 player or a PC with VLC to feed it).

I've been meaning to get a low power AM station going, get a CH6 low power TV/franken FM (broadcast music and a test pattern all the time) and automate some of my low power TV stations to have content 24-7 but I keep being buried in TV repair projects...

Is the limit 1 W or 100 mW? I seem to have 100 mW stuck in my head.

Aha! That's basically it, just needs a nice box. Surprised it costs that much but I'm old and everything seems expensive!

You're absolutely right, it's 100mW. I think mine will output up to a watt with the right copper pipe J antenna but the instructions say it's not technically allowed... :smoke:

Hi to all,
Hi Toxcrusadr,

A choice of low power AM Tx made in England.
Models are available with 10KHz USA channel spacing (9KHz in Europe)

https://www.6v6.co.uk/transmitters.html

Also the SSTRAN AMT-3000. Not produced since 2013, but was highly appreciated. Search E-Bay for second hand units.
The web site & product specs are still around :

http://www.sstran.com/

Want to build one yourself? - see the 386 AM Tx by MacroHenry on ARF "Homebrew" forum. Read all 9 pages for full description.
Uses a LM386 audio IC for modulation.

https://antiqueradios.com/forums/vie...4190&hilit=386

Audio sources:
popular : remodulating a FM station to AM Tx, streaming from i-Pod, computer, MP3 player. BlueTooth from phone. OTR (Old Time Radio) stations from the internet. Big Band music, oldies, comedy shows (Amos & Andy, etc.).

Best Regards
jhalphen
Paris/France

https://www.cool386.com/phono_osc/phono%20osc.html
A example for more hardcore DIYer, all tube model, for people wanting to use tubes for this solution.

BTW, for modernizing it, a generic Bluetooth receiver***, connected to it's input (for all only-analogue inputs), will modernize. Is possible to put receivers in same case, but eventually is needed a sceening between the "modern" part and the RF part.

***some of these receivers have pen-drive connections that serves also as a DAC, for using with PC, but searching is needed.

This popped up yesterday on my Facebook feed. CQUAM AM stereo low power transmitter using tubes.
https://www.facebook.com/story.php?i...72530823220784

I'd like to see the circuit theory of this with an explanation of whether it produces legit CQUAM or an approximation.

This all sent me to the back of the closet to find an AM stereo xmtr I bought at Kutztown many years ago from a dealer. A very home-made kit in a plastic box with a piece of tape as the top hinge. 8 AA batts or a wall wart. RCA inputs. Crystal controled for either 1000khz or 1250 khz. Input gain and RF output gain. Advertised freq response near 14khz. Antenna and ground leads. And it works! It is paired with a RS TM-152 AM Stereo receiver then to a mini Toshiba amp.

Looks like the “Alfredo lite” sold by Chris Cuff.

http://www.amstereo.org/ccuff.htm

jr

https://www.youtube.com/watch?app=desktop&v=hQXEQeqO02M

.

That is the answer. Credit is due. Thanks Chris!

Sadly I dont think they care anymore.... AM radio has gone to crap.... Dead air alot,stations that bleed like crazy not being mantained............

I dont think they would care if someone put up a clean 100 watter at this point.....

AM band seems to be fading in large metro areas, FM has duplication across the band with exception of "College" or similar stations - the best but not consistently received. Most of the remaining flagship AM stations are simulcast on an FM frequency, but it's all talk or BS of some kind.

Once-powerful signals have been downgraded as facilities age, ground planes deteriorate, etc. FM translators can increase coverage but cannot duplicate the range AM has . I find when traveling upstate or between Philadelphia and Pittsburgh, AM stations covering rural areas have better selection of music and local news, etc. Many rural FM stations now program exactly like AM used to :music:

Recently, I was given a "talking house" transmitter by a novice restorer who swears by them - another option, not sure how much power but it requires no license.

https://www.ebay.com/itm/32615261767...Bk9SR5zNxfaCZA

Once upon a time I had an FCC license with radar endorsement which proves the saying "if you don't use it....":sigh:

I visited the link and another model of Talking House, model TH 4.6, popped up in eBay's suggestions. This one has a "live radio" mode (as opposed to using a recorded message) as well as line-input and microphone jacks. I have no familiarity with these, but it would appear this one could be used as a converter box for analog audio sources.

https://www.ebay.com/itm/134017704532
https://www.ebay.com/itm/196443606158

I've been meaning to get some kind of part 15 AM broadcast transmitter rigged up. I may put it in a rack mount chassis and throw it in the stereo rack, then feed it with one of the unused outputs on my MiniDSP 4x10hd, down mixed to mono and EQ'd for AM broadcast :thmbsp: