...that is likely the harbinger of the future.
We've been talking about using SDR technology to create transmitters. Well, I just ran across something called the FM-TX180 - you can purchase it on Ebay, Aliexpress and other sites. I suspect it uses just that technology.
It's an FM transmitter that is patently overpowered and illegal to use in both Canada and the U.S. (uncertified of course), but the device also has many other features. It will accept input from bluetooth, so it is a bluetooth receiver. It can act as a soundcard/transmitter by plugging it into a USB port on your computer. And, drumroll please, it can also transmit in very low power on the AM broadcast band (to a claimed 18Mhz). They also claim range up to 3 meters for the AM transmission functionality, although that is unclear, and it could be a bit more.
If you don't use the FM transmitter part, everything else would be legal in the U.S., as I'm sure that the AM signal would fall under Part 15.209. Unfortunately, it is not certified for Canadian use (and everything has to be certified or type accepted here).
Of course, there's no way of knowing what kind of spurious emissions this thing puts out in transmitter mode.
They're cheap too, at around US$50.
Attenuate the FM signal to Part 15 specs, bump up the AM signal, clean emissions if necessary by adding the requisite filter(s) and you'd have a winning product.
Evidently the FM-TX- chips have been around awhile, a guy named BeDazzler in the Stereo Tool forums bought one 10 years ago and gave a brief review of it:
https://forums.stereotool.com/viewtopic.php?t=7098
Recently I bought one of these which we are testing in a live environment as an LPFM relay / translator in a regional location that's not really easily accessible.
It ran on the bench for 2 weeks before field deployment and I had zero issues.
You can configure them using USB+PC Software or solely via DIP switches on the board - we use DIP switches so everything is hard set before the units go out into the field. It also means no fiddling once they are installed in a case and locked.
They do come as a kit, so you can buy whatever configuration you need - ie: main board + power supply + case, etc.
I bought just the main board, then added a 2.5a 12v PSU and a nice case with a fan. Took 1 week to get here which was pretty good.
Very economical and the guy Marko from PCS has been excellent for support.
Happy to recommend PCS gear and their support.
BeDazzler.
I don't think we're talking about the same transmitter. Here it is.
Cheaper on Aliexpress.
But the same transmitter was around 10 years ago because a guy following that post had asked specifically about the FM-TX180 and provide a link to it
Again, I don't think it's the same. Same name, different transmitter. The link no longer exists, and the transmitter back then was just a board. No mention of AM either.
Again, I don't think it's the same. Same name, different transmitter. The link no longer exists, and the transmitter back then was just a board. No mention of AM either.
Perhaps not, the link in 2015 has led to here: https://web.archive.org/web/20100817005912/http://www.tugicom.com/fm-exciter/tx180.html which was the TX180A - High quality MPX ready 1W FM exciter (Packed with LCD display) preassembled board without a case, no it doesn't mention AM shortwave capability and they cost $150.
I don't think we're talking about the same transmitter. Here it is.
Cheaper on Aliexpress.
Aliexpress notification alerted me the "TX-180 AM Transmitter" today, which is what reminded me of you talking about it before. Usually they're marketed as an FM transmitter, but my alert didn't even mention FM capability, it specIfically was pushing it as an AM transmitter. I thought that curious. Other times it emphasize for its Bluetooth transmitting capable.
Anyway I never really looked too close at it before when you posted about it, but the more I look at it the more intriguing it gets. I've never known there to be a xmtr manufactured specifically made to broadcast in AM, FM and Bluetooth, it actually has 3 different antenna jacks for whichever purpose:
I
And it's a media player!
I also notice the TX-180 looks identical to the "TX-200":sold by Walmart as an analog TV transmitter.
@richpowers It doesn't transmit AM as you are thinking. Here's the specs and you will see.
Specification:
- Power supply: DC12V
- FM transmission distance: 1000 meters for a car radio and over 500 meters for a regular radio.
- Transmitting frequency: 75MHz - 108MHz
- AM signal: firstly, in order to obtain high-quality and clear sound, it is output as a modulation signal. Within a distance of 3 meters, the signal is relatively clear, clean, and of better quality than some radio stations. It can be used as a modulation signal and for testing purposes, with a smaller actual transmission distance.
- Modulation frequency: 0.1Hz - 15MHz
@mark $159 shipping.. geeze.
I see now, it's not an AM transmitter in the traditional sense.
Well, at least it was something to look at - or rather to revisit.
That's because of the tariffs, which are built into the shipping price.
It will be interesting to see what happens to prices now that at least some of the tariffs have been struck down by the Supreme Court.
At my end for Canada I see $29.66 shipping. Maybe because Canada has no tariffs on China?
For Artesian's link it shows me $16 shipping and Marks link shows me $159 shipping