Some folks may remeber me asking about an AM Stereo Transmitter in this post http://part15.us/forum/part15-forums/transmitter-talk/c-quam-am-stereo-transmitter
Well I bit the bullet and purchased this transmitter.
The sound quality is pretty good, nice and loud. The sound quality is on par with the Full Power AM station, which is a great thing.
The internal compressor is a bit weak IMHO, but seems to work well and keeps the modulation full.
A bit of an odd feature of this transmitter is it tunes from 1024 kHz to 1775 kHz.
I did a VERY brief range test at the Full Power's studio. The Transmitter was placed on my desk with the supplied wire antenna stretched onto a ceiling fan, not at the full length either. The Full Power station has 2 foot thick concrete adobe walls, my office faces the street with a window. No ground connected at all, there is no ground prong on the wall wart either.
The signal was absolutely solid for 300-500 feet before dropping to a weaker signal.
The station remained listenable beyond 1,400 feet before I reached the end of the road (closed for construction). Turning onto an adjacent street the signal remained just as strong (now on the backside of the building, so the signal had quite a bit of building to make its way through, as well as a few other buildings). The signal again popped into full strength at 500 feet.
I do not have an AM Stereo tuner available to check how well the C-Quam works.
Mighty 1650 that is better range than I got with my Talking House AM Transmitter on the wire antenna up the window inside. Not sure how much more range I get now that I have put the wire outside. That may be a project to get someone to help me with.
might be well above part 15 levels. remember it is not a certified transmitter they are manuafactured by an individual and each unit is hand made. there was not certification testing done or a easily replicable assembly process.
Which one did you get the eBay one or the Greek one linked by KC8GPD?
i got the evilbay one.
I've seen this transmitter too, there have been several models of it over the past few years I guess. The original seemed to come from the EU, and I watched the maker's demo videos and thought that the stereo received sounded pretty good.
The other thread here mentioned the C-Quam generation not being exactly to spec because of a simple circuit in these little transmitters? Maybe not exactly, but the guy who built the tube C-Quam transmitter said that it's received the same way, and that the refinements were just so that Motorola could claim that their method was unique.
Now I don't really understand the spec and what it takes to make an AM stereo signal fully, to really know what could make it less than Motorola's method, but here's the site for the tube xmitter that the guy built, and it actually does a lot of teaching on the subject.
http://electronbunker.ca/eb/AM_StereoXMTR.html
Nice that all adjustments are on outside front of cabinet including the antenna trim.
From you tube videos he's got the test equipment to check for FCC compliance.
If you have a latest model I've seen it comes with a class D output so the added power getting to the antenna can explain the good range.
300 to 500ft from inside with the wire is great!
Mark
My opinion is this, he is from the UK i guess so the AM Band there is a bit different.
They use both odd and even numbers on the Medium Wave band while we use even numbers
US and South America are 10 khz535 kHz to 1705 kHz while most of the EU/UK are 9 khz, 526.5 kHz to 1606.5 kHz. This builder probably set the transmitter up according to his region's band plan.
Shouldn't be a big deal since it looks as if it uses a knob to adjust the frequency.
Good to hear a review on this transmitter.
The particular one I got is PLL controlled in 1 kHz steps. I have a feeling the one tuned by the knob would have a drifting problem.
In a neat update, this transmitter will sing to you when you put your ear up to it. Not many part 15 transmitters have singing coils!
Singing coils sounds like a feature that could sell!
Maybe the physics guys can explain how to get the coils to sing.
The coils are acting like voice-coils in a loudspeaker.
Well the MCS 3050 arrived today. It immediately locked into my broadcast at 1470, to simply put it sounds amazing in AM Stereo. I'll put up an internet stream fed by this radio shortly.
I'm following your exploits with the C-Quam transmitter with interest. I picked up a Sony STR-AV770 which is capable to stereo AM reception, and really want to put it through its paces with some sort of transmitter.
But first, I have to get my ProCaster set up to get back on AM mono.
here's the stream link fed by the MCS 3050. i noticed some warble on the stream when the stereo locks in. I'm thinking its the streaming laptop causing this. (it has no line-in, so the stereo mic port was the way I had to go in).
I also noticed the audio is less than stellar due to the laptop. I'll put it on a better PC after Thanksgiving.