Cuthbert AM Stereo C-Quam Transmitter Kit! Finally!!!!!

[JimIO]

I'm a big fan of creativity. What is your ground system and  usfull range? Now that the nice weather is here I would like to try something. You can generate 800 or 1600 Khz with a $4 Aduino uno clone and use a $1.25 MP3 module as audio source/modulator.
Waiting on ebay for TC4420 i.c.'s for class D output.

[ThaDood]

The AM1620 side is the Radio Systems, I Am Radio, (Updated Talking House.), and the ATU (Antenna Tuning Unit.), is mounted up at the eves. I bought the thing in 2010 when it was around $400.00 at the time. The actual TX is pumping out the massive 92mW PEP from a floor rack. The GND'ing? Old outer braid RG-8 coax to an 8ft GND rod. No array below. (The manual actually tells you to ground for lightning protection.) I added a Gas Discharge Tube to aid in protection. (Albeit, I know that it will not take a direct hit, but what will?) Heck, see it all for yourself,      https://vk.com/realfreeradio      (I purposely do not use facebook and Twitter, and 4 years ago Just-In Timberlake wiped everyone's myspace. So, VK.) Anyway, the top has the PIC's of a ragtag studios, the carrier-current station AM610, the rack with the AM1620 TX, then the ATU, and the newer AM1620 copper 9ft antenna. Range? Varies, a lot. Winter time I've heard it in a parking lot over 3 miles away, albeit any noise would obliterate it. The good range towards the northern field (Very clear.) is heard over a mile driving, in the day. In November 2017, the CB whip was swapped for the 5/8th" copper pipe, with capacitive Tophat. Boomer calculated that my range could be +6% better, and I think he's right on the money. (Will the listeners notice? Doubt it.) Nighttime? Maybe 1/2 a mile over Cuba and South Bend, IN stations. (BTW, AM610 feeds audio to AM1620 in the garage.) How does it all work? Most of the time, very reliably. However, as you can see from my PIC, not the neatest installations. (Just like a real AM station!) However, PIC's of other Part #15 stations on ALPB and Part15.us sites put me to shame, but will AM C-QUAM stereo be in my future? Lookin' at it!

[ThaDood]

A mini Optimod from Cuthbert,     https://radiojayallen.com/cuthbert-6-channel-3-band-stereo-audio-compressor/        I certainly hope that it is light years better than Ramsey's Stereo Companion. That thing just sucked to high heaven with terrible S/N Ratio. From the sounds of it, this should be much better, and it's an all-in-one. I use three steps of processing currently. From the boards, to an original TERK VR-1, (Not the Audiovox version.), then an Alesis compressor (Set at 4:1 radio.), then an added 16 band EQ. The EQ was actually added to reduce harsh S's and T's from podcasts that don't use a DeEsser unit. It all works, but all-in-one package is very tempting.

[ThaDood]

Yeah, me again... Geeeeeeeeeeeez, if only Motorola did 1/2 as well as Boomer did in demoing AM stereo,     http://boomerthedog.com/am-stereo-is-cool.html     Enjoy!!!! (That Carver receiver is to die for.)

[ThaDood]

       COOL!!!! Sean's C-QUAM kit came in. And, what little time I've had to check it out, it's put together very cleverly. The PIC instructions are much the way that assembly procedures were when I went to work for that RF Plasma Generator / MRI Generator company MKS Instruments back in 2006. I did change over the .BMP's to .JPG's. Ubuntu seemed to handle that better. The PIC's are defined high enough for really big blow-ups of close views. All in all, it appears very doable, indeed.
       The plan? Build the kit the way that Sean has it, test with the 3M wire antenna on the 3rd FREQ, like 1650kHz, then implement the FREQ safety change and EXT ANT MOD's. And then, after extensive testing, swap out the I Am Radio TX for the Cuthbert TX on AM1620. That's the plan, anyway. Then? See what can be done to have AM Carrier-Current, AM610, to go stereo. I do see that Sean has it so that the kit can go either 100mW, USA Part #15 allowable with the 10ft antenna, or 400mW, which would be fine going Carrier-Current operation. Now, to get time to build and test.

[OgreVorbis]

Yeah, no kidding! Just how hard would it be to write up software for SDR's to be able to have C-QUAM capabilities? I am the last person to know this since I almost failed out of computer electronics in college, since I hated machine language.

For near the same price as this you could get a HackRF. With that, you can pretty much modulate any type of signal you want. Sure you could do c-quam with it, but I don't know how. It doesn't require assembly language programming. It uses the gnuradio software which is like a flow chart. Not sure how well it works on AM band though. Some say it works down to 10 MHz and others say 1 MHz.

[ThaDood]

Well, late in July I was able to power up the Cuthbert Transmitter and get RF out. The whole RF stage is built either Class D, or E, and for a very high impedance, which is expected for a 10ft wire antenna on MW. Unfortunately, I have very little audio pumping out of it, and the O'scope confirmed (As did my ears.), that practically nothing was coming out of the audio IC, a TDA7284 ALC chip. (You probably have one in an 80's boombox, or even a stereo VCR, that has audio leveling for recording, instead of manual adjustment.) Boomer, of Carrier-Current station AM690, was doing fine with his Cuthbert TX, so I suspected that I had a bad audio IC. So, I really didn't need it, and just bypassed it all together, since I have managed audio feeding it anyway. WOW!!! Even on a low key AM stereo walkman, what a difference from AM mono to AM stereo! As far as stereo separation? Mine is about that of an early BA1404'ed Ramsey FM-10 from 1989, but better AF response. (I've had several of those Ramsey FM-10's over the years from the original to model C.) Testing on 1580kHz from the indoor wire antenna. Even on a mono receiver, that audio has more punch to its quality. And from the indoor wire antenna, on a car stereo, range MAX's out to just over 1/4 mile. Still, for what it is, if you don't have AM Stereo around where you live, it's still a way for you to provide AM Stereo to leftover receivers that you have with that capability. I do see that AM Stations are starting to dump HD Radio for C-QUAM Stereo again. Buffalo, NY's WWKB 1520AM just turned their AM Stereo back on again. Too bad that's sports talk. The next step? I've just bought two Meduci C-QUAM boards for $28.00USD each. Having just a couple of 1990's low scale AM Stereo walkmans just doesn't cut it, so I plan to roll my own AM Stereo receivers via modifications. https://www.ebay.com/itm/163031984400

[Tim Bucknall]

No need for anything like this other than US??

Stereo on SW?....Hmmm......

if he does a constructed version that can be run right out of the box i'll bite for sure. just throwing it out there in case Cuthbert is reading this :-)

[ThaDood]

          It's been mentioned to me that the other reason that Motorola C-QUAM AM Stereo is getting a push at the hobby level is that the patents for that have expired, thus in today's terms, C-QUAM could be considered Open Source with only yours, and today's tech, being the only limits for applications. Yet, another passing thought, but a good point that I thought was pointed out to me.