While driving home from work, I happened to be monitoring 1670, listening to a weak signal from WTDY (Madison, WI). Suddenly I picked up a “talking house” transmission. It was from a realtor (Baird and Warner) advertising a house for sale along my route. He went through the house description, and at the end, he put in a plug for the “talking house” and invited people to contact him about selling their home “the talking house way”.
That’s fairly unremarkable, but something else I noticed might be of interest here… the “woop woop woop” effect! Now, what is that? Well, as the talking house signal got weaker, it was beating with the background signal from WTDY. As the message played, it would cause this low frequency “woop woop” sound, with about a 1 second periodicity. I noticed that the “wooping” effect was strongest between words, and it would eventually die out at the end of sentences or during the quiet period before the message repeated.
Now, what exactly is this? Here’s my theory. I think there are two things going on. The power supply apparently is not well enough regulated, and the PLL is slightly unstable. On modulation peaks, the extra power pulls the supply voltage, affecting the carrier frequency. The PLL corrects it, but it overshoots, causing the “woop” effect. When there’s no modulation, the thing stabilizes. This could probably be corrected fairly easily by adding some additional regulation.
So OK, all you talking house transmitter owners, have you noticed this? I was curious about these units, but it sounds like the audio quality might not be as good as the SSTran or the Rangemaster. At least not without some work!
Warble
by MRAM 1500 kHz
Quite some time ago, in another thread far, far away, I had reported that my Talking House has a noticable warble sound for weak signal reception. But, this warble is more or less constant, not varying with modulation and only noticable for weak signal reception.
It’s not your usual beat-note hetrodyne, which by the way the carrier freq is off by about 800 Hz so when the skywave signals come in it’s easy for me to identify my signal even if the modulation is barely perceptable. I did have the oscillator padded down to put it on freq and that’s when I noticed the warble. Thinking the “padding” was causing the problem I removed it but the warble remained.
It doesn’t show up on a ‘scope and our shop’s Motorola Station Monitor doesn’t show it as carrier FM’ing so it must be very subtle.
Woop-EE!
MRAM,
If yours does the warble dance too, then it must be inherent in the design!The amount of warble probably varies with frequency and from unit to unit. It might be worse at the high end of the dial.
I can’t explain why you wouldn’t have noticed it on a shop station monitor, but here are a couple of possibilities. First, I think it has a very low frequency periodicity – like about 1 Hz. That might not be as easy to see as it is to hear. Second, the deviation varies with modulation. No modulation = no deviation. It’s gotta be FM’ing because you don’t hear it when the signal is strong; only when it’s weak and you can hear it beat against another station on the frequency.
By contrast, my Rangemaster is solid as a rock. I did have to set it on frequency though. The way I did this was kind of cheesy, but it worked OK. I took a portable radio up on the roof late in the day, near sunset, when a couple of other stations are creeping up in the background. I disconnected the antenna wire inside the transmitter temporarily, to make the signal weak. Then I could beat the Rangemaster against the interfering signals and adjust it until it was on frequency. And there it stayed!
My SSTran is another story. It was exactly on frequency from Day 1. I never tried to adjust the frequency, and I have never head more than a couple of Hz beat with anything else on channel. Amazing!
WEAK-AM
Classical Music and More!
Your right about the audio quality !
Sometime ago I used a Talking House transmitter along with the external ATU unit whip antenna for over a year, at first it always had a shallow sound with no bass or mid range , I used an Eq to help clean it up somewhat but nothing comparable to the SStran or Rangemaster. I thought about using an Inovonics 222 but that would be an $800 expense and what if it did not improve the sound on my Talking House Transmitter ? So, I invested a $125. for a Ramsey Audio processor and WOW ! , it did make a big difference, it gave it a warm bassy sound along with mid range and I adjusted the highs back for a warm AM sounding station, my neighbor down the street noticed the new sound right away as he was a listener of the station, the Ramsey audio processor also extended the signal coverage because it was louder. I had not experienced anything other than a great sounding LPAM station. The one thing that I did notice was I eliminated all hums and static after attaching the ground wire to a dedicated new 8 foot grounding rod, right after I put it on the air.
Talking House transmitters work best with the external ATU whip antenna unit and an audio processor. Finding the ATU unit whip antenna is the hard part. It will extend the listenable signal coverage by 2 or more miles. Good luck.
Which PCB vers?
Interesting insights.
Can any of the of the posters here identify which Talkng House printed circuit board versions they were using?
I have two (both in the dark brown/black “DVD player chassis” package), one is PCB ver TH III-M and the other PCB ver TH 4.6, and I hadn’t observed this phenomenon. From what I’ve seen/read, the TH seems to make a lot of changes between production runs and those changes don’t seem to go in any particular direction 🙂
THe TH-III-M has GOOD RCA connex for line in and a BAD spring ANT connex while the TH 4.6 has BAD 1/8″ mini plugs for audio in and a GOOD screw ANT connex. THe TH-III-M is a brat to match audio to, the TH 4.6 can take almost anything you plug in.
WIERD 🙂
Experimental broadcasting for a better tomorrow!
Product ID
by MRAM 1500 kHz
My Talking House PCB indicates TH-II-M ver 1.2, dark brown in color. Sure would be nice to locate a schematic for it. Tweaking some of the adjustments has no effect. There is an antenna matching capacitor for the wire antenna that improves the output even after the auto-tuner has done it’s thing.
The warble I refered to is a constant, low level noise, not a whoop. The hetrodyne due to the off freq does at times appear to be FM’ed by this warble. I really think it’s jitter in the PLL but very subtle. Perhaps not enough shielding and the RF output is getting back into the PLL.
I’m using the remote ATU and whip. I’m thinking the impedance of this antenna system is a bit low for the TH output as the RF envelope can’t achieve positive 100% as the negative swing does, indicating the final working into a lower than expected impedance. When operated with the internal tuner and wire antenna, the RF envelope looks pretty good.
Overall, for what I paid, I feel the TH does OK. But, it was brand new and I got it for $10 on Ebay. The remote ATU and whip was more like $100 but if it truly was certified for use with the TH, it’s worth it as the range is much improved over the wire.
I’m using ZaraRadio ver 1.4.4 with the the Direttore SoundSolution plug-in to do the sound processing. With it’s multi-band processor-compressor-limiter, the TH sounds pretty good.
Update on my report
Listening again today a little more critically on the way home from work, the talking house I pick up does indeed have a static carrier frequency offset. But I would estimate it’s more like a few hundred Hz; not more.
Also, I have re-calibrated my brain on the period of the “woop” and I now consider it to be closer to 2 Hz than 1 Hz. And it definitely stops “wooping” when the modulation goes away, as I reported earlier.
For anyone that might be in the Chicago area, this particular talking house can be heard on Caldwell Avenue near Oakton, in the northern suburbs. I’m not sure, but I think that’s in Skokie. It’s on 1670.
WEAK-AM
Classical Music and More!
A little slow today
by MRAM 1500 kHz
The site timed out on my upload so I sent it a second time and they both showed up. So, I removed the text from here.