While we're on the TH subject, how do I tell what revision my TH TX is?
Thanks for the link to the antenna, another possibility.
As far as what I've seen for most places grounding is a major factor in range.
I'm hoping to find a non remote antenna solution. If time permits I'm thinking about placing the unit on top my aluminum carport with a the hard tubing antenna I have on it already. I will take the power adapter apart just to see if the unit is grounded through it, I couldn't really tell by looking at the patent schematics. http://wwwrench.com/th5/US6973294.pdf
Since my property is mostly porland landscaped a complex ground system would be a job. I've noticed in playiing with it, when the unit is outside it seems isolated from the house. And if it is in the house it seems isolated from the outside, like those intercoms that work off of house carrier currents.
If the unit seems to be grounded through the power adapter I'll try eliminating that ground with an extension cord and grounding it to the carport roof, just for a try.
Thanks for all the good info.
More Talking House w/warning
I still can't get rid of the doggone hum in my TH. It's either the PS or the connector in the cabinet, because it's there if I unplug the audio, but the same audio doesn't cause problems with the Spitfire TX.
I measured the voltage with my VOM on the PS and it's just over 18 vdc, center pin positive, so it's working ... but I can't tell if the hum is coming from it. Is there a way to tell if there's a short in the transformer core which wouldn't affect voltage at the connector?
The warning: On a website out of eBay, I saw a blurb about replacing the TH PS with Radio Shack no. 273-1690, the only 18v unit they sell. I think it's bogus because that unit is 18-24 vAC. Got that ... AC, not DC. I'd think that would not work, unless there is a really good bridge rectifier in the TX. which I don't see in the circuit.
Can anyone confirm this?
Thanks so much ...
I can tell you the Talking House power supply connects the barrel side of the power supply output to the ground pin of the 3 wire AC power connection. This make the house electrical ground the RF ground for the transmitter.
If you plug the power supply into an EMI/RFI surge suppressor it might act like an RF choke. That would adversly affect the transmitter when using the internal antenna tuner and wire antenna as the suppressor would effectively block the RF ground path. Also, a 3 wire to 2 wire adaptor would block the RF ground. Using the external antenna connection with a grounded antenna system should work OK regardless.
In my area we are required to jumper the water meter and water heater cold/hot pipes. The circuit breaker pannel neutral and ground are bonded and connected to a suitable single point ground. No point beyond the initial bonding point shall bond neutral and ground.
My father-in-law always had problems with dimming/brightening lights. When I went to replace his water heater and removed the grounding jumper - ZZZZAAAAPPPPPPP! Seems the neutral outside the house had broken and the water pipes became the neutral connection for the service. Since the house is very old with all metal water and drain pipes the hot water pipes had their own path to ground and carried load current. Got the service neutral fixed, everything runs much better now...
Also, a 3 wire to 2 wire adaptor would block the RF ground. Using the external antenna connection with a grounded antenna system should work OK regardless.
Assuming the external antenna RF jack ground connects to the shield of a 75 ohm cable, I guess that shield should become the RF ground, right?
Also, most 3-wire to 2-wire adapters have a little green metal lug to connect to a separate ground. But I think I tried that and still got hum. The Spitfire just has a 2-wire PS, has no hum at all using the same audio cable (except for the dual RCA > stereo miniplug adapter) which has a double wrapped thing in it ... a choke?
One other thing ... the rule is 3m total for the antenna, transmission line, and ground lead. So what is the 100 ft. 75-ohm cable that comes with the TH TX for?
Glad you got the house's service neutral fixed.
I'm not inclined to take mine apart to check, but that was noted on another converstaion (that I can't find right now) about the TH certification process.
This would mean that the OEM configfuration would not provide an RF ground via the power supply but that the RF ground could be accessed by connection to ground before the power ground pin on the PS.
This would be similar to the way I grabbed RF ground off of the negative battery terminal in the Scosche FM transmitter.
Probably should do a visual on the TH PCB to check this...
The easiest way to comply with the transmission line requirement is to locate the PA outside at the ATU. I don't know if that is what they do, since I don't own one, but that is what I would do if I were designing one.
I have had hum problems as well, I found that wrapping about 5 loops of the power cable around the power adapter takes most of it out. I also put those noise filter things for USB cables on both ends of my audio cable and that gets rid of virtually all of it.
The Talking House ATU contains:
A torroid input transformer
Two loading coils (high band-low band) with movable slugs for tuning
Single pole double throw band switch
RF volt meter circuit
A few miscellaneous resistors and capacitors
The tuning unit appears to use the same layout as the internal automatic tuner without the drive motor and associated components for it. A knob takes the place of the motor for manual tuning.
I've never been able to find out for certain that the remote ATU was certified for use with the unit.
I have read articles about putting a final output stage at the antenna. In that way you could keep whatever you use as an exciter in the house. Therefore the antenna lead would only be a few inches. I suspect someone would argue the length of the coax sheild to the exciter acting as a "long" ground.
Perhaps using a balanced line instead of coax would get around that problem.
I was surprised to find a Talking House Web Store!
Among other accessories the ATU is listed at $295.00! Of course that includes the whip antenna and 100 feet of coax priced separately at $45.00 each.
A bit pricey but desparate situations require desparate actions.
Got mine used on Ebay.
Here is a LINK TO 100 MW REPEATER.
The images are a little fuzzy but readable. I found this somewhere on the net. The idea was to place several of these around town, interconnected by coax. Each unit has the final amplifer and a whip antenna. They are driven by a common exciter.
Now, you wouldn't have to have more than one using it as a remote final output stage as discussed earlier in the thread.
Power is fed to the unit along with the driving RF signal from your transmitter through the coax. The decoupling network separates the DC power and RF which allows using the coax for both.
I have thought about adding an inline ultra-wide band antenna to mine like they use to boost catv lines on long runs, they add about .05 watts of boost and use 15 to 18 volt power, which is in the TH power supply range, if you live where CATV is available you will see them all over the lines, they are a couple of inches long and sometimes have a power cord going into them. http://www.hollandelectronics.com/catalog/catalog.php?product_id=Ultra-Wide-Band-Line-Amplifier http://www.solidsignal.com/pview.asp?mc=02&p=LA-9637&d=NAS-LA9637-Ultra-Wide-Band-Line-Amplifier-(LA9637) There is one in my CATV box but I don'y know if it is the ultra wide band or UHF variety.
Right now I need to do an antenna, I'm thinking about the AM88 verticle style antenna. Does anyone happen to know how many wraps of wire it would take on a 1" pcv tube, that would make it and easy addition on top of an existing 30' flag pole, I am looking into a free air optically connected ground system. A good ground plain is really tough around here. Maybe a charged mat ground plain like I've seen on the mobile highway construction sign and alert radio systems would work.
With all the questions on grounded raised antennas I was wondering how something like this might work, I have a 25 foot flag pole I could run this up and try it, if it is not a total waste of time. 
OK, if this will just transmit to itself you can quit laughing an know that I know nothing about this stuff. I have the TH board in a plastic enclosure and can mount it on such and get the transmitter and upper antenna portion about 5 feet above the top of the flag pole without having to drop or climb it. A friend said he had seen an isotronic ? that was simular in concept once. I don't have any antenna simulation programs or experience to work from.
One more question, if I will have the antenna isolated from any ground, is there anything that might be gained by dc biasing the whole works by say feeding the transmitter a +20v to the neg lead and a +38v to the positive lead. I know this works to run multiple voltages in autos if you make sure the ground stays floated but would a dc bias do any good with an insulated transmitter antenna setup.
I thought about experimenting with this same concept minus the radials for the rangemaster. Basically a 1.5 meter antenna on top and 1.5 meter wire from the ground lug, but isolated from ground.