Talking House V, now what?

There are others posting here who have a lot of hands on experience with the TH which I don't but my understanding is that it has an automatic antenna tuning system built in. I have read reports that this mechanically slug tuned inductor system sometimes will stick and fail to properly tune. It may be something simple like this but check back here after those with more knowledge than I have a chance to comment.

Neil

It does sound like there's something wrong with your Talking House - even with the wire antenna, you should get more range than that.

But to answer your question, the easiest way to get range is to use the matching ATU, combined with a whip antenna. It works very well, and the range that I got, at least, was good - up to a mile or more with noisy but listenable reception in with a good car radio.

Now, if the problem is with the tuning mechanism in the TH, going with an external antenna will solve your problem. But if it's something else, then no antenna will solve your problem. I would attempt to track down the actual problem before spending any more money. The build quality of the Talking House is not all that great - I own 3, and 1 of those just didn't work out of the box (something in the internals).

I would also try reception with a car AM radio. Seems like they work better than the portable radios.

Also, if you are running the antenna wire over the metal part of the window frame, that may be part of the problem. Keep trying different antenna configurations. I seem to have widely varying results with seemingly small changes. Also, maybe try a different frequency.

Some good points being made here.

More times than not, it's a shock for someone new to Part 15 to fire up their transmitter, and then see range that is vastly different from that being reported here and elsewhere.

I've been an advocate for the use of common terminology when talking about range - does that 1 mile range being reported elsewhere mean that you can listen to the radio signal clearly, or is it barely audible? And what is on the receiving end - a portable radio (which has poor sensitivity and selectivity), or a sensitive, selective car radio (selectivity is even more important than sensitivity in my view, as it stops strong signals on adjacent frequencies from bleeding over into yours - and anything on your frequency will reduce range).

It might be useful to see how far your signal is going while you're driving.

Still, 50 feet still seems light, even with a portable radio.

If you are using the "wire" antenna connection, the auto tuner will attempt to tune the wire for the frequency you have selected.

It sometimes takes a minute or so to tune. You may hear the mechanism reverse direction once or more. If the tuner cannot tune the wire the tuner will stop and the display will indicate an error.

If you hear a clicking noise and the unit errors out, the mechanism is probably stuck and requires service.

My experience using the wire antenna at different locations in the house resulted with about 300 feet of coverage at best. Using a longer wire usually won't work as the tuner is designed to work with about 8 feet of wire.

Currently, I am using the ATU remote antenna mounted atop the TV antenna on the roof. My usable range is about 1/2 mile but can be heard farther depending on weather, time of day, season, etc.

Be sure to use a 3 pin AC outlet (no 3 pin to 2 pin adapters) as the ground pin is the RF ground for the system.

I would think if you could mount the transmitter in a weather proof box you could obtain the same result as using the ATU by attaching a whip antenna to the box and connecting it to the wire antenna terminal. Not very convenient as you'd have to run AC power and an audio line to it.

As for connecting coax to the transmitter "F" connector, without the ATU, this would require some experimentation to obtain the proper match and most likely would not satisfy the terms of the certification.

Some things to note:
1) THs are made at consumer grade, I believe they use whatever are the cheapest components available for a given run ... means they may substitute values that are considered not important in this grade of equipment, or variables in component tolerances, etc. This means performance can vary at least somewhat.
2) The TH holds a valid FCC Certification for the unit itself, but it's unsure that the accessory ATU system is certified for use with it.
3) The TH wire antenna is a spec length and the unit is trimmed inside at the factory, and dependent on the TH's automatic internal tuning system. The 75ohm F connector and external cable to the ATU bypasses the trimmed wire internal system, the ATU system takes over trimming, but it's easy to do, has a little meter.
NOTE: Just plugging in an untuned whip will fail to gain anything, probably won't work at all beyond a few dozen feet.

I set up another TH 5, which doesn't reproduce audio as well as my daily-use one, but is otherwise very similar, with the wire antenna in an upstairs window of a house that is elevated couple hundred feet above sea level. Now, to be specific, that window is wood and plastic, no metal, and is an arch, so the wire curves over the top. No ground wire other than the PS and audio which came from a netbook computer with its charger att'd.

That got out about 200-400 ft in several directions, even behind the house and around other houses, and also could be heard, albeit a little noisy, down on Spring St. (our main street) about 900 ft away ... and that after dusk last year in early December.

Once again, the receiver is very important. Auto receivers are generally very good, high quality all-band receivers can also be very good, but you must remember it's not the telescoping antenna, it's the ferrite loop usually inside the back of the cabinet, so it has to be oriented for maximum reception, and kept away from noise generators, i.e., anything with motors, florescent lights, computers and wireless devices, chargers, building wiring, etc.

"2) The TH holds a valid FCC Certification for the unit itself, but it's unsure that the accessory ATU system is certified for use with it."

According to the FCC OET test data provided by the manufacturer, Radio Systems, the ATU was certified for use with the Talking House. Both are listed in the OET test data. They both carry the same FCC certification number. The test data describes the system being tested with the ATU connected to the Talking House transmitter with 8 meters of coax.

This was a hot topic some time ago. The dispute mainly focused on where the ATU was mounted for testing. The assertion was the ATU must be mounted within 1 meter of earth. The manufacturer maintains that is false as long as the optional ground connection at the ATU is not used.

The Talking House system is incorporated into the INFOSPOT system provided by Information Station Specialists. I spoke with ISS President William Baker. He maintains the same position regarding installation of the system.

Both ISS and Radio Systems maintain it is legal to elevate the ATU as long as the optional ground connection is not used.

So, it seems an easy ground on any Talking House or derivative is limited to:

1. 3 prong electric system ground.
2. Traditional ground at the antenna which is limited to 10ft inclusive of antenna and ground.

Any aerial mounting of a Talking House (i.e. above a few feet off the ground --- 10ft-500ft) is to be done without a "proper" ground.

If that sounds right or can be tweaked, let's do it and make it part of a FAQ or common questions for new broadcasters 🙂

The ATU grounding connection is electrically connected to the coax shield in the ATU.

Simply using an in-line lightning protector similar to any TV/CATV protector would serve as a proper safety ground.

And yet, it's not considered as part of the antenna ground by the manufacturer.

"Both ISS and Radio Systems maintain it is legal to elevate the ATU as long as the optional ground connection is not used."

Aha! OK thanks for setting it straight ... ummm ... I guess. Something always seems to be left hanging.

Can we then say that the (relatively)precise distance between the coax core and the shield does an adequate job of doing what it's designed to do, i.e., cancel radiation?

Coax is a funny thing. The center conductor is considered the hot. The shield is considered the cold or ground. The currents in each should be equal and opposite canceling radiation from the inside of the coax.

An electrical circuit generally requires a path out and back, i.e. lamp cord, battery, solar cell, phone line. So the RF goes out from the transmitter on the center conductor and returns on the shield.

But the interesting thing is the return current flows on the inside of the shield. If the impedance of the coax and the load at the end of the line (antenna) match, all of the power is dissipated by the antenna.

However, if the load at the end of the line (antenna) does not match the coax impedance some of the power is not dissipated by the antenna, is reflected back and flows on the outside of the coax shield referred to as common mode current. This common mode current on the outside of the shield is what causes radiation of the signal from the coax.

So, I suppose if the ATU is designed properly and the antenna matches the coax, there should be no reflected power, no common mode current, no radiation from the outside of the coax shield. This would be why it shouldn't matter how long the coax is or how high the ATU is mounted.

The preceding explanation source is from various writings on the subject I have read over the years. I'm sure someone here will clarify/correct my explanation if my memory was lacking.

The following link on this subject is a bit technical, but then this is a technical topic.

http://www.w8ji.com/coaxial_line_and_shielded_wires.htm

Thanks Rich! Excellent reference material.

Mram!

I finally had some quiet time tonight and felt ambitious about testing out the a 102' whip antenna tethered directly to the auto-tune port that the Talking House typically has a wire antenna screwed onto.

I took a piece of coax, the low grade jumper style meant for a short run from say a satellite box to an old TV and cut it.

Made approximately a 1 foot portion of coax. Left the screw terminal on one side which I screwed to the bottom of the whip antenna. The other end I stripped down to the bare center solid wire about 2-3 inches worth. Then I bent the bare copper into a rounded hook shape.

Then I untethered the wire antenna and used the included terminal thumb screw to sandwich the bare copper coax to the TH V unit.

Powered the Talking House up and within three seconds the tuning motor stopped and the audible ticks in the signal went away and the LCD stopped flashing the tuning. It tuned the antenna just fine.

So indeed, at least with a short piece of coax, the TH internal ATU will tune a 102' whip antenna.

Unsure how "tuned" the antenna truly is. I don't have any way to verify this.

Since the whip is laying horizontally (ceilings where my work bench is aren't high enough to fit the whip upright) the signal isn't as good as the wire.

Intending on getting the setup outside in the next few days when I get out to find a mount. Will be testing the wire compared to the whip both tuned on the same port with the built in ATU.

SOOOOOOOOOOOOOOOO, to those with Talking House units, absent the external ATU unit (expensive), YES, you can get the common 102' whip (Radio Shack for CB use) to self tune.