is that the seller actually had multiple items but only listed one and gave you a chance to buy one.
I've done that before and had sellers offer me the same.
Courtesy of an ebay seller, some interesting photos of the tuning mechanism in the Talking House Transmitter.
Top View
Back View
Close Up
Experimental broadcasting for a better tomorrow!
"One Possibility is that the seller actually had multiple items but only listed one and gave you a chance to buy one."
True. Also, I re-examined the time stamps and it makes a bit more sense, too - the bid records aren't always in chronological order, which can be confusing.
OTOH, the same person was the high bidder on several of that seller's auctions, and that was the person the seller said submitted a "disqualified bid" for the sale I participated in. Hmmm...
Be that as it may, I did participate in another TH auction yesterday and I did win that one - $81.00 plus $26.00 shipping, $107.00 total, much better than the $140 or so I would have paid for the second chance.. Here's a funny thing, none of the bidders involved in the sale I was curious about bid on the unit I won.
I guess I'm just an habitual conspiracy theorist 🙂
Much more to come after the unit arrives...
Experimental broadcasting for a better tomorrow!
I picked up the Talking House remote ATU on Ebay the other day. Why? Because it's my understanding that the Talking House is FCC certified to use the remote ATU/antenna with either 75' or 125' of coax. This would allow locating the transmitter in the radio shack.
I do find in the Part 15 rules (15.204 b) that it is permissible to use a final RF stage (amplifier) at the antenna which allows the exciter to be in the house. The rules state as long as the application is designed as a "system" it's OK. Of course I would think the system must comply with 15.219 limits.
So, if anyone has the paperwork for a Talking House, what does the manufacturer have to say about Certification and using the remote ATU.
From the connection instructions that are shown on a transmitter it appears that the transmetter operates in one of two states, both FCC accepted.
Mode 1 uses a random wire about 3 meters long and an internal random wire tuner to match the transmitter to the antennna for the frequency chosen.
Mode 2 is initialized by swicthing the unit output from the random wire binding post to the F connector labeled "External Antenna." The switch appears to route the transmitter output away from the auto tuner and to a direct connection to the back panel.
In Mode 2 the transmitter seems to work as an exciter and the external amplifier in the final output stage. It also appears to be hardware limited to 100 MW.
Because it is a unit designed to be set up outside there is what looks like a 102" CB whip that appears to be permanently attached to the ATU (is that correct, MRAM?) and the I'm guessing that either the ATU has a matching network inside, or that the RF out from the transmitter still uses the matching network in the transmitter, but in a slightly different way..
Experimental broadcasting for a better tomorrow!
by MRAM 1500 kHz
I purchased the Talking House ATU on Ebay from Evening Storm. The only reason I bought it was if using the remote ATU/antenna is allowed under the FCC cert for the system, that would be great, keeping the transmitter in a controlled environment!
I haven't taken the ATU apart to see what's actually inside but my guess is only a tuning network in addition to the "peaking" meter. I based that on the fact that no DC voltage appears on the coax from the transmitter which would be neccessary if there were an amplifier/final rf stage in there. Also, the ATU has a "tuning" knob and two position "high-low" frequency selector switch for above or below 1 mHz operation.
The ATU came without the whip antenna but the mount is standard and would accept the CB style 102" whip.
Unfortunately, I still don't have any confirmation that using the ATU at the end of 125' of coax is FCC authorized. I emailed Talking House quite some time ago regarding the ATU but got no response.
That's interesting. If there's no power to the unit they shouldn't call it an "External Amplifier" I guess 🙂
I was wondering why Talking House made such a point of the cable lengths offered, but if the ATU is an ATU and not an "External Amplifier" that would make sense.
My guess now would be that the "External Amplifier" is really an ATU with the internal components preset for the shorter or the longer extension cable and the 102" radiator.
That then leaves three questions -
1. How can running the signal through so much additional cable really be all that helpful?
2. Why would a person bother because the unit has great range as it comes out of the box? I'm getting several blocks from just hanging up the supplied 3 meter wire inside the house - I can't wait to see what moving the antenna outside will do!
3. As well as the original question of Part 15 compliance. A 125 foot "antenna lead" would not seem to be compliant since the three meter rule includes an antenna lead?
I wrote to TH after I bought my unit to see about buying the External Amplifier (although now I'm much less interested) and I got this response:
"I have bad news - since you did not purchase the transmitters from us, I cannot sell you accessories."
So I'm not too sure you'll be getting an answer any time soon 🙁
I wonder if we could find out anything about this equipment on the FCC site? I haven't done this research in a while so my brain is a little rusty, but I looked up the C Crane Co. FM transmitter on the FCC site a few years ago. There I found the compliance info C Crane submitted with the acceptance application and there were complete schematics and inside and outside photos of the unit.
Hmmmm....
Experimental broadcasting for a better tomorrow!
by MRAM 1500 kHz
I looked up the FCC ID number (DLB5LTT98) on the FCC site. The only info provided is the name and address of the company and the fact that the device is a Part 15 AM transmitter operating between 530 kHz and 1700 kHz. There was no detail of the "system" or allowed options.
As for the 125' coax lead in,
Part 15.204b states:
(b) A transmission system consisting of an intentional radiator, an external radio frequency
power amplifier, and an antenna, may be authorized, marketed and used under this part. Except as
described otherwise in this section, when a transmission system is authorized as a system, it must always
be marketed as a complete system and must always be used in the configuration in which it was
authorized.
That sure sounds like you can design, build and use a "system" which has an external amplifer/antenna.
Someone will probably argue that as such, 15.219 would not apply and the restrictions of 15.209 would apply. But if that were the case, would the Talking House "system" have received certification to use the optional ATU with its 100 mW transmitter. Surely that would exceed the 15.209 field strength limits. Or perhaps they would simply say that 15.204b says nothing about using a long coax.
Some things mankind wasn't meant to know or understand.
by MRAM 1500 kHz
I still haven't heard from Talking House regarding the Part 15 use of the ATU offered as an option.
Instruction Sheet for the ATU.
Very helpful.
Also nice the see that the ground side of the coax connector is a place where a ground could be attached in that mode.
I wonder which kind of tuning circuit they use?
Experimental broadcasting for a better tomorrow!
Can you tell me exactly what is the problem with this unit? I recently acquired a couple of these units for nothing and wanted to see if they would work. They do get out fairly well, but I can not figure out how to bypass the loop recording in them. Is there a way to do this? The frequency output is variable also.
Bill
Can you tell me exactly what is the problem with this unit? I recently acquired a couple of these units for nothing and wanted to see if they would work. They do get out fairly well, but I can not figure out how to bypass the loop recording in them. Is there a way to do this? The frequency output is variable also.
Bill
by MRAM 1500 kHz
With my TH, as soon as I plug an external audio source into the "direct" input jack the internal audio player is bypassed and the external audio goes on air. It would seem the internal player continues to run but the audio is not applied to the transmitter.
The "direct" input on my unit is an RCA style jack. Apparently when a plug is inserted in the jack the internal player audio path is interrupted and the external "direct" audio is applied. Perhaps the input jack on your TH is defective and not interrupting the audio path of the internal player.
Which model Talking House Transmitter do you have? Mine is a TH 2.
by MRAM 1500 kHz
With my TH, as soon as I plug an external audio source into the "direct" input jack the internal audio player is bypassed and the external audio goes on air. It would seem the internal player continues to run but the audio is not applied to the transmitter.
The "direct" input on my unit is an RCA style jack. Apparently when a plug is inserted in the jack the internal player audio path is interrupted and the external "direct" audio is applied. Perhaps the input jack on your TH is defective and not interrupting the audio path of the internal player.
Which model Talking House Transmitter do you have? Mine is a TH 2.
LPAM newbie here!
Just bought a TH from eBay. The sticker on the bottom says Model TH 4.6. Looks like little used, in original box. Came with power supply, antenna and microphone. Works fine, and sounds really nice on old tube radios. I have a 1938 Philco 5 tube small table model, a 1937 Zenith 5 tube tombstone (nice black dial!), and a 1936 Scott Allwave 23 tube console in the Tasman cabinet (my pride and joy!).
This thing is super easy to get running. I was on the air literally in 5 minutes. I have been looking at various LPAM transmitters for months. I was ready to buy an AMT3000 (not the kit version, the already built version), but this TH came up on eBay for a decent BIN price. After reading the comments here it sounded like a good option.
The built-in automatic antenna tuner really makes the most of the supplied wire antenna. Frequency setting is a breeze.
I will probably still get an AMT3000 later, but the TH unit is a great "first transmitter" IMO.
Can the AMT3000 be set for any frequency? Or is it "hard set" with a crystal? Can anyone compare it with the TH for sound quality and ease of use?