US "Talking House Transmitters ( 100 milliwatts)

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Tim Bucknall
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US "Talking House Transmitters ( 100 milliwatts)

Post by Tim Bucknall » 12 Sep 2018 17:01

these low power devices have always fascinated me, when a new improved model came out the prices of the previous version on ebay hit the floor.
I picked one up and found a step down voltage convert

compared to the spitfire AM tx it does kick out a little further , likely due to the auto atu and earth system but output is dirtier

here's an IQ file https://mega.nz/#!t0UGmK6J!JSca8EO_Nxah ... pED4YT5lx8

maybe some of the dirt is due to the voltage converter, you'll see spurs every 22.3khz either side of the fundamental

I had originally planned to put the tx on 1610khz but when i saw how dirty the output was i left it on its "out of the box" frequency of 1670

in the IQ file you'll hear the test message that came with the unit, you'll notice its massively overdriven , the only way of fixing that is to record a new message at a lower volume. I wonder if the over loud audio is intentional, it may be a primitive attempt to increase range and ensure that the audio blots out any co-channel signal

the tx looks like a set top box or dvr
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Tim Bucknall
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Re: US "Talking House Transmitters ( 100 milliwatts)

Post by Tim Bucknall » 12 Sep 2018 17:05

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Re: US "Talking House Transmitters ( 100 milliwatts)

Post by Tim Bucknall » 12 Sep 2018 17:10

IMG_20180912_170632.jpg
If any of the carrier monitoring group want a challenge the offset is 1670.031 ;-)

Americans must have high ceilings, I had to use an inverted L shape for the wire aerial.

Power is roughly equal to the hospital radio stations like Rotherham 945 and Me and JF did detect their carrier on our Asian beverage at Matlock Forest
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Re: US "Talking House Transmitters ( 100 milliwatts)

Post by Tim Bucknall » 13 Sep 2018 08:08

this is neat, during the night the aerial fell down and the tx automatically turned itself off to avoid damage
am now on 1680 on the principal that higher is better with small aerials like this
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KPC850
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Re: US "Talking House Transmitters ( 100 milliwatts)

Post by KPC850 » 19 Sep 2018 12:31

Tim Bucknall wrote:
13 Sep 2018 08:08

am now on 1680 on the principal that higher is better with small aerials like this

Though if you used it on your originally planned 1610, a good proportion of car (and other) radios over here would be able to receive it (on 1611). maybe someone local might tune in!
Toyotas I have tried will go to 1611, though German car radios (VW etc) I have tried stop at 1602.
Tim Bucknall wrote:
12 Sep 2018 17:01
maybe some of the dirt is due to the voltage converter, you'll see spurs every 22.3khz either side of the fundamental
Your voltage converter (to go from 230V to 115V) is surely just a transformer and couldn't be causing interference.

Maybe it is its own AC to DC powersupply to blame, Is the 22.3 kHz constant?, or does it drift if you change power level etc ?

Tim Bucknall
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Re: US "Talking House Transmitters ( 100 milliwatts)

Post by Tim Bucknall » 19 Sep 2018 13:34

Thanks,
despite the instructions saying go as high as you can up the band for best swr on such a short aerial the unit is much happier lower down.

Plus as you say I hadn't sufficiently considered the coverage of most radios


I've settled on 1440 until the planned Danish station appears. Then I'll hop on 1610 for sentimental geeky pirate-y reasons :D. i've had my first report..on a car radio as it happens (from a skywaves member). The signal on 1440 is several orders of magnitude better than on 1670/1680
I also checked some I/Q files by John F and found 1680 had a Ute on it so txing up there was a waste of time.

A gentleman in Finland has checked for my signal on 1440 with no luck during poor condx but referred me to dxers in the south of Finland who get UK 1 watt lpam stations with audio.

I believe the exact carrier Freq is around 1440.026
Looking at the offset list that will be a pretty distinctive offset in early evening in Europe

The spurs vary so it is indeed the PSU, thanks for that

My rationale for using 1440 is to catch the carrier monitors who will be looking for the Danish station testing

My own car radio test gave weak but clear audio at approx 4 miles

I think the tx would be even better on 15xx but some people in the neighborhood may still be listening to Radio Stoke on 1503 , no point creating problems ..they will be gone eventually

I'll let you know when I go to 1610, you may be able to hear a weak but permanent het against the Norwegian on 1611 even if you can't get audio, I would accept a het as definite reception :-)
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Re: US "Talking House Transmitters ( 100 milliwatts)

Post by Tim Bucknall » 02 Oct 2018 19:21

Switched to 1610 from 1440 as of 1st October

Should now be pushing out a bit more power, close to the maximum for this kind of basic set up.

The test audio loop now contains music as well as voice.

I expect best results due north or south of here.

Look for a weak continuous lsb het against the wk Norwegian on 1611 outside the hours of transatlantic reception.
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Re: US "Talking House Transmitters ( 100 milliwatts)

Post by Tim Bucknall » 18 Oct 2018 16:53

Stronger audio on usb so I imagine all talking house tx are the same
Since October 1st my tx has been on
1610.0325 with very distinctive trace

During my last ever hilltopping session on 9th October before we put the car up for sale I did a range test heading northeast on the A54 using CB whip and sdr.
Got around 3 miles. It will do much better going north/south. Already had 4 miles minimum when used 1440 and 1610 will be even better.

Well, it's working as good as I can get it.
The tx will stay on 1610 24/7 barring local power cuts
And I await people's overnight carrier trace reports


Part of the audio loop is a Nirvana instrumental I mixed myself from the multitrack master that leaked online some years ago.

Shazam thinks it's a cover version by someone I've never heard of but I swear it's the original recording minus vocals and other stuff
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Franco Martelli
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Re: US "Talking House Transmitters ( 100 milliwatts)

Post by Franco Martelli » 23 Oct 2018 10:13

Seriously speaking, how far can be received a signal operating on 0.1 W in a completely clear channel?
Rx: Degen DE-1103, Sangean ATS-909

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