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Re: LF: 1476 kHz AM

To: [email protected]
Subject: Re: LF: 1476 kHz AM
From: Marcus PY3CRX PY2PLL <[email protected]>
Date: Sat, 10 Nov 2018 10:33:09 -0200
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Hi Stepan ...

Good idea this FSK pattern applied to the carrier freq. This remind me several years ago at 13.55MHz or so, a segment called HiFer (there was lowfer/medfer too) ... was funny detect NA & EU stations that run a few miliwatts on a 1/4WL verticals using TTL/CMOS clock oscilators as transmitters. ID was done by frequency and freq change pattern? qrss, dfcw, sawthoot, square, triangle etc ... just a fraction of hertz was enough.

GG66rf (near S Paulo - BRA)

Em 10/11/2018 06:21, DK7FC escreveu:
Hi Marcus and Markus,

Exciting and amazing what can be done with 3 W in AM. My congrats to this success. Seems to be an amazing challenge.
You won't belive it, i did NOT receive the signal. I tried with a TECSUN PL-660er and its telescope antenna, out of the house in an urban region. No chance with this sort of QRM here :-(

Markus, maybe you can convince Ralph to transmit a 20 Hz modulated QRSS-10 signal along with the music channel he wants to transmit in the final state. The 20 Hz signal would not be audible in a speaker but would give a fine signal to detect for the QRSS / spectrogram friends worldwide. Or, even simpler and more effective: The AM carrier could be shifted by 1 Hz or so, keying some QRSS. This can be done with a simple circuit, the capacitiy diode pulling an xtal a bit, like in the old days ;-) Great stuff :-)

73, Stefan

Am 10.11.2018 04:07, schrieb Markus Vester:
Hi Marcus,

I think you've got it.

I just did another frequency measurement, by injecting a 1475.990 kHz Rubidium-derived local carrier into my AM receiver. Ralph's carrier is at 10.41 Hz (i.e. 1476 kHz +0.41 Hz), with 0.5 Hz sidebands from the AGC acting on the beeps. I'm also seeing that triangle carrier, which is probably from another unidentified broadcast station. During the night it has been swinging between -0.12 Hz and + 0.45 Hz with a 15 minute period, and has now moved up very slightly. Ralph at +0.41 Hz is just inside the top of the swing, just like the weak line in your image.

That's an awesome 9943 km then. Ralph, hold on tight to your coffee cup ;-)

Best 73,
Markus (DF6NM)

-----Ursprüngliche Mitteilung-----
Von: Marcus PY3CRX PY2PLL <[email protected]>
An: rsgb_lf_group <[email protected]>; markusvester <[email protected]>
Verschickt: Sa, 10. Nov. 2018 2:16
Betreff: Re: LF: 1476 kHz AM

Well ... just for fun ...

I set 2 receivers sharing the same mini whip: a SDR-IQ and a KiWi SDR.

On both there is two signals: one at 1476000, another at 1476260 (I read somewhere about Iran 260Hz above).

Using Argo QRSS20 I got two signatures: one that looks like an old ovenized xtal osc and a stable one.

I verified both signals using an KiWi SDR in Germany too. Of course that the 1KHz bips are there. But the same signals are there as well: the ~85mHz wanderin' carrier and the 3W one (this one stable, ~400mHz above 1476000)

May be tomorrow I check this again earlier.

Capture attached. Who knows ...


Em 09/11/2018 13:05, Markus Vester escreveu:
Thanks Tom and Clemens, that's very nice!

Indeed there are some issues with GoogleMaps, for example last time I looked didn't show the Kiwi SDR locations. As Clemens indicated, should work. Or in proper coordinates, the wire antenna is attached to the tower at 49.546575 N, 11.019437 E.

Best 73,

-----Ursprüngliche Mitteilung-----
Von: DK1IS <[email protected]>
An: rsgb_lf_group <[email protected]>
Verschickt: Fr, 9. Nov. 2018 14:13
Betreff: Re: LF: 1476 kHz AM

Am 09.11.2018 um 00:39 schrieb Markus Vester:
After the sad demise of all LW and MW broadcasts in Germany, a handful of pioneers came up who are operating legal low-powered medium wave stations in the context of a radio museum or for educational purposes. One of them is Ralph (DL2NDO, one of the participants in the legendary Donebach 137 kHz activation in 2002). He has obtained a transmitting license for 1476 kHz (former frequency of Vienna Bisamberg), built a 3 Watt AM transmitter, and with the help of a small team raised a quarterwave antenna on the Fraunhofer premises south of Erlangen (JN59MN21HF).

Yesterday they got on air for the first time, running a preliminary test transmission consisting of a switched 1000 Hz beeps (one second on, one second off, audio frequency locked to the RF carrier). This pattern will be continued for a few days, before they will eventually.take over the audio from the local DAB student radio "funklust".

The current test pattern is relatively easy to make out in the noise so it may be a good chance for some DX detections.  At night we've actually heard the beeps on Twente SDR and a couple of German Kiwi-SDRs. But I guess using narrowband signal processing techniques, the carrier and coherent tones coud make it much further. The carrier frequency is derived from an OCXO and is currently at 1476000.411 Hz.

Will anyone in the group take the challenge?

Best 73,
Markus (DF6NM)

Fb audible signal at DL0AO (JN59VK)! RX Perseus, Ant Miniwhip, see screenshot. Slight selective QSB. Similar results with their North America beverage.

By the way: all programs using GoogleMaps for QTH-locator identification seem to be inactive because of new Google restrictions.

Tom, DK1IS

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