Re: LF: Ebnaut receiver frequency stability qustion

[VIGILANT Luis Fernández <luis@vigilant.es>]

Hi EbNaut

I think that using expensive receivers is NOT the way to go. I'm using a simple mixer as downconverter. The LO is 120KHz generated from a uBlox GPS. So the 137KHz outputs as 17KHz and can be feeded to PC soundcard. The second channel of GPS provides 1pps to discipline the soundcard using Spectrum lab

Not using filters at all and no amplifier stages. So there is room for improvement, but it works

73 de Luis

EA5DOM

El 19 dic. 2018 1:33, Markus Vester <markusvester@aol.com> escribió:

Hi Chris,

Kiwi-SDR: Last year I asked the same question to John Seamons, and he explained that the GPS frequency correction is done in software, and won't actually lock the LO phase to GPS.

RSP2: It seems possible to replace the TXCO by an external 24 MHz reference. But the difficulty with the digital output is that you need to be sure that buffer over/underruns never occur in the subsequent audio processing. With an analog receiver, SpecLab can correct glitches when you feed a 1pps time reference to the other soundcard channel. Unfortunately you can't do that with an all-digital audio path.

73, Markus

-----Ursprüngliche Mitteilung-----
Von: Chris Wilson <dead.fets@gmail.com>
An: rsgb_lf_group@blacksheep.org <rsgb_lf_group@blacksheep.org>; rsgb-lf-group@groups.io <rsgb-lf-group@groups.io>; Discussion of the Lowfer (US, European, & UK) and MedFer bands <lowfer@mailman.qth.net>
Verschickt: Di, 18. Dez 2018 23:54
Betreff: LF: Ebnaut receiver frequency stability qustion

Hello  Ebnauters

Would a KiwiSDR (which I do not own but was thinking of buying) have

adequate LF frequency stability for Ebnaut reception given it uses

1PPS from a GPS receiver to stabilize the frequency? Or do I need a

receiver with a true GPS trained reference input? I see only one

cheaper price end RX with such a port, the SDRPlay RSP2, but that

expects a 24 MHz reference input rather than the common 10 MHz. I

have a Trimble Thunderbolt for a 10 MHz reference, but nothing that

could give 24 MHz.

What commercial SDR's could I look to for suitable stability please,

that are good on LF and below, and a reasonable cost? Thanks 2E0ILY

--

Best regards,

Chris                          mailto:dead.fets@gmail.com