RE: LF: VO1NA CW 477.7 kHz

[Rik Strobbe <rik.strobbe@fys.kuleuven.be>]

Just a thought:

 

what if I could set up a local WSPR station (let's say at 10 km from my QTH) that transmit 100% of the time with very low power (so it is centrainly not overloading my RX).

I would expect that propagation of a 10 km path is 100% groundwave, so the (absolute) signal level should be constant and the WSPR SNR values from that station could be used as a reference for the local QRM/QRN level.

I think that just a few mW in a short wire would be enough to produce a readable WSPR signal at 10 km.

 

73, Rik  ON7YD - OR7T

 

---

Van: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.org] namens Andy Talbot [andy.g4jnt@gmail.com]
Verzonden: dinsdag 8 maart 2016 17:05
Aan: rsgb_lf_group@blacksheep.org
Onderwerp: Re: LF: VO1NA CW 477.7 kHz

What is needed, is a software package that runs in parallel, monitoring and recoding the noise level.  It would have to work in a manner that was unaffected by the presence of signals, and also on a receiver without AGC.

Basic software techniques could sort out the first issue (see my piece in the the latest RadCom -plus) and sort noise from narrowband signals.  Any  AGC action could still upset things

Andy  G4JNT

On 8 March 2016 at 14:59, Alan Melia <alan.melia@btinternet.com> wrote:

Hi Roelof, thank you for those comments, that was my feeling but there is so much recorded informationI thought it was worth a look and sticking my neck out to see if anyone would say I was all wrong :-))

Yes for preference I would use a continuous carrier/signal but that is not always possible.

Thanks and Best Wishes
Alan
G3NYK
----- Original Message ----- From: "Roelof Bakker" <roelof@ndb.demon.nl>
To: <jcraig@mun.ca>; <rsgb_lf_group@blacksheep.org>
Sent: Tuesday, March 08, 2016 2:46 PM
Subject: Re: LF: VO1NA CW 477.7 kHz

Hello all,

Attached last night's reception of VO1NA.
Between 01:15 and 01:25 UTC, marginal aural copy was possible in CW
mode and good aural copy in Linrad's coherent mode.
As can be seen, the band noise is much lower than the previous
night.

Alan, regarding the use of WSPR for propagation study, due to the
rapid fading on 475 kHz, a continuous signal is called for and most
WSPR stations don't provide this.

The S/N indication of WSPR is nice, but useless for propagation
study as the background noise shows a lot of variation over the
course of the night and from night to night as can be seen in my
overnight Linrad fast playback screen shots.

Best regards,
Roelof
====================================================================
From: Roelof Bakker, PAoRDT
Location: Middelburg, Zealand SW Netherlands, 51 30 02 N, 03 36 02 E
Locator: JO11tm
Receiver hardware: Afedri SDR
Receiver software: Linrad
Aerial: pa0rdt-mini-whip, 5 metre up in a hawthorn tree.
====================================================================

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