Thanks Markus - great stuff- I am using the k9ay and had nulled out of one the chains to get the walking effects - unfortunately I dont have the sdr up here in Alaska (its in Oklahoma) so cant do a wideband but Ill do a series of recordings with different headings/amp equalisation and see what comes out - It certainly was a strange "160" sound... I had increased the perimeter of the k9ay on just one loop to improve my 137 khz rx - so was interested to see the affect - this is a very old D600 with the normal soundcard offsets -
Im using a L400 on 137 here and at the moment cant get the performance I want; I maybuild another PA0RDT which does somewhat better in this location
I seem to be suffering with "ground current noise" - whereby the main, 2 phase ground return earth rods are probably close to my radio earth rods location and Im getting some form of circulating and noise coming up my earth connection - one of the few times where local earthing is actually deterioating and Im just earthing at the antennae end - Ill try shoving some rods up this end of the house, far from the "mains incomer" and see what happens.
42F and a beautiful day here - sunshine and mountains, but still very deep wet snow by the antennae....
Laurence KL 1 X Wasilla AK BP51IP
From: [email protected]
To: [email protected]
CC: [email protected]
Date: Fri, 19 Feb 2010 21:34:58 +0100
Subject: Re: LF: Loran A and C
Dear Laurence,
good to read you're back in AK...
Your observation is interesting. In your region, there should now be two chains left on air. One is the Canadian West Coast chain on GRI 5990, which is still supported by US stations, including your nearest one Shoal Cove (5990 X). The other is the Russian-American GRI 5980, which should be supported by Attu (5980 W). The slow phasing effect is caused by pulsegroups of these very similar rates, walking through one another in time.
The attached screenshots are the results of feeding your wav to SpecLab's time domain scope. Using 64 averages on 5990, AM-demodulated pulsegroups from all stations from the West Canadian chain are visible. The timescale appears a bit too long because the actual samplerate was close to 22.200 kHz, rather than 22.050 as assumed by SpecLab. When going to 5980, we can see only a single group of 6 pulses. This is an unusual format for Loran-C, probably indicating an error condition by "blinking" the first two of the eight pulses. One possible reason for this might be the Russian master being down.
It would be interesting to look at an SSB recording (eg. 98.25 kHz USB). This could reveal phase coding within the pulsegroups, and possibly allow verification of the blinking secondary.
Best 73,
Markus (DF6NM)
Sent: Friday, February 19, 2010 4:42 AM
Subject: LF: Loran A and C
Being of a certain age I oft recall the musical phasing noises of Loran on 160m and kind of missed the musical sounds they made as sky waves did their thing. With the advent of the closedown of most of the American 100 khz chains save those serving Canadian and Russian chains I took a listen from here on my newly erected larger (maybe 75m) permeter E/W LF loop and phased out one signal and was left with a slowly phasing noise very similar to that heard on 160m - I dont recall hearing it before but of course a lot of the chains/half rate are off so.... Now whether this is just due to the rather unstable conditions today up here - a lot of iono smearing seen on HF but anyway heres the link of what it sounded like from here in Wasilla AK = Its a 2Mb file beware best phase noise towards the end...
Laurence KL1X "Palinville" Wasilla Alaska BP51 Eye Pee
We2 XP Q
http://kl1x.com/loranalaska.wav
ps the large loop is to improve my s/n on 137 and 500 and it seems pretty good - Ive also been running a CW beacon around 506.000 Khz this evening but low power as Im playing with the matching -
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