Re: LF: TA 3 Jan

To:	[email protected]
Subject:	Re: LF: TA 3 Jan
From:	[email protected]
Date:	Sat, 3 Jan 2004 15:13:37 EST
Reply-to:	[email protected]
Sender:	<[email protected]>

Dear LF group,

- last night, what a night! Thank you for digging in the noise, posting Argoshots and for the comments on last night's transpolar crossings. I must confess it actually happened when I had dozed off in the shack besides the TX ;-) - When my transmission started around midnight, 200W output produced 2.4A and about 170mW EMRP. As the trees near the antenna froze colder and colder during the clear night, capacitive losses slowly decreased and the current went up to nearly 2.7A at sunrise.

PA0SE wrote:
>>Am I right that you are the second continental station after CT1DRP that crossed the Atlantic?<<

At least traces of several stations (from memory, DJ2LF, IK5ZPV, OK1FIG, OM2TW, SM6PXJ and myself, probably others as well) were seen by VE1ZJ and occasionally by W1TAG and W4DEX a couple of years ago. I was lucky enough to get a couple of good screenshots from John 'ZJ on Dec. 24th, 2001. In general, openings from central Eu tend to be rarer, shorter and several dBs weaker than from England, so last night's polar crossing with similar sigs from Peter and me was somewhat unexpected. - Now that we have an example of propagation on that path, I do hope one of us sees WD2XDW one of these nights before they have to leave Alaska.

W1VD wrote:
>> Change that last paragraph entry from QRSS60 to QRSS120. Would be interesting to try it for one night to see if it brings the signals up from the further east EU stations.<<

I am not convinced that using Argo120 with 5mHz vs 10mHz FFT bandwidth really helps all that much. The theoretical 3dB improvement does not occur when you compare the detectability of a signal of given constant duration, you can only trade in some visual incoherent (power) averaging against coherent (phase-sensitive) addition. But the former does not always have to be worse, the recognition of a dash in the noise as "several bright pixels alinged in a row" even relies on it. - My bottom line: I would prefer Argo 90s-slow, it has the same 10mHz resolution as Argo 60s, but does not stretch pixels that much and runs much longer per screenfull.

DJ8WX wrote:
>> PS. Markus, how do you measure the QRG? My counter on both QRGs displayed excactly 0.05Hz minus.<<

The LO at 134.5kHz is derived from an OCXO, which was calibrated against a precise UHF-TV carrier (~10^-9) and, during all of last night, was locked to ZDF video line frequency (10^-8). The 1422.3/.4 Hz DFCW audio frequencies are generated by DL4YHF's SpecLab software, with the free-running soundcard samplerate calibrated using an audio signal derived from that same OCXO. Periodic checks on LORAN lines showed deviations which were less than 5mHz.

73, and best of luck (not only) for tonight,

Markus

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