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LF: RE: 73kHz RIP

To: [email protected]
Subject: LF: RE: 73kHz RIP
From: "Andy talbot" <[email protected]>
Date: Tue, 1 Jul 2003 12:20:20 +0100
Importance: high
Reply-to: [email protected]
Sender: <[email protected]>
On Sunday I had a pre-arranged QSO with G3YGF over the grand distance of 7.2km! Julian had an NoV but had never transmitted on teh band. In 1997 with me transmitting we raised the distance (for one way) from 20 to 100km by G3YGF progressivly driving further away during the day, using audible CW. Shortly after that I started on the SLowCW route since it was obvious this was the normal limit of my transmitting system.
On Sunday, G3YGF quickly put up a loop of Litz wire of somthing like a 10m
'diameter' polygon, and resonated this feeding in 10 Watts of RF from an old
audio amplifier. I used Spectran receive this with 15dB S/N in 4 Hz, and
copied the 'MidCW' when he hand keyed at 1s dot period. Needless to say his
copy of my 100 Watts to the Tee antenna presented no problems.
Had G3YGF still been living at his original QTH where he first heard me in
April 1997 for possibly the first home statio to home station one way - this
would have completed that QSO six years later!
Andy  G4JNT




-----Original Message-----
From:   James Moritz [SMTP:[email protected]]
Sent:   2003/07/01 12:04
To:     [email protected]
Subject:        LF: 73kHz RIP

Dear LF Group,

In the last hours of the 73kHz band, I had contacts with MI0AYZ, G3AQC,
G3LDO and finally G3XDV, before watching the final QSO on the band between
G3XDV and G3LDO - very fitting to see the stations who had the first 2-way
contact on the band  also have the last.

G3XDV was also my first QSO on the band about 3 1/2 years ago in January
2000. At that time, opinion seemed to be that 73k was a bit of a dead duck
because of the QRM from Rugby, the general fearsome noise levels and
hopeless antenna efficiency, and the band at that time being due for
withdrawal in June 2000. However, looking through my log book whilst
transmitting beacon signals last night, I find my final tally was about 90
QSOs of various sorts, including 15 stations in 4 countries in 2-way 73kHz
contacts, 15 stations in 10 countries in cross-band 73k/136k contacts, one
(G3WKL) 136k/73k cross-band contact, and 3 other stations heard but not
worked on the band. I was also involved in /P operations at Puckeridge and
Porthcurno. I spent a lot of time transmitting beacon-type signals - the
most distant report was from W4DEX in 2001. 73kHz also played an important
part in my LF antenna experiments; having roughly an octave of frequency
separation from 136k was useful in looking at how antenna performance
changed with frequency. The propagation on 73k also gave tantalizing hints
that it was a different animal from 136k, but it is taking a long time to
figure 136k out, and in the end time ran out for 73k.

So, all in all, well worth the effort, and I am sad to see the band go.
Although there did not seem to be any possibility of extending amateur
operations on 73 kHz further, hopefully in the future there will be other
amateur operations down here at the bottom end of the radio spectrum, which
I look forward to.

Cheers, Jim Moritz
73 de M0BMU




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