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Try to learn something about everything, and everything about something - Thomas Huxley

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Sun 6 Aug 2023

A quick visit to the shack in the morning and I heard SM5COP - Rune - calling CQ. I always like to say hello so I called for a brief QSO, I couldn't stay long as I had to go out - swimming with friends, a regular Sunday morning activity. We had a nice, short QSO. It's always a pleasure to work Rune.

I had a few hours in the shack later in the afternoon.

I had a think about the higher bands - I don't often stray beyond 30m, occasionally going to 20m.

I had a quick tune around and wondered if I need to use the Pre-Amp on my IC-7200 or not. On the normal lower bands it's certainly not needed, and would be counterproductive.

The accepted wisdom is that “if the noise level increases when you connect the antenna then you have enough RX sensitivity, and you don't need the Pre-Amp”

I thought I'd see which bands (if any) would warrant the Pre-Amp:

Bandp-p mV noise / Test Loadp-p mV noise / AntennaPre-Amp needed?
160 260 800 No
80 280 >300 No
60 240 >600 No
40 250 >800 No
30 280 >1000 No
20 280 >1000 No
17 260 >600 No
15 260 >600 No
12 260 ~300 Marginal Yes
10 260 260 Yes

It appears that only 12m and 10m would warrant use of the pre-amp using my existing Inverted-L antenna.

on 12m and 10m I re-did the experiment with the Pre-Amp ON

Bandp-p mV noise / Test Loadp-p mV noise / AntennaPre-Amp needed?
12 330 >1000 Yes
10 360 >600 Yes

I heard a QSO on 60m (5263kHz) between GM3WUX and G3SNT at around 1500z.

After they finished I called GM3WUX - who was a good 559 here, and no difficulty at all to copy. He struggled to make out my call, taking several attempts - eventually using straight key at around 12wpm to improve the s/n ratio - the same way QRSS works - longer dashes and dots = more chance of resolving the signal during fading and noise. It worked and we exchanged enough to complete a QSO. I copied all of Terry's transmissions, he complained of high local noise levels. This is the bane of the urban operator. Someone with a high noise floor can still radiate a good signal, easily workable by people with no man-made noise issues - but then can't hear replies. Sad for our historic and technological hobby to be taken from us by the march of “technology” in the average household.

Later, around 1600z I tuned around 30m and heard the unmistakable sound of a Bug - F8DGY - calling CQ so I replied - on my Vibroplex Champion - and had a nice QSO with Chris, near Paris, who was running 500 watts (why so much?). We had a good bug-bug QSO - his SpeedX key from 1937 and my Vibroplex from 1960.

Later still, at 1705Z, I heard another Bug calling CQ - DK8IT - and we had a good QSO again, bug-bug. Severe lightning static crashes marred my end - Gerry reported no QRN problems, I guess the storms I was hearing were in his “skip zone”?

A good BUG day.

public/radio/blog/sun_6_aug_2023.txt · Last modified: 02/04/24 20:38 BST by john