[Juergen Brustat]

Hi Bob,
you are 100% right. I did learn Morse Code many years ago, but nowadays it is mostly out of my brain.
Each time I hear SAQ I regret understanding only small parts of it.
Therefore revitalizing Morse Code is for me one of those tasks one usually plans at the beginning of a year.
Wish me good success !
73 from DL2JMB Juergen Brustat

[Juergen Brustat]

Hi Bob,
I just had a look at the receive diagram on your website. You didn’t really use a 22 uH coil, did you ?
Because with a 4.7 nF capacitor it would resonate at about 500 kHz . I suppose, it’s only a typing error
and should read 22 mH, which would resonate at 15.8 kHz. The 100 k resistor broadens the selectivity curve
and when we consider component tolerances, SAQ might be well included. So far, so good, but :
the input impedance of your PC is probably not greater than a few kOhms and transformed parallel
to the tuned circuit will kill any signal received. So, I recommend using another transformer,
perhaps 100k:10k or 100k:1k, and it will work.
Instead of coil + transformer you could use a second winding on the coil only.
For testing, use the Russian Alpha signals at 12 an 15 kHz. They are much weaker than SAQ,
at least in western Europe.
Wish you good success ! DL2JMB Juergen

[Juergen Brustat]

Hallo Vassily,
sorry you didn’t receive SAQ, but I am convinced this is a problem of your antenna.
The distance Sweden to Moscow is about the same as to southern France, where they had good reception.
At 17 kHz the impedance of your 20m wire antenna is very high and not properly matched to the input impedance of your computer.
So try a transformer ( perhaps 1 MOhm : 1 kOhm = 30:1) or better an active antenna amplifier ( maybe a very simple one,
depending on your local interference situation) and you’ll be happy again.
Wish you a Happy New Year 2016 (though you start that year 7 days later ?). Regards dl2jmb juergen

[Author]

Replies