On Mon, 22 Sep 2008, JB wrote:


"carlos2007" wrote in message
...

This is the question:

Would you swap a Drake r8b for a Collins 51 S1? Why do I ask this?

I have a Drake R8B and a Wellbrook 1530+ antenna, and pick up a lot
ot QRM and noise S5 - 6 so I cannot do DX, I have tried with other
antennas and the result is the same.

I have read in other forums that receivers with valvel are less noiser
and one owner of the Collins 51 s1 says that QRM and noises do not
exist.

Do you think that it is worth swapping it?

Thanks. Any comments are very welcomed

You need to try to reduce the QRM (man made). If you can run the radio from
battery and make the noise go away by killing the mains, you have something
to work on. If it is really QRN (nature's noise) that's just tough. That
antenna has a preamp. Not always a good thing. The amplifier will amplify
signal AND noise. If you are able to selectively bypass it, you will have
more options. If there is too much noise and signal, all you do is risk the
extra noise generated in the amplifier. The theory behind a loop, is that
you lose some signal, but you can orient it to lose more noise, so you can
hear signal that might be obliterated otherwise. It is best to have more of
a wire antenna, high and in the clear to catch signal at the risk of
catching more noise, so that you can switch back and forth for the best
reception. Even fine painted wire for stealth is better than nothing.

The fact of life, is that the ionosphere will either reflect the signal or
absorb it and either you will hear it or not. QRN goes up and down. The
Collins is a neat thing if you have room for both but I wouldn't swap them.


And the Collins would be a big shock to anyone who grew up with modern
solid state receivers.

Tune 500KHz, shift the band, then tune another 500KHz, shift the band
again.

Lesser receivers of the period suffered from lots of things like
not so great definition on the tuning dial, but you could tune a 2:1
range per band.

Current synthesized receivers don't have different bands for the
shortwave spectrum, it's done invisibly inside so you can tune
from the top of the broadcast band to the 30MHz with one swoop
of the tuning knob (well, numerous turns and more of them the
finer the tuning steps, but no bandswitching needed). They also
often have the ability to enter a frequency from a keypad, so
you can jump easily to the general area you want to tune.

Michael VE2BVW