--- In digitalradio@yahoogroups.com, "frankk2ncc" <frank.k2...@...> wrote:
>
> That sounds like a very reasonable request. Well written and good job!
>
> f, k2ncc
>
I agree with Frank that this was a reasonable and civilized response. I have
since read W1AW's reply as well, and it, too, seems reasonable. Here is a
response from this cross-posted message on the linuxham forums that is perhaps
a more practical way for individuals to respond to this situation and other
similar ones ...
- Doug/KE7SEI
----- from Brian, WB6RQN/J79BPL -------------------
Re: An open letter: W1AW and 80m psk31 interference
Posted by: "Brian Lloyd" brian-wb6...@lloyd.com briancj6a
Mon Sep 21, 2009 9:35 pm (PDT)
On Mon, Sep 21, 2009 at 9:07 PM, Rik van Riel <r...@surriel. com> wrote:
>
>
> Due to an unfortunate coincidence, W1AW's CW broadcasts pretty
> much wipe out the 80m psk31 sub-band for a significant fraction
> of the time. To try and address this, I have sent the following
> open letter to W1AW at the ARRL, and also published it on my web
> site: http://surriel. com/radio/ w1aw-psk- interference
Perhaps there is something wrong with me but I don't understand why
this might be a problem. If W1AW is transmitting, just set your
filters to eliminate W1AW and continue operating. If their signal is
clean, and I bet it is, it is no more than 100-150 Hz wide, no threat
to signals beyond that.
Oh, I bet I know what you are complaining about. You are probably
trying to receive the entire PSK subband with a 3kHz-wide filter and
W1AW is capturing your AGC, reducing the gain for all the other
signals. That strikes me as a problem with your receiving setup, not
with W1AW's transmitter.
Here are a couple of suggestions for how you could deal with this:
1. Turn off your AGC and go with manual RF gain control. Most rigs
have enough dynamic range to be able to deal with W1AW's signal at
full gain without AGC so it would just be a really strong signal in
the passband. With AGC off W1AW would not reduce the gain for the
other stations you are trying to receive.
2. Switch to a narrower filter. A 500Hz CW filter would allow you to
narrow your receiver bandwidth to reject W1AW and still use AGC for
the signals in the passband.
3. If you don't have a narrower filter, offset tune the radio so that
W1AW is off the edge of the filter. Fldigi provides rig control so if
you have set that up, you can offset tune the rig but fldigi will
still properly display the frequency in the waterfall and it will
properly log the center frequency for your PSK31 QSO.
I have three different rigs I use for PSK (and other digital modes)
and every one of them lets me work PSK in the presence of a strong
signal. One of the rigs I run is a Small Wonder Labs PSK-20 QRP PSK
transceiver. It has no AGC at all. It is a joy to use on PSK because
strong signals don't block weaker signals. When I am using my K2, I
just narrow the filter and offset tune so that the undesired signal is
outside the passband and the desired signal is inside. No problem. I
also have a Flex 5000. On it I just drag my filter skirts to pass only
the signal I am copying. I then depend on the Flex 5000's
panadaptor/waterfal l display to locate other signals to copy. Yet
again, no problem.
So I hope this helps. One of these techniques should work with your
rig and eliminate the problem. Good luck and good DX.
--
73 de Brian, WB6RQN/J79BPL
