[Lowfer] My personal comments about WSPR reception - Long reading

[Andy - KU4XR]

Narrow Filtering; IF, and Audio ::: Please !!!!! Don't pull out
the wet noodles to whip me yet. I want to comment on my own
personal experiences with WSPR reception in noisey conditions.
It is a Noted fact that WSPR does its own narrow DSP processing,
and the general consensus is that narrow IF bandwidths, and
narrow Audio bandwidths are not necessary to decode a WSPR 
transmission.... BUT !!!!! The software developer, Joe - K1JT
has commented on various posts on WSPRnet, that there may be
times when a narrow filter may be an asset, Namely, in the
presence of a strong nearby signal that causes heavy AGC action
to reduce the RF gain of the receiver, and squashes the dynamic
range....He still contends that typical atmospheric noise can be
handled by WSPR's own filtering while decoding... May I mention
again that WSPR started out as a software for EME'er's, and 
Pingers, then found use on 6 meters, and started its migration
into HF. This past summer, it started getting noticed on 160 meters
during the 160 meter WSPR summer project.. I participated in that
effort somewhat, when the static levels were peaking at typical
summer levels for 160 meters, at 30 to 40 dB over S-9...
NOW; my personal comments... I have had times where using a 
narrow filter made the difference between getting a WSPR decode,
and NOT getting one. Heavy continuous static bursts will obliterate
a weak WSPR signal. During the summer, I could run my dual 500 KHz
IF filters, and see the difference in the amount of decodes that I
got versus using the standard 2.4 KHz Bandwidth. The narrow filters
would allow the weak signals to make it thru, where the wider filter
allowed too much wideband noise in, and wiped out the weaker signal.
I even used software DSP filtering to narrow the bandwidth down to
220 Hz wide...Yes this will give a higher SNR reading.. WHY ??
Because WSPR is hearing more of the WSPR signal, and less noise...
Finally; on to my comments about WSPR for a lowFER signal.
What do we have on 1750 meters ?? Strong signals from the LWBC'ers,
strong PLC's, sometimes horrendous manmade noise to contend with, 
and of course mother natures noisy effects...factor in an already
very,very,very, weak signal that you're trying to receive and, MAN !!
what a scenario...... If you haven't figured it out by now; YES; I
am recommending that you at least " TRY " using narrow filters on
1750 meters, and see for yourself as to whether or not you get any
benefit from it.... It certainly won't hurt anything, and personally,
I'm not as concerned about an inflated SNR reading, as I am about
getting a decode.... For the sake of noting it; any filtering you do
will need to be centered at 1500 cycles ( Hz if you like ) to be in
the center of the WSPR transmission. In my experience, many of the
options on the radio have helped at various times. Notch filtering
of a strong signal if it's not right on top of a weak signal.
IF Shift has also helped on occasion with a signal that was close 
to the frequency, and I was able to shift it some. At LF; I have
even saw the time when turning on the attenuator helped...I have
not personally had good results by trying to use the RF Gain
control on the radio to adjust the volume, and gain level. That
has most of the time killed the weak signal in the process, your
results may be different though... The key point I am attempting 
to get at is this; whatever you have in your arsenal, try them all 
to see which,if any, accomplishes the desired end,..... A Decode..

I hope this post dosen't turn into a thread of tirades, and end
up getting completely off topic...

73 all, until the next time:


Andy - KU4XR - EM75xr - Friendsville, TN. USA

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