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Running stations with k3

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WILLIE BABER

Running stations with k3

Hello All,

I did M/M with a big station in the NW running Icom 7700. Needless to say comparison between K3 (one was on site) versus Icom radios came into discussion during rest periods. Yes, the Icom 7700 played quite well, giving what some called "full-body" cw and easy to pick-out-stations while running them.

I like all radios...well almost all of them. Having said that, you can easily get "full-body" cw and better running of station if you simulate the front-end of the Icom radio using K3. To do this, set the first I-F filter to ssb bandwidth (2.7khz) and then use the DSP to deliver 500 hz passband. You will hear stations that are within the 2.7khz window but not quite on your frequency (similar to 7700) while running stations, and without having to fool so often with RIT.

Once you go to 400 hz in the first I-F of K3 you are in serious high dynamic range territory...better have a k-pod on RIT and forget about "full-body" cw, which requires a wider first I-F. Of course when you need a narrow first I-F you can have several of them in K3.

My two cents.

73, Will, wj9b

CWops #1085
CWA Advisor levels II and III
http://cwops.org/
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Guy Olinger K2AV

Re: Running stations with k3

The killer for that wide roofer approach is that loud enough stations can
pump the hardware AGC before the signal gets to the DSP.

The "full body" (whatever that means) CW technique will NOT work in a DX
test I've been in (Will knows where) with that 45 over S9 Italian station
running 15 kW and a 4 element beam on 40m pointed at the US when the band
is wide open, and who has parked 400 Hz above or below me, AND I am trying
to copy an S0 (if even that strong) basement noodle antenna QRP station.

I want the skirts of the roofing filter and the DSP to COINCIDE and when I
hit the edge of the 450 or 350 Hz, I want the skirts do a VERY sharp dive
to oblivion. This gives me a 450 kHz running bandwidth and a 350 running
bandwidth, which I can shift in 10 Hz steps, dropping a signal on the edge
about 10 dB per 10 Hz step.

This way I get the same excellent selectivity with a K3 that I had with my
MP with cascaded INRAD filters in the 8 and 455 IF's. K3 is not superior to
the MP in selectivity or audio quality, but the K3 front end and low noise
opened up a new layer on 40 meters, going down past the DL and OK basement
noodle QRP stations and exposing the RUSSIAN basement noodle QRP stations.

We thought that was band crap listening to the MP, but turned out to be RX
IMD, RX noise crap generated by the MP. Finally exposed by not being there
in the K3.

If my skirts do NOT dive maximally, then the 15 kW Italian is going to pump
the K3's hardware AGC and make copy of my basement noodle QRP stations
impossible.

I do know those (so far all in the western US) who insist that the DSP
selectivity is all they need. They might be right, out where they are.

Idaho is not exactly the land of monster signals. If one really wants to do
"full body CW" out there, a 700 Hz roofer would be a better choice to be in
front of the DSP. Do you really want your AGC pumped by the next two or
three stations above and below your frequency?

I've spent my time with radios with too-wide high IF selectivity. NEVER
AGAIN.

Besides, having the steep diving combined selectivity converts key clicks
to spikes, which the K3 NB and AGC circuits handle splendidly, allowing key
click elimination, another K3 advantage trying to keep a run frequency 400
Hz from a 45 over S9 15 kW Italian station.

You think I'm kidding about 15 kW and 4 elements on 40m? Think again. Not
kidding about 45 over 9 on a calibrated K3 S meter either. Though we *were*
listening on a five element wide spaced (190 feet end to end) 40m quad.

73, Guy K2AV

On Mon, Sep 19, 2016 at 9:21 PM, WILLIE BABER <[hidden email]> wrote:

> Hello All,
>
> I did M/M with a big station in the NW running Icom 7700. Needless to say
> comparison between K3 (one was on site) versus Icom radios came into
> discussion during rest periods. Yes, the Icom 7700 played quite well,
> giving what some called "full-body" cw and easy to pick-out-stations while
> running them.
>
> I like all radios...well almost all of them. Having said that, you can
> easily get "full-body" cw and better running of station if you simulate the
> front-end of the Icom radio using K3. To do this, set the first I-F filter
> to ssb bandwidth (2.7khz) and then use the DSP to deliver 500 hz passband.
> You will hear stations that are within the 2.7khz window but not quite on
> your frequency (similar to 7700) while running stations, and without having
> to fool so often with RIT.
>
> Once you go to 400 hz in the first I-F of K3 you are in serious high
> dynamic range territory...better have a k-pod on RIT and forget about
> "full-body" cw, which requires a wider first I-F. Of course when you need
> a narrow first I-F you can have several of them in K3.
>
> My two cents.
>
> 73, Will, wj9b
>
> CWops #1085
> CWA Advisor levels II and III
> http://cwops.org/
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

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Matt Murphy

Re: Running stations with k3

Interesting!

Can anyone explain why zero beat CW would sound more "full bodied" with a
2.7 KHz IF than with, say, a 400 Hz IF bandwidth? It would seem that the
CW signal was typically narrower than either one, so there would not be any
information lost on a zero beat signal.

Is there some sort of audio harmonic that exists only when the IF bandwidth
is sufficiently wide? Or could the wider bandwidth effectively change the
perceived audio impact of AGC (depending on band noise)?

Is there a measurement of the distortion introduced by an IF filter across
both the signal *and* the noise? I think noise sounds better (smoother?)
with a wider IF filter bandwidth. Of course, the purpose of the narrower
filter is to reduce IMD from nearby signals, not to make noise sound
pleasant.

I'm curious if anyone has thoughts or insights about any of the above...

73,
Matt NQ6N

On Tue, Sep 20, 2016 at 11:45 AM, Guy Olinger K2AV <[hidden email]>
wrote:

> The killer for that wide roofer approach is that loud enough stations can
> pump the hardware AGC before the signal gets to the DSP.
>
> The "full body" (whatever that means) CW technique will NOT work in a DX
> test I've been in (Will knows where) with that 45 over S9 Italian station
> running 15 kW and a 4 element beam on 40m pointed at the US when the band
> is wide open, and who has parked 400 Hz above or below me, AND I am trying
> to copy an S0 (if even that strong) basement noodle antenna QRP station.
>
> I want the skirts of the roofing filter and the DSP to COINCIDE and when I
> hit the edge of the 450 or 350 Hz, I want the skirts do a VERY sharp dive
> to oblivion. This gives me a 450 kHz running bandwidth and a 350 running
> bandwidth, which I can shift in 10 Hz steps, dropping a signal on the edge
> about 10 dB per 10 Hz step.
>
> This way I get the same excellent selectivity with a K3 that I had with my
> MP with cascaded INRAD filters in the 8 and 455 IF's. K3 is not superior to
> the MP in selectivity or audio quality, but the K3 front end and low noise
> opened up a new layer on 40 meters, going down past the DL and OK basement
> noodle QRP stations and exposing the RUSSIAN basement noodle QRP stations.
>
> We thought that was band crap listening to the MP, but turned out to be RX
> IMD, RX noise crap generated by the MP. Finally exposed by not being there
> in the K3.
>
> If my skirts do NOT dive maximally, then the 15 kW Italian is going to pump
> the K3's hardware AGC and make copy of my basement noodle QRP stations
> impossible.
>
> I do know those (so far all in the western US) who insist that the DSP
> selectivity is all they need. They might be right, out where they are.
>
> Idaho is not exactly the land of monster signals. If one really wants to do
> "full body CW" out there, a 700 Hz roofer would be a better choice to be in
> front of the DSP. Do you really want your AGC pumped by the next two or
> three stations above and below your frequency?
>
> I've spent my time with radios with too-wide high IF selectivity. NEVER
> AGAIN.
>
> Besides, having the steep diving combined selectivity converts key clicks
> to spikes, which the K3 NB and AGC circuits handle splendidly, allowing key
> click elimination, another K3 advantage trying to keep a run frequency 400
> Hz from a 45 over S9 15 kW Italian station.
>
> You think I'm kidding about 15 kW and 4 elements on 40m? Think again. Not
> kidding about 45 over 9 on a calibrated K3 S meter either. Though we *were*
> listening on a five element wide spaced (190 feet end to end) 40m quad.
>
> 73, Guy K2AV
>
>
>
> On Mon, Sep 19, 2016 at 9:21 PM, WILLIE BABER <[hidden email]>
> wrote:
>
> > Hello All,
> >
> > I did M/M with a big station in the NW running Icom 7700. Needless to
> say
> > comparison between K3 (one was on site) versus Icom radios came into
> > discussion during rest periods. Yes, the Icom 7700 played quite well,
> > giving what some called "full-body" cw and easy to pick-out-stations
> while
> > running them.
> >
> > I like all radios...well almost all of them. Having said that, you can
> > easily get "full-body" cw and better running of station if you simulate
> the
> > front-end of the Icom radio using K3. To do this, set the first I-F
> filter
> > to ssb bandwidth (2.7khz) and then use the DSP to deliver 500 hz
> passband.
> > You will hear stations that are within the 2.7khz window but not quite on
> > your frequency (similar to 7700) while running stations, and without
> having
> > to fool so often with RIT.
> >
> > Once you go to 400 hz in the first I-F of K3 you are in serious high
> > dynamic range territory...better have a k-pod on RIT and forget about
> > "full-body" cw, which requires a wider first I-F. Of course when you
> need
> > a narrow first I-F you can have several of them in K3.
> >
> > My two cents.
> >
> > 73, Will, wj9b
> >
> > CWops #1085
> > CWA Advisor levels II and III
> > http://cwops.org/
> > ______________________________________________________________
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:[hidden email]
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
> > Message delivered to [hidden email]
> >
> ______________________________________________________________
> Elecraft mailing list
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> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

Jim Brown-10

Re: Running stations with k3

For one thing, you would hear more clicks with the broader filter. You
would, of course, also hear MORE signals.

73, Jim K9YC

On Tue,9/20/2016 2:08 PM, Matt Murphy wrote:
> Can anyone explain why zero beat CW would sound more "full bodied" with a
> 2.7 KHz IF than with, say, a 400 Hz IF bandwidth?

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Deni F5VJC

Re: Running stations with k3

In reply to this post by Guy Olinger K2AV

This is the degeneration of Amateur radio, yes really, it's true. These
signals from Eu are invariably the dirtiest worst you will ever hear on the
bands, spewing crap all over the band.

Below...

"The "full body" (whatever that means) CW technique will NOT work in a DX
test I've been in (Will knows where) with that 45 over S9 Italian station
running 15 kW and a 4 element beam on 40m pointed at the US when the band
is wide open, and who has parked 400 Hz above or below me, AND I am trying
to copy an S0 (if even that strong) basement noodle antenna QRP station."

73 F5VJC

On 20 September 2016 at 20:45, Guy Olinger K2AV <[hidden email]> wrote:

WILLIE BABER

Re: Running stations with k3

In reply to this post by WILLIE BABER

It wasn't my term. But I think "full-bodied" cw means a slightly wider I-F to establish background noise that some ops want to hear, particularly if the receiver has exceptional gain distribution and in-band IMD, which the latest Icoms do have. This gives articulation to cw signal outs of a quiet back ground of noise, and so long as you are not dealing with an exceptionally strong signal nearby, hard-wired fast agc can give relative strength to the competing signals. Then, a good cw op can pick out stations actually easier than with a 400hz filter where RIT becomes more necessary. Of course on the Icom radio there is no choice but to do this because 3khz is the narrowest setting, though you could ask for more DSP filtering.

So, here again, is what I mean: set you K3 for 2.7khz and I-F DSP at 500hz and tune in a s-9 signal. Now engage your narrow cw filter (I can do 400hz, 250hz, and 200hz). Listen to the I-F back ground noise decrease relative to the signal. Notice too that 2.7 hz with 500hz of DSP sounds more "full-bodied" than 400hz, 250hz, 200hz. Of course, this is all good when you are trying to hear a weak signal anyway as opposed to running a pileup of stations.

My point is (or was in the discussion about this) if you like running stations with an Icom you can enjoy running them in the same way with K3. But what has to happen to the Icom radio when a signal like the one Guy describes gets within the 3 khz roofing filter?

On the k3 you can engage a 200 hz filter and carry on the east coast -EU battle If there is an advantage to contesting in Idaho it is that EU stations from over the pole are seldom over s-9 and don't blink, you will miss the EU opening, hi. However, I have seen east coast signals nearly peg the meter of k3 a few times in 300z cwt.

73, Will, wj9b
KX1, k2, so2r K3/P3

CWops #1085
CWA Advisor levels II and III
http://cwops.org/

--------------------------------------------
On Tue, 9/20/16, Ron D'Eau Claire <[hidden email]> wrote:

Subject: Re: [Elecraft] Running stations with k3
To: "'F5vjc'" <[hidden email]>, "'Guy Olinger K2AV'" <[hidden email]>
Cc: "'Elecraft Reflector Reflector'" <[hidden email]>
Date: Tuesday, September 20, 2016, 6:03 PM

A very long time ago
(1950's) we called 'em "California
Kilowatts" knowing
that their driver
stages were running a kilowatt at least and then the big
amp following...

On A.M. (not so much SSB then) 100% modulation
was a starter. 150% produced
a nice splatter
that told everyone across the band that you were "on
the
air". The same with CW using very
square wave keying that announced your
presence over many kc/s with clicks that
allowed everyone to read your call
and know
that "Big Al" (or whomever) was on his key.

They seemed rampant on 75 and
20 meters.

So the
geography has shifted, but not the crazy interests of some
operators.

BTW, if you are interested in a 15 kW H.F. amp
check out the "Tsunami":

http://ta5fa.blogspot.com/2013/03/15kw-hf-rf-amplifier-tube.html

I'm sure that some
operators would use it to drive a "big" final amp,
Hi! We
can hope they don't find a way.

73, Ron AC7AC

-----Original Message-----
From: Elecraft [mailto:[hidden email]]
On Behalf Of F5vjc
Sent: Tuesday, September
20, 2016 3:01 PM
To: Guy Olinger K2AV
Cc: Elecraft Reflector Reflector
Subject: Re: [Elecraft] Running stations with
k3

This is the degeneration
of Amateur radio, yes really, it's true. These
signals from Eu are invariably the dirtiest
worst you will ever hear on the
bands,
spewing crap all over the band.

Below...

"The "full body" (whatever that
means) CW technique will NOT work in a DX
test I've been in (Will knows where) with
that 45 over S9 Italian station
running 15
kW and a 4 element beam on 40m pointed at the US when the
band is
wide open, and who has parked 400 Hz
above or below me, AND I am trying to
copy
an S0 (if even that strong) basement noodle antenna QRP
station."

73 F5VJC

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Bill W4ZV

Re: Running stations with k3

WILLIE BABER wrote

It wasn't my term. But I think "full-bodied" cw means a slightly wider I-F to establish background noise that some ops want to hear, particularly if the receiver has exceptional gain distribution and in-band IMD, which the latest Icoms do have. This gives articulation to cw signal outs of a quiet back ground of noise, and so long as you are not dealing with an exceptionally strong signal nearby, hard-wired fast agc can give relative strength to the competing signals. Then, a good cw op can pick out stations actually easier than with a 400hz filter where RIT becomes more necessary. Of course on the Icom radio there is no choice but to do this because 3khz is the narrowest setting, though you could ask for more DSP filtering.

This is nothing new. K3ZO has been doing this for about 30 years (at least) using wide filters and his ears as DSP. I did this long ago with a TS-930S using SSB filters with CW VBT fully engaged which shifts two IF filters in opposite directions giving a broad overall response but peaked in the center. See K3ZO's comments here:

http://elecraft.365791.n2.nabble.com/K3-CW-Rx-Audio-td467894.html#a467895

As Guy said this technique will NOT work on extremely crowded bands on the East Coast but I have used it on 10 meters where it was not uncommon for JAs to reply well off-frequency. It absolutely WILL NOT work for 160 contests loaded with S9+++ signals spaced every 200 Hz.

Interestingly enough I use this technique with APF for ultra weak signal DXing on 160. I set my 200 Hz filters (in diversity) to engage at 400 Hz (i.e. the DSP filter is 400 Hz but preceded by the broad shape factor 200 Hz XTAL filter). This gives more presence (i.e. "full-bodied" sound) to the weak signal by allowing it to be differentiated from noise by my ear/brain while APF is engaged. The net result is a broad overall response but with a very narrow ~10 dB peak in the center (from APF).

73, Bill W4ZV

Guy Olinger K2AV

Re: Running stations with k3

On Wed, Sep 21, 2016 at 6:59 AM, Bill W4ZV <[hidden email]> wrote:

> This is nothing new. K3ZO has been doing this for about 30 years (at
> least)
> using wide filters and his ears as DSP.
>

Some people really CAN do this. For some years while he was living in NC, I
had the pleasure of operating with W2CS at the NY4A multi/multi sessions.
There were some number of neat things he could do, that I could not make
happen in my brain, including the K3ZO method and typing 100% copy well
behind the signal while carrying on an unrelated conversation.

I think I figured out I can't copy CW and chew gum at the same time or
something pretty close. So beware of presentation of methodology as general
technique, that actually requires some not-so-common physical talents to
pull off. I *do* know that K3ZO and W2CS *can* do that, and I also know
that I *cannot*. And I also know that my chances of typing CW well behind
the signal and carrying on a separate conversation in the room about how
deep to plant radials at the same time are simply, factually, ZERO. :>)

I do know how to turn K3 diversity into a sound stage and spread signals in
a pile up around an audio "horizon". So I'm not totally devoid. :>)

73, Guy K2AV
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WILLIE BABER

Re: Running stations with k3

In reply to this post by WILLIE BABER

Well, I didn't mention who it was that made the comment about what we now can call the k3zo method. However, the guy who sees an advantage in a 3 khz roofing filter can do just that!!

73, wj9b

CWops #1085
CWA Advisor levels II and III
http://cwops.org/

--------------------------------------------
On Wed, 9/21/16, Guy Olinger K2AV <[hidden email]> wrote:

Subject: Re: [Elecraft] Running stations with k3
To: "Bill W4ZV" <[hidden email]>
Cc: "Elecraft Reflector" <[hidden email]>
Date: Wednesday, September 21, 2016, 10:43 AM

On Wed, Sep 21, 2016 at
6:59 AM, Bill W4ZV <[hidden email]>
wrote:

> This is nothing
new. K3ZO has been doing this for about 30 years (at
> least)
> using wide
filters and his ears as DSP.
>

Some people really CAN do
this. For some years while he was living in NC, I
had the pleasure of operating with W2CS at the
NY4A multi/multi sessions.
There were some
number of neat things he could do, that I could not make
happen in my brain, including the K3ZO method
and typing 100% copy well
behind the signal
while carrying on an unrelated conversation.

I think I figured out I
can't copy CW and chew gum at the same time or
something pretty close. So beware of
presentation of methodology as general
technique, that actually requires some
not-so-common physical talents to
pull off.
I *do* know that K3ZO and W2CS *can* do that, and I also
know
that I *cannot*. And I also know that
my chances of typing CW well behind
the
signal and carrying on a separate conversation in the room
about how
deep to plant radials at the same
time are simply, factually, ZERO. :>)

I do know how to turn K3
diversity into a sound stage and spread signals in
a pile up around an audio "horizon".
So I'm not totally devoid. :>)

73, Guy K2AV
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Jim Brown-10

Re: Running stations with k3

In reply to this post by Bill W4ZV

On Wed,9/21/2016 3:59 AM, Bill W4ZV wrote:
> This is nothing new. K3ZO has been doing this for about 30 years (at least)
> using wide filters and his ears as DSP. I did this long ago with a TS-930S
> using SSB filters with CW VBT fully engaged which shifts two IF filters in
> opposite directions giving a broad overall response but peaked in the
> center. See K3ZO's comments here:

Now we're getting to the good part of this thread, which I've found
quite illuminating, because it explains user preferences for one radio
over another that aren't obvious. Thanks to Will, Guy, and Bill for
their very useful contributions to the discussion.

There's another VERY important factor related to bandwidth -- when we
narrow the bandwidth to copy a very weak signal buried in noise (as
opposed to QRM), the filter tends to ring at its skirts, making it more
difficult to copy rather than easier. I find this to be true independent
of which filter alignment I've chosen, and it's predicted entirely by
classic filter theory. The K2, which sounds great when listening through
its TX filter, has a multi-element crystal filter that it realigns to
vary the bandwidth, sounds just awful when set for narrow SSB
bandwidths. It's all due to the extreme phase shift in those filters.

As another example from my work in pro audio, I was hired to try to
clean some really nasty buzz out of a "jailhouse" recording. This was in
the late '70s, and DSP didn't exist. My tool was a very high quality,
very narrow tunable notch filter with high and low pass filters, and I
passed the recording though it a half dozen times to attack the
harmonics of the buzz. With each pass, I reduced the buzz, but I also
introduced more phase shift. So as the signal to noise improved, the
intelligibility degraded.

73, Jim K9YC

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Matt Murphy

Re: Running stations with k3

> Now we're getting to the good part of this thread, which I've found quite
illuminating, because it explains user preferences for one radio over
another that aren't obvious. Thanks to Will, Guy, and Bill for their very
useful contributions to the discussion.

I agree, this is a very interesting topic. I've heard some lore about the
TS-830 and 930, and the Yaesu FT-990 having very desirable receiver
characteristics for hearing weak signals in pileups.... not necessarily due
to a specific design goal or commensurate with minimizing close-in IMD,
but as a byproduct of the overall receiver design whose distortion
characteristics happen to work nicely in a pileup.

In terms of the phase shift introduced by filters, I assume the distortion
introduced by the filter is commensurate with the steepness of the skirts?

On Wed, Sep 21, 2016 at 10:32 AM, Jim Brown <[hidden email]>
wrote:

> On Wed,9/21/2016 3:59 AM, Bill W4ZV wrote:
>
>> This is nothing new. K3ZO has been doing this for about 30 years (at
>> least)
>> using wide filters and his ears as DSP. I did this long ago with a
>> TS-930S
>> using SSB filters with CW VBT fully engaged which shifts two IF filters in
>> opposite directions giving a broad overall response but peaked in the
>> center. See K3ZO's comments here:
>>
>
> Now we're getting to the good part of this thread, which I've found quite
> illuminating, because it explains user preferences for one radio over
> another that aren't obvious. Thanks to Will, Guy, and Bill for their very
> useful contributions to the discussion.
>
> There's another VERY important factor related to bandwidth -- when we
> narrow the bandwidth to copy a very weak signal buried in noise (as opposed
> to QRM), the filter tends to ring at its skirts, making it more difficult
> to copy rather than easier. I find this to be true independent of which
> filter alignment I've chosen, and it's predicted entirely by classic filter
> theory. The K2, which sounds great when listening through its TX filter,
> has a multi-element crystal filter that it realigns to vary the bandwidth,
> sounds just awful when set for narrow SSB bandwidths. It's all due to the
> extreme phase shift in those filters.
>
> As another example from my work in pro audio, I was hired to try to clean
> some really nasty buzz out of a "jailhouse" recording. This was in the late
> '70s, and DSP didn't exist. My tool was a very high quality, very narrow
> tunable notch filter with high and low pass filters, and I passed the
> recording though it a half dozen times to attack the harmonics of the buzz.
> With each pass, I reduced the buzz, but I also introduced more phase shift.
> So as the signal to noise improved, the intelligibility degraded.
>
> 73, Jim K9YC
>
>
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k6dgw

Re: Running stations with k3

In reply to this post by Guy Olinger K2AV

OK, this is probably a good place to ask:

When trying to copy a weak-ish signal in noise and "other stuff" in the
50's, one of my crewmates at the coastal marine station told me to lay
the cans on the desk, face up. It works. I don't know why, maybe
someone here knows. Surprisingly, I generally didn't need to turn the
gain up much if at all.

The receiver I used most on our HF frequencies was a brand new Collins
51J4. The military version was the R-388A. It had 6 and 3 KHz mech
filters, and a separate, adjustable crystal filter. Did not cover 500
Kcs which was particularly noise and full of signals at night, however
the trick worked on those receivers too, so it wasn't just the mech filter.

73,

Fred K6DGW
- Sparks NV DM09dn

- Northern California Contest Club
- CU in the Cal QSO Party 1-2 Oct 2016
- www.cqp.org

On 9/21/2016 9:43 AM, Guy Olinger K2AV wrote:
> On Wed, Sep 21, 2016 at 6:59 AM, Bill W4ZV <[hidden email]> wrote:
>
>> This is nothing new. K3ZO has been doing this for about 30 years (at
>> least)
>> using wide filters and his ears as DSP.

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