More information - Need help with fluctuating power output on K2

[Dean44]

With further testing I have found that the power output fluctuates mostly on
the 80 thru 20 meter bands and 80 is the worst. It seems to jump back and
forth rather than slowly drifting. It seems like the power control knob does
not have very consistent control over the actual output.

I did some signal tracing and found that the same fluctuation is evident in
the signal right after the "Xmit Mixer Output". This signal jumps from 27 to
36 mV as the out put power jumps back and forth. While doing this test with
the output power set for 5W, the real output power jumps from 3.5 to 6.5
almost each time that I press the tune button to send. Since this is a
pretty early stage, I don't think that the ALC control circuit is causing
it. Doesn't the ALC adjust power after this stage? The VCO output just
before the Xmit Mixer tested normal and stable on transmit and receive. What
else could be causing the fluctuating signal at the Xmit Mixer Output?

I have still been using the radio and just running it on full power where is
seems more stable. I have found that if the power drops while on full power,
I can turn the power knob down and back up 2 or 3 times to make the power
come back up. I know that the POT is working good because the power that
reads out that it is calling for (when not transmitting) is very linear and
stable.

Thanks again for any and all help!

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[Stephen W. Kercel]

Fellow Elecrafters:

I have a strange problem with my K2/100 on 80 meters.

The situation is as follows:

I work QRP DX at the low end of 80 M, (say 3508 kHz or thereabouts)
with a requested power of 4.5 watts, and get an indicated 5 watts out.

I then check into the Pine Tree Net on 3596 kHz and crank up the
requested power to 10 watts (this is before the relay clicks; I'm
still in QRP mode), and I get about 10 watts out. So far so good, right?

Then I go back to 3508 kHz, without resetting the power request level
knob, but the rig puts out 5 watts, even though the display
acknowledges my ten watt request. If I go back to 3596 the output
goes back to 10 watts in agreement with the requested level.

Note the essential point, when I make a big excursion in frequency,
the radio is putting out a level of power substantially different
from the requested level.

I can correct the output level at the low end by sweeping the
requested level either low (near 0) or high enough to make the QRO
relay click, and then adjust it down to and desired QRP level, and
the rig will put out approximately the requested level of power.

The phenomenon occurs whether I change frequency by switching VFOs
preset to the two frequencies, or if I retune one VFO using the tuning knob.

This is not an issue of varying antenna impedance. I get this effect
with a commercial dry dummy load as well as a real (very well matched) antenna.

I can also create the effect the other way around. If I request 5
watts at the 3596 then go to the low end and request 10 watts, then
go back to 3596 with the knob in the 10 watt position, I still get 5
watts until I jigger the power level request knob.

I have tried to reproduce this effect on 40 meters, requesting 5 and
10 watt levels at frequencies differing by about 100 kHz. In that
case I get what I would regard as normal behavior. The rig always
puts out the approximately the requested level of power irrespective
of when I set the power level request knob.

Has anyone else run into this phenomenon?

Is it a quirk in the software?

Is something wrong with the radio?

73,

Steve Kercel
AA4AK


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[Don Wilhelm-3]

Steve,

Have you perhaps increased the value of R98 on the bottom of the RF Board to
give you a more stable power control at high power?  If so, it will make the
power control at lower power more sluggish.  That is the only thing I can
think of which would make a difference.

There is nothing band dependent about the power control that I am aware of,
but the overall gain of the transmitter does vary from band to band, and
that combined with the granularity of the power control may be causing the
effect. The K2 remembers the power setting unless the power request is
changed or the band is changed.  So the real power output that you are
observing may be dependent on the exact steps that you are using to observe
this phenonomon.

You did say that you verify the power output level on the K2 display?  Can
you provide the sequence you are using to do that?  The normal transmit
display does not show the power output level, so you must be doing something
other than a keydown.

It would also be of interest to know if the same thing happens with the
wider range QRP levels - power the K2 through the low power jack only
(disconnect or turn off the power to the KPA100).

73,
Don W3FPR

> -----Original Message-----
>
> I have a strange problem with my K2/100 on 80 meters.
>
> The situation is as follows:
>
> I work QRP DX at the low end of 80 M, (say 3508 kHz or thereabouts)
> with a requested power of 4.5 watts, and get an indicated 5 watts out.
>
> I then check into the Pine Tree Net on 3596 kHz and crank up the
> requested power to 10 watts (this is before the relay clicks; I'm
> still in QRP mode), and I get about 10 watts out. So far so good, right?
>
> Then I go back to 3508 kHz, without resetting the power request level
> knob, but the rig puts out 5 watts, even though the display
> acknowledges my ten watt request. If I go back to 3596 the output
> goes back to 10 watts in agreement with the requested level.
>
> Note the essential point, when I make a big excursion in frequency,
> the radio is putting out a level of power substantially different
> from the requested level.
>
> I can correct the output level at the low end by sweeping the
> requested level either low (near 0) or high enough to make the QRO
> relay click, and then adjust it down to and desired QRP level, and
> the rig will put out approximately the requested level of power.
>
> The phenomenon occurs whether I change frequency by switching VFOs
> preset to the two frequencies, or if I retune one VFO using the
> tuning knob.
>
> This is not an issue of varying antenna impedance. I get this effect
> with a commercial dry dummy load as well as a real (very well
> matched) antenna.
>
> I can also create the effect the other way around. If I request 5
> watts at the 3596 then go to the low end and request 10 watts, then
> go back to 3596 with the knob in the 10 watt position, I still get 5
> watts until I jigger the power level request knob.
>
> I have tried to reproduce this effect on 40 meters, requesting 5 and
> 10 watt levels at frequencies differing by about 100 kHz. In that
> case I get what I would regard as normal behavior. The rig always
> puts out the approximately the requested level of power irrespective
> of when I set the power level request knob.
>
> Has anyone else run into this phenomenon?
>
> Is it a quirk in the software?
>
> Is something wrong with the radio?
>
> 73,
>
> Steve Kercel
> AA4AK
>
>
> _______________________________________________
> Elecraft mailing list
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>
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>
>

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[Geoffrey Mackenzie-Kennedy-2]

Stephen W. Kercel AA4AK wrote:

> I have a strange problem with my K2/100 on 80 meters.
>
> The situation is as follows:
>
> I work QRP DX at the low end of 80 M, (say 3508 kHz or thereabouts) with a
> requested power of 4.5 watts, and get an indicated 5 watts out.
>
> I then check into the Pine Tree Net on 3596 kHz and crank up the requested
> power to 10 watts (this is before the relay clicks; I'm still in QRP
> mode), and I get about 10 watts out. So far so good, right?
>
> Then I go back to 3508 kHz, without resetting the power request level
> knob, but the rig puts out 5 watts, even though the display acknowledges
> my ten watt request. If I go back to 3596 the output goes back to 10 watts
> in agreement with the requested level.
>

 <snip>
>
> Has anyone else run into this phenomenon?

-----------------------------------------------------------------

Steve,

After checking I find that my K2/100 #3255 behaves in the same way on 80m
when feeding a good dummy load. - do not have any 80m antenna.  As you say
the problem does not appear to arise on other bands. I  notice other strange
behaviour on 80m related to 'power request', but I would need to run various
tests before making any comment.

73,
Geoff
GM4ESD





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[Stephen W. Kercel]

Don:

Thanks very much for your various suggestions.

I have made no mods at all. R98 is the original value.

I did not think that there was anything band dependent about the
power level. That has led me to wonder if the problem might be a
software glitch.

The phenomenon does depend on exact steps, but is repeatable if I do
those steps.

I verify the level of requested power by tweaking the power knob very
slightly. If I was at 10 watts and tweak it down a bit the display
momentarily shows a numerical 9.5 watts. I can then tweak it back up
and get the 10 watt reading. However, when the anomalous behavior is
occurring the bar graph shows 4 or 5 watts on key down.

Running the rig from the low power jack as a diagnostic is a good
idea. However, I'll need to make up a new power supply lead before I
try it. I've never used anything but the Anderson lead thus far.

Thanks again,

Steve


At 07:28 AM 9/25/2006, Don Wilhelm wrote:

>Steve,
>
>Have you perhaps increased the value of R98 on the bottom of the RF Board to
>give you a more stable power control at high power?  If so, it will make the
>power control at lower power more sluggish.  That is the only thing I can
>think of which would make a difference.
>
>There is nothing band dependent about the power control that I am aware of,
>but the overall gain of the transmitter does vary from band to band, and
>that combined with the granularity of the power control may be causing the
>effect. The K2 remembers the power setting unless the power request is
>changed or the band is changed.  So the real power output that you are
>observing may be dependent on the exact steps that you are using to observe
>this phenonomon.
>
>You did say that you verify the power output level on the K2 display?  Can
>you provide the sequence you are using to do that?  The normal transmit
>display does not show the power output level, so you must be doing something
>other than a keydown.
>
>It would also be of interest to know if the same thing happens with the
>wider range QRP levels - power the K2 through the low power jack only
>(disconnect or turn off the power to the KPA100).
>
>73,
>Don W3FPR
>
>
> > -----Original Message-----
> >
> > I have a strange problem with my K2/100 on 80 meters.
> >
> > The situation is as follows:
> >
> > I work QRP DX at the low end of 80 M, (say 3508 kHz or thereabouts)
> > with a requested power of 4.5 watts, and get an indicated 5 watts out.
> >
> > I then check into the Pine Tree Net on 3596 kHz and crank up the
> > requested power to 10 watts (this is before the relay clicks; I'm
> > still in QRP mode), and I get about 10 watts out. So far so good, right?
> >
> > Then I go back to 3508 kHz, without resetting the power request level
> > knob, but the rig puts out 5 watts, even though the display
> > acknowledges my ten watt request. If I go back to 3596 the output
> > goes back to 10 watts in agreement with the requested level.
> >
> > Note the essential point, when I make a big excursion in frequency,
> > the radio is putting out a level of power substantially different
> > from the requested level.
> >
> > I can correct the output level at the low end by sweeping the
> > requested level either low (near 0) or high enough to make the QRO
> > relay click, and then adjust it down to and desired QRP level, and
> > the rig will put out approximately the requested level of power.
> >
> > The phenomenon occurs whether I change frequency by switching VFOs
> > preset to the two frequencies, or if I retune one VFO using the
> > tuning knob.
> >
> > This is not an issue of varying antenna impedance. I get this effect
> > with a commercial dry dummy load as well as a real (very well
> > matched) antenna.
> >
> > I can also create the effect the other way around. If I request 5
> > watts at the 3596 then go to the low end and request 10 watts, then
> > go back to 3596 with the knob in the 10 watt position, I still get 5
> > watts until I jigger the power level request knob.
> >
> > I have tried to reproduce this effect on 40 meters, requesting 5 and
> > 10 watt levels at frequencies differing by about 100 kHz. In that
> > case I get what I would regard as normal behavior. The rig always
> > puts out the approximately the requested level of power irrespective
> > of when I set the power level request knob.
> >
> > Has anyone else run into this phenomenon?
> >
> > Is it a quirk in the software?
> >
> > Is something wrong with the radio?
> >
> > 73,
> >
> > Steve Kercel
> > AA4AK
> >
> >
> > _______________________________________________
> > Elecraft mailing list
> > Post to: [hidden email]
> > You must be a subscriber to post to the list.
> > Subscriber Info (Addr. Change, sub, unsub etc.):
> >  http://mailman.qth.net/mailman/listinfo/elecraft
> >
> > Help: http://mailman.qth.net/subscribers.htm
> > Elecraft web page: http://www.elecraft.com
> >
> >
> > --
> > No virus found in this incoming message.
> > Checked by AVG Free Edition.
> > Version: 7.1.405 / Virus Database: 268.12.8/455 - Release Date: 9/22/2006
> >
> >

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[Torsten Clay]

>Fellow Elecrafters:
>
>I have a strange problem with my K2/100 on 80 meters.
>
>The situation is as follows:
>
>I work QRP DX at the low end of 80 M, (say 3508 kHz or thereabouts) with a requested >power of 4.5 watts, and get an indicated 5 watts out.
>
>I then check into the Pine Tree Net on 3596 kHz and crank up the requested power to >10 watts (this is before the relay clicks; I'm still in QRP mode), and I get about 10 watts >out. So far so good, right?
>
>Then I go back to 3508 kHz, without resetting the power request level knob, but the rig >puts out 5 watts, even though the display acknowledges my ten watt request. If I go >back to 3596 the output goes back to 10 watts in agreement with the requested level.

I have seen similar power output glitches with my K2/100. See the link below. In one case, I was getting 160W output on 1.8MHz. This is really bad when you are driving an amp! Having the KPA100 doesn't matter though, the same effect occurs in the basic K2.

I believe these issues are because the K2's TX agc doesn't have any "memory" about what drive level is needed on different bands, but always tries to correct in real time. The agc level for a given power output varies quite a bit on different bands. Changing frequencies rapidly appears to confuse the agc in some cases. In my case increasing the resistor in the agc (R98 if I remember) helped.

see:

http://www.ac6rm.net/mailarchive/html/elecraft-list/2006-07/msg00684.html

Tor
N4OGW


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[Arie Kleingeld PA3A]

Guys,

Still building #3612 bit by bit here.

1. Bare K2: no problem.
2. SSB module: disappointment as expected (very low output with my hc-4
element), replaced one resistor (easy mod), now much better.
3. Antenna tuner: Wow, excellent
4. BFO adjustments using Spectrogram: very good results, icing on the
cake (thanks Tom)
5. Built and installed the noiseblanker this weekend, but .... does it
work?

I tried to test the noisblanker (have an electric fence nearby). It does
not seem to blank noise.
Measured several voltages on several transistors, controller and RF amp.
Nothing really strange except for the current to the agc input of the RF
AMP. I measured the voltage accross RP1 -3/4. With full signal (+40 over
9) 0,2V (connection 4 positive over 3) and with no signal minus 0,1 V (3
positive over 4).
What I would expect (checked the datasheet of the mc1350p) is voltages
of about 0,4V to 0,8V (0,1 mA to 0,2 mA through the 3k9 resistor). I
think the f AMP is faulty (?)

Can anybody verify these results?

Thanks in advance.

73
Arie PA3A


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[Darrell Bellerive]

Arie,

Test the noise blanker by rubbing a screwdriver across Q21.

The noise blanker as built does not help with electric fences, you need to
modify it. See http://www.qsl.net/ve3mcf/elecraft_reflect/KNB2_Mods.txt and
http://www.qsl.net/ve3mcf/elecraft_reflect/K2_Noise_Blanker_Electric_fence.txt

Darrell   VA7TO   K2#5093

On September 25, 2006 11:52 am, Arie Kleingeld PA3A wrote:
> I tried to test the noisblanker (have an electric fence nearby). It does
> not seem to blank noise.
--
Darrell Bellerive
Amateur Radio Stations VA7TO and VE7CLA
Grand Forks, British Columbia, Canada
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[Darwin, Keith]

There is a part of me that says "if you're having to search for a way to
test the NB, then you didn't need it in the first place"

:-)

- Keith KD1E -
- K2 5411 -

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[Evert Bakker (PA2KW)]

Hello Arie,

I can confirm that the noise blanker does not work at all with electric
fence pulses. Unfortunately I experienced that the noise blanker is very
critical to the type of noise. Up to now I did not find any "real life
noise" that could be handled by the NB. I heard several comments that it
should work well with ignition type of noise sources. So I was very
surprised that I could not see any difference with or without the NB when
having troubles with the electric fence. So, you are not the only one having
doubts about this NB.

Evert, PA2KW

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Arie Kleingeld PA3A
Sent: Monday, September 25, 2006 20:52
To: [hidden email]
Subject: [Elecraft] noiseblanker

Guys,

Still building #3612 bit by bit here.

1. Bare K2: no problem.
2. SSB module: disappointment as expected (very low output with my hc-4
element), replaced one resistor (easy mod), now much better.
3. Antenna tuner: Wow, excellent
4. BFO adjustments using Spectrogram: very good results, icing on the
cake (thanks Tom)
5. Built and installed the noiseblanker this weekend, but .... does it
work?

I tried to test the noisblanker (have an electric fence nearby). It does
not seem to blank noise.
Measured several voltages on several transistors, controller and RF amp.
Nothing really strange except for the current to the agc input of the RF
AMP. I measured the voltage accross RP1 -3/4. With full signal (+40 over
9) 0,2V (connection 4 positive over 3) and with no signal minus 0,1 V (3
positive over 4).
What I would expect (checked the datasheet of the mc1350p) is voltages
of about 0,4V to 0,8V (0,1 mA to 0,2 mA through the 3k9 resistor). I
think the f AMP is faulty (?)

Can anybody verify these results?

Thanks in advance.

73
Arie PA3A


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[Arie Kleingeld PA3A]

Darrell, Greg, Darwin,

Great wisdom this reflector brings ...  (Yoda, Starwars VII).


Tested the noisblanker rubbing a screwdriver across the first RF amp
Q21.
Yep, makes a difference. Now waiting for a nice thunderstorm or some
static rain :-)

Thanks all.

Okay, what's next? Ah yes, the DSP module...

73,
Arie PA3A

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[Tom Hammond-3]

Arie:

>Tested the noisblanker rubbing a screwdriver across the first RF amp
>Q21. Yep, makes a difference. Now waiting for a nice thunderstorm or some
>static rain :-)

Don't expect ANY help with atmospheric noises such as that which
comes from lightning and thunderstorms.

The NB (as with virtually ALL NBs) is designed to work on
short-duration repetitive pulses, such as sparkplug noise, the XYLs
hand mixer or sewing machine, line noise, etc.

My KNB2 DOES work on local electric fences, and it will often help to
reduce the corona on the antennas as a result of static build-up from
passing storms (because the corona discharge is fairly repetitive).

I find that my KNB2 generally works very well on those things for
which it was designed to work. Sometimes, if the actual STRENGTH of
the noise is low, it will not be enough to trigger the NB, however I
have, in some instances. been able to fix that by turning the PREAMP
on... making all signals (and noises) stronger, and up to a level
where the NB can detect the noise.

73,

Tom   N0SS

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[k6dgw]

FWIW:  I live around electric fences.  For the most part, they are owned
by city-folk who have recently bought a place out here, have never seen
an electric fence, and don't know what to do with one (some don't even
know not to touch it, but they tend to learn :-) ).  Pretty much like
clockwork, one will pop up in the HF bands, particularly in the winter.
  I've found the best solution is to take my KX1 out, find the arc(s),
ground the fence, fix them, and remove the ground.  I talk to the owner
the first time, and they're always a happy to have me do it, often it
gets into their TV and cordless phones as well.  After that, I just do
it.  They think I'm a great neighbor, they have no idea that it takes
only 30 sec or so to fix it, and I keep my mouth shut.  YMMV

The NB on my TS-850 doesn't do much with the pulses either, don't know why.

Fred K6DGW
Auburn CA CM98lw

Evert Bakker (PA2KW) wrote:

> Hello Arie,
>
> I can confirm that the noise blanker does not work at all with electric
> fence pulses. Unfortunately I experienced that the noise blanker is very
> critical to the type of noise. Up to now I did not find any "real life
> noise" that could be handled by the NB. I heard several comments that it
> should work well with ignition type of noise sources. So I was very
> surprised that I could not see any difference with or without the NB when
> having troubles with the electric fence. So, you are not the only one having
> doubts about this NB.
>
> Evert, PA2KW

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[Stephen W. Kercel]

Elecrafters:

The seemingly peculiar behavior that I have been observing on 80 M
turns out to be normal for a K2.

Gary at Elecraft sent me the following message.

73,

Steve
AA4AK



This is just due to the bandpass filter rolloff and the way the ALC in the
K2 works. If you test the rig in transmit by using the Tune button, the rig
will be able to measure and set the RF level better. Some bands have more
overall power gain than others. So it is often necessary to transmit for a
short time with the Tune and Power knobs to ensure the desired RF output is
being produced.

An improvement in the ALC action and power control accuracy for a specific
K2 can be had by doing the modifications shown here:

http://www.elecraft.com/Apps/Power_Control_Mod.html

--
73, Gary AB7MY
=========
[hidden email]
Elecraft Technical Support





At 10:07 AM 9/25/2006, Geoffrey Mackenzie-Kennedy wrote:

>Stephen W. Kercel AA4AK wrote:
>
>>I have a strange problem with my K2/100 on 80 meters.
>>
>>The situation is as follows:
>>
>>I work QRP DX at the low end of 80 M, (say 3508 kHz or thereabouts)
>>with a requested power of 4.5 watts, and get an indicated 5 watts out.
>>
>>I then check into the Pine Tree Net on 3596 kHz and crank up the
>>requested power to 10 watts (this is before the relay clicks; I'm
>>still in QRP mode), and I get about 10 watts out. So far so good, right?
>>
>>Then I go back to 3508 kHz, without resetting the power request
>>level knob, but the rig puts out 5 watts, even though the display
>>acknowledges my ten watt request. If I go back to 3596 the output
>>goes back to 10 watts in agreement with the requested level.
><snip>
>>
>>Has anyone else run into this phenomenon?
>
>-----------------------------------------------------------------
>
>Steve,
>
>After checking I find that my K2/100 #3255 behaves in the same way
>on 80m when feeding a good dummy load. - do not have any 80m
>antenna.  As you say the problem does not appear to arise on other
>bands. I  notice other strange behaviour on 80m related to 'power
>request', but I would need to run various tests before making any comment.
>
>73,
>Geoff
>GM4ESD
>
>
>
>
>
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[Torsten Clay]

>
> This is just due to the bandpass filter rolloff and the way the ALC in the
> K2 works. If you test the rig in transmit by using the Tune button, the rig
> will be able to measure and set the RF level better. Some bands have more
> overall power gain than others.

>So it is often necessary to transmit for a
> short time with the Tune and Power knobs to ensure the desired RF output is
> being produced.

I do not understand the last sentence above.

Does this imply that the alc works differently when Tune is pressed than when the key is closed?

Tor
N4OGW
 

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[Mike Harris-9]

G'day

| The noise blanker as built does not help with electric fences, you need
to
| modify it. See http://www.qsl.net/ve3mcf/elecraft_reflect/KNB2_Mods.txt 
and
|
http://www.qsl.net/ve3mcf/elecraft_reflect/K2_Noise_Blanker_Electric_fence.txt

Not so in my case.  I noticed an S9+ pulsing, popped on the NB and the
pulsing went away.  Traced to a temporary electric fence in the neighbours
garden.  Got to keep the equine terrorists off my willow bushes.  Why do
they always want to eat what is on the other side of the fence?

Regards,

Mike VP8NO

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[Ron D'Eau Claire-2]

You'll find that sometimes you need to turn on the preamp for the noise
blanker to "do its stuff" even though the noise sounds VERY loud! I've not
dug inside to see what's happening to the signal levels but on 80 meters
there are a couple of lamp dimmers that can blow the cans off of my head
<G>. Turning on the NB at either level does nothing, but add the preamp and
the noise disappears.

Ron AC7AC

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Arie Kleingeld PA3A
Sent: Monday, September 25, 2006 12:53 PM
To: [hidden email]
Subject: RE: [Elecraft] noiseblanker



Darrell, Greg, Darwin,

Great wisdom this reflector brings ...  (Yoda, Starwars VII).


Tested the noisblanker rubbing a screwdriver across the first RF amp Q21.
Yep, makes a difference. Now waiting for a nice thunderstorm or some static
rain :-)

Thanks all.

Okay, what's next? Ah yes, the DSP module...

73,
Arie PA3A

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[Stephen Arnold]

Hello Elecrafters,

Somewhat off topic (I have built a K2/100, which works great!-) but I'm
sure that this group will know the answer.

Question: How do you go about detecting common mode current on the outside
braid of your co-axial cable and then measuring or quantifying the amount
thereof?

I've done some web surfing re this issue and it appears that for EMI
testing they use a wide band RF pickup of some sort and a sprectrum
analyzer. Given that I don't have a spectrum analyzer and that I'm not
concerned with laboratory accuracy is there a simple way of finding out
the level of common mode current floating on your coax?

Thanks in advance.

73, Steve
VK2SJA



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[Geoffrey Mackenzie-Kennedy-2]

Steve, VK2SJA wrote:

> I've done some web surfing re this issue and it appears that for EMI
> testing they use a wide band RF pickup of some sort and a sprectrum
> analyzer. Given that I don't have a spectrum analyzer and that I'm not
> concerned with laboratory accuracy is there a simple way of finding out
> the level of common mode current floating on your coax?

----------------------------------------------------

Yes, there is a simple device that is very easy to build which will detect
common mode current on the outside of coax, and can be thought of as a
'current transformer' plus detector driving a meter. Without  calibration,
which would require other test equipment, the device will let you know if
there is common mode current flowing and whether it decreases or increases
after making a change. Other versions are useful for detecting RF current in
things such as above ground telephone cables which could be affecting an
antenna's performance.

Please let me know off- list if you are interested in seeing details.

73,
Geoff
GM4ESD



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