Re: [Elecraft] KPA1500 Power Supply noise

[Vic Rosenthal]

I used to maintain computers used by farmers. I’m surprised they didn’t plant 
crops in them. There was enough soil there. Floppy disks (this was a long time 
ago) were unusable due to the abrasive action of the dirt.

Victor 4X6GP 

> On 28 Mar 2021, at 4:24, Steve Hall <99sun...@gmail.com> wrote:
> 
> Regarding placement of the KPA1500 power supply.
> After repairing and maintaining residential home computers professionally
> for several years, be advised that floor placement will allow 5X the dust
> to be sucked into the unit.  Units with air flow in and out are like vacuum
> cleaners.  I recommend raising the unit, even if only a foot or two, to
> reduce dust intake.  Units on the floor were packed with dust as compared
> to units on desks.
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[Elecraft] I’m embarrassed....my KPA500

[Tom Ewing via Elecraft]

It was in DEMO mode 🤦‍♂️  

Works like a champ now. 

Thanks for the input, and I learned something today. 

Best 73,

Tom
W0XXX

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[Elecraft] Elecraft CW Net Announcement

[kevinr]

Good Evening,

   The rain has been falling less often.  Today there was sun for much 
of the day.  I followed the eastern edge of my property from corner pole 
to corner pole.  This was next to impossible before they thinned the 
forest.  Bright green moss dominated the scene. It is too early for the 
ferns and alder leaves.  Very few insects.  That will change.  However, 
more snow is due tomorrow. Luckily the daffodils aren't blooming yet.  
They often get covered by the last big snow of the season.


   The sun has a few spots but there is more activity coming. During 
the equinox ions slip through cracks in our magnetosphere. For a few 
weeks aurora are stimulated with fewer ions.  I am unsure how this 
relates to propagation.  But the longer daylight period enhances the 
ionosphere.  I don't expect too much noise but I don't expect strong 
signals either.  We shall see.



Please join us on (or near):

14050 kHz at 2200z Sunday (3 PM PDT Sunday)
  7047 kHz at z Monday (5 PM PDT Sunday)

   73,
  Kevin. KD5ONS


-






The flower that smiles to-day
To-morrow dies;
All that we wish to stay
Tempts and then flies.
What is this world’s delight?
Lightning that mocks the night,
Brief even as bright.


I met a traveller from an antique land
Who said: "Two vast and trunkless legs of stone
Stand in the desert . . . Near them, on the sand,
Half sunk, a shattered visage lies, whose frown,
And wrinkled lip, and sneer of cold command,
Tell that its sculptor well those passions read
Which yet survive, stamped on these lifeless things,
The hand that mocked them, and the heart that fed:
And on the pedestal these words appear:
'My name is Ozymandias, king of kings:
Look on my works, ye Mighty, and despair!'
Nothing beside remains. Round the decay
Of that colossal wreck, boundless and bare
The lone and level sands stretch far away."

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Re: [Elecraft] KPA1500 Power Supply noise

[Steve Hall]

Regarding placement of the KPA1500 power supply.
After repairing and maintaining residential home computers professionally
for several years, be advised that floor placement will allow 5X the dust
to be sucked into the unit.  Units with air flow in and out are like vacuum
cleaners.  I recommend raising the unit, even if only a foot or two, to
reduce dust intake.  Units on the floor were packed with dust as compared
to units on desks.
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Re: [Elecraft] Kpa500 not playing with my IC-7600

[Ken Winterling]

Tom,

While I do not have an IC-7600 I do use an IC-7610 with a KPA500; the cable
should be the same.
I use a DIY band data cable to connect the IC-7610 to the KPA500 and it has
worked for almost three years.

I'm curious as to the exact part numbers of the cables you purchased from
the two different vendors.
What are the vendor names?
Do you have a schematic diagram of either/both cables?

If you are interested, I can send you a schematic of the cable I built.

73,

Ken
WA2LBI





On Sat, Mar 27, 2021 at 2:43 PM Tom Ewing via Elecraft

wrote:

>
> Good day, and thanks for reading.
>
> My newly acquired KPA500 doesn’t want to play with my IC-7600.
>
> In operate mode when I key the radio, the LEDs on the KPA500 display solid
> into the yellow, and there is no output. The amp is not faulting.
>
> I’m using an Icom 7 pin DIN cable (two actually from two different
> vendors) and tried two different radios, both IC-7600s with the same
> result.
>
> In the KPA menus, I have set the “radio” option to “analog”.
>
> Am I missing something else?
>
> Thanks in advance.
>
> Tom
> W0XXX
>
>
>
>
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Re: [Elecraft] Questions on KXBC3 charging mechanism

[Walter Underwood]

I think this is answered in the manual. For 2500 mAh cells, this is on page 4.
The KXBC3 charges at 200 mA throughout the charging time set, suggesting that 
2000 mAH cells would be charged in 10 hours (referred in battery literature as 
a C/10 rate). However, the charging process is not 100% efficient, so 
additional charging time must be added, typically 20%. So a fully depleted 2000 
mAH battery would require about 12 hours to reach full capacity.

The charging time must be adjusted for batteries of different capacity as 
follows: Charging Time (hours) = 1.2 X (cell mAH rating) / 200

For example, to charge fully depleted 2500 mAH cells: 1.2 X 2500 / 200 = 15 
hours (Set charger for 16 hours) 

https://ftp.elecraft.com/KX3/Manuals%20Downloads/E740167%20Elecraft%20KXBC3%20Installation%20and%20Operation%20Rev%20B1.pdf

wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)

> On Mar 27, 2021, at 3:46 PM, Geert Jan de Groot  wrote:
> 
> Hi,
> 
> Searching the web and searching the mail archive didn't find the result I was 
> looking for, but I found a number of broken links pointing to now-defunct 
> Yahoo groups on this matter..
> 
> I'm confused on the charging method used on the KXBC3 charger.
> The standard low-current charge method for NiMH is "14 hours, 0.1C", so in 
> the case of my 1900mAh eneloops, 14 hours of 190 mA. The KX3 manual doesn't 
> say much, but the KXBC3 manual specifies a 200mA charge current.
> That would suggest that 14-16 hours should give a full charge without too 
> much overcurrent.
> 
> However, while charging I noticed that the KX3 draws close to 500mA, so I am 
> not sure. Given that normal receiver operation draws 200mA, I fail to see how 
> this would work with 200mA charge current - numbers don't add up.
> 
> I looked at the schematics. There is a low-drop voltage regulator (U2, 
> LT1965) that seems to be used as current source. The regulator can be 
> controlled via pin6 (shutdown pin). The voltage regulator supplies 2 
> resistors R8 and R9 (12E each). The 3.3V output voltage over the resulting 6E 
> resistance suggests a current source of roughly 500mA, which is closer to my 
> measurements. There is an additional 20E resistor R10 which is switched using 
> Q1 which would drive the current up to 710mA.
> 
> However, even being "low voltage drop" the regulator would need 3.3V input 
> voltage and likely a little more, say 4V. Batteries on their way charging 
> have a voltage of 10.5V, which means that this circuit alone needs 14.5V 
> input voltage to function, but the charger is specified . So the current 
> source can't give full current because the input voltage is too low to 
> function.
> 
> Also, the charge time isn't 14 hours, but selectable 4, 8, 12, 16 hours. I 
> don't see how that would work - people doing 2850mAh cells, as reporting on 
> the reflector, won't be able to get a full charge even after 16 hours, not 
> with the 200mA specified in the manual. And what are the 4 and 8 hour charge 
> settings for?
> 
> I guess the figures really don't add up and I don't understand how this is 
> supposed to work. Can someone enlighten me?
> 
> 73,
> 
> Geert Jan
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Re: [Elecraft] How and How Often to Clean KPA-1500 Cooling Systems?

[W0MU Mike Fatchett]

I would encourage people to get the gear off the floor.  My computers 
that were on the floor got far more dirty than when I had them setting 
up higher. YMMV


W0MU

On 3/27/2021 4:22 PM, Ken K6MR wrote:

As you know, I run my amp in a single amp, SO2R configuration.  During a heavy 
2BSIQ session on RTTY, temps reach 90 deg C.  Fans go to 5 occasionally.  Not a 
problem.  Don’t worry.

My power supply does get quite the dust bunny on top.  I just hit it with the 
vacuum every week when doing the shack.  I haven’t noticed the same problem 
with the RF deck.  Perhaps with the fans on super high speed it blows itself 
out.  I’ve had the power supply case off twice, and didn’t see a build up 
internally.  So I’m pretty sure it’s not an issue if you vacuum it regularly.

I have the amp and power supply in a bookshelf type cabinet in the closet.  One 
thing I did when I first set it up was to make a seal around the back of the RF 
desk.  It is a piece of cardboard, stapled to the back edge of the bookshelf, 
and cut to just fit around the rear of the amp.  This keeps the amp from 
sucking in hot exhaust from the top vents back into the amp.  Of course this 
won’t be a problem if you have the amp on a desk with nothing above it.  I have 
the minimum recommended clearance of 2” above the amp, and 4” above the power 
supply.

Ken K6MR

From: N4ZR
Sent: Saturday, March 27, 2021 13:09
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] How and How Often to Clean KPA-1500 Cooling Systems?

I'm uncomfortable with temp above 70C.  I infer from the manual that the
displayed temp is that of the final transistor heat sink, and they say
it will hard fault at 112C.  Not in my shack!  Still looking for an
answer to the cleaning question, though, particularly for the power supply.

73, Pete N4ZR
Check out the new Reverse Beacon Network
web server at .
For spots, please use your favorite
"retail" DX cluster.

On 3/27/2021 2:44 PM, Jim Brown wrote:

On 3/27/2021 9:23 AM, N4ZR wrote:

The other day I noticed some buildup of dust on the top vents of my
power supply.

Neighbor K6XX is the mfg engineer for both of Elecraft's amps. Bob
lost everything (except one of his towers) in a big wildfire this
summer, along with three other hams I know. For a contest a few months
ago, he borrowed my KPA1500, and when he returned it, told me it was
super dusty. My shack is pretty dusty, and I was running the fans all
the time, often at a high setting, because I use WSJT modes on 6M and
160 a lot. His advice was to set the fan speed default to zero and let
the amp determine the fan speed. Using 120 sec TX cycles at 1kW on
160, I've seen 95C temps, and the amp is still happy. I wouldn't do
that on 6M, where the amp is least efficient.

73, Jim K9YC
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[Elecraft] Questions on KXBC3 charging mechanism

[Geert Jan de Groot]

Hi,

Searching the web and searching the mail archive didn't find the result 
I was looking for, but I found a number of broken links pointing to 
now-defunct Yahoo groups on this matter..


I'm confused on the charging method used on the KXBC3 charger.
The standard low-current charge method for NiMH is "14 hours, 0.1C", so 
in the case of my 1900mAh eneloops, 14 hours of 190 mA. The KX3 manual 
doesn't say much, but the KXBC3 manual specifies a 200mA charge current.
That would suggest that 14-16 hours should give a full charge without 
too much overcurrent.


However, while charging I noticed that the KX3 draws close to 500mA, so 
I am not sure. Given that normal receiver operation draws 200mA, I fail 
to see how this would work with 200mA charge current - numbers don't add up.


I looked at the schematics. There is a low-drop voltage regulator (U2, 
LT1965) that seems to be used as current source. The regulator can be 
controlled via pin6 (shutdown pin). The voltage regulator supplies 2 
resistors R8 and R9 (12E each). The 3.3V output voltage over the 
resulting 6E resistance suggests a current source of roughly 500mA, 
which is closer to my measurements. There is an additional 20E resistor 
R10 which is switched using Q1 which would drive the current up to 710mA.


However, even being "low voltage drop" the regulator would need 3.3V 
input voltage and likely a little more, say 4V. Batteries on their way 
charging have a voltage of 10.5V, which means that this circuit alone 
needs 14.5V input voltage to function, but the charger is specified . So 
the current source can't give full current because the input voltage is 
too low to function.


Also, the charge time isn't 14 hours, but selectable 4, 8, 12, 16 hours. 
I don't see how that would work - people doing 2850mAh cells, as 
reporting on the reflector, won't be able to get a full charge even 
after 16 hours, not with the 200mA specified in the manual. And what are 
the 4 and 8 hour charge settings for?


I guess the figures really don't add up and I don't understand how this 
is supposed to work. Can someone enlighten me?


73,

Geert Jan
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Re: [Elecraft] How and How Often to Clean KPA-1500 Cooling Systems?

[Ken K6MR]

As you know, I run my amp in a single amp, SO2R configuration.  During a heavy 
2BSIQ session on RTTY, temps reach 90 deg C.  Fans go to 5 occasionally.  Not a 
problem.  Don’t worry.

My power supply does get quite the dust bunny on top.  I just hit it with the 
vacuum every week when doing the shack.  I haven’t noticed the same problem 
with the RF deck.  Perhaps with the fans on super high speed it blows itself 
out.  I’ve had the power supply case off twice, and didn’t see a build up 
internally.  So I’m pretty sure it’s not an issue if you vacuum it regularly.

I have the amp and power supply in a bookshelf type cabinet in the closet.  One 
thing I did when I first set it up was to make a seal around the back of the RF 
desk.  It is a piece of cardboard, stapled to the back edge of the bookshelf, 
and cut to just fit around the rear of the amp.  This keeps the amp from 
sucking in hot exhaust from the top vents back into the amp.  Of course this 
won’t be a problem if you have the amp on a desk with nothing above it.  I have 
the minimum recommended clearance of 2” above the amp, and 4” above the power 
supply.

Ken K6MR

From: N4ZR
Sent: Saturday, March 27, 2021 13:09
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] How and How Often to Clean KPA-1500 Cooling Systems?

I'm uncomfortable with temp above 70C.  I infer from the manual that the
displayed temp is that of the final transistor heat sink, and they say
it will hard fault at 112C.  Not in my shack!  Still looking for an
answer to the cleaning question, though, particularly for the power supply.

73, Pete N4ZR
Check out the new Reverse Beacon Network
web server at .
For spots, please use your favorite
"retail" DX cluster.

On 3/27/2021 2:44 PM, Jim Brown wrote:
> On 3/27/2021 9:23 AM, N4ZR wrote:
>> The other day I noticed some buildup of dust on the top vents of my
>> power supply.
>
> Neighbor K6XX is the mfg engineer for both of Elecraft's amps. Bob
> lost everything (except one of his towers) in a big wildfire this
> summer, along with three other hams I know. For a contest a few months
> ago, he borrowed my KPA1500, and when he returned it, told me it was
> super dusty. My shack is pretty dusty, and I was running the fans all
> the time, often at a high setting, because I use WSJT modes on 6M and
> 160 a lot. His advice was to set the fan speed default to zero and let
> the amp determine the fan speed. Using 120 sec TX cycles at 1kW on
> 160, I've seen 95C temps, and the amp is still happy. I wouldn't do
> that on 6M, where the amp is least efficient.
>
> 73, Jim K9YC
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Re: [Elecraft] How and How Often to Clean KPA-1500 Cooling Systems?

[N4ZR]

I'm uncomfortable with temp above 70C.  I infer from the manual that the 
displayed temp is that of the final transistor heat sink, and they say 
it will hard fault at 112C.  Not in my shack!  Still looking for an 
answer to the cleaning question, though, particularly for the power supply.


73, Pete N4ZR
Check out the new Reverse Beacon Network
web server at .
For spots, please use your favorite
"retail" DX cluster.

On 3/27/2021 2:44 PM, Jim Brown wrote:

On 3/27/2021 9:23 AM, N4ZR wrote:
The other day I noticed some buildup of dust on the top vents of my 
power supply.


Neighbor K6XX is the mfg engineer for both of Elecraft's amps. Bob 
lost everything (except one of his towers) in a big wildfire this 
summer, along with three other hams I know. For a contest a few months 
ago, he borrowed my KPA1500, and when he returned it, told me it was 
super dusty. My shack is pretty dusty, and I was running the fans all 
the time, often at a high setting, because I use WSJT modes on 6M and 
160 a lot. His advice was to set the fan speed default to zero and let 
the amp determine the fan speed. Using 120 sec TX cycles at 1kW on 
160, I've seen 95C temps, and the amp is still happy. I wouldn't do 
that on 6M, where the amp is least efficient.


73, Jim K9YC
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Re: [Elecraft] How and How Often to Clean KPA-1500 Cooling Systems?

[Jim Brown]

On 3/27/2021 9:23 AM, N4ZR wrote:
The other day I noticed some buildup of dust on the top vents of my 
power supply.


Neighbor K6XX is the mfg engineer for both of Elecraft's amps. Bob lost 
everything (except one of his towers) in a big wildfire this summer, 
along with three other hams I know. For a contest a few months ago, he 
borrowed my KPA1500, and when he returned it, told me it was super 
dusty. My shack is pretty dusty, and I was running the fans all the 
time, often at a high setting, because I use WSJT modes on 6M and 160 a 
lot. His advice was to set the fan speed default to zero and let the amp 
determine the fan speed. Using 120 sec TX cycles at 1kW on 160, I've 
seen 95C temps, and the amp is still happy. I wouldn't do that on 6M, 
where the amp is least efficient.


73, Jim K9YC
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[Elecraft] Kpa500 not playing with my IC-7600

[Tom Ewing via Elecraft]

Good day, and thanks for reading. 

My newly acquired KPA500 doesn’t want to play with my IC-7600. 

In operate mode when I key the radio, the LEDs on the KPA500 display solid into 
the yellow, and there is no output. The amp is not faulting. 

I’m using an Icom 7 pin DIN cable (two actually from two different vendors) and 
tried two different radios, both IC-7600s with the same result. 

In the KPA menus, I have set the “radio” option to “analog”. 

Am I missing something else?

Thanks in advance. 

Tom
W0XXX


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Re: [Elecraft] K3 - no output power

[Christian Janssen DL1MGB]

Hi all,

just wanted to let you know that my K3 is back again with full output power.

We found the Diode D1 on the LPA board. On the anode side, it had shown full 
power, on the other side, nothing. When unsoldering it, it was already very 
loose. The diode itself was intact, but had no contact at all. Most probably it 
got loose after heating up and unsoldering itself. New diode soldered in, TUNE, 
smoke. After comparing some voltages around the diode, we found Q6 to be 
faulty. That's why more than the maximum rated current of 1A flowed through the 
diode. Changed also the transistor and now everything was working again, full 
power, no smoke, no smell.

Most probably, it has to do with the same problem as DK3WE already experienced 
8 years ago: http://www.the-mule.de/?p=1275#more-1275 

Many thanks again for DD0VS for helping me in finding the faulty parts!

73s Chris DL1MGB




Am 24.03.2021 um 21:03 schrieb Christian Janssen DL1MGB:
> Hello,
> 
> it happened during the Russian DX Contest last Saturday, from one second to 
> another. No output. When I tune the display looks like this: 
> http://dl1mgb.com/temp/k3_no_power.jpg
> 
> Following conditions:
> 
> - sending into a 50 ohm dummy load
> - no matter how many watts are set with PWR knob
> - Test mode off
> - TX INH off
> - all driver transistors working (three screw test)
> - no output power also on external watt meter
> - happens on all bands
> - happens with KPA set to "not inst"
> - knocking on housing doesn't change anything
> - when starting the antenna tuner, it says 5.0 watts, but no output on the 
> external watt meter
> 
> I am running out of ideas :-)
> 
> 73s Chris DL1MGB
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> Message delivered to ch...@dl1mgb.com 
> 
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Re: [Elecraft] K3 PA to Motherboard Pin Connection Workaround Mod

[exbpi]

Thanks Alan and Ken, K6MR...have what I need from both. 

Great help...thank you

Mike
K7PI

-Original Message-
From: Alan - G4GNX  
Sent: Saturday, March 27, 2021 10:24 AM
To: ex...@comcast.net
Subject: Re: [Elecraft] K3 PA to Motherboard Pin Connection Workaround Mod

Is the attached what you're looking for?

73,

Alan. G4GNX


-- Original Message --
From: ex...@comcast.net
To: Elecraft@mailman.qth.net
Sent: 27/03/2021 16:16:27
Subject: [Elecraft] K3 PA to Motherboard Pin Connection Workaround Mod

>Will someone on the list who has the workaround mod supplied by 
>Elecraft Support to bypass or repair the pin connections of the PA to 
>motherboard on the K3 email them to me?
>
>
>
>Thanks
>
>
>
>Mike
>
>K7PI
>
>ex...@comcast.net 
>

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[Elecraft] How and How Often to Clean KPA-1500 Cooling Systems?

[N4ZR]

The other day I noticed some buildup of dust on the top vents of my 
power supply.  I used a vacuum on them and was surprised by how much 
appeared to come out from inside.  This raised a question - how often is 
it recommended to clean the cooling systems of the amp and its power 
supply, and what's the best way to do it?


--
73, Pete N4ZR
Check out the new Reverse Beacon Network
web server at .
For spots, please use your favorite
"retail" DX cluster.

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Re: [Elecraft] KPA1500 Power Supply noise

[N4ZR]

Not heard here, although my KPA-1500 gets fairly heavy use.  Power 
supply is on the floor, which no doubt helps with noise.


73, Pete N4ZR
Check out the new Reverse Beacon Network
web server at .
For spots, please use your favorite
"retail" DX cluster.

On 3/27/2021 11:06 AM, David Needham wrote:

My KPA1500 Power Supply is making a noise that has gotten progressively
louder over time when I transmit. It sounds like a hissing (but it is not
arcing) when I transmit. The noise is modulated by SSB speech or CW or
digital modes keying, louder at higher power levels now during the CQWW WPX
Phone contest.

I am pretty sure it is not RF getting into the Power Supply. I have
followed K9YC practices of bonding the K3, KPA1500 Power Supply and RF
decks to the ground bus. All cables going into and between are wound on
snap on or toroid ferrites.

Has anyone else run across this? I plan to open up the power supply and
check for loose parts and do some more testing after the contest.


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[Elecraft] K3 PA to Motherboard Pin Connection Workaround Mod

[exbpi]

Will someone on the list who has the workaround mod supplied by Elecraft
Support to bypass or repair the pin connections of the PA to motherboard on
the K3 email them to me?

 

Thanks

 

Mike

K7PI

ex...@comcast.net  

 

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[Elecraft] KPA1500 Power Supply noise

[David Needham]

My KPA1500 Power Supply is making a noise that has gotten progressively
louder over time when I transmit. It sounds like a hissing (but it is not
arcing) when I transmit. The noise is modulated by SSB speech or CW or
digital modes keying, louder at higher power levels now during the CQWW WPX
Phone contest.

I am pretty sure it is not RF getting into the Power Supply. I have
followed K9YC practices of bonding the K3, KPA1500 Power Supply and RF
decks to the ground bus. All cables going into and between are wound on
snap on or toroid ferrites.

Has anyone else run across this? I plan to open up the power supply and
check for loose parts and do some more testing after the contest.

-- 
Thank you!
David Needham, AA4VT (formerly K4AJA and K8AJA)
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[Elecraft] 75 meter Net and Location 01:00 Sunday Night/Monday

[Paul Van Dyke]

I am moving us a small distance away...
Please take note of 3.775  3.775 at 01:00 UTC
AND there is the chance someone will be there ...
75m is funny that way
Sunday night in the US and Monday morning in UTC Land

Keep smiling and be safe
"See" you on the Nets

73   Paul Van Dyke   KB9AVO
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[Elecraft] KPA500 Bias-set Procedure

[Gene]

I am looking for the procedure to set the bias after replacing the finals
in the KPA500.  Any advice would be most appreciated.
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