"That's the point. The ALC cable protects the KPA-500 when the operator
"spaces" and leaves the exciter power control at full power (100+ Watt) level."
My experience, and I have 10 Hz logger data, shows that the amp alarms, sets
fault FL06, and drops into standby mode with no change in the ALC
I should have said that this explanation is only valid with WSJT-X split mode
is not in use. When split mode is used the situation is either simpler or
more complex depending on your perspective.
In WSJT-X split mode the audio frequency is constrained to the range 1500-2000
Hz. If the TX
"What is really confusing is that WSJT-X leaves the tune frequency at whatever
it was when you last transmitted, so if you tune around, click on some signals,
have a listen and then try using TUNE the audio frequency could be anywhere
unless you take specific action."
Nothing to get confused
"46C = 118F"
46 deg C = 114.8 deg F. Maybe it was a typo?
73,
Andy k3wyc
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The KPA500 provides a serial interface command ^FS; which returns the fan
speed. This command is not included in the KPA500 Programmer's Reference but
is mentioned in a firmware release note.
The KPA1500 Programming Reference does not mention the ^FS; command. Is fan
speed interrogation
to date as new commands have been added.
73,
Andy k3wyc
From: ANDY DURBIN <a.dur...@msn.com>
Sent: Saturday, May 19, 2018 7:47 AM
To: elecraft@mailman.qth.net
Subject: KPA1500 fan speed interrogation
The KPA500 provides a serial interface command ^FS;
>From the KPA500 kit build manual:
"If airflow arrows are visible on the fan housing, they will show that air will
be blown out of the back of the KPA500."
It was a bit surprising to me that the KPA500 fan airflow is the opposite of
natural convective flow but I accepted that was the intended
"That's perfectly normal at that low power output. The 50% spec is at full
output."
Thanks for pointing that out. I did a spot check on the same band with KPA500
indicated output of 490 W (LP-100A 500W) and found the efficiency was 60.6%
(61.9% if LP-100A power is used).
73,
Andy k3wyc
___
From: Bob McGraw K4TAX <rmcg...@blomand.net>
Sent: Monday, May 21, 2018 6:57 PM
To: ANDY DURBIN
Subject: Re: [Elecraft] KPA1500 fan speeds and fan noise
Andy:
There are basically two types of radial blade fans and specific
application for each one. Those that "blow" and thos
"The KPA500 actually runs cooler at just-below-fault power output than it does
at either 500 or even 400 watts output."
I ran a quick test to see if I saw the similar results with my KPA500. The
quality of the data is limited by the low resolution of power returned by the
^WS command but it
"Simple logic. One should (is supposed to) listen on the frequency before
transmitting. Can't do this if one is configured to receive on a different
frequency. "
Sorry, but that's a very "old school" way of thinking. With digital modes that
use VFO split operation the usual way to check if
Sorry, there was a typo in the table. It should read:
WS pwr LP100 pwr
0024.9
1025.8
2526.4 <
2528.7
3029.8
3039.6
4040.3
73,
Andy k3wyc
From: ANDY DURBIN <
The KPA500 provides the ^WS; serial interface interrogation which returns
output power and SWR. The power and SWR are reported for STBY and OPER modes.
In OPER mode the power seems to have a resolution of 1 Watt. In STBY, if I
increment my drive power in 1 Watt steps the power reported by
30
33.9 30
34.6 30
35.8 30
36.5 30
37.7 30
38.4 30
39.6 30
40.3 40
The question remains the same. Is the low resolution of WS indicated power
intended?
73,
Andy k3wyc
From: ANDY DURBIN
Can the KAT500 L and C values be manually incremented and decremented? There
appear to be no controls on the front panel to allow this and I was unable to
download the KAT500 utility to see if manual control is supported there.
Thanks and 73,
Andy, k3wyc
Andy k3wyc
From: Michael Blake
Sent: Saturday, June 16, 2018 7:12 AM
To: ANDY DURBIN
Cc: Elecraft Reflector
Subject: Re: [Elecraft] KAT500 maual tuning?
Yes, the KAT500 Utility provides this function.
Michael Blake
k9...@mac.com<mailto:k9...@icloud.com>
On Jun 16, 2018, at 10:07
Thanks!
My search for KAT500 utility took me to
http://www.elecraft.com/KAT500/kat500_software.htm.old and I did not notice
the "old"!
73,
Andy k3wyc
From: d...@elecraft.com
Sent: Saturday, June 16, 2018 7:21 AM
To: 'ANDY DURBIN'; 'Michael Blak
"Will 15A house line supply enough juice for the K3S, KPA500, KAT500, and in
the future a P3 Panadaper?"
When I added my KPA500 to my TS-590S station I found the drop in mains voltage
unacceptable. I made some changes in power distribution and now have a web
power switch connected directly to
If you are making a home-brew loop why not make the capacitor too?My loop
works fine at 100 W input but not yet tested at 500 W. I borrowed the
capacitor design concept but the implementation details are mine. Capacitor
components are hardware store copper pipe, copper pipe couplers, and
"I'm pretty sure I am seeing people running data WELL beyond the band plan into
the SSB section of several bands... 20m for almost certain."
Quite possibly the RF second harmonic of an in-band 40 m signal. It's unlikely
that anyone would hope to work a data mode QSO far away from the accepted
Up until this weekend I had experienced 3 PA DISS faults with my new KPA500.
I provided data to Elecraft and, after a fairly long and informative email
exchange, I was told the fault is very rare and most likely caused by some
problem at my station.
I developed a 10 frames per second data
"Drag a wire behind you like they tow banners."
If it were as simple as you suggest then I think a few of us would be doing it.
Picking up banners with an aircraft in flight is a skill that most pilots don't
have. It would be far better to use a retractable antenna. However, a legal
. However, I found nothing in the
documentation that suggested the KPA500 would fault frequently with a reported
SWR of 1.4:1 and with power and SWR never peaking in to the amber regions.
73,
Andy k3wyc
From: ANDY DURBIN <a.dur...@msn.com>
Sent: Saturday,
,
Andy k3wyc
From: Michael Blake <k9...@mac.com>
Sent: Monday, May 28, 2018 6:10 AM
To: ANDY DURBIN
Cc: elecraft@mailman.qth.net
Subject: Re: [Elecraft] PA DISS fault and relationship to SWR
Andy, I have seen this too. My remote tuner will sometimes quit wi
"It might be but the amp is designed to work with radios other than K3s."
The KPA1500 and KPA500 are both capable of receiving frequency from
transceivers other than the K3S, so is the KAT500. I don't see how not using a
K3S puts any limitation on my proposal.
73,
Andy k3wyc
"If 1.5:1 does this, then that's good enough in my book. Furthermore, a
better match might entail higher tuner losses. So why worry about it?
My test data for my KPA500 show there is a very significant difference in PA
dissipation and also in harmonic output for loads giving indicated 1.4:1
"How about "stroke 7" or "slant 7"?"
I verbalize k3wyc/7 as k3wyc slant seven. What I'm asking is - why don't
stations who are actually operating portable use "slant papa"? I'm suggesting
that the reason may be that "portable" is so extensively misused.
73,
Andy k3wyc
"/QRP often, but not always, indicates a field operation, and they're sort of
fun to work, at least for me."
And sometimes it means someone running 5 W to a 6 ele Yagi at 75 ft! That
station has far higher ERP that I do running 100 W with my modest antennas.
If I was portable in UK, where
Can someone please point me to a definition or specification for the KPA500 -
K3 AUX Bus. I have the KPA500 Programmer's Reference but this appears to only
cover the KPA500 - PC interface.
Thanks and 73,
Andy k3wyc
__
Elecraft
From: Don Wilhelm <donw...@embarqmail.com>
Sent: Sunday, April 29, 2018 2:45 PM
To: ANDY DURBIN; elecraft@mailman.qth.net
Subject: Re: [Elecraft] KPA500/K3 AUX bus specification
The AUXBUS protocol is Elecraft proprietary and is not published.
It is the singl
any damage is to exceed Io max of the 2N7002K.
What risks have I overlooked? I don't want to void the warranty while there
are still unresolved issues with my KPA500.
73,
Andy k3wyc
From: Don Wilhelm <donw...@embarqmail.com>
Sent: Sunday, April 29, 20
"How is it any different than the RTTY setups used for DXpeditions that would
do essentially the same thing, listen over a wide range and stack the calls
heard?"
The, in my opinion huge, difference is that FT8 DXpedition mode does not even
require the operator to be in the shack to complete
I have been using WSJT-X since before version 1.0 was made available. I was
also an early adopter of JT9 and FT8. I have enjoyed using JT65, JT9, and FT8
for HF and 6 m QSO. Using DXpedition mode to work KH1 was a different
experience. I felt that the operator had been taken much too far
"That is FT8. There is no involvement once the contact starts."
That is only true is you choose to make it true. In basic FT8 mode "auto
sequence" and "Call 1st" are operator options which I sometimes choose to
disable. I also sometimes change my TX frequency in the middle of a QSO if I
My KPA500 receives serial data (listen only) from my TS-590 and follows TS-590
band changes without needing RF input. If I connect the KPA500 and KAT500
with an AUX cable will the KAT500 be selected to the same band as the KPA500
before receiving RF input? If so, what minimum pin connection
"The short answer is that neither the KPA500 or KAT500 can source signals -
they can only read them from a transceiver and then follow its direction. This
means that they can both read the status information from a Kenwood's COM port
and act on it."
Now I'm getting confused. Based on earlier
It's clear that both the KPA500 and KAT500 must be RS-232 transmitters as well
as RS-232 receivers. If that were not true then the PC utilities could not
function. My station data logger has been polling, and receiving responses
from, my KPA500 since I first built it.
Now I know that the
"My question would be how any KL7's did you work? 99% of openings do not happen
"Up here"."
And that is my problem! Only Alaska left to work for 6 m WAS and it seems that
even in the best openings there are very few Alaska stations even listening.
Yesterday I did see that KL7KY and KL7HBK
"Clearly there has to be some hysteresis to stop hunting. 25% of a segment
width might width be a good number to choose, but this would require the
current frequency counter to have improved resolution."
Why wouldn't it be preferable to use the transceiver's exact TX frequency, if
available,
KX3 has the option to output aux bus on ACC2 "TRN CTRL (output; XV-series
transverter control using Elecraft auxBus prototcol)". Why wouldn't you
connect this directly to the aux bus input pin of the KPA500. Isn't that what
it is for?
Not discouraging Arduino projects though as I am
When I first started using my KPA500 I found the hum/buzz during high power CW
operation to be intolerable. Elecraft support sent me a paper on hum
reduction, a longer transformer bolt, and additional rubber washers. I did not
use any of this new hardware but now have acceptable hum/buzz
Can anyone point me to a specification for any aviation headset that claims the
microphone has active noise cancellation? Can anyone point me to a
specification for any non-aviation headset that claims the microphone has
active noise cancellation?
Many/most aviation headsets use noise
"but here's my question -- what is the CATA1ASC for?"
http://n1mm.hamdocs.com/tiki-index.php?page=Macros
As a TS-590 owner it's interesting that KY command as implemented by Elecraft
does not conform to the Kenwood definition. The Elecraft implementation is
much better since it allows KY
"Instead I chose one of SDR-based alternatives which does more, better, at
lower cost, and - crucially - continues to evolve. Meanwhile, the P3 falls
farther behind. "
While my TS-590 panadapter solution is not directly related to K3 integration
it may be of interest to those considering how
"but with horrible negative going spikes at each return to zero"
I need to correct that. The spikes are somewhat random. For some
interrogation responses the data word is completely free of negative going
spikes. For other responses there are multiple negative going spikes. When
the spikes
"can you confirm that the KXUSB uses TTL signal levels rather than standard
RS232 levels? "
I just put a scope on a breakout of the signals between a KXUSB and my KAT500.
I needed to do this for another purpose anyway. The simple answer seems to
be the (my) interface is neither TTL nor
"It also seems like this fan logic could be built into the KPA1500 firmware if
the result is a quieter and cooler amp. on receive."
Actually it seems as though Elecraft chose to go the other way - delay the fan
speed increase until a higher temperature. See KPA1500 firmware release notes:
"There was a similar post about the KPA500 in the last year or so. Elecraft
responded that the amp was designed for 500 Watts running less was less
efficient and running amp at low power was doing it no favors. "
Here is an example of measured PA dissipation for a KPA500:
I placed my Android phone on top of my KPA500 and made a recording while making
a few cycles of FT8 TX/RX. The audio files can be found here:
https://www.dropbox.com/sh/amfy3dz8pgl083n/AAAKi2GYripXyIDjiLpJ2hDwa?dl=0
One file is the raw recording. The second has been processed in Audacity
"Gotta unsubscribe. Can’t take 20 emails a day about nothing. "
You could, perhaps, try a different way of participating. I receive zero emails
from this "list". I simply visit the archive and read the discussions I'm
interested in.
Try this -
"Of course 250v fuses are also fine with 120v amp wiring but the amperage will
double."
There is so much more to learn when the discussion gets back on topic!
Andy k3wyc
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Home:
17, 2018 6:05 AM
To: ANDY DURBIN
Cc: elecraft@mailman.qth.net
Subject: Re: [Elecraft] KPA500 thermal clicks
“Clicks” caused by the “Z” bracket are well documented and normal. Personally,
I don’t find this “intolerable” or even slightly annoying. My wall clock
“ticks” every second.
Sent from
If you want to talk about weak signal vs low power please start another thread.
Please don't take the discussion away from the topic I started.
In that new thread I'll be happy to tell you about my antenna, the signal
reports I received, and the QSO I struggled to complete this morning.
"I'd appreciate a pointer to any discussions of Z bracket clicks. My search
didn't find anything."
I looked again and this time found some discussion here -
https://forums.qrz.com/index.php?threads/elecraft-kpa500-pinging-during-operating.591521/
and here -
The problem with relying on RF detection is that the station is configured
after TX starts rather than before TX starts. Perhaps for some owners this is
not an issue. For me it is a significant issue. If the band change requires a
change of antenna then my LP-100A may alarm on SWR before
I'd like to understand all the operational advantages of integrating a K3 with
a KPA500 and KAT500 that are not available to those who chose to use a TS-590
instead of a K3.
I know about:
1. KPA500 and KAT500 know TX frequency and configure band, antenna, and
tuning solution before
Thanks Dick.
73,
Andy k3wyc
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Please
An easy way to find and copy the configuration files is as follows:
In the utility select Save Configuration - This will open an Explorer window to
allow you to specify a file name.
Don't specify a file name
Pick the file you want to copy and right click it
Select Copy
Cancel the file save
My default KAT500 configuration for 6 meters is Mode - Manual, Antenna -1,
Others - Bypassed. If I select Mode - Bypass I hear a relay click but Antenna
and Others are unchanged. There is no change in SWR.
What changes between Mode - Manual, Others - Bypassed and Mode - Bypass, Others
-
"I doubt that a phone recording has the proper range to qualify as a test
device."
I think some people have misunderstood the reason for making the recording. The
purpose was to establish a baseline. If any mechanical changes I make change
the acoustic signature of the clicks then I have
"it is hard to tell if the overall ticking is tracking the temp"
It's quite instructive to view the file in Audacity. That shows clearly that
the groups of clicks that happen during the heating cycle are about half the
amplitude of the group of click that happen during the cooling cycles. The
The clicking of my KPA500 is almost intolerable and I'd like to know if what
I'm experiencing is typical.
In an FT8 TX/RX cycle with output power 126 W my KPA500 clicks 7-8 times
during 15 second transmit and 7-8 times during 15 second receive. In these
TX/RX cycles my logger shows the
Confirmed as a firmware defect by Elecraft. I don't understand how this has
gone unnoticed for so long. Doesn't anyone else use bypass mode?
73,
Andy k3wyc
From: ANDY DURBIN
Sent: Tuesday, July 3, 2018 11:02 AM
To: elecraft@mailman.qth.net
Subject: KAT500
"My first thought is that, since the antenna controller just sniffs for data, I
could add a DB-9 Y-cable to provide the extra port at the controller serial
port location. However, packets could still collide ...does the protocol handle
this? Is there some sort of multiplexer available?"
If
"TXD is really pin 3."
One end's TXD is the other end's RXD. That's obvious to those who have used
RS-233 for a while but if someone needs to ask then it may not be obvious. Find
the TXD pin on the source and connect it the RXD pin on the destination.
Sometimes it's easier to look with a
"No, TXD is TXD all the way through the path. Yes, the DTE TXD will have the
drivers, and the DCE will have receivers, but it is TXD from end to end. RXD
is the other way around because the DCE drives that line. Transmit and receive
are named with respect to the DTE."
That's great when one
"What do the numbers displayed after the Tune State mean? "
If this was answered I missed it. Where can I find the "decoder" for KAT500
Utility "Tune State". I thought I could solve it by experiment but not been
able to yet.
Thanks and 73,
Andy k3wyc
I've been using Alpha Delta model Delta-4 switches for manual antenna
selection. I thought that having the ability to auto select the appropriate
antenna with my KAT500 would be a significant improvement for my station. I
don't have a K3 so I created a band decoder that drives the KAT500 band
"I have similar issue and was told in this mailing list that the issue came
from antenna port isolation but it was within specification."
Ok, but where is the specification? I don't see it in the specifications in the
KAT500 Owners Manual (page 2).
If I browse the DX Engineering catalog I do
" From your explanation, it sounds like you've switched the active KAT500
antenna port to a dummy load on which you're hearing a local 6m station. If
that's correct, I don't believe you're looking at port isolation, you're just
receiving a local guy on your dummy load, which wouldn't be at all
"I suppose the only way to get good isolation data will be to do a sweep of the
KPA500 and Alpha Delta switch"
Sorry - that should have read "I suppose the only way to get good isolation
data will be to do a sweep of the KAT500 and Alpha Delta switch".
TMGS?
73,
Andy k3wuc
I have a new KAT500 and am learning how to use it. I have set up the antenna
switching table in the expectation that the table will be followed when I'm in
Automatic mode. However, I find that the antenna switching table is also in
effect when I'm in Manual mode. I cannot manually select the
I've experimented more with the available selections but I still don't see why
my KAT500 does what is does.
Here is a specific example of a case that I don't understand:
My configuration for 40 is Enabled 2 and 3. Preferred 2
My configuration for 20 is Enabled 1 and 3. Preferred 1
I
"I want to learn about vanity call signs, why would I want one? What do they
represent?"
A vanity call is one that is self selected rather than being the next in order
assigned by FCC. The main reason for getting one is vanity. Many select a
vanity call that represents their name or
k3wyc
From: Mike Morrow
Sent: Friday, July 13, 2018 2:21 PM
To: ANDY DURBIN; elecraft@mailman.qth.net
Subject: Re: [Elecraft] OT OT OT OT Vanity call question OT OT OT OT
> I want to learn about vanity call signs, why would I want one?
You have pos
I find the "clicks" my KPA500 makes as its temperature changes to be quite
distracting. Part of the problem is that I'm chasing a problem where the
KPA500 changes band spuriously and the thermal clicks sound too much like the
relays re-configuring the LPF.
To what extend does the thermal
"If you can figure out how to keep the relatively thin "Z" panel from expanding
and contracting as it is heated and cooled, you will have a solution to the
problem."
If the Z bracket really is the source of the noise, and I'm not yet convinced
it is, then there is no need to stop it expanding
I found this quite annoying too. My approach was to try to understand how the
Z bracket temperature varied relative to the heat sink temperature. I placed a
thermistor on the front end of the Z bracket and another on the heat sink fin
closest to the Z bracket. I logged the standard PA
"The keying interrupt must be provided by the ATU in order to avoid hot
switching the ATU relays when it tunes. This cannot be determined anywhere but
in the ATU, thus it must provide the break.
That key line break is pretty important to the life of the ATU."
Thanks to Jack and Dick for
"Someone asked me recently whether a KAT500 could be remote-controlled"
It wasn't me that asked but I have been considering using the KAT500 as a
remote tuner as I need higher power capability than my current MFJ-993BRT.
However, my approach was going to be to buy just the KAT500 board and
is not needed to protect the KAT500.
Andy, k3wyc
From: Jack Brindle
Sent: Saturday, November 3, 2018 12:58 PM
To: ANDY DURBIN
Cc: elecraft@mailman.qth.net
Subject: Re: [Elecraft] KAT500 as a remote-controlled tuner
The keying interrupt must be provided
From: Jack Brindle
Sent: Saturday, November 3, 2018 7:07 PM
To: ANDY DURBIN
Cc: elecraft@mailman.qth.net
Subject: Re: [Elecraft] KAT500 as a remote-controlled tuner
The answer is yes. But then it won’t tune and the cores will overheat from
excess power trying
I'd like to hear from who has successfully tailored KAT500 serial interface
commands FCCS and FCMD to overcome a frequency stability issue. I cannot
reconcile the results of my experiments with the command descriptions.
Yes, I have a request in with support but the relevant specialist is
"was told that the WSJT-X would not effect TX INHIBIT on the K3S."
I did a quick check on my TS-590S with WSJT-X ver 1.9.1. TX inhibit is not
cleared by WSJT-X and there is no transmission. If WSJT-X could clear a TX
inhibit it would, in my opinion, be an appalling design flaw.
I have been
"How does one implement TX Inhibit on a Kenwood TS-590?"
On a TS-590S TX inhibit is menu 60. The EX command is used to change menu
settings over CAT. For a TS-590S -
EX0600; reads the inhibit status
EX06001; sets TX inhibit
EX06000; clears TX inhibit
For a TS-590SG the menu
"The unit was powered on and it came up in operate mode while the HF radio was
in TX at 100w on 6M. End result is that the magic smoke got out. :)"
I suspect this is a very common mistake for ops who sometimes use the amp and
sometimes operate barefoot. I thought the KPA500 was designed to
"My KPA500 does not power up in operate. It always powers up in Standby."
Mine too. I also drop to STBY on band change. Both are user configurable and,
since this is my first amp, I chose settings that leaned towards safety rather
than operator convenience. I forget what the defaults were.
Hum level depends on PA current draw from the torroidal transformer. What is
your PA voltage key down? What is the complex impedance of the antenna system
as measured at the amplifier?
I reduced my KPA500 hum level from intolerable to acceptable by adjusting the
transformer voltage tap and
"At least the Elecraft menu items are spelled out in abbreviated English and
not a string of numbers. "
Setting TX Inhibit from the Kenwood TS-590 menu simply requires selecting the
menu number, where the selection is declared in plain English, and then
selecting "on" or "off".
If you want
"Are you saying that you have to send the radio a serial command to engage and
disengage the inhibit property?
TS-590 TX Inhibit can be activated by CAT as I described or by a manual menu
selection. There is no hardware TX inhibit for the TS-590S or TS-590SG. I think
that is a significant
"The Elecraft KPA500 amplifier also works efficiently into a load SWR of 1.5:1"
Any such claim is at best misleading. There may be some 1.5:1 loads that that
the KPA500 will be happy with but there are other 1.5:1 loads that it will
object to, to the point of giving multiple PA DISS faults.
"The ONLY good use of ALC between rig and amp is to protect the amp from a
failure in the antenna system. "
The KPA500 doesn't work that way so I'd be surprised if the KPA1500 did. For
the KPA500 a badly mismatched load will trip the reflected power fault without
making any change to the ALC
" I thought the KPA500 was designed to protect against that user error. Seems I
was wrong. "
According to the KPA500 Owner's Manual the KPA500 should react to excessive
drive by first switching in the attenuator and, if that is not sufficient drive
reduction, issuing hard fault 06 and
>From "KPA100 failure" topic -
"Thirdly, were the PA transistors tight? If not, the PA transistors will heat
the board around the transistors and not be thermally coupled to the heatsink.
Are the thermal pads properly in place? After initial assembly (and anytime
afterwards if the thermal
"Hope you check your windows setting, you might be surprised."
No surprises here. I have never had my rig CODEC as the default sound playback
device. I don't have Windows 10 but, in every earlier version I have used, it
is easy to ensure that the rig CODEC is not the default playback device.
"I've looked at the boards and cannot see where it came off. I also looked at
the pictures Elecraft submitted to the FCC and they do not show it."
What doesn't work that used to work? If nothing, then maybe they slipped it in
there just to confuse you. From the photo it looks as though it
"The leads of the resistor look like they are bent at the end as if it was
soldered to surface of the board"
I suspect you are right. I looked at the (perhaps intentionally) out of focus
FCC photos and I see a wire ended resistor bridging surface mount pads in the
lower left of the "Bottom
A history of CW pitch matching would seem to be incomplete without a mention of
the BFO (Beat Frequency Oscillator).
When I started operating CW I had separate TX and RX. TX was homebrew and the
RX was an AR-88D.A common technique for tuning a CW station was to set the
BFO to zero offset,
"Find a signal, turn on CWT, then tap SPOT to tune it in. A second tap of SPOT
may get even closer, especially if there's a lot of band noise."
and
"I'm a great fan of using the auto-spot feature, and love to show it off to all
shack visitors, as an example of yet another reason they need to
"If someone else has a better way of explaining it, I would like to see it."
Don't have a KPA1500 but I do have a KAT500. For that tuner there is a clear
distinction between being in BYPASS mode, and not being in BYPASS mode but
having the ATU relays in the bypassed position. The bypass
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