Re: [Elecraft] KPA500 Issue

[Jack Brindle via Elecraft]

Now let me answer my own question. There is a key-line interrupter adapter that 
I believe comes with the AUXIO cable. This is an HD-15 type adapter that will 
block the PTT signal from the K3 to the AUXIO cable. Use this, then you will 
need to connect the K3 to the KAT500/KPA500 using a phono cable. You will 
probably want to add a switch so that you can select the K3 or Icom radios for 
the PTT line to the KPA/KAT.

Once again, Fred Cady had the answer in his “Elecraft KPA500 Amplifier and 
KAT500 Tuner” guide. I really miss that guy…

73,
Jack W6FB


> On Mar 31, 2022, at 11:47 PM, Jack Brindle via Elecraft 
>  wrote:
> 
> OK, now this is starting to make sense. Jim’s K3 has a KIO3, not the newer 
> KIO3B. On the older board, the BAND and PTT lines have pullup resistors to 
> the Vcc rail.
> When the K3 is powered off, that Vcc rail is at 0 volts, which means the 
> pull-ups are now pulldowns. Thus the K3 is inadvertently keying the KPA500. 
> If the KPA
> detects that the KEY input is low when the user tries to put it into OPER 
> mode, the amplifier will reject the request and stay in STBY. Thus the 
> condition that
> Jim is seeing.
> 
> Try disconnecting the AUXIO cable from the KPA500 and see if it now operates 
> properly. You may actually need to connect the KAT500 to the KPA using both 
> the AuxIO
> and phono cables (for PTT) depending on which radio is in use. 
> 
> The main issue is how to disconnect the PTT signal from the K3 to the KPA 
> when using the Icom. Otherwise you may be able to leave the AuxIO cable 
> connected.
> I know that Fred Cady discussed sharing a KPA between two radios in his book, 
> but has anyone solved this situation - one radio is a K3, the other something 
> else?
> 
> 73,
> Jack, W6FB
> 
>> On Mar 31, 2022, at 9:11 PM, James Bennett via Elecraft 
>>  wrote:
>> 
>> Bob -
>> 
>> The * appears when I key the K3 and the amp is in operate mode. Likewise if 
>> I key the 705 and the amp is in operate mode, with the K3 powered on.
>> 
>> If I power off the K3 and place the amp in operate mode WITHOUT KEYING IT, 
>> the * appears, so you are correct - the amp thinks it is being keyed.
>> 
>> There is a jack on the 705 that allows one to key an external amp. I have 
>> that line running to the amp. Disconnecting it makes no difference the * 
>> appears as soon as I put the amp into operate mode. If I power on the K3, 
>> this does not happen. However, with the K3 powered on and that cable 
>> disconnected, the amp does not key at all, so it is working as expected - 
>> but only with the K3 powered on. Somewhere the K3 is getting its foot in the 
>> door when powered off…
>> 
>> Jim / K7TXA
>> 
>> p.s. do you have any idea what Jack was talking about when he said "switch 
>> the RADIO setting of the KPA from K3 to something else, either Serial or 
>> Analog”??
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Re: [Elecraft] KPA500 Issue

[Jack Brindle via Elecraft]

OK, now this is starting to make sense. Jim’s K3 has a KIO3, not the newer 
KIO3B. On the older board, the BAND and PTT lines have pullup resistors to the 
Vcc rail.
When the K3 is powered off, that Vcc rail is at 0 volts, which means the 
pull-ups are now pulldowns. Thus the K3 is inadvertently keying the KPA500. If 
the KPA
detects that the KEY input is low when the user tries to put it into OPER mode, 
the amplifier will reject the request and stay in STBY. Thus the condition that
Jim is seeing.

Try disconnecting the AUXIO cable from the KPA500 and see if it now operates 
properly. You may actually need to connect the KAT500 to the KPA using both the 
AuxIO
and phono cables (for PTT) depending on which radio is in use. 

The main issue is how to disconnect the PTT signal from the K3 to the KPA when 
using the Icom. Otherwise you may be able to leave the AuxIO cable connected.
I know that Fred Cady discussed sharing a KPA between two radios in his book, 
but has anyone solved this situation - one radio is a K3, the other something 
else?

73,
Jack, W6FB

> On Mar 31, 2022, at 9:11 PM, James Bennett via Elecraft 
>  wrote:
> 
> Bob -
> 
> The * appears when I key the K3 and the amp is in operate mode. Likewise if I 
> key the 705 and the amp is in operate mode, with the K3 powered on.
> 
> If I power off the K3 and place the amp in operate mode WITHOUT KEYING IT, 
> the * appears, so you are correct - the amp thinks it is being keyed.
> 
> There is a jack on the 705 that allows one to key an external amp. I have 
> that line running to the amp. Disconnecting it makes no difference the * 
> appears as soon as I put the amp into operate mode. If I power on the K3, 
> this does not happen. However, with the K3 powered on and that cable 
> disconnected, the amp does not key at all, so it is working as expected - but 
> only with the K3 powered on. Somewhere the K3 is getting its foot in the door 
> when powered off…
> 
> Jim / K7TXA
> 
> p.s. do you have any idea what Jack was talking about when he said "switch 
> the RADIO setting of the KPA from K3 to something else, either Serial or 
> Analog”??
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Re: [Elecraft] KPA500 Issue

[Jack Brindle via Elecraft]

The reason I don’t suspect the PIN diodes is that the KPA works properly with 
the K3. The K3 does not have a magical ability to repair KPA PIN diodes, so it 
most likely is not a problem there.

This is probably a K3 without the new K3S I/O board, which means it has pull-up 
resistors on the BAND lines. When the K3 is powered off it pulls those lines 
down, which is the same as 60 meters.
But, it will only change the band one time in this situation. 

My biggest curiosity is why unplugging the AuxIO cable will cause the KPA to 
not go into OPER mode. There must be something else connected for this to 
happen. Jim, you might try unplugging the cable from the back of the KPA to 
test this. Once we have that working, we can move on from there. And perhaps 
find a way to get our direct email path working again...

73,
Jack, W6FB


> On Mar 31, 2022, at 5:39 PM, Andy Durbin  wrote:
> 
> "However, what I’m seeing is that when the amp is in OPER mode, my receive 
> signal strength drops way, way off to the point I have to go full AF volume 
> to hear signals. If I put the amp in STBY, signal levels go back to normal."
> 
> These exact symptoms have been associated in past reports with a failure of 
> the TR switch PIN diodes.  Jack's idea of incorrect band can be easily 
> confirmed, or eliminated, by looking at the KPA500 band display.
> 
> Andy, k3wyc
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Re: [Elecraft] KPA500 Issue

[Jack Brindle via Elecraft]

The email I sent earlier. You might look in your junk folder, Jim…

73,
Jack, W6FB


> From: Jack Brindle 
> Subject: Re: KPA500 Issue
> Date: March 31, 2022 at 2:40:26 PM CDT
> To: James Bennett 
> 
> On the KPA front panel, hold the menu button to go into the menus, then 
> scroll down to the RADIO setting.
> 
> I’m contemplating why the KPA won’t go into OPER with the AuxIO cable 
> installed. That doesn’t make sense. What version of firmware do you have 
> installed? The KPA menu has a firmware selection that displays the version.



> On Mar 31, 2022, at 7:00 PM, James Bennett via Elecraft 
>  wrote:
> 
> I was unable to try Jack’s suggestion of disconnecting the AUXIO cable - 
> doing so made the KPA5000 not able to go into Operate mode. So, I wanted to 
> do the other option he mentioned - changing the “radio” setting of the KPA to 
> Serial or Analog. Unfortunately, I have no idea where that setting is. It 
> isn’t in my version of the KPA Utility: V1.19.9.6. I sent Jack an email about 
> it but he’s evidently off-line. Anyidea where that setting might be found?
> 
> My KPA shows the correct band on its display. The failure ONLY happens with 
> the K3 powered off. When it is powered up and set to the correct band, the 
> audio level in the IC-705 does not change when switching the amp from operate 
> to standby.
> 
> Jim / K7TXA
> 
>> On Mar 31, 2022, at 4:39 PM, Andy Durbin > > wrote:
>> 
>> "However, what I’m seeing is that when the amp is in OPER mode, my receive 
>> signal strength drops way, way off to the point I have to go full AF volume 
>> to hear signals. If I put the amp in STBY, signal levels go back to normal."
>> 
>> These exact symptoms have been associated in past reports with a failure of 
>> the TR switch PIN diodes. Jack's idea of incorrect band can be easily 
>> confirmed, or eliminated, by looking at the KPA500 band display.
>> 
>> Andy, k3wyc
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Re: [Elecraft] KPA500 Issue

[Andy Durbin]

"p.s. do you have any idea what Jack was talking about when he said "switch the 
RADIO setting of the KPA from K3 to something else, either Serial or Analog”??"

KPA500 menu / Radio / (Serial/Analog/BCD/K3).

Andy, k3wyc

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Re: [Elecraft] KPA500 Issue

[James Bennett via Elecraft]

Bob -

The * appears when I key the K3 and the amp is in operate mode. Likewise if I 
key the 705 and the amp is in operate mode, with the K3 powered on.

If I power off the K3 and place the amp in operate mode WITHOUT KEYING IT, the 
* appears, so you are correct - the amp thinks it is being keyed.

There is a jack on the 705 that allows one to key an external amp. I have that 
line running to the amp. Disconnecting it makes no difference the * appears as 
soon as I put the amp into operate mode. If I power on the K3, this does not 
happen. However, with the K3 powered on and that cable disconnected, the amp 
does not key at all, so it is working as expected - but only with the K3 
powered on. Somewhere the K3 is getting its foot in the door when powered off…

Jim / K7TXA

p.s. do you have any idea what Jack was talking about when he said "switch the 
RADIO setting of the KPA from K3 to something else, either Serial or Analog”??
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[Elecraft] K3 Part Needed

[Gary H. Harmon, Jr. via Elecraft]

A good friend needs a KIO3B or KI03B card for his K3.  It engaged in a
lightning strike and loss.

 

Best 73,

 

Gary H. Harmon, Jr. - K5JWK

HAM Radio, HEATHKIT, and ATARI Archaeologist

6003 Archwood

San Antonio, TX 78239-1504

(210) 657-1549 

(210) 884-6926 

ghar...@idworld.net

 

"Retirement = Every day is a Saturday except Sunday"

"Real radios glow in the dark"

"Too many projects, not enough time"

 

http://www.grissomroadcoc.org

 

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Re: [Elecraft] Elecraft Digest, Vol 215, Issue 15

[Ed Cole]

Thanks Bob,

My late night calculating in my head was off by factor of ten

5ppm at 10-MHz is +/- 50Hz and at 30-MHz 150-Hz

And I forgot that the TCXO-03 actually performed at 0.5ppm so one got 
ten times better stability suing the TCXO-03.


I reviewed my actual notes for testing with the TCXO-03 + EXREF 
stabilized by an OCXO at 10-MHz having +/-5 E-12 short term stability. 
I have a K3/10 so power output was set to 10w for the tests.


I measured 28 MHz with -1.5 Hz offset, and
50-MHz with -2.5 Hz offset, tests repeated the next day within 1-Hz.

Measurements per my EIP-538 frequency meter which was externally locked 
to a Rubidium source of +/-5 E-11. [I was a beta tester on the EXREF]


That effectively brings the K3 down to .05ppm.  On 28-MHz I figure I'm 
within 2-Hz which is great for running VHF/UHF transverters that can add 
up to 10-Hz drift running modes like FT8 or JT65.


On 2m using my K3 with 25w transverter, I see total upward drift of 7-Hz 
after running 30-minutes of JT-65.  One wants to limit max drift to 
20-Hz running digital modes.


At 432 and 1296 my transverters have PLL local oscillators so only drift 
is from the K3.  Note I run the K3 transverter I/F at 1mw so there is 
virtually no heating inside the K3 to cause drift.


Running a K3 with 100w might yield different results.  My understanding 
is that the K4 has the EXREF as standard, if one wants to use an 
external frequency standard (correct me if that is not true).


73, Ed - KL7UW



On 3/31/2022 3:35 PM, elecraft-requ...@mailman.qth.net wrote:

From: Bob McGraw
To:elecraft@mailman.qth.net
Subject: [Elecraft] TCXO
Message-ID:<4b5a4813-135d-f484-171d-be99a71a3...@benlomand.net>
Content-Type: text/plain; charset=UTF-8; format=flowed

The TCXO is the reference frequency for about everything that takes
place in the radio.? It is the master clock.? If it is incorrect, then
everything else is incorrect, for the most part.

A 5 ppm TCXO, or 5 parts per million, can have an error of ±250 Hz on
6 meters.?? Where as a 0.5 ppm TCXO can have an error of 25 Hz on 6
meters.?? It just depends on how accurate and stable you desire your
radio to be.

Oh, the frequency read-out on the front is just that, a read out.? It is
not a frequency measurement of the exact frequency. Many will put their
radio on 14.255.000 and swear it is on that frequency.? But with a 5 ppm
TCXO it could be ± 71 Hz.? Where as with a 0.5 ppm it would be ± 7
Hz.? Of course one must consider crystal and component ageing and
perform very easy calibration procedure at regular intervals.? I check
and adjust mine once a month and can maintain ± 2 Hz or or better.

I ordered mine with the 1 ppm TCXO with F/W corrected to 0.5 ppm.

73

Bob, K4TAX

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Re: [Elecraft] KPA500 Issue

[kd4iz]

Jim, All,

James Bennett Wrote:

> However, what I?m seeing is that when the amp is in OPER mode, my receive 
> signal strength drops way, way off to the point I have to go full AF volume 
> to hear signals. If I put the amp in STBY, signal levels go back to normal. I 
> also notice that the amp fan doesn?t take too long to crank up to high speed, 
> and the PA temp is sitting around 67 C.

I occasionally use an IC-705 to drive either a KXPA100, a KPA500/KAT500 pair, 
or both in cascade. I have a keyline splitter (the one for the KX3 to the KXPA) 
that allows me to cascade the KXPA100 to the KPA500. 

After I accidentally popped ~100W into the input of the KPA500 while 
experimenting with the switching arrangement, my system suddenly had the 
identical problem Jim describes, a much attenuated signal on receive and normal 
transmit. It was R9. Taking the amp apart was much more involved than replacing 
the resistor. I found R9 split in two and the two halves standing (yes, really) 
on the solder pads. (photo available on request).

The very kind folk at the mothership sent me a replacement for R9, a surface 
mount 50 ohm resistor, and it was an easy repair. I have everything set up with 
switching so I don't do it again. 

Now, when I put the IC-705 into the "cascade" mix, I set the rig output power 
to 5% which results in a 25-30W output from the KXPA100. 30W will drive the 
KPA500 to full power. I also use a sequential check list every time I bring the 
IC-705 into the shack to avoid the uncomfortable "oops" moment again. 

Note: make sure that the keyline that goes to the IC-705 has a 480 ohm resistor 
in series with the keyline jack tip when using a KXPA100... without it you 
can't use the IC-705 voice memories or the "DV TX Message" data in DR/DV mode 
without having the rig lock up in a transmit key up loop. The series resistor 
seems to have no effect on the ability of the 705 to key the KPA500. Please ask 
me offline if you have any additional questions about this setup. It has been 
stable and predictable ever since the repair was done 2 years back.

Jack Spitznagel – KD4IZ
kd...@arrl.net






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[Elecraft] Transverters discontinued?

[Thorpe, Jeffrey]

I noticed in Fred Cady's "Assembling the KX3-Line Station" that he mentions the 
Elecraft XV222 and XV423 transverters. I hadn't paid attention to that until 
just getting my 2m option for my KX3. On the website I see that all that's 
available are manuals. Are these things history now?

Jeff KG7HDZ
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[Elecraft] KPA500 Issue

[Bob McGraw]

Are you seeing and * on the KPA500 screen when using the IC-705 and the 
amp is in Operate mode?   If so, the amp is being keyed while the IC-705 
is in receive mode.  Confirmed by the fact when the amp is in STBY that 
signals are normal.


Check your amp keying interface and cable wiring.  You should be able to 
prove and Amp Key command from the IC-705 to the KPA500. Thus when the 
IC-705 is keyed, likewise the amp.


73

Bob, K4TAX




On 3/31/2022 6:35 PM, elecraft-requ...@mailman.qth.net wrote:

Message: 17
Date: Thu, 31 Mar 2022 11:52:29 -0600
From: James Bennett
To: Elecraft Reflector Reflector
Subject: [Elecraft] KPA500 Issue
Message-ID:
Content-Type: text/plain;   charset=utf-8

Having an issue with my KPA500 and a non-elecraft radio. I?ve got an Icom 
IC-705 connected to my KPA500 and KAT500. By dropping the 705?s output power to 
4 watts and pressing Tune on the KAT500 with the amp in OPER mode, I?m able to 
get the tuner to give me a good match on just about all bands to my Zerofive 
Flagpole Vertical. Then, turning the power level up to max (10 watts) on the 
IC-705, the amp gives me anywhere from 210 to 250 watts output, depending on 
the band. And that?s fine for me right now.

However, what I?m seeing is that when the amp is in OPER mode, my receive 
signal strength drops way, way off to the point I have to go full AF volume to 
hear signals. If I put the amp in STBY, signal levels go back to normal. I also 
notice that the amp fan doesn?t take too long to crank up to high speed, and 
the PA temp is sitting around 67 C.

I also have a K3. When I power up the K3 and switch the antenna over to the K3 
on the same band as the IC-705 - there is no drop in signal level on it when 
switching between OPER and STBY on the amp. And, yes, when I?m using the 
IC-705, I press the corresponding BAND button on the amp.

OK - some further info: if I have the K3 sitting on the same band as the IC-705 
this does not happen - going from STBY to OPER on the amp makes no difference 
on receive level on the IC-705. But if I power off the K3, the IC-705 reverts 
to its partially-deaf state.

Somewhere long ago in a far distant galaxy, I recall Jack W6FB mentioning that 
the K3 pulls some signal to zero when it is powered off. I suspect that may be 
what is happening here but for the life of me I can?t recall the exact 
conversation. I?d like to get to the point where I can run the IC-705 with this 
tuner and amp without having the K3 in the equation, as the K3 will be going on 
the sale block in the near future, in anticipation of a K4D delivery.

Any ideas?  Jack - are you listening?:-)

Jim / K7TXA


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[Elecraft] KPA500 Issue

[Bob McGraw]

Are you seeing and * on the KPA500 screen when using the IC-705 and the 
amp is in Operate mode?   If so, the amp is being keyed while the IC-705 
is in receive mode.  Confirmed by the fact when the amp is in STBY that 
signals are normal.


Check your amp keying interface and cable wiring.  You should be able to 
prove and Amp Key command from the IC-705 to the KPA500. Thus when the 
IC-705 is keyed, likewise the amp.


73

Bob, K4TAX




On 3/31/2022 6:35 PM, elecraft-requ...@mailman.qth.net wrote:

Message: 17
Date: Thu, 31 Mar 2022 11:52:29 -0600
From: James Bennett
To: Elecraft Reflector Reflector
Subject: [Elecraft] KPA500 Issue
Message-ID:
Content-Type: text/plain;   charset=utf-8

Having an issue with my KPA500 and a non-elecraft radio. I?ve got an Icom 
IC-705 connected to my KPA500 and KAT500. By dropping the 705?s output power to 
4 watts and pressing Tune on the KAT500 with the amp in OPER mode, I?m able to 
get the tuner to give me a good match on just about all bands to my Zerofive 
Flagpole Vertical. Then, turning the power level up to max (10 watts) on the 
IC-705, the amp gives me anywhere from 210 to 250 watts output, depending on 
the band. And that?s fine for me right now.

However, what I?m seeing is that when the amp is in OPER mode, my receive 
signal strength drops way, way off to the point I have to go full AF volume to 
hear signals. If I put the amp in STBY, signal levels go back to normal. I also 
notice that the amp fan doesn?t take too long to crank up to high speed, and 
the PA temp is sitting around 67 C.

I also have a K3. When I power up the K3 and switch the antenna over to the K3 
on the same band as the IC-705 - there is no drop in signal level on it when 
switching between OPER and STBY on the amp. And, yes, when I?m using the 
IC-705, I press the corresponding BAND button on the amp.

OK - some further info: if I have the K3 sitting on the same band as the IC-705 
this does not happen - going from STBY to OPER on the amp makes no difference 
on receive level on the IC-705. But if I power off the K3, the IC-705 reverts 
to its partially-deaf state.

Somewhere long ago in a far distant galaxy, I recall Jack W6FB mentioning that 
the K3 pulls some signal to zero when it is powered off. I suspect that may be 
what is happening here but for the life of me I can?t recall the exact 
conversation. I?d like to get to the point where I can run the IC-705 with this 
tuner and amp without having the K3 in the equation, as the K3 will be going on 
the sale block in the near future, in anticipation of a K4D delivery.

Any ideas?  Jack - are you listening?:-)

Jim / K7TXA


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Re: [Elecraft] KPA500 Issue

[Lyle Johnson]

Jim,
See page 38 of the Rev E1 KPA500 operating manual for how to set the radio
in the KPA500 menu (not KPA500 utility).  This is the current version of
the manual a available on the Elecraft website.
73,
Lyle Kk7P

On Thu, Mar 31, 2022 at 5:12 PM Jim Clymer  wrote:

> In my case, it was not the PIN diodes themselves, but failure of R9. I'm
> away from my shack right now, so may not have the resistor ID correct. It
> is a 48 Ohm resistor. I fixed the problem by parallel connecting a pair of
> 1/4 W, 100 Ohm resistors across the open one. Problem solved. Been fine
> since.
> There is documentation of this problem. A German ham wrote to me with a
> link to the solution. If no one steps forward before tomorrow, I'll try to
> post the info in the morning.
> 73,
> Jim -  WS6X
>
> On Thu, Mar 31, 2022, 6:40 PM Andy Durbin  wrote:
>
> > "However, what I’m seeing is that when the amp is in OPER mode, my
> receive
> > signal strength drops way, way off to the point I have to go full AF
> volume
> > to hear signals. If I put the amp in STBY, signal levels go back to
> normal."
> >
> > These exact symptoms have been associated in past reports with a failure
> > of the TR switch PIN diodes.  Jack's idea of incorrect band can be easily
> > confirmed, or eliminated, by looking at the KPA500 band display.
> >
> > Andy, k3wyc
> >
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Re: [Elecraft] KPA500 Issue

[Jim Clymer]

In my case, it was not the PIN diodes themselves, but failure of R9. I'm
away from my shack right now, so may not have the resistor ID correct. It
is a 48 Ohm resistor. I fixed the problem by parallel connecting a pair of
1/4 W, 100 Ohm resistors across the open one. Problem solved. Been fine
since.
There is documentation of this problem. A German ham wrote to me with a
link to the solution. If no one steps forward before tomorrow, I'll try to
post the info in the morning.
73,
Jim -  WS6X

On Thu, Mar 31, 2022, 6:40 PM Andy Durbin  wrote:

> "However, what I’m seeing is that when the amp is in OPER mode, my receive
> signal strength drops way, way off to the point I have to go full AF volume
> to hear signals. If I put the amp in STBY, signal levels go back to normal."
>
> These exact symptoms have been associated in past reports with a failure
> of the TR switch PIN diodes.  Jack's idea of incorrect band can be easily
> confirmed, or eliminated, by looking at the KPA500 band display.
>
> Andy, k3wyc
>
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Re: [Elecraft] KPA500 Issue

[James Bennett via Elecraft]

I was unable to try Jack’s suggestion of disconnecting the AUXIO cable - doing 
so made the KPA5000 not able to go into Operate mode. So, I wanted to do the 
other option he mentioned - changing the “radio” setting of the KPA to Serial 
or Analog. Unfortunately, I have no idea where that setting is. It isn’t in my 
version of the KPA Utility: V1.19.9.6. I sent Jack an email about it but he’s 
evidently off-line. Anyidea where that setting might be found?

My KPA shows the correct band on its display. The failure ONLY happens with the 
K3 powered off. When it is powered up and set to the correct band, the audio 
level in the IC-705 does not change when switching the amp from operate to 
standby.

Jim / K7TXA

> On Mar 31, 2022, at 4:39 PM, Andy Durbin  wrote:
> 
> "However, what I’m seeing is that when the amp is in OPER mode, my receive 
> signal strength drops way, way off to the point I have to go full AF volume 
> to hear signals. If I put the amp in STBY, signal levels go back to normal."
> 
> These exact symptoms have been associated in past reports with a failure of 
> the TR switch PIN diodes.  Jack's idea of incorrect band can be easily 
> confirmed, or eliminated, by looking at the KPA500 band display.
> 
> Andy, k3wyc
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Re: [Elecraft] TCXO

[Andy Durbin]

"What are the uses for the TCXO option in a K3? Why would I want one?"

TCXO means "Temperature Compensated Crystal Oscillator".   You need one if the 
frequency drift caused by rig temperature change causes a problem at the 
frequencies, and with the modes, you operate.  Leave the rig powered all the 
time in a temperature controlled environment and you may not need one.  If you 
turn on a stone cold rig and expect to operate before the temperature 
stabilizes then you probably do, especially  with narrow band digital modes.

Temperature Compensated tells you nothing about the accuracy of the oscillator 
frequency.  It just says how much the frequency will change with temperature.  
I don't know what TCXO are compatible with the K3 but there are some quite 
nasty "TCXO" being purchased by Kenwood TS-590 owners.  Frequency stability 
with temperature is only one measure of a TCXO.  Spectral purity is at least as 
important.

Andy, k3wyc
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Re: [Elecraft] KPA500 Issue

[Andy Durbin]

"However, what I’m seeing is that when the amp is in OPER mode, my receive 
signal strength drops way, way off to the point I have to go full AF volume to 
hear signals. If I put the amp in STBY, signal levels go back to normal."

These exact symptoms have been associated in past reports with a failure of the 
TR switch PIN diodes.  Jack's idea of incorrect band can be easily confirmed, 
or eliminated, by looking at the KPA500 band display.

Andy, k3wyc
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[Elecraft] TCXO

[Bob McGraw]

The TCXO is the reference frequency for about everything that takes 
place in the radio.  It is the master clock.  If it is incorrect, then 
everything else is incorrect, for the most part.


A 5 ppm TCXO, or 5 parts per million, can have an error of +/-250 Hz on 
6 meters.   Where as a 0.5 ppm TCXO can have an error of 25 Hz on 6 
meters.   It just depends on how accurate and stable you desire your 
radio to be.


Oh, the frequency read-out on the front is just that, a read out.  It is 
not a frequency measurement of the exact frequency. Many will put their 
radio on 14.255.000 and swear it is on that frequency.  But with a 5 ppm 
TCXO it could be +/- 71 Hz.  Where as with a 0.5 ppm it would be +/- 7 
Hz.  Of course one must consider crystal and component ageing and 
perform very easy calibration procedure at regular intervals.  I check 
and adjust mine once a month and can maintain +/- 2 Hz or or better.


I ordered mine with the 1 ppm TCXO with F/W corrected to 0.5 ppm.

73

Bob, K4TAX


On 3/30/2022 3:25 PM, elecraft-requ...@mailman.qth.net wrote:

Message: 1
Date: Wed, 30 Mar 2022 07:44:49 -0500
From: rikoski
To:elecraft@mailman.qth.net
Cc: Richard Rikoski
Subject: [Elecraft] TCXO
Message-ID:<11ce6286-6d21-47fd-9734-4b1646d35...@rikoski.com>
Content-Type: text/plain;   charset=us-ascii

What are the uses for the TCXO option in a K3?

Why would I want one? Thanks,

73 W9ZD


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Re: [Elecraft] KPA500 Issue

[Jack Brindle via Elecraft]

m;

What happens when you disconnect the AuxIO cable from the K3 to the KPA? The 
other solution is to switch the RADIO setting of the KPA from K3 to something 
else, either Serial or Analog. If nothing is connected to the analog band input 
with RADIO = ANALOG, the KPA should work as usual. Likewise if nothing is 
connected to the “Radio” serial port with RADIO=“SERIAL” then it should work 
just fine, but no automatic band selection will occur.

It sounds like the K3 is overriding the front panel selection, keeping the 
KPA’s low pass filters on a band that is not the one you desire for the IC-705.

Let me know if this helps.

73m,
Jack, W6FB


> On Mar 31, 2022, at 12:52 PM, James Bennett via Elecraft 
>  wrote:
> 
> Having an issue with my KPA500 and a non-elecraft radio. I’ve got an Icom 
> IC-705 connected to my KPA500 and KAT500. By dropping the 705’s output power 
> to 4 watts and pressing Tune on the KAT500 with the amp in OPER mode, I’m 
> able to get the tuner to give me a good match on just about all bands to my 
> Zerofive Flagpole Vertical. Then, turning the power level up to max (10 
> watts) on the IC-705, the amp gives me anywhere from 210 to 250 watts output, 
> depending on the band. And that’s fine for me right now.
> 
> However, what I’m seeing is that when the amp is in OPER mode, my receive 
> signal strength drops way, way off to the point I have to go full AF volume 
> to hear signals. If I put the amp in STBY, signal levels go back to normal. I 
> also notice that the amp fan doesn’t take too long to crank up to high speed, 
> and the PA temp is sitting around 67 C. 
> 
> I also have a K3. When I power up the K3 and switch the antenna over to the 
> K3 on the same band as the IC-705 - there is no drop in signal level on it 
> when switching between OPER and STBY on the amp. And, yes, when I’m using the 
> IC-705, I press the corresponding BAND button on the amp.
> 
> OK - some further info: if I have the K3 sitting on the same band as the 
> IC-705 this does not happen - going from STBY to OPER on the amp makes no 
> difference on receive level on the IC-705. But if I power off the K3, the 
> IC-705 reverts to its partially-deaf state.
> 
> Somewhere long ago in a far distant galaxy, I recall Jack W6FB mentioning 
> that the K3 pulls some signal to zero when it is powered off. I suspect that 
> may be what is happening here but for the life of me I can’t recall the exact 
> conversation. I’d like to get to the point where I can run the IC-705 with 
> this tuner and amp without having the K3 in the equation, as the K3 will be 
> going on the sale block in the near future, in anticipation of a K4D 
> delivery. 
> 
> Any ideas?  Jack - are you listening? :-)
> 
> Jim / K7TXA
> 
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[Elecraft] KPA500 Issue

[James Bennett via Elecraft]

Having an issue with my KPA500 and a non-elecraft radio. I’ve got an Icom 
IC-705 connected to my KPA500 and KAT500. By dropping the 705’s output power to 
4 watts and pressing Tune on the KAT500 with the amp in OPER mode, I’m able to 
get the tuner to give me a good match on just about all bands to my Zerofive 
Flagpole Vertical. Then, turning the power level up to max (10 watts) on the 
IC-705, the amp gives me anywhere from 210 to 250 watts output, depending on 
the band. And that’s fine for me right now.

However, what I’m seeing is that when the amp is in OPER mode, my receive 
signal strength drops way, way off to the point I have to go full AF volume to 
hear signals. If I put the amp in STBY, signal levels go back to normal. I also 
notice that the amp fan doesn’t take too long to crank up to high speed, and 
the PA temp is sitting around 67 C. 

I also have a K3. When I power up the K3 and switch the antenna over to the K3 
on the same band as the IC-705 - there is no drop in signal level on it when 
switching between OPER and STBY on the amp. And, yes, when I’m using the 
IC-705, I press the corresponding BAND button on the amp.

OK - some further info: if I have the K3 sitting on the same band as the IC-705 
this does not happen - going from STBY to OPER on the amp makes no difference 
on receive level on the IC-705. But if I power off the K3, the IC-705 reverts 
to its partially-deaf state.

Somewhere long ago in a far distant galaxy, I recall Jack W6FB mentioning that 
the K3 pulls some signal to zero when it is powered off. I suspect that may be 
what is happening here but for the life of me I can’t recall the exact 
conversation. I’d like to get to the point where I can run the IC-705 with this 
tuner and amp without having the K3 in the equation, as the K3 will be going on 
the sale block in the near future, in anticipation of a K4D delivery. 

Any ideas?  Jack - are you listening? :-)

Jim / K7TXA

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[Elecraft] K3/KPA-1500 - Unexpected shift in per-band power

[john]

I thought the saying was: "When all else fails, read the manual".

John KK9A

Jim Brown K9YC wrote:

With every new thing that comes into my life, my first action is to 
RTFM. I am VERY frustrated that I can't do that with my Android phone, 
and was equally frustrated 20 years ago when asked to teach a course to 
students using Apple computers.

73, Jim K9YC

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Re: [Elecraft] TCXO

[Ed Cole]

To add a little to what Lance-W7GJ said:

Every K3 has a TCXO.  Standard is the TCXO-01 with 5ppm stability which 
fine if you only run CW/SSB/AM/FM. TCXO stands for Temperature Controled 
Xtal Oscillator.  I provides the frequency standard for the K3 
synthesizers to lock to.  5ppm translates as 5*10^-6 or on 10-MHz 
frequency is within 5-Hz; 30-MHz its 15-Hz.


TCXO-03 improves this to 1ppm: 1-Hz at 10-MHz; 3-Hz at 30-MHz

If you buy the TCXO-03 option and add the K3EXREF board this improves to 
2-Hz at 30-MHz.  The EXREF compares the TCXO with a high standard 10-MHz 
reference oscillator like an OCXO or GPSDO.  When the TCXO drifts off 
frequency the EXREF corrects that about every 4-seconds.


High frequency stability is needed when running certain digital modes 
such as FT8.  Also, useful if your K3 is driving a VHF/UHF/mw transverter.


73, Ed - KL7UW


Date: Wed, 30 Mar 2022 07:44:49 -0500
From: rikoski 
To: elecraft@mailman.qth.net
Cc: Richard Rikoski 
Subject: [Elecraft] TCXO
Message-ID: <11ce6286-6d21-47fd-9734-4b1646d35...@rikoski.com>
Content-Type: text/plain;   charset=us-ascii

What are the uses for the TCXO option in a K3?

Why would I want one? Thanks,

73 W9ZD
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