Elecraft

K3 Strange Power Output Problem

Classic

List

Threaded

14 messages Options

Ed G

K3 Strange Power Output Problem

Hello,
I noticed this power output anomaly today while trying to work the NSS station. My K3 was in split mode, transmitting on 10.113.5. While I was listening on 9.448 (the NSS transmit frequency), I noticed that even though my K3 power level was set at 100 watts, the K3 was only putting out about 20 watts. Two different power meters (the K3 internal meter and an outboard LP-100A) gave me the 20 watt reading.
When I listened on my transmit frequency of 10.113.5, I was getting the full 100 watts out. A quick investigation showed that as I tuned my listening frequency down, I got the full 100 watts out until I got to about 9.850 mHz. When I listened below that, K3 transmit power on 10.113.5 dropped immediately down to 20 watts.
Not sure why I am seeing this? One additional note – I hear a relay click inside the K3 when I tune my receive frequency below 9.850. I see the anomaly with the subreceiver either on or off.
--Ed—

Sent from Mail for Windows 10

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

markmusick

Re: K3 Strange Power Output Problem

Hi Ed,
You don't have a transmit problem at all. It is not an anomaly.
The amateur band starts at 10.100 MHz. You shouldn't be transmitting below that frequency. I'm surprised the K3 allowed you to do that.
The K3/K3S gives an out of band error and won't transmit beyond some amount below and above the amateur band limits, I believe allowing for MARS frequencies.
The reason for the relay click and your lower output is due to switching of the bandpass filters in the K3. They are not designed to transmit down there. This is also why you are seeing a reduction in receive sensitivity. You need the BPF3A to receive outside the ham bands. Again, because you are limited by the bandpass filters for the ham bands in the K3.
If you have more questions, let us know here on the reflector and we will try to answer them for you.

73,
Mark, WB9CIF

-----Original Message-----
From: [hidden email] <[hidden email]> On Behalf Of Ed G
Sent: Saturday, May 12, 2018 7:25 PM
To: [hidden email]
Subject: [Elecraft] K3 Strange Power Output Problem

Hello,
I noticed this power output anomaly today while trying to work the NSS station. My K3 was in split mode, transmitting on 10.113.5. While I was listening on 9.448 (the NSS transmit frequency), I noticed that even though my K3 power level was set at 100 watts, the K3 was only putting out about 20 watts. Two different power meters (the K3 internal meter and an outboard LP-100A) gave me the 20 watt reading.
When I listened on my transmit frequency of 10.113.5, I was getting the full 100 watts out. A quick investigation showed that as I tuned my listening frequency down, I got the full 100 watts out until I got to about 9.850 mHz. When I listened below that, K3 transmit power on 10.113.5 dropped immediately down to 20 watts.
Not sure why I am seeing this? One additional note – I hear a relay click inside the K3 when I tune my receive frequency below 9.850. I see the anomaly with the subreceiver either on or off.
--Ed—

Sent from Mail for Windows 10

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email]

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Ed G

Re: K3 Strange Power Output Problem

Hi Mark! I am transmitting on 10.113, and I do not change this. I am in Split mode, listening for NSS (who is transmitting on 9.448). I am only seeing about 20 watts out, even though the K3 Power setting says 100 watts.

If I change my RECEIVE frequency – not my transmit frequency – once I get above 9.850 on RECEIVE, my power out returns to the expected 100 watts.

--Ed—

Sent from Mail for Windows 10

From: Mark E. Musick
Sent: Saturday, May 12, 2018 4:36 PM
To: 'Ed G'; [hidden email]
Subject: RE: [Elecraft] K3 Strange Power Output Problem

Hi Ed,
You don't have a transmit problem at all. It is not an anomaly.
The amateur band starts at 10.100 MHz. You shouldn't be transmitting below that frequency. I'm surprised the K3 allowed you to do that.
The K3/K3S gives an out of band error and won't transmit beyond some amount below and above the amateur band limits, I believe allowing for MARS frequencies.
The reason for the relay click and your lower output is due to switching of the bandpass filters in the K3. They are not designed to transmit down there. This is also why you are seeing a reduction in receive sensitivity. You need the BPF3A to receive outside the ham bands. Again, because you are limited by the bandpass filters for the ham bands in the K3.
If you have more questions, let us know here on the reflector and we will try to answer them for you.

73,
Mark, WB9CIF

-----Original Message-----
From: [hidden email] <[hidden email]> On Behalf Of Ed G
Sent: Saturday, May 12, 2018 7:25 PM
To: [hidden email]
Subject: [Elecraft] K3 Strange Power Output Problem

Hello,
I noticed this power output anomaly today while trying to work the NSS station. My K3 was in split mode, transmitting on 10.113.5. While I was listening on 9.448 (the NSS transmit frequency), I noticed that even though my K3 power level was set at 100 watts, the K3 was only putting out about 20 watts. Two different power meters (the K3 internal meter and an outboard LP-100A) gave me the 20 watt reading.
When I listened on my transmit frequency of 10.113.5, I was getting the full 100 watts out. A quick investigation showed that as I tuned my listening frequency down, I got the full 100 watts out until I got to about 9.850 mHz. When I listened below that, K3 transmit power on 10.113.5 dropped immediately down to 20 watts.
Not sure why I am seeing this? One additional note – I hear a relay click inside the K3 when I tune my receive frequency below 9.850. I see the anomaly with the subreceiver either on or off.
--Ed—

Sent from Mail for Windows 10

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email]

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Brian Hunt

Re: K3 Strange Power Output Problem

In reply to this post by Ed G

I ran into this today too, different frequencies though. I recently installed the KBPF3 module and have it enabled full time. I think what happened is the VFO-A frequency sets the BPF segment to be used and with the wide split, it's not the right one for the VFO-B TX frequency to use. Therefore you don't get enough drive through to the amplifier stages. The K3 will not switch BPF segments to go between RX and TX states. I got an ERR:TXG indicating something was afoul in the BPF setup.

I tried to set the KBPF3 to 'not installed' but botched it since I didn't remember you had to cycle K3 power to reconfigure that option. By then NSS had faded into the noise. Oh well, got 'em on one band.

73, Brian, K0DTJ
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

donovanf

Re: K3 Strange Power Output Problem

In reply to this post by Ed G

Hi Ed,

We had exactly the same problem with all six of our MARS modified
K3 transceivers at NSS.

We were forced to replace our MARS modified K3 transceiver transmitting
on 9448 kHz with an old FT-1000MP... Only on other bands where our
assigned MARS frequency was very close to the edge of the ham band did
the K3 produce near normal RF output power but only if VFO A was
set to listen just inside the edge of the ham band nearest to our MARS\
transmitting frequency on VFO B.

This is the behavior we discovered with all of our K3 transceivers:

- Transmitting on 9448 kHz or any other MARS frequency on either
VFO A or VFO B works perfectly but only when not operating split .

- Operating split with both VFO A and VFO B set for any
frequencies within the same ham band works perfectly.

However -- when selecting split operation -- VFO B RF output power
steadily drops as VFO A is tuned to receive at an increasingly large
frequency split relative to VFO B transmitting on a fixed MARS freq.

It appears that when operating split and transmitting on VFO B on a
MARS frequency, the K3 bandpass filter associated with the VFO A
receiving VFO is always selected for use with the VFO B split transmitter
outside the ham band. When VFO B is tuned to transmit outside the
ham band (e.g. 9448 KHz and VFO A listening on 10113) the VFO B
transmitted signal on 9448 kHz cannot pass through the standard 30 meter
bandpass filter automatically selected by the K3 for use with VFO A.

Proposed solution: the K3 must dynamically select the proper KBPF3
bandpass filter before transmitting on a VFO B split frequency outside
the ham bands. Then the K3 must dynamically switch back the stock
K3 band pass filter each time the K3 switches from VFO B transmit
to VFO A receive inside the ham band..

This exact same problem occurs on every band, not just 30 meters. For
example on 80 meters NSS was transmitting with VFO B on 4038 kHz.
We were forced listen with VFO A set just below 4000 kHz. As a
result we were forced to ask CW stations to call us just below 4000 kHz,
an unusual operating practice. If we tuned VFO A to receive on 3530 kHz
the VFO B transmitter power output on 4038 kHz was dramatically lowered.

N3CW experienced exactly the same problem when transmitting with
inside the 30 meter ham band and listening on 9448 kHz.

Hopefully the capability to dynamically select to proper bandpass
filter before each transmission can be added to the K3 before the next
Armed Forces Day Cross-Band Test in twelve months...

73
Frank
W3LPL

----- Original Message -----

From: "Ed G" <[hidden email]>
To: "Mark E. Musick" <[hidden email]>, [hidden email]
Sent: Saturday, May 12, 2018 8:45:02 PM
Subject: Re: [Elecraft] K3 Strange Power Output Problem

Hi Mark! I am transmitting on 10.113, and I do not change this. I am in Split mode, listening for NSS (who is transmitting on 9.448). I am only seeing about 20 watts out, even though the K3 Power setting says 100 watts.

If I change my RECEIVE frequency – not my transmit frequency – once I get above 9.850 on RECEIVE, my power out returns to the expected 100 watts.

--Ed—

Sent from Mail for Windows 10

From: Mark E. Musick
Sent: Saturday, May 12, 2018 4:36 PM
To: 'Ed G'; [hidden email]
Subject: RE: [Elecraft] K3 Strange Power Output Problem

Hi Ed,
You don't have a transmit problem at all. It is not an anomaly.
The amateur band starts at 10.100 MHz. You shouldn't be transmitting below that frequency. I'm surprised the K3 allowed you to do that.
The K3/K3S gives an out of band error and won't transmit beyond some amount below and above the amateur band limits, I believe allowing for MARS frequencies.
The reason for the relay click and your lower output is due to switching of the bandpass filters in the K3. They are not designed to transmit down there. This is also why you are seeing a reduction in receive sensitivity. You need the BPF3A to receive outside the ham bands. Again, because you are limited by the bandpass filters for the ham bands in the K3.
If you have more questions, let us know here on the reflector and we will try to answer them for you.

73,
Mark, WB9CIF

-----Original Message-----
From: [hidden email] <[hidden email]> On Behalf Of Ed G
Sent: Saturday, May 12, 2018 7:25 PM
To: [hidden email]
Subject: [Elecraft] K3 Strange Power Output Problem

Hello,
I noticed this power output anomaly today while trying to work the NSS station. My K3 was in split mode, transmitting on 10.113.5. While I was listening on 9.448 (the NSS transmit frequency), I noticed that even though my K3 power level was set at 100 watts, the K3 was only putting out about 20 watts. Two different power meters (the K3 internal meter and an outboard LP-100A) gave me the 20 watt reading.
When I listened on my transmit frequency of 10.113.5, I was getting the full 100 watts out. A quick investigation showed that as I tuned my listening frequency down, I got the full 100 watts out until I got to about 9.850 mHz. When I listened below that, K3 transmit power on 10.113.5 dropped immediately down to 20 watts.
Not sure why I am seeing this? One additional note – I hear a relay click inside the K3 when I tune my receive frequency below 9.850. I see the anomaly with the subreceiver either on or off.
--Ed—

Sent from Mail for Windows 10

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email]

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Wes Stewart-2

Re: K3 Strange Power Output Problem

In reply to this post by markmusick

Another reading comprehension problem.

On 5/12/2018 1:36 PM, Mark E. Musick wrote:
> Hi Ed,
> You don't have a transmit problem at all. It is not an anomaly.
> The amateur band starts at 10.100 MHz. You shouldn't be transmitting below that frequency.
>
> Hello,
> I noticed this power output anomaly today while trying to work the NSS station. My K3 was in split mode, transmitting on 10.113.5.

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

wayne burdick

Re: K3 Strange Power Output Problem

Administrator

I have to admit, operating SPLIT between a ham band and a MARS band that falls outside the nearest ham-band filter isn’t something that occurred to me when writing the firmware. But I can change the filter selection algorithm to accommodate this case as long as a KBPF3 module is installed.

Technical details:

Since the K3/K3S is a downconversion superhet, we use very narrow ham-band filters. One of the narrowest is the 30 meter filter.

To preserve the rig’s exceptional dynamic range, we switch the band pass filters with relays, not diodes. This means we can’t switch filters at T/R rates.

So to handle the case being discussed, we’d have to select the 7-10 MHz KBPF3 filter for both RX and TX.

73,
Wayne
N6KR

----
http://www.elecraft.com

> On May 13, 2018, at 6:10 AM, Wes Stewart <[hidden email]> wrote:
>
> Another reading comprehension problem.
>
>> On 5/12/2018 1:36 PM, Mark E. Musick wrote:
>> Hi Ed,
>> You don't have a transmit problem at all. It is not an anomaly.
>> The amateur band starts at 10.100 MHz. You shouldn't be transmitting below that frequency.
>>
>> Hello,
>> I noticed this power output anomaly today while trying to work the NSS station. My K3 was in split mode, transmitting on 10.113.5.
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

Bob Wilson, N6TV

Re: K3 Strange Power Output Problem

In reply to this post by donovanf

I can't replicate this problem with the KBPF3 installed in the Sub Rx
instead of the main. CONFIG:KBPF3 says "Not Inst", for main, "Sub Nor"
when I tap SUB.

If you have the KRX3 Sub Receiver installed, a possible workaround is to
operate with SPLIT *OFF*, SUB ON. Now you're transmitting on A, listening
on both.

Try putting VFO A on 10.115 and listen with VFO B (SUB) on 9.448. Perhaps
RX on Sub will be attenuated. Tapping B-SET + Pre-Amp may help bring some
sensitivity back.

If you want to listen to VFO B with both ears, set *CONFIG:L-MIX-R* to *b
b*.

73,
Bob, N6TV

On Sat, May 12, 2018 at 11:36 PM, <[hidden email]> wrote:

> It appears that when operating split and transmitting on VFO B on a
> MARS frequency, the K3 bandpass filter associated with the VFO A
> receiving VFO is always selected for use with the VFO B split transmitter
> outside the ham band. When VFO B is tuned to transmit outside the
> ham band (e.g. 9448 KHz and VFO A listening on 10113) the VFO B
> transmitted signal on 9448 kHz cannot pass through the standard 30 meter
> bandpass filter automatically selected by the K3 for use with VFO A.
>
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

donovanf

Re: K3 Strange Power Output Problem

In reply to this post by wayne burdick

Hi Wayne,

The MARS to ham band K3 cross-band problem affects every band,
but it was extremely severe on 30 meters because the NSS assigned
frequency -- 9448 kHz -- was almost 700 kHz from our typical
10128 kHz receiving frequency.

Since switching between the K3 bandpass filters and the KBPF3
band pass filters at T/R rates isn't a workable solution, how about
this external BNC cable solution since my K3 transceivers have
KRX3 sub receivers?

If I understand the K3 internal receiver antenna switching correctly
a single external BNC jumper cable allows the K3 to transmit and
receive on VFO A on MARS frequencies and listen to any amateur
band on the sub receiver:

- Connect the RX ANT OUT connector to the RX ANT IN connector

- Tap the main RX ANT button which connects ANT 1 to the RX ANT OUT
connector and switches the input of the main receiver to the RX ANT IN
connector (connected by the external BNC cable to RX ANT OUT)

- Tap SUB to turn the sub receiver on

- Hold BSET and tap ANT to set the sub receiver input to MAIN. This
allows the subreceiver to listen on the RX ANT connected to the main
receiver.

I'm sorry I didn't think of this yesterday...

tks

73
Frank
W3LPL

----- Original Message -----

From: "Wayne Burdick" <[hidden email]>
To: "Elecraft" <[hidden email]>
Sent: Sunday, May 13, 2018 4:06:51 PM
Subject: Re: [Elecraft] K3 Strange Power Output Problem

I have to admit, operating SPLIT between a ham band and a MARS band that falls outside the nearest ham-band filter isn’t something that occurred to me when writing the firmware. But I can change the filter selection algorithm to accommodate this case as long as a KBPF3 module is installed.

Technical details:

Since the K3/K3S is a downconversion superhet, we use very narrow ham-band filters. One of the narrowest is the 30 meter filter.

To preserve the rig’s exceptional dynamic range, we switch the band pass filters with relays, not diodes. This means we can’t switch filters at T/R rates.

So to handle the case being discussed, we’d have to select the 7-10 MHz KBPF3 filter for both RX and TX.

73,
Wayne
N6KR

----
http://www.elecraft.com

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Don Wilhelm

Re: K3 Strange Power Output Problem

Frank,

You still have the K3 Low Pass Filters to deal with.
The KBPF3 in the sub and the use of a separate RX antenna may produce
better results.

But then Wayne is the guy to say what other obstacles might be in the way.

73,
Don W3FPR

On 5/13/2018 7:45 PM, [hidden email] wrote:

> Hi Wayne,
>
>
> The MARS to ham band K3 cross-band problem affects every band,
> but it was extremely severe on 30 meters because the NSS assigned
> frequency -- 9448 kHz -- was almost 700 kHz from our typical
> 10128 kHz receiving frequency.
>
>
> Since switching between the K3 bandpass filters and the KBPF3
> band pass filters at T/R rates isn't a workable solution, how about
> this external BNC cable solution since my K3 transceivers have
> KRX3 sub receivers?
>
>
> If I understand the K3 internal receiver antenna switching correctly
> a single external BNC jumper cable allows the K3 to transmit and
> receive on VFO A on MARS frequencies and listen to any amateur
> band on the sub receiver:
>
>
> - Connect the RX ANT OUT connector to the RX ANT IN connector
>
>
> - Tap the main RX ANT button which connects ANT 1 to the RX ANT OUT
> connector and switches the input of the main receiver to the RX ANT IN
> connector (connected by the external BNC cable to RX ANT OUT)
>
>
> - Tap SUB to turn the sub receiver on
>
>
> - Hold BSET and tap ANT to set the sub receiver input to MAIN. This
> allows the subreceiver to listen on the RX ANT connected to the main
> receiver.
>
>
> I'm sorry I didn't think of this yesterday...
>
>
> tks
>
>
> 73
> Frank
> W3LPL
>
>
>
>
>
>
>
> ----- Original Message -----
>
> From: "Wayne Burdick" <[hidden email]>
> To: "Elecraft" <[hidden email]>
> Sent: Sunday, May 13, 2018 4:06:51 PM
> Subject: Re: [Elecraft] K3 Strange Power Output Problem
>
> I have to admit, operating SPLIT between a ham band and a MARS band that falls outside the nearest ham-band filter isn’t something that occurred to me when writing the firmware. But I can change the filter selection algorithm to accommodate this case as long as a KBPF3 module is installed.
>
> Technical details:
>
> Since the K3/K3S is a downconversion superhet, we use very narrow ham-band filters. One of the narrowest is the 30 meter filter.
>
> To preserve the rig’s exceptional dynamic range, we switch the band pass filters with relays, not diodes. This means we can’t switch filters at T/R rates.
>
> So to handle the case being discussed, we’d have to select the 7-10 MHz KBPF3 filter for both RX and TX.
>
> 73,
> Wayne
> N6KR
>
>
> ----
> http://www.elecraft.com
>
>> On May 13, 2018, at 6:10 AM, Wes Stewart <[hidden email]> wrote:
>>
>> Another reading comprehension problem.
>>
>>> On 5/12/2018 1:36 PM, Mark E. Musick wrote:
>>> Hi Ed,
>>> You don't have a transmit problem at all. It is not an anomaly.
>>> The amateur band starts at 10.100 MHz. You shouldn't be transmitting below that frequency.
>>>
>>> Hello,
>>> I noticed this power output anomaly today while trying to work the NSS station. My K3 was in split mode, transmitting on 10.113.5.
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

donovanf

Re: K3 Strange Power Output Problem

Hi Don,

Fortunately I have a year to implement a solution! If worse comes
to a worse, I could use a small external T/R relay to switch the
antenna between K3 ANT1 and the KRX3 sub receiver AUX input...

Is any publicly available performance data available for the low
pass and bandpass filters in the K3 and the KBPF3?

Its hard to devise a solution without this knowledge!

Thanks for your help!

73
Frank
W3LPL

----- Original Message -----

From: "Don Wilhelm" <[hidden email]>
To: [hidden email], "Elecraft" <[hidden email]>
Sent: Monday, May 14, 2018 12:02:17 AM
Subject: Re: [Elecraft] K3 Strange Power Output Problem

Frank,

You still have the K3 Low Pass Filters to deal with.
The KBPF3 in the sub and the use of a separate RX antenna may produce
better results.

But then Wayne is the guy to say what other obstacles might be in the way.

73,
Don W3FPR

On 5/13/2018 7:45 PM, [hidden email] wrote:

Bob Wilson, N6TV

Re: K3 Strange Power Output Problem

In reply to this post by donovanf

On Sun, May 13, 2018 at 5:17 PM, <[hidden email]> wrote:

> Its hard to devise a solution without this knowledge!

Frank,

It's also hard to suggest a solution without a clear understanding of the
problem, which seems different than N3CW's original question.

It's not clear to me what you need to achieve at NSS. I think you are
saying you want listen to *both* widely-separated frequencies at the same
time, using different antennas, one for the MAIN, one for the SUB? Or
maybe you want to use the TX antenna for both receivers? Or maybe a
separate RX antenna for both receivers?

The SUB listens to either what is selected by MAIN (RX ANT or TX ANT) or to
AUX, which is a totally separate RX ANT input that seems to bypass all the
filters in the MAIN. With the SUB on, hold RX ANT to switch the SubRx to
listen on AUX. This is a perfect input if your RX antenna is miles away
from your TX antenna, which I assume is the case at NSS.

Otherwise, if you want to listen to the TX ANT with both receivers, feed RX
ANT OUT to *both* RX ANT IN *and* to AUX via an external 50 ohm splitter
such as the Mini-Circuits ZFSC-2-6
<https://www.minicircuits.com/pdfs/ZFSC-2-6%2B.pdf>, and now both receivers
are listening to the same antenna, but with totally different receive paths.

If you want to listen to a dedicated well-separated RX antenna in both
receivers, instead of listening on the TX antenna, use an external splitter
to feed the RX antenna to both RX ANT IN and to AUX.

Repeating, do not use SPLIT mode, just tap SUB to TX on A, receive on both
A and B, or just receive on B (CONFIG:L-MIX-R B B), whatever you require.

73,
Bob, N6TV

On Sun, May 13, 2018 at 4:45 PM, <[hidden email]> wrote:

DaleJ

Re: K3 Strange Power Output Problem

In reply to this post by Ed G

I had this same problem operating split while listening to 18.150 and transmitting on 16.298.5 the K3s would show zero output. However operating split from 20 meters to 16.298.5 worked. Yes I have the KBPF3, The other freq’s we used split worked fine.

Dale, K9VUJ/AFA5DJ
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

donovanf

Re: K3 Strange Power Output Problem

In reply to this post by Bob Wilson, N6TV

Hi Bob,

Thanks, I'll try your ideas. We have a year to get ready for our next
NSS operation...

NSS was a Field Day style operation with AB-577 towers, all of the
NSS towers and buildings were demolished 20 years ago except for
three 600 foot towers that are all in the red zone of a firing range!
Because its a Field Day style operation, we don't have enough time
to install separate receiving antennas despite our 500+ acre NSS site...

Our objective is to transmit on our assigned MARS frequencies outside
the ham bands (e.g., 9448 kHz) and listen inside the adjacent ham band
(e.g., 10128 kHz). We don't need to listen to both frequencies at the
same time.

Our K3 main receiver and KRX3 subreceiver share the same antenna
and the transceivers have KBPF3 bandpass filters installed in the
main receiver only .

Before we began NSS operations on Saturday morning we had no idea
that the K3 could not perform out of ham band split operations without
using the KRX3 sub receiver. When we realized that our transmit
power output was severely reduced by using wide split (e.g.,
9448 / 10128 kHz) we started to search for a solution...

We were not successful using the K3 transceivers with a wide split
so on those bands with wide splits (e;g., 9448/10128) we removed
the K3 transceivers and substituted our old FT-1000MPs instead.
They worked very well and were very easy to use. The K3 is far
from easy to use in this application!

As was suggested, operation of the K3 transceiver to meet our needs is
much easier if we install a KBPF3 in each KRX3 subreceiver, since
K3 operators almost always use their KRX3 sub receiver with SPLIT
enabled, which forces the transmitter to transmit on the sub receive
frequency. But a KRX3 sub receiver with no KBPF3 installed
can't listen outside the ham bands where we transmit. So the
commonly used SPLIT operation with the KRX3 can't meet our needs
with our K3 transceivers with no KBPF3 installed in our KRX3 sub receivers

If I had known not to tap SPLIT as I've always done when not transmitting
on MARS frequencies, I may have been successful since we would then
have been transmitting through the Main Receiver KBPF3 on the
VFO A MARS frequency, and listening to the KRX3 sub receiver
in the ham bands.

I'll try split operation on 9448/10128 well before next year by not using
SPLIT and listening on 10128 with the KRX3 sub receiver...

Thanks Bob,

73
Frank
W3LPL

----- Original Message -----

From: "Bob Wilson, N6TV" <[hidden email]>
To: "Frank Donovan, W3LPL" <[hidden email]>, "Elecraft Reflector" <[hidden email]>
Sent: Monday, May 14, 2018 12:34:36 AM
Subject: Re: [Elecraft] K3 Strange Power Output Problem

On Sun, May 13, 2018 at 5:17 PM, < [hidden email] > wrote:

Its hard to devise a solution without this knowledge!

Frank,

It's also hard to suggest a solution without a clear understanding of the problem, which seems different than N3CW's original question.

It's not clear to me what you need to achieve at NSS. I think you are saying you want listen to both widely-separated frequencies at the same time, using different antennas, one for the MAIN, one for the SUB? Or maybe you want to use the TX antenna for both receivers? Or maybe a separate RX antenna for both receivers?

The SUB listens to either what is selected by MAIN (RX ANT or TX ANT) or to AUX, which is a totally separate RX ANT input that seems to bypass all the filters in the MAIN. With the SUB on, hold RX ANT to switch the SubRx to listen on AUX. This is a perfect input if your RX antenna is miles away from your TX antenna, which I assume is the case at NSS.

Otherwise, if you want to listen to the TX ANT with both receivers, feed RX ANT OUT to both RX ANT IN and to AUX via an external 50 ohm splitter such as the Mini-Circuits ZFSC-2-6 , and now both receivers are listening to the same antenna, but with totally different receive paths.

If you want to listen to a dedicated well-separated RX antenna in both receivers, instead of listening on the TX antenna , use an external splitter to feed the RX antenna to both RX ANT IN and to AUX.

Repeating, do not use SPLIT mode, just tap SUB to TX on A, receive on both A and B, or just receive on B (CONFIG:L-MIX-R B B), whatever you require.

73,
Bob, N6TV

On Sun, May 13, 2018 at 4:45 PM, < [hidden email] > wrote:

<blockquote>
Hi Wayne,

The MARS to ham band K3 cross-band problem affects every band,
but it was extremely severe on 30 meters because the NSS assigned
frequency -- 9448 kHz -- was almost 700 kHz from our typical
10128 kHz receiving frequency.

Since switching between the K3 bandpass filters and the KBPF3
band pass filters at T/R rates isn't a workable solution, how about
this external BNC cable solution since my K3 transceivers have
KRX3 sub receivers?

If I understand the K3 internal receiver antenna switching correctly
a single external BNC jumper cable allows the K3 to transmit and
receive on VFO A on MARS frequencies and listen to any amateur
band on the sub receiver:

- Connect the RX ANT OUT connector to the RX ANT IN connector

- Tap the main RX ANT button which connects ANT 1 to the RX ANT OUT
connector and switches the input of the main receiver to the RX ANT IN
connector (connected by the external BNC cable to RX ANT OUT)

- Tap SUB to turn the sub receiver on

- Hold BSET and tap ANT to set the sub receiver input to MAIN. This
allows the subreceiver to listen on the RX ANT connected to the main
receiver.

I'm sorry I didn't think of this yesterday...

tks

73
Frank
W3LPL
</blockquote>

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]