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How to Isolate 2nd Transceiver in two Radio Base Station (WU6R / Mark)

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How to Isolate 2nd Transceiver in two Radio Base Station (WU6R / Mark)

I see lots shack photos with two transceiver setups, especially two Elecraft K3S radios; how do you isolate the 2nd transceiver or SDR receiver (SDR Play, for example) so that you do not damage one transceiver while transmitting with the other? I am assuming there is a way to use both radios at the same time.

Can I safely use an antenna switch to switch between multiple transceivers using one antenna, or will I risk damaging the non-transmitting radio on the other side of the antenna switch?

If there is a way to do this can anyone explain their setup?

Thanks.

Mark
WU6R
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Dick Dievendorff-4

Re: How to Isolate 2nd Transceiver in two Radio Base Station (WU6R / Mark)

I just googled “bandpass filter so2r” and found a number of useful discussions and product references on this topic.

73 de Dick, K6KR

> On Jan 1, 2019, at 04:34, Mark Wheeler via Elecraft <[hidden email]> wrote:
>
>
> I see lots shack photos with two transceiver setups, especially two Elecraft K3S radios; how do you isolate the 2nd transceiver or SDR receiver (SDR Play, for example) so that you do not damage one transceiver while transmitting with the other? I am assuming there is a way to use both radios at the same time.
>
> Can I safely use an antenna switch to switch between multiple transceivers using one antenna, or will I risk damaging the non-transmitting radio on the other side of the antenna switch?
>
> If there is a way to do this can anyone explain their setup?
>
> Thanks.
>
> Mark
> WU6R
> ______________________________________________________________
> 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]

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Roger-3

Re: How to Isolate 2nd Transceiver in two Radio Base Station (WU6R / Mark)

In reply to this post by Elecraft mailing list

Mark,

it mainly depends on the "between port isolation" of the switch that you are
going to use and the output power. There are some minor things to pay
attention too like a poor quality (= poor shielded) interconnection cable. A
10 ft coax with poor shielding can pick up enough energy (especially under
high power conditions) to put your receiver/s on risk. The higher the
frequency and the higher the power you are running the higher will be the
picked up power with all other variables constant.

A typical laboratory grade switch will have an isolation of 100 dB or more.
Thats how good the shielding of your cable has to be in order to take
advantage of the switch´s isolation. A typical ham radio coax switch (DAIWA,
Ameritron, MFJ, ALPHA Delta and alike) has about 60 dB at best and sometimes
only 40 dB at 28 MHz. With one kilowatt on the port in use you have 100 mW
(S 9+93!!) leaking thru to the unused ports. How much it is exactly depends
on the length of the cable connected to the unused port and the termination
(radio on or off etc.)

If 2 radios to one antenna (or vice versa) is all you need then a two-way
coax switch could provide some extra relief as you can terminate the unused
port with 50 ohms and get another few dB of isolation. Multiport switches
for 3,4,5 or more ports with isolation more than 80 dB are hard to get and
EXPENSIVE!

Roger/DL5RBW

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Don Wilhelm

Re: How to Isolate 2nd Transceiver in two Radio Base Station (WU6R / Mark)

In reply to this post by Elecraft mailing list

Mark,

The assumption that "there is a way to use both radios at the same time"
is the real base of the problem.

A lot depends on the power level you are running - the problem get worse
as the power is increased.

If you can reduce the pickup on the antenna used by the non-transmitting
radio, that will help a lot. A horizontal antenna on one and a vertical
on the other radio may be sufficient at lower powers. Physical
separation between the antennas will help as well, as well as good
common mode chokes on the feedline - use one at each end of the feedline
to choke off RF that is picked up on the non-transmit feedline.

If you do not have to listen to the non-transmit radio(s) during
transmitting, the problem becomes one of only protecting the other
radio(s) front end. There are devices to accomplish that, or you could
simplify things by adding a relay that is activated to short the input
of the non-transmit radio when transmitting by the other radio. That
relay (or relays) can be activated by the transmitting radio's amp
keying output.

As you can imagine, this can get complicated with only 2 radios, but you
also mentioned the inclusion of SDRplay, which may mean more than 2
receivers, and the situation becomes even more complex.

73,
Don W3FPR

On 1/1/2019 7:34 AM, Mark Wheeler via Elecraft wrote:

>
> I see lots shack photos with two transceiver setups, especially two
> Elecraft K3S radios; how do you isolate the 2nd transceiver or SDR
> receiver (SDR Play, for example) so that you do not damage one
> transceiver while transmitting with the other? I am assuming there is a
> way to use both radios at the same time.
>
> Can I safely use an antenna switch to switch between multiple
> transceivers using one antenna, or will I risk damaging the
> non-transmitting radio on the other side of the antenna switch?

Elecraft mailing list

Re: How to Isolate 2nd Transceiver in two Radio Base Station (WU6R / Mark)

In reply to this post by Elecraft mailing list

Don,

Thank you.
Mark

On Jan 01, 2019, at 10:14 AM, Don Wilhelm <[hidden email]> wrote:

Mark,

The assumption that "there is a way to use both radios at the same time"
is the real base of the problem.

A lot depends on the power level you are running - the problem get worse
as the power is increased.

If you can reduce the pickup on the antenna used by the non-transmitting
radio, that will help a lot. A horizontal antenna on one and a vertical
on the other radio may be sufficient at lower powers. Physical
separation between the antennas will help as well, as well as good
common mode chokes on the feedline - use one at each end of the feedline
to choke off RF that is picked up on the non-transmit feedline.

If you do not have to listen to the non-transmit radio(s) during
transmitting, the problem becomes one of only protecting the other
radio(s) front end. There are devices to accomplish that, or you could
simplify things by adding a relay that is activated to short the input
of the non-transmit radio when transmitting by the other radio. That
relay (or relays) can be activated by the transmitting radio's amp
keying output.

As you can imagine, this can get complicated with only 2 radios, but you
also mentioned the inclusion of SDRplay, which may mean more than 2
receivers, and the situation becomes even more complex.

73,
Don W3FPR

On 1/1/2019 7:34 AM, Mark Wheeler via Elecraft wrote:

I see lots shack photos with two transceiver setups, especially two
Elecraft K3S radios; how do you isolate the 2nd transceiver or SDR
receiver (SDR Play, for example) so that you do not damage one
transceiver while transmitting with the other? I am assuming there is a
way to use both radios at the same time.

Can I safely use an antenna switch to switch between multiple
transceivers using one antenna, or will I risk damaging the
non-transmitting radio on the other side of the antenna switch?
______________________________________________________________
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Help: http://mailman.qth.net/mmfaq.htm
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Elecraft mailing list

Re: How to Isolate 2nd Transceiver in two Radio Base Station (WU6R / Mark)

In reply to this post by Elecraft mailing list

Dick,

Thanks.
Mark

On Jan 01, 2019, at 07:46 AM, Dick Dievendorff <[hidden email]> wrote:

I just googled “bandpass filter so2r” and found a number of useful discussions and product references on this topic.

73 de Dick, K6KR

On Jan 1, 2019, at 04:34, Mark Wheeler via Elecraft <[hidden email]> wrote:

I see lots shack photos with two transceiver setups, especially two Elecraft K3S radios; how do you isolate the 2nd transceiver or SDR receiver (SDR Play, for example) so that you do not damage one transceiver while transmitting with the other? I am assuming there is a way to use both radios at the same time.

Can I safely use an antenna switch to switch between multiple transceivers using one antenna, or will I risk damaging the non-transmitting radio on the other side of the antenna switch?

If there is a way to do this can anyone explain their setup?

Thanks.

Mark
WU6R
______________________________________________________________
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Help: http://mailman.qth.net/mmfaq.htm
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john@kk9a.com

Re: How to Isolate 2nd Transceiver in two Radio Base Station (WU6R / Mark)

In reply to this post by Elecraft mailing list

Two transceivers is a typical contesting setup. I do not believe that you
are contester so it would probably have little value to you. Typically a two
radio station on operator setup (SO2R) has one transceiver on one band and
the other on a different band with filters to protect the receivers. With
super human operating skills very high run rates are possible:
https://www.youtube.com/watch?v=bIW1Z1uFbRw&t=259s

John KK9A

Mark Wheeler mark3575 at icloud.com

I see lots shack photos with two transceiver setups, especially two Elecraft
K3S radios; how do you isolate the 2nd transceiver or SDR receiver (SDR
Play, for example) so that you do not damage one transceiver while
transmitting with the other? I am assuming there is a way to use both
radios at the same time.

Can I safely use an antenna switch to switch between multiple transceivers
using one antenna, or will I risk damaging the non-transmitting radio on the
other side of the antenna switch?

If there is a way to do this can anyone explain their setup?

Thanks.

Mark
WU6R

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

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Please help support this email list: http://www.qsl.net/donate.html
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Bob McGraw - K4TAX

Re: How to Isolate 2nd Transceiver in two Radio Base Station (WU6R / Mark)

Think Field Day where it is normal to run several transceivers at the same time. Antenna separation and orientation is a key factor plus good quality band pass filters for each radio.

Bob, K4TAX

Sent from my iPhone

> On Jan 1, 2019, at 11:27 AM, <[hidden email]> <[hidden email]> wrote:
>
> Two transceivers is a typical contesting setup. I do not believe that you
> are contester so it would probably have little value to you. Typically a two
> radio station on operator setup (SO2R) has one transceiver on one band and
> the other on a different band with filters to protect the receivers. With
> super human operating skills very high run rates are possible:
> https://www.youtube.com/watch?v=bIW1Z1uFbRw&t=259s
>
> John KK9A
>
>
>
> Mark Wheeler mark3575 at icloud.com
>
> I see lots shack photos with two transceiver setups, especially two Elecraft
> K3S radios; how do you isolate the 2nd transceiver or SDR receiver (SDR
> Play, for example) so that you do not damage one transceiver while
> transmitting with the other? I am assuming there is a way to use both
> radios at the same time.
>
> Can I safely use an antenna switch to switch between multiple transceivers
> using one antenna, or will I risk damaging the non-transmitting radio on the
> other side of the antenna switch?
>
> If there is a way to do this can anyone explain their setup?
>
> Thanks.
>
> Mark
> WU6R
>
> ______________________________________________________________
> 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

Re: How to Isolate 2nd Transceiver in two Radio Base Station (WU6R / Mark)

In reply to this post by john@kk9a.com

Mark

The MFJ 1708-SDR will isolate a second rig/recover (designed more for SDR devices like the SDPplay) while the main rig transmits.

https://www.hamradio.com/detail.cfm?pid=H0-016017

This is not a classic SO2R setup.

Paul
W6PNG/M0SN

> On Jan 1, 2019, at 9:27 AM, <[hidden email]> <[hidden email]> wrote:
>
> Two transceivers is a typical contesting setup. I do not believe that you
> are contester so it would probably have little value to you. Typically a two
> radio station on operator setup (SO2R) has one transceiver on one band and
> the other on a different band with filters to protect the receivers. With
> super human operating skills very high run rates are possible:
> https://www.youtube.com/watch?v=bIW1Z1uFbRw&t=259s
>
> John KK9A
>
>
>
> Mark Wheeler mark3575 at icloud.com
>
> I see lots shack photos with two transceiver setups, especially two Elecraft
> K3S radios; how do you isolate the 2nd transceiver or SDR receiver (SDR
> Play, for example) so that you do not damage one transceiver while
> transmitting with the other? I am assuming there is a way to use both
> radios at the same time.
>
> Can I safely use an antenna switch to switch between multiple transceivers
> using one antenna, or will I risk damaging the non-transmitting radio on the
> other side of the antenna switch?
>
> If there is a way to do this can anyone explain their setup?
>
> Thanks.
>
> Mark
> WU6R
>
> ______________________________________________________________
> 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

Re: How to Isolate 2nd Transceiver in two Radio Base Station (WU6R / Mark)

In reply to this post by Bob McGraw - K4TAX

Thanks Bob.

Mark

> On Jan 1, 2019, at 1:22 PM, Bob McGraw K4TAX <[hidden email]> wrote:
>
> Think Field Day where it is normal to run several transceivers at the same time. Antenna separation and orientation is a key factor plus good quality band pass filters for each radio.
>
> Bob, K4TAX
>
>
> Sent from my iPhone
>
>> On Jan 1, 2019, at 11:27 AM, <[hidden email]> <[hidden email]> wrote:
>>
>> Two transceivers is a typical contesting setup. I do not believe that you
>> are contester so it would probably have little value to you. Typically a two
>> radio station on operator setup (SO2R) has one transceiver on one band and
>> the other on a different band with filters to protect the receivers. With
>> super human operating skills very high run rates are possible:
>> https://www.youtube.com/watch?v=bIW1Z1uFbRw&t=259s
>>
>> John KK9A
>>
>>
>>
>> Mark Wheeler mark3575 at icloud.com
>>
>> I see lots shack photos with two transceiver setups, especially two Elecraft
>> K3S radios; how do you isolate the 2nd transceiver or SDR receiver (SDR
>> Play, for example) so that you do not damage one transceiver while
>> transmitting with the other? I am assuming there is a way to use both
>> radios at the same time.
>>
>> Can I safely use an antenna switch to switch between multiple transceivers
>> using one antenna, or will I risk damaging the non-transmitting radio on the
>> other side of the antenna switch?
>>
>> If there is a way to do this can anyone explain their setup?
>>
>> Thanks.
>>
>> Mark
>> WU6R
>>
>> ______________________________________________________________
>> 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]
>>
>
>