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K3 Receiver Protection

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K3 Receiver Protection

My station consists of two K-3's, each with a dedicated legal limit amplifier and SteppIr antenna. To minimize interference between bands I am using Array Solutions Bandpass filters. However, if both rigs accidentally wind up on the same band I run the risk of overloading the front end of the opposite rig and damaging the receiver (which I've done once...). Does anyone have a way of taking the band data information and disabling transmit capability on both rigs if they are on the same band? How are others using SO2R avoiding same band transmission and subsequent receiver damage? Anyone have any experience with the Array Solutions AS-RXFEP front end protector?

Thanks,
Jeff Larimore
K0RG
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Don Wilhelm-4

Re: K3 Receiver Protection

Jeff,

That is a logic question seeking an answer. I don't know of a simple
solution, but it is a matter of selecting a match of the outputs of 2
band data decoders. If any two are the same, assert TX INH to both K3s.

That function could be implemented with a number of NAND gates or XOR
gates at the outputs of the 2 band decoders. The exact implementation
of the logic gates is "left to the student", there are several
possibilities, but it would take a number of external logic gates to
implement.

If you are really into logical devices, you could program a chip to do
that directly from the band data outputs - if all 4 of the outputs from
both K3s are a match, assert TX INH to both transceivers.

I do not know of an existing device that will provide that function, so
the implementation would have to be created 'from scratch'. Yes, it is
possible, it is just a matter of "a few logic gates".

73,
Don W3FPR

On 6/1/2014 12:04 AM, Jeff via Elecraft wrote:
> My station consists of two K-3's, each with a dedicated legal limit amplifier and SteppIr antenna. To minimize interference between bands I am using Array Solutions Bandpass filters. However, if both rigs accidentally wind up on the same band I run the risk of overloading the front end of the opposite rig and damaging the receiver (which I've done once...). Does anyone have a way of taking the band data information and disabling transmit capability on both rigs if they are on the same band? How are others using SO2R avoiding same band transmission and subsequent receiver damage? Anyone have any experience with the Array Solutions AS-RXFEP front end protector?
>

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Win Kriegl DK9IP/KH7CD

Re: K3 Receiver Protection

In reply to this post by Elecraft mailing list

Hi Jeff,

I have done that by comparing BAND DATA signals from both K3s using a
74HC688 8-Bit Comparator. When both BAND DATA signals are equal the P=Q
output from the HC688 disables transmitting on both K3s (TXinh). I used
the HC688 because I have decimal BAND DATA signals from my band filter.
If you want 12V logic or only need 4 Bit (BCD BAND DATA) you can use
CMOS 4063 (4-Bit Comparator) as well.

This circuit saved K3 frontend several times :-)

73, Win DK9IP

Am 01.06.2014 06:04, schrieb Jeff via Elecraft:

>
> My station consists of two K-3's, each with a dedicated legal limit amplifier and SteppIr antenna. To minimize interference between bands I am using Array Solutions Bandpass filters. However, if both rigs accidentally wind up on the same band I run the risk of overloading the front end of the opposite rig and damaging the receiver (which I've done once...). Does anyone have a way of taking the band data information and disabling transmit capability on both rigs if they are on the same band? How are others using SO2R avoiding same band transmission and subsequent receiver damage? Anyone have any experience with the Array Solutions AS-RXFEP front end protector?
>
> Thanks,
> Jeff Larimore
> K0RG
> ______________________________________________________________
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dmb@lightstream.net

Re: K3 Receiver Protection

In reply to this post by Elecraft mailing list

Hello Jeff,

I use the Array Solutions AS-RXFEP inline w/ my K3 AUX (2nd rx input). At
times the rx antenna is within 20 feet of the tx antenna. Without the
protector in place the receiver COR relay was being triggered with as
little as 20 watts at times, but with the RXFEP inserted, I could run 500W
from the KPA500 without ever engaging the COR. According to the Array
Solutions documentation, the input to the receiver is limited to .3v
(0dBm), and the internal components of the device can handle 10 watts.

I keep the device inline with the 2nd receiver input at all times,
regardless of which rx antenna I'm using, and it has worked perfectly (and
silently).

73, Dale
WA8SRA

>
> My station consists of two K-3's, each with a dedicated legal limit
> amplifier and SteppIr antenna. To minimize interference between bands I am
> using Array Solutions Bandpass filters. However, if both rigs accidentally
> wind up on the same band I run the risk of overloading the front end of
> the opposite rig and damaging the receiver (which I've done once...). Does
> anyone have a way of taking the band data information and disabling
> transmit capability on both rigs if they are on the same band? How are
> others using SO2R avoiding same band transmission and subsequent receiver
> damage? Anyone have any experience with the Array Solutions AS-RXFEP front
> end protector?
>
> Thanks,
> Jeff Larimore
> K0RG
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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Phil Salas

Re: K3 Receiver Protection

In reply to this post by Don Wilhelm-4

Take a look at the transceiver front-end protector in the “Articles” section of my website at www.ad5x.com. It operates full QSK (I tested it to 80WPM). Works great.

Phil – AD5X
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Richard Thorne-4

Re: K3 Receiver Protection

In reply to this post by Elecraft mailing list

Larry,

The Microham mk2r+ will do exactly what you want to accomplish. If both
rigs are on the same frequency, neither will transmit.

It is, however, an expensive solution. I was lucky and picked up a used
one at a very good price.

Rich - N5ZC

On 5/31/2014 11:04 PM, Jeff via Elecraft wrote:

> My station consists of two K-3's, each with a dedicated legal limit amplifier and SteppIr antenna. To minimize interference between bands I am using Array Solutions Bandpass filters. However, if both rigs accidentally wind up on the same band I run the risk of overloading the front end of the opposite rig and damaging the receiver (which I've done once...). Does anyone have a way of taking the band data information and disabling transmit capability on both rigs if they are on the same band? How are others using SO2R avoiding same band transmission and subsequent receiver damage? Anyone have any experience with the Array Solutions AS-RXFEP front end protector?
>
> Thanks,
> Jeff Larimore
> K0RG
> ______________________________________________________________
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Joe Subich, W4TV-4

Re: K3 Receiver Protection

In reply to this post by Elecraft mailing list

> How are others using SO2R avoiding same band transmission and
> subsequent receiver damage?

SO2R controllers like the microHAM MK2R+ have built-in "same band"
interlocks that prevent PTT if both rigs are on the same band or
if one rig stops responding to control polling. Some of the "contest"
software also prevents selecting the same band on both rigs.

I have not seen any dedicated hardware that compares "band data" from
the K3 or Yaesu rigs and opens the PTT lines or asserts the inhibit
lines if both rigs are on the same band but it would not be difficult
to do so with a PIC or even a programmable gate array.

73,

... Joe, W4TV

On 2014-06-01 12:04 AM, Jeff via Elecraft wrote:

>
> My station consists of two K-3's, each with a dedicated legal limit
> amplifier and SteppIr antenna. To minimize interference between bands
> I am using Array Solutions Bandpass filters. However, if both rigs
> accidentally wind up on the same band I run the risk of overloading
> the front end of the opposite rig and damaging the receiver (which
> I've done once...). Does anyone have a way of taking the band data
> information and disabling transmit capability on both rigs if they
> are on the same band? How are others using SO2R avoiding same band
> transmission and subsequent receiver damage? Anyone have any
> experience with the Array Solutions AS-RXFEP front end protector?
>
> Thanks, Jeff Larimore K0RG
> ______________________________________________________________
> Elecraft mailing list Home:
> http://mailman.qth.net/mailman/listinfo/elecraft Help:
> http://mailman.qth.net/mmfaq.htm Post:
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Joe Subich, W4TV-4

Re: K3 Receiver Protection

A simple interlock can be built with a single quad XOR gate package,
half a dual 4 input NOR package and a few transistors/resistors if one
is driving the inhibit input. Add half of a quad NOR gate package if
you want to disable PTT.

73,

... Joe, W4TV

On 2014-06-01 10:54 AM, Joe Subich, W4TV wrote:

>
>> How are others using SO2R avoiding same band transmission and
>> subsequent receiver damage?
>
> SO2R controllers like the microHAM MK2R+ have built-in "same band"
> interlocks that prevent PTT if both rigs are on the same band or
> if one rig stops responding to control polling. Some of the "contest"
> software also prevents selecting the same band on both rigs.
>
> I have not seen any dedicated hardware that compares "band data" from
> the K3 or Yaesu rigs and opens the PTT lines or asserts the inhibit
> lines if both rigs are on the same band but it would not be difficult
> to do so with a PIC or even a programmable gate array.
>
> 73,
>
> ... Joe, W4TV
>
>
> On 2014-06-01 12:04 AM, Jeff via Elecraft wrote:
>>
>> My station consists of two K-3's, each with a dedicated legal limit
>> amplifier and SteppIr antenna. To minimize interference between bands
>> I am using Array Solutions Bandpass filters. However, if both rigs
>> accidentally wind up on the same band I run the risk of overloading
>> the front end of the opposite rig and damaging the receiver (which
>> I've done once...). Does anyone have a way of taking the band data
>> information and disabling transmit capability on both rigs if they
>> are on the same band? How are others using SO2R avoiding same band
>> transmission and subsequent receiver damage? Anyone have any
>> experience with the Array Solutions AS-RXFEP front end protector?
>>
>> Thanks, Jeff Larimore K0RG
>> ______________________________________________________________
>> 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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Elecraft mailing list

Re: K3 Receiver Protection

In reply to this post by Don Wilhelm-4

This would be a good place to use an Arduino. If the serial ports of
the K3s are available, it would only take a small bit of code to achieve
this.

Doug -- K0DXV

On 05/31/2014 10:46 PM, Don Wilhelm wrote:

> Jeff,
>
> That is a logic question seeking an answer. I don't know of a simple
> solution, but it is a matter of selecting a match of the outputs of 2
> band data decoders. If any two are the same, assert TX INH to both K3s.
>
> That function could be implemented with a number of NAND gates or XOR
> gates at the outputs of the 2 band decoders. The exact implementation
> of the logic gates is "left to the student", there are several
> possibilities, but it would take a number of external logic gates to
> implement.
>
> If you are really into logical devices, you could program a chip to do
> that directly from the band data outputs - if all 4 of the outputs
> from both K3s are a match, assert TX INH to both transceivers.
>
> I do not know of an existing device that will provide that function,
> so the implementation would have to be created 'from scratch'. Yes,
> it is possible, it is just a matter of "a few logic gates".
>
> 73,
> Don W3FPR
>
> On 6/1/2014 12:04 AM, Jeff via Elecraft wrote:
>> My station consists of two K-3's, each with a dedicated legal limit
>> amplifier and SteppIr antenna. To minimize interference between bands
>> I am using Array Solutions Bandpass filters. However, if both rigs
>> accidentally wind up on the same band I run the risk of overloading
>> the front end of the opposite rig and damaging the receiver (which
>> I've done once...). Does anyone have a way of taking the band data
>> information and disabling transmit capability on both rigs if they
>> are on the same band? How are others using SO2R avoiding same band
>> transmission and subsequent receiver damage? Anyone have any
>> experience with the Array Solutions AS-RXFEP front end protector?
>>
>
> ______________________________________________________________
> 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]
>

Joe Subich, W4TV-4

Re: K3 Receiver Protection

> If the serial ports of the K3s are available,

They tend not to be when doing SO2R - the logger has them tied up.
Of course if the Arduino is capable of handling four 38,400 bps
ports at the same time one can pass the logger data through the
device.

73,

... Joe, W4TV

On 2014-06-01 11:19 AM, Doug Person via Elecraft wrote:

> This would be a good place to use an Arduino. If the serial ports of
> the K3s are available, it would only take a small bit of code to achieve
> this.
>
> Doug -- K0DXV
>
> On 05/31/2014 10:46 PM, Don Wilhelm wrote:
>> Jeff,
>>
>> That is a logic question seeking an answer. I don't know of a simple
>> solution, but it is a matter of selecting a match of the outputs of 2
>> band data decoders. If any two are the same, assert TX INH to both K3s.
>>
>> That function could be implemented with a number of NAND gates or XOR
>> gates at the outputs of the 2 band decoders. The exact implementation
>> of the logic gates is "left to the student", there are several
>> possibilities, but it would take a number of external logic gates to
>> implement.
>>
>> If you are really into logical devices, you could program a chip to do
>> that directly from the band data outputs - if all 4 of the outputs
>> from both K3s are a match, assert TX INH to both transceivers.
>>
>> I do not know of an existing device that will provide that function,
>> so the implementation would have to be created 'from scratch'. Yes,
>> it is possible, it is just a matter of "a few logic gates".
>>
>> 73,
>> Don W3FPR
>>
>> On 6/1/2014 12:04 AM, Jeff via Elecraft wrote:
>>> My station consists of two K-3's, each with a dedicated legal limit
>>> amplifier and SteppIr antenna. To minimize interference between bands
>>> I am using Array Solutions Bandpass filters. However, if both rigs
>>> accidentally wind up on the same band I run the risk of overloading
>>> the front end of the opposite rig and damaging the receiver (which
>>> I've done once...). Does anyone have a way of taking the band data
>>> information and disabling transmit capability on both rigs if they
>>> are on the same band? How are others using SO2R avoiding same band
>>> transmission and subsequent receiver damage? Anyone have any
>>> experience with the Array Solutions AS-RXFEP front end protector?
>>>
>>
>> ______________________________________________________________
>> 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
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alsopb

Re: K3 Receiver Protection

In reply to this post by Elecraft mailing list

While you're in the programming mode, how about some preventative medicine.

Prevent one rig from switching to a band that the other rig is on. If
it tries, switch back to the old band.

73 de Brian/K3KO

On 6/1/2014 11:19 AM, Doug Person via Elecraft wrote:

> This would be a good place to use an Arduino. If the serial ports of
> the K3s are available, it would only take a small bit of code to
> achieve this.
>
> Doug -- K0DXV
>
> On 05/31/2014 10:46 PM, Don Wilhelm wrote:
>> Jeff,
>>
>> That is a logic question seeking an answer. I don't know of a simple
>> solution, but it is a matter of selecting a match of the outputs of 2
>> band data decoders. If any two are the same, assert TX INH to both K3s.
>>
>> That function could be implemented with a number of NAND gates or XOR
>> gates at the outputs of the 2 band decoders. The exact
>> implementation of the logic gates is "left to the student", there are
>> several possibilities, but it would take a number of external logic
>> gates to implement.
>>
>> If you are really into logical devices, you could program a chip to
>> do that directly from the band data outputs - if all 4 of the outputs
>> from both K3s are a match, assert TX INH to both transceivers.
>>
>> I do not know of an existing device that will provide that function,
>> so the implementation would have to be created 'from scratch'. Yes,
>> it is possible, it is just a matter of "a few logic gates".
>>
>> 73,
>> Don W3FPR
>>
>> On 6/1/2014 12:04 AM, Jeff via Elecraft wrote:
>>> My station consists of two K-3's, each with a dedicated legal limit
>>> amplifier and SteppIr antenna. To minimize interference between
>>> bands I am using Array Solutions Bandpass filters. However, if both
>>> rigs accidentally wind up on the same band I run the risk of
>>> overloading the front end of the opposite rig and damaging the
>>> receiver (which I've done once...). Does anyone have a way of taking
>>> the band data information and disabling transmit capability on both
>>> rigs if they are on the same band? How are others using SO2R
>>> avoiding same band transmission and subsequent receiver damage?
>>> Anyone have any experience with the Array Solutions AS-RXFEP front
>>> end protector?
>>>
>>
>> ______________________________________________________________
>> 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
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>
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>
>
> -----
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>
>

Cady, Fred

Re: K3 Receiver Protection

In reply to this post by Joe Subich, W4TV-4

Check out a 74LS85 4 bit comparator. A single chip with the A=B output going to each of the K3's ACC pin 7, TX INH inputs.
73,
Fred KE7X

> -----Original Message-----
> From: Elecraft [mailto:[hidden email]] On Behalf Of
> Joe Subich, W4TV
> Sent: Sunday, June 01, 2014 9:28 AM
> To: [hidden email]
> Subject: Re: [Elecraft] K3 Receiver Protection
>
>
> > If the serial ports of the K3s are available,
>
> They tend not to be when doing SO2R - the logger has them tied up.
> Of course if the Arduino is capable of handling four 38,400 bps ports
> at the same time one can pass the logger data through the device.
>
> 73,
>
> ... Joe, W4TV
>
>
> On 2014-06-01 11:19 AM, Doug Person via Elecraft wrote:
> > This would be a good place to use an Arduino. If the serial ports of
> > the K3s are available, it would only take a small bit of code to
> > achieve this.
> >
> > Doug -- K0DXV
> >
> > On 05/31/2014 10:46 PM, Don Wilhelm wrote:
> >> Jeff,
> >>
> >> That is a logic question seeking an answer. I don't know of a
> simple
> >> solution, but it is a matter of selecting a match of the outputs of
> 2
> >> band data decoders. If any two are the same, assert TX INH to both
> K3s.
> >>
> >> That function could be implemented with a number of NAND gates or
> XOR
> >> gates at the outputs of the 2 band decoders. The exact
> >> implementation of the logic gates is "left to the student", there
> are
> >> several possibilities, but it would take a number of external logic
> >> gates to implement.
> >>
> >> If you are really into logical devices, you could program a chip to
> >> do that directly from the band data outputs - if all 4 of the
> outputs
> >> from both K3s are a match, assert TX INH to both transceivers.
> >>
> >> I do not know of an existing device that will provide that function,
> >> so the implementation would have to be created 'from scratch'. Yes,
> >> it is possible, it is just a matter of "a few logic gates".
> >>
> >> 73,
> >> Don W3FPR
> >>
> >> On 6/1/2014 12:04 AM, Jeff via Elecraft wrote:
> >>> My station consists of two K-3's, each with a dedicated legal limit
> >>> amplifier and SteppIr antenna. To minimize interference between
> >>> bands I am using Array Solutions Bandpass filters. However, if both
> >>> rigs accidentally wind up on the same band I run the risk of
> >>> overloading the front end of the opposite rig and damaging the
> >>> receiver (which I've done once...). Does anyone have a way of
> taking
> >>> the band data information and disabling transmit capability on both
> >>> rigs if they are on the same band? How are others using SO2R
> >>> avoiding same band transmission and subsequent receiver damage?
> >>> Anyone have any experience with the Array Solutions AS-RXFEP front
> end protector?
> >>>
> >>
> >> ______________________________________________________________
> >> 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]
> >
> ______________________________________________________________
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jeff stai-2

Re: K3 Receiver Protection

The simplest "get you there now" solution is to simply disable
complimentary bands in each K3. Set up the left radio for 80-20-10 and the
right radio for 160-40-15, for one example.

You didn't buy Steppirs to exclude bands on each radio, but this will give
you protection now while you pursue one of the other suggestions.
(Obviously, avoid using direct frequency entry to change bands...)

Also, highly recommend purchasing this book, for the next steps of keeping
one radio from bothering the other:

http://www.inrad.net/product.php?productid=248

Have fun! 73 jeff wk6i

On Sun, Jun 1, 2014 at 9:44 AM, Cady, Fred <[hidden email]> wrote:

> Check out a 74LS85 4 bit comparator. A single chip with the A=B output
> going to each of the K3's ACC pin 7, TX INH inputs.
> 73,
> Fred KE7X
>
>
> > -----Original Message-----
> > From: Elecraft [mailto:[hidden email]] On Behalf Of
> > Joe Subich, W4TV
> > Sent: Sunday, June 01, 2014 9:28 AM
> > To: [hidden email]
> > Subject: Re: [Elecraft] K3 Receiver Protection
> >
> >
> > > If the serial ports of the K3s are available,
> >
> > They tend not to be when doing SO2R - the logger has them tied up.
> > Of course if the Arduino is capable of handling four 38,400 bps ports
> > at the same time one can pass the logger data through the device.
> >
> > 73,
> >
> > ... Joe, W4TV
> >
> >
> > On 2014-06-01 11:19 AM, Doug Person via Elecraft wrote:
> > > This would be a good place to use an Arduino. If the serial ports of
> > > the K3s are available, it would only take a small bit of code to
> > > achieve this.
> > >
> > > Doug -- K0DXV
> > >
> > > On 05/31/2014 10:46 PM, Don Wilhelm wrote:
> > >> Jeff,
> > >>
> > >> That is a logic question seeking an answer. I don't know of a
> > simple
> > >> solution, but it is a matter of selecting a match of the outputs of
> > 2
> > >> band data decoders. If any two are the same, assert TX INH to both
> > K3s.
> > >>
> > >> That function could be implemented with a number of NAND gates or
> > XOR
> > >> gates at the outputs of the 2 band decoders. The exact
> > >> implementation of the logic gates is "left to the student", there
> > are
> > >> several possibilities, but it would take a number of external logic
> > >> gates to implement.
> > >>
> > >> If you are really into logical devices, you could program a chip to
> > >> do that directly from the band data outputs - if all 4 of the
> > outputs
> > >> from both K3s are a match, assert TX INH to both transceivers.
> > >>
> > >> I do not know of an existing device that will provide that function,
> > >> so the implementation would have to be created 'from scratch'. Yes,
> > >> it is possible, it is just a matter of "a few logic gates".
> > >>
> > >> 73,
> > >> Don W3FPR
> > >>
> > >> On 6/1/2014 12:04 AM, Jeff via Elecraft wrote:
> > >>> My station consists of two K-3's, each with a dedicated legal limit
> > >>> amplifier and SteppIr antenna. To minimize interference between
> > >>> bands I am using Array Solutions Bandpass filters. However, if both
> > >>> rigs accidentally wind up on the same band I run the risk of
> > >>> overloading the front end of the opposite rig and damaging the
> > >>> receiver (which I've done once...). Does anyone have a way of
> > taking
> > >>> the band data information and disabling transmit capability on both
> > >>> rigs if they are on the same band? How are others using SO2R
> > >>> avoiding same band transmission and subsequent receiver damage?
> > >>> Anyone have any experience with the Array Solutions AS-RXFEP front
> > end protector?
> > >>>
> > >>
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