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Diversity reception in the K3

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DaleJ

Diversity reception in the K3

Going beyond pushing a button, could someone explain how diversity reception is accomplished in the K3? How are the two receivers locked together, phase coherently.

Tnx 73
Dale, K9VUJ
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gm3sek

Re: Diversity reception in the K3

The frequencies of the two receivers in the K3 are locked together for
diversity by sending identical instructions to the two identical
synthesizers which also share the same clock oscillator.

RF phase doesn't need to be coherent for diversity reception as
implemented in the K3, because the two signals are only combined at
audio frequency (usually between the operator's ears). There may be
small difference in time delay (group delay) through the roofing filters
in the two receivers but in practice this doesn't seem to be a problem.

73 from Ian GM3SEK

>-----Original Message-----
>From: Elecraft [mailto:[hidden email]] On Behalf Of
>DaleJ
>Sent: 18 January 2015 09:28
>To: [hidden email]
>Subject: [Elecraft] Diversity reception in the K3
>
>Going beyond pushing a button, could someone explain how diversity
>reception is accomplished in the K3? How are the two receivers locked
>together, phase coherently.
>
>Tnx 73
>Dale, K9VUJ
>______________________________________________________________
>Elecraft mailing list
>Home: http://mailman.qth.net/mailman/listinfo/elecraft
>Help: http://mailman.qth.net/mmfaq.htm
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>
>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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NY6C

Re: Diversity reception in the K3

I use diversity receive quite a bit. It was actually the main thing that got me looking at a K3 in the first place…great feature.

-Greg NY6C

> On Jan 18, 2015, at 5:48 AM, Ian White <[hidden email]> wrote:
>
>
> The frequencies of the two receivers in the K3 are locked together for
> diversity by sending identical instructions to the two identical
> synthesizers which also share the same clock oscillator.
>
> RF phase doesn't need to be coherent for diversity reception as
> implemented in the K3, because the two signals are only combined at
> audio frequency (usually between the operator's ears). There may be
> small difference in time delay (group delay) through the roofing filters
> in the two receivers but in practice this doesn't seem to be a problem.
>
>
> 73 from Ian GM3SEK
>
>
>> -----Original Message-----
>> From: Elecraft [mailto:[hidden email]] On Behalf Of
>> DaleJ
>> Sent: 18 January 2015 09:28
>> To: [hidden email]
>> Subject: [Elecraft] Diversity reception in the K3
>>
>> Going beyond pushing a button, could someone explain how diversity
>> reception is accomplished in the K3? How are the two receivers locked
>> together, phase coherently.
>>
>> Tnx 73
>> Dale, K9VUJ
>> ______________________________________________________________
>> 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]
>
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> Message delivered to [hidden email]
>

Edward R Cole

Re: Diversity reception in the K3

In reply to this post by DaleJ

Ian,

My impression is that the two received signals are in phase-lock at
the first IF before the roofing filters. I export both IF outputs to
a pair of LP-Pan that are run by one xtal oscillator so their
baseband IQ outputs are locked in phase for use in my adaptive
dual-pol receiving system (using MAP65 sw).

With two phase-locked IQ streams polarity angle information can be
determined by special sw routines that compare the relative amplitude
of two orthogonally polarized signals. I use this for 2m-eme but it
could be used with any two orthogonally polarized antennas (eg on HF:
to horz dipoles at right angles to each other).

73, Ed - KL7UW
http://www.kl7uw.com/MAP65.htm

----------
From: "Ian White" <[hidden email]>
To: "'DaleJ'" <[hidden email]>, <[hidden email]>
Subject: Re: [Elecraft] Diversity reception in the K3
Message-ID: <003001d0331d$2016aed0$60440c70$@co.uk>
Content-Type: text/plain; charset="us-ascii"

The frequencies of the two receivers in the K3 are locked together for
diversity by sending identical instructions to the two identical
synthesizers which also share the same clock oscillator.

RF phase doesn't need to be coherent for diversity reception as
implemented in the K3, because the two signals are only combined at
audio frequency (usually between the operator's ears). There may be
small difference in time delay (group delay) through the roofing filters
in the two receivers but in practice this doesn't seem to be a problem.

73 from Ian GM3SEK

73, Ed - KL7UW
http://www.kl7uw.com
"Kits made by KL7UW"
Dubus Mag business:
[hidden email]

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Vic Rosenthal

Re: Diversity reception in the K3

In reply to this post by NY6C

Me too. Some people think it is primarily useful on low bands, but I use
it on all the bands 40 thru 10 meters (which are the only ones I
currently have antennas for).

I am using an R8 vertical for transmitting and one RX channel, and a
Pixel Loop for the other channel. They are only about 25 feet (7.6 m)
apart and are both vertically polarized, but there is definitely a
diversity effect. I find that QSB is greatly reduced and CW copy is much
better with diversity active. The only times I don't use it are when
there is too much noise on the vertical or when I need the subreceiver
for a pileup.

On 18 Jan 2015 20:48, Greg Miller wrote:

> I use diversity receive quite a bit. It was actually the main thing that got me looking at a K3 in the first place…great feature.
>
> -Greg NY6C
>
>> On Jan 18, 2015, at 5:48 AM, Ian White <[hidden email]> wrote:
>>
>>
>> The frequencies of the two receivers in the K3 are locked together for
>> diversity by sending identical instructions to the two identical
>> synthesizers which also share the same clock oscillator.
>>
>> RF phase doesn't need to be coherent for diversity reception as
>> implemented in the K3, because the two signals are only combined at
>> audio frequency (usually between the operator's ears). There may be
>> small difference in time delay (group delay) through the roofing filters
>> in the two receivers but in practice this doesn't seem to be a problem.
>>
>>
>> 73 from Ian GM3SEK

--
73,
Vic, 4X6GP/K2VCO
Rehovot, Israel
http://www.qsl.net/k2vco/
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gm3sek

Re: Diversity reception in the K3

In reply to this post by Edward R Cole

Thanks for that information, Ed.

While the LO frequency remains constant, the two LOs will be locked in
phase so the RF signal streams will be locked in phase as well. The
relative phase may be arbitrary, depending on exactly how the two
separate sets of synthesizer tuning instructions were loaded and then
executed, but MAP65 will probably factor out any fixed phase
differences.

73 from Ian GM3SEK

>-----Original Message-----
>From: Elecraft [mailto:[hidden email]] On Behalf Of
>Edward R Cole
>Sent: 18 January 2015 19:13
>To: [hidden email]
>Subject: Re: [Elecraft] Diversity reception in the K3
>
>Ian,
>
>My impression is that the two received signals are in phase-lock at
>the first IF before the roofing filters. I export both IF outputs to
>a pair of LP-Pan that are run by one xtal oscillator so their
>baseband IQ outputs are locked in phase for use in my adaptive
>dual-pol receiving system (using MAP65 sw).
>
>With two phase-locked IQ streams polarity angle information can be
>determined by special sw routines that compare the relative amplitude
>of two orthogonally polarized signals. I use this for 2m-eme but it
>could be used with any two orthogonally polarized antennas (eg on HF:
>to horz dipoles at right angles to each other).
>
>73, Ed - KL7UW
>http://www.kl7uw.com/MAP65.htm
>
>----------
>From: "Ian White" <[hidden email]>
>To: "'DaleJ'" <[hidden email]>, <[hidden email]>
>Subject: Re: [Elecraft] Diversity reception in the K3
>Message-ID: <003001d0331d$2016aed0$60440c70$@co.uk>
>Content-Type: text/plain; charset="us-ascii"
>
>
>The frequencies of the two receivers in the K3 are locked together for
>diversity by sending identical instructions to the two identical
>synthesizers which also share the same clock oscillator.
>
>RF phase doesn't need to be coherent for diversity reception as
>implemented in the K3, because the two signals are only combined at
>audio frequency (usually between the operator's ears). There may be
>small difference in time delay (group delay) through the roofing

filters

>in the two receivers but in practice this doesn't seem to be a problem.
>
>
>73 from Ian GM3SEK
>
>
>73, Ed - KL7UW
>http://www.kl7uw.com
> "Kits made by KL7UW"
>Dubus Mag business:
> [hidden email]