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K3 Sub-receiver use

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Richard Ferch

Re: K3 Sub-receiver use

Guy Olinger wrote:

> That aside, I believe someone using the sub-RX with the TX in split,
> while leaving the main RX to feed the P3, would accomplish the same
> end.

Afraid not, Guy. Cross-band split is not supported, so the envisaged
mode of operation (main RX on 6m feeding the P3, subRX and TX on HF)
would not work. You could listen to the subRX on HF, but the TX would
have to be on 6m.

If the *only* purpose for the panadapter is to act as an indicator of
activity on the 6m band, you would hardly need all the integration of a
P3 anyway. There are other ways to tell when 6m is open, ranging from
www.vhfdx.net/spots/map.php to a simple non-integrated CW Skimmer-type
display (with a SoftRock, LP-PAN, etc. - this would still require the
mod to the KRX3).

That said, I think that once you have used an integrated panadapter, you
might not want to give it up. You might find yourself wanting to use the
panadapter full-time with the main RX and falling back on other methods
to tell you what's happening on 6m, perhaps supplemented by leaving the
subRX on the 6m calling frequency when you weren't using it on HF for
split operation, diversity mode, etc.

73,
Rich VE3KI
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Mike Harris

Re: K3 Sub-receiver use

In reply to this post by Guy, K2AV

G'day,

-3dB if the sub-RX is enabled.

Regards,

Mike VP8NO

----- Original Message -----
From: "Guy Olinger K2AV" <[hidden email]>
To: <[hidden email]>
Cc: "Elecraft-forum" <[hidden email]>
Sent: Tuesday, May 25, 2010 11:50 PM
Subject: Re: [Elecraft] K3 Sub-receiver use

That aside, I believe someone using the sub-RX with the TX in split,
while leaving the main RX to feed the P3, would accomplish the same
end. This WOULD be a problem on other rigs where the second RX is
an
inferior RX, or not available. In the K3 the sub-RX is a fully
equal
clone of the main RX, making various A/B flippity-do tricks possible
without sacrificing performance in any way.

73, Guy.

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Alan Bloom-2

Re: K3 Sub-receiver use

In reply to this post by Brett Howard

On Tue, 2010-05-25 at 22:36 -0700, Brett Howard wrote:
> Can the P3 at least show where the sub RX is and its BW and what not if
> its on the same screen full of where the Main RX is?

Yes, that's the way it works normally. Even though P3 is receiving the
main receiver's IF output, there is a cursor on the screen to show where
the sub receiver is tuned, assuming it is within the currently-displayed
span.

Alan N1AL

>
> ~Brett
>
> On Tue, 2010-05-25 at 21:25 -0700, Alan Bloom wrote:
> > Yes, the P3 assumes it is connected to the main receiver's IF output, so
> > if it is actually connected to the sub-RX it would still work but would
> > not display the correct frequencies and levels. If this becomes popular
> > enough maybe we should think about adding sub-RX support to P3 firmware.
> >
> > Alan N1AL
> >
> >
> > On Tue, 2010-05-25 at 23:50 -0400, Guy Olinger K2AV wrote:
> > > Wouldn't there be a K3 interoperating with P3 firmware issue with
> > > running the P3 on the sub-RX? Just because you could feed a
> > > **stand-alone** box with a non-company mod for sub-RX IF, does not
> > > mean the P3 would change the sub-RX with a click on the P3. There is a
> > > lot of proprietary communication between the K3 and the P3 over the
> > > serial connection.
> > >
> > > Wouldn't a sub-RX feed to a P3 need to be specifically supported by
> > > Elecraft firmware, both in K3 and P3? Last remarks from them in this
> > > thread were negative, particularly about isolation at a switch.
> > >
> > > That aside, I believe someone using the sub-RX with the TX in split,
> > > while leaving the main RX to feed the P3, would accomplish the same
> > > end. This WOULD be a problem on other rigs where the second RX is an
> > > inferior RX, or not available. In the K3 the sub-RX is a fully equal
> > > clone of the main RX, making various A/B flippity-do tricks possible
> > > without sacrificing performance in any way.
> > >
> > > 73, Guy.
> > >
> > > On Tue, May 25, 2010 at 9:48 PM, Alan Bloom <[hidden email]> wrote:
> > > > Hi Rudolf,
> > > >
> > > > At the bottom of this message I will copy a posting from W3SZ on the
> > > > LP-PAN email list that describes how he added IF output to his K3
> > > > sub-receiver. He used the Z10000 buffer amp from Clifton Labs:
> > > > http://www.cliftonlaboratories.com/z10000_buffer_amp.htm
> > > >
> > > > If you don't mind modifying your K3, it looks like that should allow you
> > > > to use the sub-receiver with a P3. When I get time I'll have to try it
> > > > on my K3 and see how it works.
> > > >
> > > > Alan N1AL
> > > >
> > > >
> > > >
> > > > On Tue, 2010-05-25 at 22:01 +0200, hb9ari wrote:
> > > >> Hi Rich,
> > > >>
> > > >> Very bad news !
> > > >>
> > > >> That was my 1st idea when ordering the P3
> > > >> to use it for "wide" span use for phone mode.
> > > >> (50Mhz in priority during possible "apertures")
> > > >> For digi mode, as JT65, the ~2kHz width
> > > >> of "waterfall" is 100% sufficient, because
> > > >> frequencies are well defined (for ex 14.076Mhz)
> > > >> I'm quite sure now that it was a bad idea to have ordered
> > > >> a P3 but, with your accurate explanation, i will
> > > >> renounce to the sub-receiver ordering (and
> > > >> roofing filters)!
> > > >>
> > > >> I regret that a P3 connection to the sub-rcvr
> > > >> is not possible, and, as i'm not an RF engineer,
> > > >> i don't understand the reason(s)!
> > > >>
> > > >> At my point of vue, it's not 100% correct to say that
> > > >> the KRX3 is like a 2nd receiver !
> > > >>
> > > >> Just in time to stop for the KRX3 ordering but for the P3...
> > > >> may be eBay ?
> > > >>
> > > >> My best 73,
> > > >> Rudolf, HB9ARI
> > > >
> > > > ============================================================
> > > >
> > > > -------- Forwarded Message --------
> > > > From: w3sz <[hidden email]>
> > > > Reply-to: [hidden email]
> > > > To: [hidden email]
> > > > Cc: [hidden email]
> > > > Subject: [LP-PAN] KRX3 IF tap up and running
> > > > Date: Fri, 02 Jan 2009 00:56:35 -0500
> > > >
> > > > Hi Larry,
> > > >
> > > > I didn't get a chance to hook up the LP-Pans yet [because the audio
> > > > cables I need are up at my hilltop QTH], but I did install the KRX3
> > > > and its Z10000 buffer amp, and both the main K3 IF output and the KRX3
> > > > subreceiver IF output seem to be working fine. I ran the main IF to
> > > > the main receiver on my Flex5000 and the KRX3 subIF to the subreceiver
> > > > on the Flex5000.
> > > >
> > > > Everything seems to be OK in terms of how I chose to get the IF from the KRX3.
> > > >
> > > > I am working a long day tomorrow as well as Saturday AM, but I am
> > > > hoping to get a chance to run up to the hilltop and pick up the audio
> > > > cables and then get the LP Pans hooked up Saturday afternoon.
> > > >
> > > > This is a brief summary of what I did with the KRX3:
> > > >
> > > > I used the Z10000 as buffer amp inside the KRX3.
> > > >
> > > > I got +12V from a 12SA pad near to P86A.
> > > > Power and RF connections to the Z10000 were done from the underside of
> > > > the Z10000.
> > > >
> > > > I took IF output from KRX3 from P86A and used RG174U to take this to
> > > > input of Z10000.
> > > >
> > > > I mounted Z10000 on an unused FL position using a 1/2 inch standoff.
> > > >
> > > > I mounted a dual female SMA connector in the REF hole at the bottom
> > > > corner of the K3 just below the official IF out BNC. I then used a
> > > > right angle premade small surplus coaxial cable to take the signal to
> > > > the KRX3 and thus the Z10000.
> > > >
> > > > I entered the KRX3 at the back left corner opposite to J92, because
> > > > there was already an opening there.
> > > >
> > > > I ran the coax inside the KRX3 bottom shell, beneath the main KRX3
> > > > PCB. I brought it up to the Z10000 by running it through an unused
> > > > hole meant for an FL standoff.
> > > >
> > > > At first check, using the two subreceivers on the Flex5000 to receive
> > > > the IF signals from the K3, the main K3 and the KRX3 subreceiver IF
> > > > outputs seem to be equivalent.
> > > >
> > > > When constructing the Z10000, I used the -U [Universal] options, not
> > > > the K2 options. I chose to set it up for zero gain, and thus chose
> > > > R907 to be 499 ohms, and R905 to be 4.7K, as per section 2.3.3 of the
> > > > Z10000 manual.
> > > >
> > > > I attached a jpg file with the two IFs from the K3 going to the Flex
> > > > 5000. The K3 main IF goes to the main Flex receiver and the DRX3 sub
> > > > IF goes to the Flex sub receiver. The signal is Radio Moscow on 40
> > > > meters.
> > > >
> > > > 73,
> > > >
> > > > Roger Rehr
> > > > W3SZ
> > > > http://www.nitehawk.com/w3sz
> > > >
> > > >
> > > >
> > > > ______________________________________________________________
> > > > 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
> > > >
> >
> >
> > ______________________________________________________________
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> > 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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N5GE

Re: K3 Sub-receiver use

In reply to this post by Alan Bloom-2

On Tue, 25 May 2010 21:25:15 -0700, Alan Bloom <[hidden email]>
wrote:

Ouch!

Does this mean that the P3 will not display the frequency of or the
signals seen by the KRX3?

If that is true, it is a show stopper for me.

TOM, N5GE BT 73 ES GUD LUK
AR DE N5GE SK

http://www.n5ge.com

>Yes, the P3 assumes it is connected to the main receiver's IF output, so
>if it is actually connected to the sub-RX it would still work but would
>not display the correct frequencies and levels. If this becomes popular
>enough maybe we should think about adding sub-RX support to P3 firmware.
>
>Alan N1AL
>
[snip]

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Amateur Radio Operator N5GE

Alan Bloom-2

Re: K3 Sub-receiver use

The P3 is connected to the main receiver's IF output, so it is showing
the signals being received by the main RX. However there is a cursor on
the screen that shows the frequency and bandwidth of the sub-RX, as long
as its frequency is within range of the currently-displayed span.

That's exactly what you want as long as the main and sub are using the
same antenna. If they are using different antennas then there may
occasionally be a signal that could be heard on the sub-RX that doesn't
appear on the P3, but that should be pretty rare.

Alan N1AL

On Wed, 2010-05-26 at 11:29 -0500, Radio Amateur N5GE wrote:

> On Tue, 25 May 2010 21:25:15 -0700, Alan Bloom <[hidden email]>
> wrote:
>
> Ouch!
>
> Does this mean that the P3 will not display the frequency of or the
> signals seen by the KRX3?
>
> If that is true, it is a show stopper for me.
>
> TOM, N5GE BT 73 ES GUD LUK
> AR DE N5GE SK
>
> http://www.n5ge.com
>
> >Yes, the P3 assumes it is connected to the main receiver's IF output, so
> >if it is actually connected to the sub-RX it would still work but would
> >not display the correct frequencies and levels. If this becomes popular
> >enough maybe we should think about adding sub-RX support to P3 firmware.
> >
> >Alan N1AL
> >
> [snip]
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
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Guy, K2AV

Re: K3 Sub-receiver use

In reply to this post by N5GE

The trick involved in that switch is a very high isolation between the
two IF's (RXA and RXB) currently very nicely highly isolated. If that
is degraded, then one starts hearing in one receiver the contents of
the other. Not at all a trivial modification, as high isolation
switches are not cheap. So I suspect dynamically selecting display on
one RX or the other has a big price tag to it. And perhaps has an
internal space price to it.

I would think, however, that when installing a sub-RX, that perhaps it
could be cabled and the K3 options set to use the sub-RX on the P3 all
the time, WITHOUT opening the pandora's box of high-isolation
switching of RX IF's. This would be in the same vein as choosing the
RX paths when installing the sub-RX to start with. Without the time
to think that through carefully, I'd currently chose that were it
available.

73, Guy.

On Wed, May 26, 2010 at 12:29 PM, Radio Amateur N5GE <[hidden email]> wrote:

> On Tue, 25 May 2010 21:25:15 -0700, Alan Bloom <[hidden email]>
> wrote:
>
> Ouch!
>
> Does this mean that the P3 will not display the frequency of or the
> signals seen by the KRX3?
>
> If that is true, it is a show stopper for me.
>
> TOM, N5GE BT 73 ES GUD LUK
> AR DE N5GE SK
>
> http://www.n5ge.com
>
>>Yes, the P3 assumes it is connected to the main receiver's IF output, so
>>if it is actually connected to the sub-RX it would still work but would
>>not display the correct frequencies and levels. If this becomes popular
>>enough maybe we should think about adding sub-RX support to P3 firmware.
>>
>>Alan N1AL
>>
> [snip]
>
> ______________________________________________________________
> 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
>

Edward R Cole

Re: K3 Sub-receiver use

In reply to this post by hb9ari@bluewin.ch

Like Roger, W3SZ, I will use my sub Rx on 2m eme with a
transverter. Instead of the LP-Pan I will connect my SDR-IQ to the
IF output for obtaining a panoramic display of up to 190-KHz of a
band. This will be centered on the K3 IF frequency and track with it
as I tune the K3.

But I purchased the sub Rx option so that I could receive 2m from a
second set of antennas that were polarized opposite the main
Rx. This has some advantages in 2m eme which I will not go into.

I do not recall the exact way you wanted to monitor 6m, but could you
not do this with the main Rx plus P3 and use the sub Rx for the other
band you wish to use? I haven't explored doing this, but can one
transmit on a different band than one receives using the main
Rx? Can one transmit and receive using the sub Rx? The main problem
with this idea might be in antenna selection (but does not the
antenna tuner allow for auto switching between Tx and Rx? I did not
opt for the tuner so not enough familiar how it can be configured.

In any case, it seems a shame to give up on your idea just be cause
the radio is not equipped from the factory. The mod Roger uses does
not appear to be that difficult, even if one has the find a fellow
ham to help with the actual conversion.

(But then I do lots of home construction)

73, Ed - KL7UW

------------------------------

Message: 18
Date: Tue, 25 May 2010 18:48:20 -0700
From: Alan Bloom <[hidden email]>
Subject: Re: [Elecraft] K3 Sub-receiver use
To: hb9ari <[hidden email]>
Cc: Elecraft-forum <[hidden email]>
Message-ID: <1274838500.1492.43.camel@ulinux-desktop>
Content-Type: text/plain; charset="UTF-8"

Hi Rudolf,

At the bottom of this message I will copy a posting from W3SZ on the
LP-PAN email list that describes how he added IF output to his K3
sub-receiver. He used the Z10000 buffer amp from Clifton Labs:
http://www.cliftonlaboratories.com/z10000_buffer_amp.htm

If you don't mind modifying your K3, it looks like that should allow you
to use the sub-receiver with a P3. When I get time I'll have to try it
on my K3 and see how it works.

Alan N1AL

On Tue, 2010-05-25 at 22:01 +0200, hb9ari wrote:
> Hi Rich,
>
> Very bad news !
>
> That was my 1st idea when ordering the P3
> to use it for "wide" span use for phone mode.
...snip...
>
> Just in time to stop for the KRX3 ordering but for the P3...
> may be eBay ?
>
> My best 73,
> Rudolf, HB9ARI
----snipped the attachment-----

73, Ed - KL7UW, WD2XSH/45
======================================
BP40IQ 500 KHz - 10-GHz www.kl7uw.com
EME: 144-600w, 432-100w, 1296-60w, 3400-fall 2010
DUBUS Magazine USA Rep [hidden email]
======================================

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hb9ari@bluewin.ch

Re: K3 Sub-receiver use

In reply to this post by Guy, K2AV

Hi Guy,

It's that way i was thinking to use the P3!
-1- ALWAYS on the sub-receiver output.
-2- ALWAYS on a separated antenna.

My idea was to externally switch the 6m
(or internally if possible?) antenna from
K3 sub-rcvr to main RF when some activity
was "detected" on th P3. When "working"
on 6m, no necessity, (always speaking
for me..) to "monitor" a 10 to 20m band!

In my case, as i'm very space limited,
no room for a 2nd 10 to 20m separated
antenna for diversity...
But a separated 6m antenna is feasible.
(for the moment, i use only a vertical for
6m, no DX, but not too bads QSO)

73,

Rudolf, HB9ARI

Guy Olinger K2AV wrote:

> The trick involved in that switch is a very high isolation between the
> two IF's (RXA and RXB) currently very nicely highly isolated. If that
> is degraded, then one starts hearing in one receiver the contents of
> the other. Not at all a trivial modification, as high isolation
> switches are not cheap. So I suspect dynamically selecting display on
> one RX or the other has a big price tag to it. And perhaps has an
> internal space price to it.
>
> I would think, however, that when installing a sub-RX, that perhaps it
> could be cabled and the K3 options set to use the sub-RX on the P3 all
> the time, WITHOUT opening the pandora's box of high-isolation
> switching of RX IF's. This would be in the same vein as choosing the
> RX paths when installing the sub-RX to start with. Without the time
> to think that through carefully, I'd currently chose that were it
> available.
>
> 73, Guy.
>
> On Wed, May 26, 2010 at 12:29 PM, Radio Amateur N5GE <[hidden email]> wrote:
>
>> On Tue, 25 May 2010 21:25:15 -0700, Alan Bloom <[hidden email]>
>> wrote:
>>
>> Ouch!
>>
>> Does this mean that the P3 will not display the frequency of or the
>> signals seen by the KRX3?
>>
>> If that is true, it is a show stopper for me.
>>
>> TOM, N5GE BT 73 ES GUD LUK
>> AR DE N5GE SK
>>
>> http://www.n5ge.com
>>
>>
>>> Yes, the P3 assumes it is connected to the main receiver's IF output, so
>>> if it is actually connected to the sub-RX it would still work but would
>>> not display the correct frequencies and levels. If this becomes popular
>>> enough maybe we should think about adding sub-RX support to P3 firmware.
>>>
>>> Alan N1AL
>>>
>>>
>> [snip]
>>
>> ______________________________________________________________
>> 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
>>
>>
> ______________________________________________________________
> 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
>
>

Guy, K2AV

Re: K3 Sub-receiver use

Yeah,

The rub is getting Wayne to add an option that will look at the subRX
for the P3 interface functions. Think you might get what you're
asking for.

Others are asking for that to be switchable back and forth between the
two *dynamically*. This involves both IF's and allows for signals in
the IF of one RX to be heard in the other. This would a switch with
100 dB isolation. It would be an expensive option, plus some
significant new code. Don't think this complexity is commercially
feasibility.

BTW, none of this would allow the subRX to listen while transmitting.
They are all in the same box and running full duplex will require
circuits with isolations in the 140, 150 dB range to work right.
Talking about military applications, and very expensive radios for
that kind of thing.

73, Guy.

On Mon, May 31, 2010 at 3:04 AM, hb9ari <[hidden email]> wrote:

> Hi Guy,
>
> It's that way i was thinking to use the P3!
> -1- ALWAYS on the sub-receiver output.
> -2- ALWAYS on a separated antenna.
>
> My idea was to externally switch the 6m
> (or internally if possible?) antenna from
> K3 sub-rcvr to main RF when some activity
> was "detected" on th P3. When "working"
> on 6m, no necessity, (always speaking
> for me..) to "monitor" a 10 to 20m band!
>
> In my case, as i'm very space limited,
> no room for a 2nd 10 to 20m separated
> antenna for diversity...
> But a separated 6m antenna is feasible.
> (for the moment, i use only a vertical for
> 6m, no DX, but not too bads QSO)
>
>
> 73,
>
> Rudolf, HB9ARI
>
> Guy Olinger K2AV wrote:
>> The trick involved in that switch is a very high isolation between the
>> two IF's (RXA and RXB) currently very nicely highly isolated. If that
>> is degraded, then one starts hearing in one receiver the contents of
>> the other. Not at all a trivial modification, as high isolation
>> switches are not cheap. So I suspect dynamically selecting display on
>> one RX or the other has a big price tag to it. And perhaps has an
>> internal space price to it.
>>
>> I would think, however, that when installing a sub-RX, that perhaps it
>> could be cabled and the K3 options set to use the sub-RX on the P3 all
>> the time, WITHOUT opening the pandora's box of high-isolation
>> switching of RX IF's. This would be in the same vein as choosing the
>> RX paths when installing the sub-RX to start with. Without the time
>> to think that through carefully, I'd currently chose that were it
>> available.
>>
>> 73, Guy.
>>
>> On Wed, May 26, 2010 at 12:29 PM, Radio Amateur N5GE <[hidden email]> wrote:
>>
>>> On Tue, 25 May 2010 21:25:15 -0700, Alan Bloom <[hidden email]>
>>> wrote:
>>>
>>> Ouch!
>>>
>>> Does this mean that the P3 will not display the frequency of or the
>>> signals seen by the KRX3?
>>>
>>> If that is true, it is a show stopper for me.
>>>
>>> TOM, N5GE BT 73 ES GUD LUK
>>> AR DE N5GE SK
>>>
>>> http://www.n5ge.com
>>>
>>>
>>>> Yes, the P3 assumes it is connected to the main receiver's IF output, so
>>>> if it is actually connected to the sub-RX it would still work but would
>>>> not display the correct frequencies and levels. If this becomes popular
>>>> enough maybe we should think about adding sub-RX support to P3 firmware.
>>>>
>>>> Alan N1AL
>>>>
>>>>
>>> [snip]
>>>
>>> ______________________________________________________________
>>> Elecraft mailing list
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W8JI

Re: K3 Sub-receiver use

Others are asking for that to be switchable back and forth
between the
two *dynamically*. This involves both IF's and allows for
signals in
the IF of one RX to be heard in the other. This would a
switch with
100 dB isolation. It would be an expensive option, plus
some
significant new code. Don't think this complexity is
commercially
feasibility.>>

I can get in that range in a 50 ohm system with a single
relay at HF in a proper layout using the right style of
relay.

I have not tried it with miniature relays, but I see no
reason why it could not be done. It would probably take
three $2 SPDT relays the size of a sixteen pin DIP package.

73 Tom

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Guy, K2AV

Re: K3 Sub-receiver use

I don't doubt for an instant what you say.

I'm thinking the common ground path issues and cable routing issues
would get it, not that you couldn't do it with the relays
"standalone". And then the complaints would start about hearing
signals move in one RX while tuning on the other, starting with 6m and
moving down.

And parts are not the only cost. After all you can't weigh software,
worry or frustration.

73, Guy.

On Mon, May 31, 2010 at 11:06 AM, Tom W8JI <[hidden email]> wrote:

> Others are asking for that to be switchable back and forth between the
> two *dynamically*. This involves both IF's and allows for signals in
> the IF of one RX to be heard in the other. This would a switch with
> 100 dB isolation. It would be an expensive option, plus some
> significant new code. Don't think this complexity is commercially
> feasibility.>>
>
> I can get in that range in a 50 ohm system with a single relay at HF in a
> proper layout using the right style of relay.
>
> I have not tried it with miniature relays, but I see no reason why it could
> not be done. It would probably take three $2 SPDT relays the size of a
> sixteen pin DIP package.
>
> 73 Tom
>

hb9ari@bluewin.ch

Re: K3 Sub-receiver use

In reply to this post by Guy, K2AV

Hi Guy,

All OK !

Effectively, i don't envisage to "look" for 50MHz activity
on the P3 during transmitting on lower bands.

I will look at the K3 schematics how are switched
antennas, KAT3, KRX3, etc.
I'm not 100% ok with all these connections for the moment...
and how TX/RX switching is done...

I've the KAT3 installed and i'm using ANT2 input
for 50MHz antenna.

I think that P3 "monitoring" can be useful also
for K144XV or external transverter users on higher bands
where some "nice" apertures can appears.

Thank you to you, Guy, and all OM for very good informations
and help in my choice!

73 QRO,
Rudolf, HB9ARI

Guy Olinger K2AV wrote:

> Yeah,
>
> The rub is getting Wayne to add an option that will look at the subRX
> for the P3 interface functions. Think you might get what you're
> asking for.
>
> Others are asking for that to be switchable back and forth between the
> two *dynamically*. This involves both IF's and allows for signals in
> the IF of one RX to be heard in the other. This would a switch with
> 100 dB isolation. It would be an expensive option, plus some
> significant new code. Don't think this complexity is commercially
> feasibility.
>
> BTW, none of this would allow the subRX to listen while transmitting.
> They are all in the same box and running full duplex will require
> circuits with isolations in the 140, 150 dB range to work right.
> Talking about military applications, and very expensive radios for
> that kind of thing.
>
> 73, Guy.
>
> On Mon, May 31, 2010 at 3:04 AM, hb9ari <[hidden email]> wrote:
>
>> Hi Guy,
>>
>> It's that way i was thinking to use the P3!
>> -1- ALWAYS on the sub-receiver output.
>> -2- ALWAYS on a separated antenna.
>>
>> My idea was to externally switch the 6m
>> (or internally if possible?) antenna from
>> K3 sub-rcvr to main RF when some activity
>> was "detected" on th P3. When "working"
>> on 6m, no necessity, (always speaking
>> for me..) to "monitor" a 10 to 20m band!
>>
>> In my case, as i'm very space limited,
>> no room for a 2nd 10 to 20m separated
>> antenna for diversity...
>> But a separated 6m antenna is feasible.
>> (for the moment, i use only a vertical for
>> 6m, no DX, but not too bads QSO)
>>
>>
>> 73,
>>
>> Rudolf, HB9ARI
>>
>> Guy Olinger K2AV wrote:
>>
>>> The trick involved in that switch is a very high isolation between the
>>> two IF's (RXA and RXB) currently very nicely highly isolated. If that
>>> is degraded, then one starts hearing in one receiver the contents of
>>> the other. Not at all a trivial modification, as high isolation
>>> switches are not cheap. So I suspect dynamically selecting display on
>>> one RX or the other has a big price tag to it. And perhaps has an
>>> internal space price to it.
>>>
>>> I would think, however, that when installing a sub-RX, that perhaps it
>>> could be cabled and the K3 options set to use the sub-RX on the P3 all
>>> the time, WITHOUT opening the pandora's box of high-isolation
>>> switching of RX IF's. This would be in the same vein as choosing the
>>> RX paths when installing the sub-RX to start with. Without the time
>>> to think that through carefully, I'd currently chose that were it
>>> available.
>>>
>>> 73, Guy.
>>>
>>> On Wed, May 26, 2010 at 12:29 PM, Radio Amateur N5GE <[hidden email]> wrote:
>>>
>>>
>>>> On Tue, 25 May 2010 21:25:15 -0700, Alan Bloom <[hidden email]>
>>>> wrote:
>>>>
>>>> Ouch!
>>>>
>>>> Does this mean that the P3 will not display the frequency of or the
>>>> signals seen by the KRX3?
>>>>
>>>> If that is true, it is a show stopper for me.
>>>>
>>>> TOM, N5GE BT 73 ES GUD LUK
>>>> AR DE N5GE SK
>>>>
>>>> http://www.n5ge.com
>>>>
>>>>
>>>>
>>>>> Yes, the P3 assumes it is connected to the main receiver's IF output, so
>>>>> if it is actually connected to the sub-RX it would still work but would
>>>>> not display the correct frequencies and levels. If this becomes popular
>>>>> enough maybe we should think about adding sub-RX support to P3 firmware.
>>>>>
>>>>> Alan N1AL
>>>>>
>>>>>
>>>>>
>>>> [snip]
>>>>
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>>>>
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>
>

Alan Bloom-2

Re: K3 Sub-receiver use

In reply to this post by Guy, K2AV

The K3's S-meter reads up to S9 + 60 dB, which is -13 dBm. The noise
floor in 500 Hz bandwidth with preamp on is around -136 dBm. So an IF
switch really needs more than 120 dB isolation to avoid cross-talk
between the main and sub-receivers.

That is certainly possible but it's not trivial either. As Guy says,
you have to pay careful attention to grounding, power supply decoupling,
and other alternate paths in addition to the switch isolation.

If you want to switch in real time (say on alternate sweeps, so the P3
can display both main and sub "at the same time") then you'd need to use
solid-state switches. Probably several sections to get the required
isolation.

It should all be do-able. A nice project for Wayne in his "spare
time." :=)

Alan N1AL

On Mon, 2010-05-31 at 12:33 -0400, Guy Olinger K2AV wrote:

> I don't doubt for an instant what you say.
>
> I'm thinking the common ground path issues and cable routing issues
> would get it, not that you couldn't do it with the relays
> "standalone". And then the complaints would start about hearing
> signals move in one RX while tuning on the other, starting with 6m and
> moving down.
>
> And parts are not the only cost. After all you can't weigh software,
> worry or frustration.
>
> 73, Guy.
>
> On Mon, May 31, 2010 at 11:06 AM, Tom W8JI <[hidden email]> wrote:
> > Others are asking for that to be switchable back and forth between the
> > two *dynamically*. This involves both IF's and allows for signals in
> > the IF of one RX to be heard in the other. This would a switch with
> > 100 dB isolation. It would be an expensive option, plus some
> > significant new code. Don't think this complexity is commercially
> > feasibility.>>
> >
> > I can get in that range in a 50 ohm system with a single relay at HF in a
> > proper layout using the right style of relay.
> >
> > I have not tried it with miniature relays, but I see no reason why it could
> > not be done. It would probably take three $2 SPDT relays the size of a
> > sixteen pin DIP package.
> >
> > 73 Tom
> >
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Joe Subich, W4TV-4

Re: K3 Sub-receiver use

> If you want to switch in real time (say on alternate sweeps, so the
> P3 can display both main and sub "at the same time") then you'd need
> to use solid-state switches. Probably several sections to get the
> required isolation.

I don't know that the requirement is for alternate sweep display -
just the ability to select main or sub-RX without the need to open
the K3 and make wholesale cable changes.

73,

... Joe, W4TV

On 5/31/2010 3:49 PM, Alan Bloom wrote:

> The K3's S-meter reads up to S9 + 60 dB, which is -13 dBm. The noise
> floor in 500 Hz bandwidth with preamp on is around -136 dBm. So an IF
> switch really needs more than 120 dB isolation to avoid cross-talk
> between the main and sub-receivers.
>
> That is certainly possible but it's not trivial either. As Guy says,
> you have to pay careful attention to grounding, power supply decoupling,
> and other alternate paths in addition to the switch isolation.
>
> If you want to switch in real time (say on alternate sweeps, so the P3
> can display both main and sub "at the same time") then you'd need to use
> solid-state switches. Probably several sections to get the required
> isolation.
>
> It should all be do-able. A nice project for Wayne in his "spare
> time." :=)
>
> Alan N1AL
>
>
> On Mon, 2010-05-31 at 12:33 -0400, Guy Olinger K2AV wrote:
>> I don't doubt for an instant what you say.
>>
>> I'm thinking the common ground path issues and cable routing issues
>> would get it, not that you couldn't do it with the relays
>> "standalone". And then the complaints would start about hearing
>> signals move in one RX while tuning on the other, starting with 6m and
>> moving down.
>>
>> And parts are not the only cost. After all you can't weigh software,
>> worry or frustration.
>>
>> 73, Guy.
>>
>> On Mon, May 31, 2010 at 11:06 AM, Tom W8JI<[hidden email]> wrote:
>>> Others are asking for that to be switchable back and forth between the
>>> two *dynamically*. This involves both IF's and allows for signals in
>>> the IF of one RX to be heard in the other. This would a switch with
>>> 100 dB isolation. It would be an expensive option, plus some
>>> significant new code. Don't think this complexity is commercially
>>> feasibility.>>
>>>
>>> I can get in that range in a 50 ohm system with a single relay at HF in a
>>> proper layout using the right style of relay.
>>>
>>> I have not tried it with miniature relays, but I see no reason why it could
>>> not be done. It would probably take three $2 SPDT relays the size of a
>>> sixteen pin DIP package.
>>>
>>> 73 Tom
>>>
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>
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