K3 SoftRock 6.2 plus Z10000 buffer?

[Andrew Catanzaro]

Lyle and Jack,

I have a Tony Parks SoftRock v6.2 Lite for 30 meters.  It's packaged for use
with the K3.  The included crystal is 32.7680 MHz and the divide-by-four
frequency is 8.192 MHz.  Combined with Jack's Z10000 buffer amp with 70 dB
of isolation, is the local oscillator isolated and offset from the K3's IF
enough so that it won't degrade the Elecraft's performance with IMD, BDR,
etc.?

Please respond to me on and off list as well as I receive only the digest.
Thanks.

Andy W9NJY
K3 #152
-------------------------------------------------------------------

Message: 19
Date: Fri, 14 Mar 2008 11:00:26 -0400
From: Jack Smith <[hidden email]>
Subject: [Elecraft] Second kit run - Z10000 buffer amplifier for IF
pickoff K2 and Isolation (K3)
To: [hidden email]
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

I've decided to go ahead with a second kit run of the Z10000 buffer
amplifier. The Z10000 provides an isolated (70 dB isolation at 4.9 MHz)
IF sample when installed in a  transceiver. It may also be used as an
isolation amplifier with a transceiver with an IF output port. (General
purpose, not limited to the K2.)

The Z10000 will be available with several options, including one that
permits it to be installed in the K2 and an electronics-only kit such as
might be used with a K3, which has a built-in IF port. The Z10000 is not
limited to the K2/K3 transceivers and has been used to provide a
buffered IF sample with a variety of equipment employing IF frequencies
in the range from 455 KHz to 73 MHz.

The Z10000's primary purpose for K2/K3 owners is to use a Softrock as a
panadapter via the Z10000 IF sample, and to provide additional isolation
for the K3 IF output port. Note that even with 70 dB of isolation, it
will almost certainly be necessary to offset the Softrock's frequency
from the receiver's IF frequency to avoid interference.

I've added pricing and options data at the 14 March 2008 entry at <
URL:http://www.cliftonlaboratories.com/Updates.htm >. Availability is
mid-April.

I plan to order parts next week, and if you are interested in purchasing
a Z10000, I would appreciate an E-mail indicating which options and
quantities you are interested in.

Jack K8ZOA
www.cliftonlaboratories.com


_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Jack Smith-6]

Looking at the K3's filter plots, the center frequency is 8215 KHz, so
the LO leakage is  be 23 KHz from the center. Even with the FM filter,
this looks like adequate spacing.

A leakage signal at around -105 to -110 dBm 23 KHz offset would, I
believe, not be a problem.

Unfortunately, my K3 won't be delivered for a month or two more (ordered
in May 2007, but waiting on the second receiver to be sorted out) so I
can't make measurements but the available data says it should be workable.

One caveat is is how close to the nominal crystal frequency the Softrock
oscillator puts the actual frequency. The actual frequency depends on
whether your 32.768 MHz crystal is cut for series or parallel resonance
and the nominal load capacitance if parallel as well as the various
components in the Softrock oscillator circuit. I don't recall at the
moment whether the Softrock oscillator operates the crystal in parallel
or series resonance.

Jack K8ZOA



Andrew Catanzaro wrote:

> Lyle and Jack,
>
> I have a Tony Parks SoftRock v6.2 Lite for 30 meters.  It's packaged
> for use with the K3.  The included crystal is 32.7680 MHz and the
> divide-by-four frequency is 8.192 MHz.  Combined with Jack's Z10000
> buffer amp with 70 dB of isolation, is the local oscillator isolated
> and offset from the K3's IF enough so that it won't degrade the
> Elecraft's performance with IMD, BDR, etc.?
>
> Please respond to me on and off list as well as I receive only the
> digest. Thanks.
>
> Andy W9NJY
> K3 #152
> -------------------------------------------------------------------
>
> Message: 19
> Date: Fri, 14 Mar 2008 11:00:26 -0400
> From: Jack Smith <[hidden email]>
> Subject: [Elecraft] Second kit run - Z10000 buffer amplifier for IF
> pickoff K2 and Isolation (K3)
> To: [hidden email]
> Message-ID: <[hidden email]>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> I've decided to go ahead with a second kit run of the Z10000 buffer
> amplifier. The Z10000 provides an isolated (70 dB isolation at 4.9 MHz)
> IF sample when installed in a  transceiver. It may also be used as an
> isolation amplifier with a transceiver with an IF output port. (General
> purpose, not limited to the K2.)
>
> The Z10000 will be available with several options, including one that
> permits it to be installed in the K2 and an electronics-only kit such as
> might be used with a K3, which has a built-in IF port. The Z10000 is not
> limited to the K2/K3 transceivers and has been used to provide a
> buffered IF sample with a variety of equipment employing IF frequencies
> in the range from 455 KHz to 73 MHz.
>
> The Z10000's primary purpose for K2/K3 owners is to use a Softrock as a
> panadapter via the Z10000 IF sample, and to provide additional isolation
> for the K3 IF output port. Note that even with 70 dB of isolation, it
> will almost certainly be necessary to offset the Softrock's frequency
> from the receiver's IF frequency to avoid interference.
>
> I've added pricing and options data at the 14 March 2008 entry at <
> URL:http://www.cliftonlaboratories.com/Updates.htm >. Availability is
> mid-April.
>
> I plan to order parts next week, and if you are interested in purchasing
> a Z10000, I would appreciate an E-mail indicating which options and
> quantities you are interested in.
>
> Jack K8ZOA
> www.cliftonlaboratories.com
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft   
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[KK7P]

> I have a Tony Parks SoftRock v6.2 Lite for 30 meters.  It's packaged for
> use with the K3.  The included crystal is 32.7680 MHz and the
> divide-by-four frequency is 8.192 MHz.  Combined with Jack's Z10000
> buffer amp with 70 dB of isolation, is the local oscillator isolated and
> offset from the K3's IF enough so that it won't degrade the Elecraft's
> performance with IMD, BDR, etc.?

The isolation, coupled with the actual LO frequency being as far removed
from the IF as you state, may be sufficient to protect the K3 from
performance degradation.  The only way to know,of course, is to make a
comprehensive set of measurements, then attach the pandaptor, then make
the same set of measurements and verify none are degraded.  I have not
made this set of comparative measurements under these conditions, so I
cannot state categorically that there will be no adverse impact to the
K3 under any and all circumstances.

It seems clear, though, that the Z10000 buffer amp will dramatically
improve things when attempting to use a softrock as a panadaptor.

Not asked, but relevant, is whether this combination will give you the
panadaptor performance you expect.  The LP-PAN project, for example,
found it necessary to add an 8.215 MHz bandpass filter to the front end
of the "softrock" portion of the system.  And of course the performance
is highly dependent on the soundcard you use for the baseband IQ output
from the softrock.

73,

Lyle KK7P

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com