Topics

Alternative transverter IF

Colin Smithers
 

Hi all, 

I'm New here.

Does anyone know how to set a transverter IF to 28.5MHz, or any other frequency that is not 28,0, 50,0 etc? The incremental oscillator shift only goes so far i think.

Reason is I built a 70 MHz transverter from 28.5 as using 28.0 results in a a difficult spurious product.

If not I can always continue to subtract .5 in my head as i have done for the last 35+ years :-)

(Also sent to the elecraft group)

Thanks and 73, Colin G4CWH

Ray Maxfield
 

Colin…..

You need to change the Transverter Oscillator Frequency.

Most likely a Crystal, or if a Newer DDS Oscillator, the Frequency it is running at.

Try to find the Make and model on the internet to get the Data / Information

About your Transverter……..    Ray    WA6VAB    

 

From: Colin Smithers
Sent: Saturday, May 23, 2020 3:36 PM
To: Elecraft-K3@groups.io
Subject: [Elecraft-K3] Alternative transverter IF

 

Hi all, 

I'm New here.

Does anyone know how to set a transverter IF to 28.5MHz, or any other frequency that is not 28,0, 50,0 etc? The incremental oscillator shift only goes so far i think.

Reason is I built a 70 MHz transverter from 28.5 as using 28.0 results in a a difficult spurious product.

If not I can always continue to subtract .5 in my head as i have done for the last 35+ years :-)

(Also sent to the elecraft group)

Thanks and 73, Colin G4CWH

 

David Ferrington, M0XDF
 

I could be wrong, but can’t you pick your freq. on the K3?

-73 de M0XDF

On 24 May 2020, at 03:56, Ray Maxfield <wa6vab@...> wrote:



Colin…..

You need to change the Transverter Oscillator Frequency.

Most likely a Crystal, or if a Newer DDS Oscillator, the Frequency it is running at.

Try to find the Make and model on the internet to get the Data / Information

About your Transverter……..    Ray    WA6VAB    

 

From: Colin Smithers
Sent: Saturday, May 23, 2020 3:36 PM
To: Elecraft-K3@groups.io
Subject: [Elecraft-K3] Alternative transverter IF

 

Hi all, 

I'm New here.

Does anyone know how to set a transverter IF to 28.5MHz, or any other frequency that is not 28,0, 50,0 etc? The incremental oscillator shift only goes so far i think.

Reason is I built a 70 MHz transverter from 28.5 as using 28.0 results in a a difficult spurious product.

If not I can always continue to subtract .5 in my head as i have done for the last 35+ years :-)

(Also sent to the elecraft group)

Thanks and 73, Colin G4CWH

 

Colin Smithers
 

Hi Ray,

I built the transverter. If you run the LO at 42 MHz then 28.0 is the IF, but there is a bad spurious, its in the math. Which is why I then modified it to 42.5 all those years ago.

I do think the answer lies in altering the K3 internal math, or putting up with having to subtract 500 kHz.

73, Colin


On 24 May 2020, at 03:56, Ray Maxfield via groups.io <wa6vab@...> wrote:



Colin…..

You need to change the Transverter Oscillator Frequency.

Most likely a Crystal, or if a Newer DDS Oscillator, the Frequency it is running at.

Try to find the Make and model on the internet to get the Data / Information

About your Transverter……..    Ray    WA6VAB    

 

From: Colin Smithers
Sent: Saturday, May 23, 2020 3:36 PM
To: Elecraft-K3@groups.io
Subject: [Elecraft-K3] Alternative transverter IF

 

Hi all, 

I'm New here.

Does anyone know how to set a transverter IF to 28.5MHz, or any other frequency that is not 28,0, 50,0 etc? The incremental oscillator shift only goes so far i think.

Reason is I built a 70 MHz transverter from 28.5 as using 28.0 results in a a difficult spurious product.

If not I can always continue to subtract .5 in my head as i have done for the last 35+ years :-)

(Also sent to the elecraft group)

Thanks and 73, Colin G4CWH

 

Colin Smithers
 

That is the question! But how? I can only set 28.0, or 50.0. Etc

Its possible I’m missing something obvious. Please have a go and tell me what you find 😊

73, Colin


On 24 May 2020, at 13:50, David Ferrington, M0XDF via groups.io <M0XDF@...> wrote:

 I could be wrong, but can’t you pick your freq. on the K3?

-73 de M0XDF

On 24 May 2020, at 03:56, Ray Maxfield <wa6vab@...> wrote:



Colin…..

You need to change the Transverter Oscillator Frequency.

Most likely a Crystal, or if a Newer DDS Oscillator, the Frequency it is running at.

Try to find the Make and model on the internet to get the Data / Information

About your Transverter……..    Ray    WA6VAB    

 

From: Colin Smithers
Sent: Saturday, May 23, 2020 3:36 PM
To: Elecraft-K3@groups.io
Subject: [Elecraft-K3] Alternative transverter IF

 

Hi all, 

I'm New here.

Does anyone know how to set a transverter IF to 28.5MHz, or any other frequency that is not 28,0, 50,0 etc? The incremental oscillator shift only goes so far i think.

Reason is I built a 70 MHz transverter from 28.5 as using 28.0 results in a a difficult spurious product.

If not I can always continue to subtract .5 in my head as i have done for the last 35+ years :-)

(Also sent to the elecraft group)

Thanks and 73, Colin G4CWH

 

Alan Baker
 

I checked the K3 and Cady books and there doesn't appear to be any way of doing what you want. You can set the band, but not a particular offset in the band. Unfortunately the offset provided is only correctional and won't shift far enough for your purpose.

73,

Alan. G4GNX


------ Original Message ------
From: "Colin Smithers" <colin@...>
Sent: 23/05/2020 23:15:47
Subject: [Elecraft-K3] Alternative transverter IF

Hi all, 

I'm New here.

Does anyone know how to set a transverter IF to 28.5MHz, or any other frequency that is not 28,0, 50,0 etc? The incremental oscillator shift only goes so far i think.

Reason is I built a 70 MHz transverter from 28.5 as using 28.0 results in a a difficult spurious product.

If not I can always continue to subtract .5 in my head as i have done for the last 35+ years :-)

(Also sent to the elecraft group)

Thanks and 73, Colin G4CWH

Colin Smithers
 

Thanks Alan. That was all I could find too, hence this post.

73, Colin G4CWH


On 25 May 2020, at 00:14, Alan Baker via groups.io <g4gnx@...> wrote:


I checked the K3 and Cady books and there doesn't appear to be any way of doing what you want. You can set the band, but not a particular offset in the band. Unfortunately the offset provided is only correctional and won't shift far enough for your purpose.

73,

Alan. G4GNX


------ Original Message ------
From: "Colin Smithers" <colin@...>
Sent: 23/05/2020 23:15:47
Subject: [Elecraft-K3] Alternative transverter IF

Hi all, 

I'm New here.

Does anyone know how to set a transverter IF to 28.5MHz, or any other frequency that is not 28,0, 50,0 etc? The incremental oscillator shift only goes so far i think.

Reason is I built a 70 MHz transverter from 28.5 as using 28.0 results in a a difficult spurious product.

If not I can always continue to subtract .5 in my head as i have done for the last 35+ years :-)

(Also sent to the elecraft group)

Thanks and 73, Colin G4CWH

Carl Moreschi
 

One way to do this is by running my N4PY Pegasus Plus software to control your K3. My software supports up to 5 transverter setups. The IF frequency can be set to anything. This allows the correct frequency to be displayed in the software.

Carl Moreschi N4PY
127 River Moss Way
Hertford, NC 27944
www.n4py.com

On 5/25/2020 2:52 AM, Colin Smithers wrote:
Thanks Alan. That was all I could find too, hence this post.

73, Colin G4CWH


On 25 May 2020, at 00:14, Alan Baker via groups.io
<g4gnx=g4gnx.com@groups.io> wrote:


I checked the K3 and Cady books and there doesn't appear to be any way
of doing what you want. You can set the band, but not a particular
offset in the band. Unfortunately the offset provided is only
correctional and won't shift far enough for your purpose.

73,

Alan. G4GNX


------ Original Message ------
From: "Colin Smithers" <colin@...
<mailto:colin@...>>
To: Elecraft-K3@groups.io <mailto:Elecraft-K3@groups.io>
Sent: 23/05/2020 23:15:47
Subject: [Elecraft-K3] Alternative transverter IF

Hi all,

I'm New here.

Does anyone know how to set a transverter IF to 28.5MHz, or any other
frequency that is not 28,0, 50,0 etc? The incremental oscillator
shift only goes so far i think.

Reason is I built a 70 MHz transverter from 28.5 as using 28.0
results in a a difficult spurious product.

If not I can always continue to subtract .5 in my head as i have done
for the last 35+ years :-)

(Also sent to the elecraft group)

Thanks and 73, Colin G4CWH

Colin Smithers
 

Thanks Carl, very interesting, I was unaware of your software.

One question: Does the K3 remember that non-standard IF when used stand-alone at a later date - e,g, when out /P?

73, Colin

G4CWH

-----Original Message-----
From: Elecraft-K3@groups.io [mailto:Elecraft-K3@groups.io] On Behalf Of Carl Moreschi via groups.io
Sent: 25 May 2020 11:42
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] Alternative transverter IF

One way to do this is by running my N4PY Pegasus Plus software to
control your K3. My software supports up to 5 transverter setups. The
IF frequency can be set to anything. This allows the correct frequency
to be displayed in the software.

Carl Moreschi N4PY
127 River Moss Way
Hertford, NC 27944
www.n4py.com

On 5/25/2020 2:52 AM, Colin Smithers wrote:
Thanks Alan. That was all I could find too, hence this post.

73, Colin G4CWH


On 25 May 2020, at 00:14, Alan Baker via groups.io
<g4gnx=g4gnx.com@groups.io> wrote:


I checked the K3 and Cady books and there doesn't appear to be any way
of doing what you want. You can set the band, but not a particular
offset in the band. Unfortunately the offset provided is only
correctional and won't shift far enough for your purpose.

73,

Alan. G4GNX


------ Original Message ------
From: "Colin Smithers" <colin@...
<mailto:colin@...>>
To: Elecraft-K3@groups.io <mailto:Elecraft-K3@groups.io>
Sent: 23/05/2020 23:15:47
Subject: [Elecraft-K3] Alternative transverter IF

Hi all,

I'm New here.

Does anyone know how to set a transverter IF to 28.5MHz, or any other
frequency that is not 28,0, 50,0 etc? The incremental oscillator
shift only goes so far i think.

Reason is I built a 70 MHz transverter from 28.5 as using 28.0
results in a a difficult spurious product.

If not I can always continue to subtract .5 in my head as i have done
for the last 35+ years :-)

(Also sent to the elecraft group)

Thanks and 73, Colin G4CWH

Carl Moreschi
 

No the non-standard IF is just used in my program. Used in this way the K3 is unaware a transverter is being used. The K3 will show 28.xx mhz but my program will show the true transverter frequency. My program also has settings for the transverter drive level. And supports up to 5 different transverters.

Carl Moreschi N4PY
127 River Moss Way
Hertford, NC 27944
www.n4py.com

On 5/25/2020 7:37 AM, Colin Smithers wrote:
Thanks Carl, very interesting, I was unaware of your software.

One question: Does the K3 remember that non-standard IF when used stand-alone at a later date - e,g, when out /P?

73, Colin

G4CWH

-----Original Message-----
From: Elecraft-K3@groups.io [mailto:Elecraft-K3@groups.io] On Behalf Of Carl Moreschi via groups.io
Sent: 25 May 2020 11:42
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] Alternative transverter IF

One way to do this is by running my N4PY Pegasus Plus software to
control your K3. My software supports up to 5 transverter setups. The
IF frequency can be set to anything. This allows the correct frequency
to be displayed in the software.

Carl Moreschi N4PY
127 River Moss Way
Hertford, NC 27944
www.n4py.com

On 5/25/2020 2:52 AM, Colin Smithers wrote:
Thanks Alan. That was all I could find too, hence this post.

73, Colin G4CWH


On 25 May 2020, at 00:14, Alan Baker via groups.io
<g4gnx=g4gnx.com@groups.io> wrote:


I checked the K3 and Cady books and there doesn't appear to be any way
of doing what you want. You can set the band, but not a particular
offset in the band. Unfortunately the offset provided is only
correctional and won't shift far enough for your purpose.

73,

Alan. G4GNX


------ Original Message ------
From: "Colin Smithers"<colin@...
<mailto:colin@...>>
To: Elecraft-K3@groups.io<mailto:Elecraft-K3@groups.io>
Sent: 23/05/2020 23:15:47
Subject: [Elecraft-K3] Alternative transverter IF

Hi all,

I'm New here.

Does anyone know how to set a transverter IF to 28.5MHz, or any other
frequency that is not 28,0, 50,0 etc? The incremental oscillator
shift only goes so far i think.

Reason is I built a 70 MHz transverter from 28.5 as using 28.0
results in a a difficult spurious product.

If not I can always continue to subtract .5 in my head as i have done
for the last 35+ years :-)

(Also sent to the elecraft group)

Thanks and 73, Colin G4CWH



Geert Jan de Groot
 

     I can only set 28.0, or 50.0. Etc
Perhaps setting the XVx RF setting one MHz off would work for you. Your transverter IF would then be 29 MHz instead of 28 MHz.

I agree that setting the RF settings in steps of 100 kHz would be nice, but I don't see that happen for the K3.

Peter G3SMT
 

Would it not be more expedient to fit a 42MHz crystal to the transverter and solve all the issues that way.

73

Peter   G3SMT


On 25/05/2020 00:14, Alan Baker wrote:
I checked the K3 and Cady books and there doesn't appear to be any way of doing what you want. You can set the band, but not a particular offset in the band. Unfortunately the offset provided is only correctional and won't shift far enough for your purpose.

73,

Alan. G4GNX


------ Original Message ------
From: "Colin Smithers" <colin@...>
Sent: 23/05/2020 23:15:47
Subject: [Elecraft-K3] Alternative transverter IF

Hi all, 

I'm New here.

Does anyone know how to set a transverter IF to 28.5MHz, or any other frequency that is not 28,0, 50,0 etc? The incremental oscillator shift only goes so far i think.

Reason is I built a 70 MHz transverter from 28.5 as using 28.0 results in a a difficult spurious product.

If not I can always continue to subtract .5 in my head as i have done for the last 35+ years :-)

(Also sent to the elecraft group)

Thanks and 73, Colin G4CWH

Geert Jan de Groot
 

Peter, the TS indicated that using 42 MHz LO gives bad image rejection. Do the math. That's why he is using 41.5 MHz instead.

Colin Smithers
 

Thanks for that thought, Geert. Yes that would work. I was just hoping that there was a front panel entry or utility program solution.

 

However, so far it doesn’t seem as though there is.

 

73, Colin

 

From: Elecraft-K3@groups.io [mailto:Elecraft-K3@groups.io] On Behalf Of Geert Jan de Groot via groups.io
Sent: 25 May 2020 15:03
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] Alternative transverter IF

 

     I can only set 28.0, or 50.0. Etc

Perhaps setting the XVx RF setting one MHz off would work for you. Your transverter IF would then be 29 MHz instead of 28 MHz.

I agree that setting the RF settings in steps of 100 kHz would be nice, but I don't see that happen for the K3.

Peter G3SMT
 

Geert,

Thank you for the update, I must have missed that post.  I use a similar conversion system without any issues although I do not understand how moving 500kHz changes the image rejection.

Back to the drawing board.

73

Peter


On 25/05/2020 16:26, Geert Jan de Groot wrote:
Peter, the TS indicated that using 42 MHz LO gives bad image rejection. Do the math. That's why he is using 41.5 MHz instead.