I have a receiver I am considering modifying for other bands outside of what
it covers. It is a dual conversion superhet design. Before I modify it,
I'd like to see how the new frequencies would affect the mixer output. Is
there any decent freeware available that would allow me to see all mixer
outputs and to determine if any outputs might be a problem?

Thanks,
Mike

The free RFSim99 package, which has a wonderful set of tools just in
the RFSim99 application itself, also includes a separate program called
"Spur Search" which should do just what you want. A Google or similar
search should turn up several places from which you can download
RFSim99.

Cheers,
Tom

Thanks! Already downloading it!

"K7ITM" wrote in message
oups.com...
The free RFSim99 package, which has a wonderful set of tools just in
the RFSim99 application itself, also includes a separate program called
"Spur Search" which should do just what you want. A Google or similar
search should turn up several places from which you can download
RFSim99.

Cheers,
Tom

Oh boy! In the olden days I have seen mixer products charts. I think the
idea was to plot the places where all the harmonics of the two inputs
produced products so you could pick an L.O. and IF which didn't have
problems. However, I'm at a loss to point to anything. I probably have one
buried in the reams of stuff I saved to use in the future...argggg
I'm sure Excel can do this if you want to put in all the formulas (and know
what to calculate)

73, Steve, K9DCI

Perhaps a search on mixing charts or similar terms...

Hmmmm Googling this got nil:
Receiver mixer "mixing charts" -"23-channel"

"Mike Rhoads" wrote in message
ink.net...
I have a receiver I am considering modifying for other bands outside of
what
it covers. It is a dual conversion superhet design. Before I modify it,
I'd like to see how the new frequencies would affect the mixer output. Is
there any decent freeware available that would allow me to see all mixer
outputs and to determine if any outputs might be a problem?

Thanks,
Mike

In article ,
Steve Nosko wrote:

Oh boy! In the olden days I have seen mixer products charts. I think the
idea was to plot the places where all the harmonics of the two inputs
produced products so you could pick an L.O. and IF which didn't have
problems. However, I'm at a loss to point to anything. I probably have one
buried in the reams of stuff I saved to use in the future...argggg
I'm sure Excel can do this if you want to put in all the formulas (and know
what to calculate)

Shouldn't be dreadfully hard, I think.

Assuming two frequencies F1 and F2, you'll get mixing products at
the sum (F1+F2) and difference (abs(F1-F2)). To deal with harmonics
and higher-order mixing products, I believe you can generalize this by
including two integer multiplier factors M and N whose values run from
1 up to as high as you care to go. Then, expect mixing products to be
at (M*F1)+(N*F2) and abs((M*F1)-(N*F2)). The amplitudes of the mixing
products will be lower as the multipliers go up... you could probably
kluge in an estimation formula of some sort.

Calculate the various mixing frequencies, and estimated levels in a
square matrix, link the data to a two-column arrangement, and generate
a plot of level vs. frequency.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Hi,


I have a receiver I am considering modifying for other bands outside of what
it covers. It is a dual conversion superhet design. Before I modify it,
I'd like to see how the new frequencies would affect the mixer output. Is
there any decent freeware available that would allow me to see all mixer
outputs and to determine if any outputs might be a problem?

Thanks,
Mike

'Electronics' for September 2nd, 1976 had a simple 49-step spur
analysis program for the HP-25 by John R. Coleman of Harris
Electronic Systems which I assume will port to most other HP
calculators using RPN. I haven't tried it myself of late but it
worked fine some years ago. I can email a copy to anyone who wants
it.


Cheers - Joe

Mike Rhoads wrote:

I have a receiver I am considering modifying for other bands outside of
what
it covers. It is a dual conversion superhet design. Before I modify it,
I'd like to see how the new frequencies would affect the mixer output. Is
there any decent freeware available that would allow me to see all mixer
outputs and to determine if any outputs might be a problem?

Thanks,
Mike

Hi,

Check out the software package from Fritz Dellsperger.
http://fritz.dellsperger.net/

He have a IM.zip program, a graphic intermodulation program. Looks a bit
more advanced than what RF99 gives you.


Cheers

Dan / M0DFI