222 Transverter Issues

[glenn.d]

Hello list.

Just finished my elecraft 222 transverter and have a couple of issue.
1 - The input attenuator is overly sensitive. I believe this is R22. I hardley touch it and the voltage level goes way beyone the suggested 2 volts. I replaced it with a 10 turn pot and have a little more control but it seems way to critical.

Also, when trying to get it on frequency it was 2.5 KHZ high was the best I could do. I bought the optional crystal heater and got it closer but it is still a little high. The odd thing here is I just about have to remove the slugs in L4A and L19. Logic would tell you increasing the inductance should lower the frequency but both of these coils have the oppistie effect. Any idea why this is the case?

Thanks,
Dave N6TEB
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[Ron D'Eau Claire-2]

Dave, a few others noticed that sensitivity in the adjustable attenuator
pot, R22, as well and I was asked to take a look at it.

The 2 volts was an arbitrary figure. All that's needed is to be sure the
stages aren't being driven into limiting so you'll get nice, clean peaks
when making the adjustments. We've done some testing and found that you can
go as high as 10 volts and still be fine.

A new errata was released December 9 and is now on the Elecraft web site for
download. In addition to changing that reference level from 2 volts to 10
volts, it also contains two manual supplements. Supplement II contains a
summary of all the transverter jumper settings. I'm sure you will find it
handy. (Supplement I is for instructions for a K2 equipped with the K60XV
module with their transverters.)

If you find that R22 is set near minimum, it will be very critical. It's
perfectly okay to configure the jumpers J3, J4, J5 and J6 for more
attenuation ahead of R22 as shown under "I.F. Power Control" in the addendum
in order to reduce the overall gain and make R22 sit nearer mid-range. As
you will see in the addendum, there are specific jumper settings for each
I.F. tx power range. If R22 is close to minimum and touchy, simply configure
the jumpers for the next higher input power level. The adjustable attenuator
should have overlap across the fixed ranges to accommodate any input level
from 0.01 mW (-20dBm) up to 5 watts.

About the Local Oscillator frequency error, only the XV50 has a frequency
netting adjustment. That's why the manual contains no instructions for
setting the L.O. frequency for the XV144 or XV222.  

If you are using your XV222 with an Elecraft K2, there is an offset that you
can dial in at the K2 using the MENU commands for each transverter to allow
for variations in the L.O. crystal frequencies so the K2 frequency display
is exactly right. It's described in the documentation that came with your
firmware. Those data sheets are also available at www.elecraft.com.

If you're using another rig for the 28 MHz I.F. and would like to get a
little closer to the ideal L.O. frequency, I suggest dropping a note to
[hidden email] about the issue. I'm not the design engineer on the
transverter, so I can't suggest specific changes, but Gary in support is an
invaluable resource!

Ron AC7AC  



-----Original Message-----

Hello list.

Just finished my elecraft 222 transverter and have a couple of issue.
1 - The input attenuator is overly sensitive. I believe this is R22. I
hardley touch it and the voltage level goes way beyone the suggested 2
volts. I replaced it with a 10 turn pot and have a little more control but
it seems way to critical.

Also, when trying to get it on frequency it was 2.5 KHZ high was the best I
could do. I bought the optional crystal heater and got it closer but it is
still a little high. The odd thing here is I just about have to remove the
slugs in L4A and L19. Logic would tell you increasing the inductance should
lower the frequency but both of these coils have the oppistie effect. Any
idea why this is the case?

Thanks,
Dave N6TEB


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Elecraft web page: http://www.elecraft.com