R20 - align HF SSB so spot on?

[g8tzl2004]

I have recently acquired an R20.

On HF USB, the R20 is about 400Hz low. On LSB, the R20 is about 100Hz low.

I want to realign the R20 so that it is more or less spot on - particularily on USB as a 400Hz error is way too much for "easy" listening using 1KHz steps - having to switch to 100Hz steps is a real pain.

I have a copy of the service manual but I would be grateful for any comments from others who have previously realigned their R20's.

Thanks

 

[Fast1eddie]

Would be interesting to see how tight your adjustment will do. I have the test equipment but no manual.

 

[g8tzl2004]

Service manual can be downloaded from Mods.dk site - a Google search will find it

I have basic test equipment but would like to hear other peoples experiences...there has been quite a few other requests for help on realignment over the years on various sites but no answers

I think SSB alignment is usually an "iterative" process ie. you adjust LSB and it effect USB as well. R20 service manual is not that user friendly...hopefully somebody with SSB alignment experience can provide some insights

 

[g8tzl2004]

Anybody realigned their R20 to get SSB spot on?

Its been a few years since I posted original request!!

 

[toad99]

R20 SSB

I aligned my R20 a couple of years ago so that the USB and LSB shift is correct. Use the service manual procedure to enter the adjustment mode. I used WWV instead of a frequency generator, and set the shifts so that the 1 kHz tone remained at 1 kHz when shifting from USB to LSB. I had to make several attempts at each shift adjustment to get it right, but finally got the shifts to be audibly equal.

 

[g8tzl2004]

Thanks toad99.

I need to read up again on the procedure.

I thought about using a Volmet (continuous aircraft weather info loop on USB 5.505MHz etc) but I guess I will have the problem of how to get LSB spot on? Am I right in thinking that you can't just align on USB as you need to get both USB and LSB in balance?

 

[toad99]

Yes, you will have to adjust both the LSB and USB shifts. When you adjust the shift, there will be a number in the display that you will change. Be sure to write this number down (both the before and after adjustment) so you can determine which way to adjust. I just made my adjustments by listening to WWV and trying to get the 1 kHz tone to sound the same in AM, USB, and LSB. I got close enough to make SSB listening using larger tuning steps satisfactory.

 

[g8tzl2004]

Thanks.

I wonder why Icom did not align the R20 SSB spot on in the factory!!! Icom ham stuff is usually spot on

 

[toad99]

I don't know. My IC-R75 ssb shift is perfect - the tone on WWV does not change at all from AM to USB to LSB.