[amsat-bb] Re: Yaesu FT-897 and HRD satellite tracking problem

Dave Matthews dave at lostfrogs.com
Wed Dec 26 15:07:04 PST 2007

Thanks Alan!

I also have a bunch of those tiny chokes, and other small ferrites, and 
pi network filters for rf as well, and I will install them on my next 
USB to CAT project as you have suggested.  (To be completed in the next 
few days from a kit.)  I think that really is a last ditch effort since 
I believe the problem is not RF noise related, but rather a shortcoming 
in the Yaesu rig.  But I have been wrong many times before and I have an 
abundance of crows that visit by back yard, I may have to make a meal of 

I do find that reducing the update frequency in the tracker program 
'current data' makes it less obnoxious, so that is good news!

So I will continue to work on RF noise abatement.  Thanks for the response!

Thanks again Alan!
Dave, KI4PSR

Alan P. Biddle wrote:
> Dave,
> Something to try is to put a choke in series with the individual leads in
> the CT-62 line.  These are small, about the size of a 1 watt resistor with
> the conductor through the center.  They will have no effect on the
> relatively low frequency components in the CAT signal, but may help with the
> RF pulses.  I used this very successfully with another interface, though
> each situation is different.  I have a drawer full of them if you wish to
> try them.  Also, you may be able to bypass the RF with some disc capacitors.
> 73s,
> Alan
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