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Re: 38k4 questions



Hi Colin,

Catching up on my e-mail after returning from Field Day and noticed this
from you.

There was a discussion a while back about the frequencies of various birds
drifting a little (more or less time in the Sun I think), and I've since
been in the habit of checking once in a while to see if I'm getting solid
signal -- the FT-736R has a DISC postion on the meter.  When I noticed that
I wasn't getting a solid DCD (and no data of course) until the meter was
indicating above S9, I started adjusting the tuning manually.  I found that
I could get solid signal and data at S3 about 16KHz low.  About then the
Satellite went off and I haven't been able to experiment anymore.  I haven't
done any adjustments to the IDF board yet, but I intend to put my 'scope on
the output and check the "eye" pattern when we get the bird back.

Which coil did you have to tune?  That might be something to check instead
of (or in addition to) the frequency off-set, but I don't want to "granch"
any more componets then I have already!!  ;-)

Bye the way, I did get a few pictures down that  CCD Display 97 1.21 won't
view, when do you think you might have the new version available?

73  Tom  n0ntx


----- Original Message -----
From: Colin Hurst <hurst_cj@msn.com.au>
To: Thomas McDaniel <TomMcD@ix.netcom.com>
Cc: Roy Welch (E-mail) <rdwelch@swbell.net>; Diggs, Steve
<Diggs@daugherty.com>; 'Mark L. Hammond' <hammond@surrealnet.net>; Stacey
Mills <w4sm@cstone.net>
Sent: Saturday, June 24, 2000 01:24
Subject: Re: [amsat-bb] 38k4 questions


> Dear Tom,
>
> Very interested in you post to amsat-bb re the 16kHz.
> Just for the record as your response is due to an ongoing
> thread. I have an IFD in my FT736R and it works real fine.
> Installed just like the instructions, no problems.
>
> The only problem I had was to tune the coil on the IFD
> to try and improve the low signal performance. Must have
> applied too much downwards force and graunched the slug.
> Ulf sent me a replacement coil and we were back in business.
> Its a very delicate device.
>
> Back in January I was achieveing excellent performance.
> In recent times I have been disappointed with my download
> performance and have been experimenting with masthead
> preamps etc etc.
>
> I had not given offset a thought. However I will certainly take
> your comments on board and give that a try when it gets out
> of that eclipse. Would be interested to know how you tripped
> over that one. On the subject of eclipse with Uo-36 I doubt
> whether we will see any improvement till the week following
> the 12th August. The period from 14th June to 16th August
> shows UO-36 in eclipse greater than 30% per day peaking
>  to 37%. Not good from a power budget perspective.
>
> Best regards,
> Colin VK5HI
>
>
> > Hi Steve,
> >
> > My IFD seems to work perfectly in a FT-736R!!
> >
> > I did have trouble with the initial installation -- when I tightened the
> nut
> > on the steel stand-off next to L17, the inductor jumped off the board.
> > Either the board wasn't perfectly flat or my stand-off mounting was off
a
> > little.  The second time I was able to carefully solder it back on and
> leave
> > the nut off of that stand-off.  And it now works as advertised!!  I
would
> > recommend plastic stand-offs.  ;-)
> >
> > One thing that I found through experimentation is that the center
> frequency
> > for best data through-put is about 16KHz lower than it should be.  I set
> my
> > TrakBox for 437.384MHz and I now get better than 90% with the best
> downloads
> > over 2MB.  With the frequency set for 437.400MHz I only get good data
with
> a
> > signal over S9 with downloads about similar to the 9600 birds.
> >
> > Unfortunately, we haven't had a pass since the 16th so my
experimentation


------------------------snip-------------------------

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