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Re: Me and my stupid Drakes...again.



The HP spectrum analyser gives absolute power measurements (+/- 2 dB) at the
marker so you can look at the differences and determine gain. The DEM preamp
has about 17 dB of gain which is normal. However, the Drake converters don't
look good because they have 26 and 20 dB of loss. They should have
considerable gain.

73,

John
KD6OZH

----- Original Message -----
From: "Timothy S. Zibrat" <tzibrat@adelphia.net>
To: "Amsat-Bb" <amsat-bb@AMSAT.Org>
Sent: Thursday, 07 June 2001 13:20 UTC
Subject: [amsat-bb] Me and my stupid Drakes...again.


> Hello everyone,
>
> I recently purchased a DEM 13ULNA kit and I wanted to see how it performed
> after construction.  I have access to an RF chamber and spectrum analyzer
at
> work so here is what I did:
>
> I have two Drakes (as you all probably know by now).
> One of them has the "simple" mods and the other has all of the mods.
> (By the way, in reference to my previous thread "Different versions of
Drake
> 2880?", I replaced that mystery capacitor with the 51 ohm resistor and
> turned my Toko filter around, and everything seems to be working fine now.
> I also touched up a few solder joints, what did the trick I'm not sure,
but
> it seems to work.)
>
> I built a signal source and placed it in the RF chamber about 1 meter from
> the receiving antenna.  I connected each Drake by itself and then with the
> DEM preamp.  If you would like to see the results, they are located here:
>
> http://home.adelphia.net/~tzibrat/spectrum.htm
>
> Now remember I am a newbie here, and I don't have much experience with
this
> type of test equipment.  My question is, how do I interpret all of the
> information I am getting from the analyzer?
>
> Since my Drakes have been on the bench for quite some time, I haven't
tried
> them out on AO-40 or UO-11.  Is AO-40 still receivable with a BBQ dish at
> the current squint of 30 degrees or so?  According to the spreadsheet, I
> should be able to hear it, assuming I put the numbers in right.
>
> Thanks for any help!
>
> Regards,
> Tim
> K3TZ
>
> ----
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