SB620

[Stewart D. Lyon]

Peter,
The same thing happens with the SB-301. In this case the next circuit
element is the crystal filter which presents a very low impedance to the
signal at its tuned frequency and effectively shorts the signal out.
Therefore there is nothing left for the SB-620 to display at its center
frequency. A solution might be to add a FET source follower between the
mixer and the filter and something I might try someday.

73, Stu W6CUX


----- Original Message -----
From: "PETER C JOHNSON" <w1ca at JUNO.COM>
To: <HEATH at LISTSERV.TEMPE.GOV>
Sent: Saturday, December 16, 2000 12:17 PM
Subject: SB620


> I need some help figuring out a problem with a scanalizer.
> The signals on the left side of the screen are large, but as you tune
> them into the center of the screen so you can hear them on the rcvr they
> all but disappear, going from say 2 inches tall to about 1/4 of an inch,
> then when you tune by them they get bigger on the right side of the
> screen but not as big as on the left. I see no grass at the bottom of the
> screen, the signals just come up out of a flat trace. I went through the
> alignment in the book but that was right on. I am using a Drake 2B rcvr
> and the coupling cap is the size and connection recommended in the book.
> The rcvr is as hot as the one in my Atlas so I know its not rcvr sens.
> I'm contemplating changing the if amp in the scope but would like a
> little input first.
> Is this close to how they worked, this I doubt, or am I just accustom to
> the Tektronix pan adapters. Any help would be appreciated because I've
> never seen a heath scanalizer work.
> Thank you
> W1CA

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