SB310 Questions

[W6CUX]

I made the changes to a SB301 which were posted at:
http://bama.edebris.com/manuals/heath/sb301/ SB301.txt
and should be directly applicable to a 310 since they are essentially the
same circuit. At the time (1997) I did not have any equipment to measure
improvements. Since then I bought a Elecraft QX-1 signal source. With it I
was able to measure an improvement in the noise floor of about 4db --
from -134dbm to -138dbm.

This really improved the reception of the -301 of the computer / cable-TV
birdies and powerline spikes on 40 where they run about S-6/7 all the time.
In the real world any increase in the sensitivity is not worth the trouble.
What's more important is oscillator stability and selectivity which are both
good on the -301/310.

As to the marked crystal postions on the chassis, the are just a road map of
which crystal goes into which socket.


----- Original Message -----
From: "Orrin Bentz" <minmar at 2Z.NET>
To: <HEATH at LISTSERV.TEMPE.GOV>
Sent: Saturday, June 05, 2004 6:47 PM
Subject: Re: SB310 Qusetions


> Hello
>
> Does anyone have or know of a list of modifications to this receiver to
> increase it's performance?
>
> Also there are 9 unused hetrodyne crystal positions on the right front
> of the chassis. They are marked with a freq. but there are no holes to
> mount the crystal holders. What are these for?
>
> Also can someone please send me just the operating instructions part of
> the manual in ADOBE format. I down loaded what I could from BAMA but it
> is abbreviated.
>
> Thanks loads
>
> Orrin Bentz
>
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