SBA-104-1 Interest?

[Gerald C. Lemay]

I have one of those noise blankers installed in my SB-303. I agree with
you. One of the things I would add would be a bandpass filter ahead of the
blanker. For example, the Drake noise blankers used in the TR-4 series
(includes the TR-6) and R-4C's (includes the SPR-4), all have some form of
bandpass of around 8 khz ahead of the circuit. any narrower and the noise
pulses would be widened. Any wider and we're back to square one. The
Heathkit noise blanker works well on a noisy band with few strong signals.
For example, the high end of 10 meters. It is completely useless on the 80-
20 meter bands. Another feature the Drake blankers had was a delay circuit
in the signal path. As the signal and noise are split into separate noise
and signal paths, the signal path needs to be delayed by an amount equal in
time with the noise processing circuits. Otherwise, the blanking pulse
arrives later than the signal thus reducing effectiveness
> To All:
>
> About the SB-104 noise blanker. I remember servicing a ton of SB-104s
> at Heath, many with the noise blanker accessory installed. In most
> situations, these noise blankers added more problems than it solved
> (intermods) by the time the threshold was set high enough that produced
> effective blanking. Some waveforms received with just the right pulse
> repetition frequency and duration seem to "fit" the noise blanker and
> it worked; most noise pulses in the real world did not, however.
> Therefore many individuals would set the threshold too high, making the
> receiver appear to have more in-band signals (intermodulation). Ugly.
>
> What I would do, assuming I had the time and there was enough interest,
> would be to re-design this small noise blanker board. One of the major
> problems in doing this are the PCB-mounted card edge connectors. I
> can't seem to locate them anymore. Any suggestions?
>
> Dave Kechkaylo, W8DLK
>
> -----Original Message-----
> From: Gerald Lemay [mailto:w1id at FCGNETWORKS.NET]
> Sent: Tuesday, February 26, 2002 9:17 PM
> To: HEATH at LISTSERV.TEMPE.GOV
> Subject: Re: SBA-104-1 Interest?
>
>
> The price would seem a bit steep considering there is very little to
> the noise blanker circuit. As I remember there's a couple of IC's and
>switching transistors. Add a few resistors, capacitors and RFC's. The
>board would probably not be that expensive. I think you can get
>single-sided boards in quantities for less than $20. Of course, you have
>to add documentation and assembly instructions plus profit. Also don't
>forget the people who would buy the kit and unfortunately don't know
>which end of the soldering iron to hold. Those people could take away
>quite a bit of your time and probably show little if any regard for all
>your efforts. Guess you can tell I don't like dealing with the public!
>
>
> -----Original Message-----
> From: Heathkit Owners and Collectors List
> [mailto:HEATH at LISTSERV.TEMPE.GOV] On Behalf Of Don Peterson
> Sent: Tuesday, February 26, 2002 11:28 AM
> To: HEATH at LISTSERV.TEMPE.GOV
> Subject: SBA-104-1 Interest?
>
>
> I am considering offering a "re-manufactured" version of the SBA-104-1.
> This "kit" would offer a single sided, silk screened PC board fashioned
> after the original Heathkit with a complete kit of parts to build the
> noise blanker. It would use the same design/parts list as the original.
> I expect the kit would sell in the $75.00 area.
>
> If I can get enough interest from individuals using the SB-104 or
> SB-104A, then I can justify the PC board investment.  I don't know how
> many are still using this rig.  And how many might need the noise
> blanker.
>
> Any interest out there????
>
> Don
>
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