[HBR] Current day HBR

[Shoppa, Tim]

Walt writes:
> Adding general coverage by means of an alternate set of coils that
> connects additional tuning capacitance (the 3-gang AM/FM cap
> previously described) won't yield a top grade general coverage
> receiver. For one thing, general coverage receivers with mechanical
> tuning need major attention to the tuning rate. A GC functioning
> version of an HBR will be very tough to use on GC SSB signals, even if
> it's fine on the ham bands.

Thing is, I'm not sure that in general a new tuning capacitor is necessary.

I haven't completely reverse-engineered the SWL-oriented HBR
coilset that I inherited, but each coil set nicely covers a SWL band.

Note that the HBR coilset design allowed for varying ratios of
bandspread/bandcenter ratio using several well known strategies.

The bandspread ratio is nicely set by the coil taps/fixed cap/variable
cap in each coil and seems to be adequate for a typical SWL band
plus some margins on each end. And each SWL band is, realistically, not
too awful broader than a ham band.

I would be hard pressed to come up with a good reason for a SWL coilset
That covered two different SW bands. Maybe 16M and 19M on the same coilset.

I look at other ham+SWL receivers of the era - the Drake 2B (got SWL
Using ham band crystal images, or with custom crystals, and there was
LOTS of room for custom crystals and a lot of SWL's used 2B's)
or later the Heath SB-303 nee SB-313 and that seems like the
right level of "general coverage" to me (while not truly being
general coverage in the derogatory sense I otherwise use it!)

Tim N3QE