[HBR] HB-65, anyone, anyone?

[N2EY at aol.com]

In a message dated 12/1/06 5:24:22 PM Eastern Standard Time, 
shoppa_hbr at trailing-edge.com writes:


> The 1966 ARRL handbook has a very nice looking receiver called the
> "HB-65" in it. 

That rx is also in the '65 Handbook. It's not in the 1964 or 1967 HBs, 
though. 

1967 brought the HB-67, which is an 80 meter receiver with 4555 kc IF 
preceded by a four-band crystal controlled converter.

The base receiver has a 1700kc IF and tunes 40 and
> 
> 80 meters, with a 7360 at the front end. Then there's a crystal-
> controlled converter with a RF stage for tuning 20, 15, and 11/10 meters.

The basic receiver is double conversion - IFs at 1700 and 100 kc. 1700 gives 
band imaging and good image rejection, while 100 gives reasonable 'phone 
selectivity. 

Adding the converter makes it triple conversion on 20 thriugh 10.

I don't think it tunes 10 meters as designed, though. Check the het xtals - 
it doesn't have one for below 28 Mc.

The design of the HB-65 was obviously influenced by the "Miser's Dream" which 
was in QST about the same time, and by the W6TC HBRs. 
> 
> Looks to me a lot like DeMaw's solid state receivers of the 70's.

How? 

The HB-65 uses only LC filtering - no xtal or mechanical filters. Multiple 
conversions, too. 

> Very well-balanced radio, not too much gain, no whiz-bang features,
> well thought-out bandswitching that doesn't try to give the kitchen
> sink but instead gives exactly what is needed in a ham receiver.
> 

Sort of.

For all that complexity, there's no sharp filter for CW. The AGC is audio 
derived and the selectivity is so far from the antenna on 20 through 10 that the 
dynamic range is probably compromised. Some unusual tubes, too. Uses a lot of 
IF transformers that are difficult to get today (two 1700 kc, four 100 kc, 
plus 100 kc. BFO). Even though it has AGC there's no S meter.

> What issue of QST had the HB-65 in it? 

It was never in QST.

The ARRL Handbook projects come from three sources:

1) Projects that were originally QST articles written by the ARRL Hq staff. 
2) Projects that were originally QST articles written by hams not on the ARRL 
Hq staff.  
3) Projects that were developed by the ARRL Hq staff specifically for the 
Handbook.

How much of each type appeared in the Handbook varied over time. My 
impression of the '65 and '67 Handbooks (I don't have a '66) is that most of the 
projects in them are from the 3) category, above. The HB-65 is definitely 3).


>Was it (by my guess) Doug DeMaw?
> 
> It's almost certainly a W1DX (By Goodman) design and construction project. 

---

The HB-65 has some good ideas but it could be a lot better.

Here's how I'd build that sort of rx:

First off, if a source of good 1700 kc xtals can be found, build crystal 
filters for 1700 and eliminate the conversion to 100 kc and all the hard to get 
IFTs. Perhaps a variable bandwidth ladder filter as used in the Elecraft rigs? 
Or perhaps package the filters as subassemblies, with one for CW and one for 
SSB, or even more.

Moving the selectivity closer to the antenna will improve the dynamic range, 
and simplify the rx. 

Next, I don't know if I'd use a 7360 as shown, or in a balanced circuit. 
Maybe try a different beam-deflection tube like the 6JH8 or 6ME8, or maybe a 
Pullen or other triode mixer. In fact a receiver like that might be a good test-bed 
for different mixers.

I'd build the VFO as a unit, rather than on the chassis, and I'd include some 
kind of buffering/isolation. Maybe an ARC-5 tx capacitor with built-in dial 
drive. Since the VFO tunes just one range, why not unitize it?

The dual diode product detector could probably be replaced by an active 
tube-type detector that would have some gain, easing the requirements for audio 
gain. I'd use a bigger chassis in order to have more room and a bigger panel. A 
balanced mixer in the converter (maybe a beam-deflection tube?) to eliminate IF 
feedthrough problems mentioned in the article. 

An interesting feature of the design is that it covers the WARC bands as-is, 
with a little creative use of the preselector tuning and the bands tuning 
backwards.

To receive 30 meters, (I'm assuming the converter tuned circuits will tune 
down to 10 Mc., or can be modified to do so),  select the 15 meter xtal (14.0 
Mc.) and peak the 7360 grid circuit for 80 meter reception. 10.1 will show up at 
3.9 Mc. on the dial and 10.15 will show up at 3.85. WWV at 10.0 can be tuned 
in at 4.0 on the dial.

To receive 17 meters, select the top-end-of-10-meters xtal (22.0 Mc.) and 
peak the 7360 grid circuit for 80 meter reception. 18.068 will show up at 3.932 
Mc. on the dial and 18.168 will show up at 3.832. 

To receive 12 meters, select the bottom-end-of-10-meters xtal (21.1 Mc.) and 
peak the 7360 grid circuit for 80 meter reception. 24.890 will show up at 
3.790 Mc. on the dial and 24.990 will show up at 3.890.

Of course one could add xtals and get the WARC bands to line up nicely, but 
that means more quartz and extra coils.

73 de Jim, N2EY