[HBR] I'v finally started the HBR-16

[Bill Higgs]

Hello fellow listers,

Now that the holidays are behind us, I have finally got a start on the =
HBR. Currently, all that is done is basic metalwork and planning, but I =
expect to drill more holes over the weekend and maybe even mount the =
tuning mechanism and some tube sockets.

Rather than try the typical prefab chassis, panel, and cabinet, I built =
my own foundation from bits and pieces. The chassis itself is the top =
cover from a digital thingy I picked up at a hamfest for $1, and the =
front and rear panels are made from two pieces of aluminum I got at a =
yard sale last summer for 50 cents each (pebble grain, even). So far, =
cost is up to $2. To hold it all together, I spent $3.50 for some angle =
aluminum and another $2 for some flathead #6 screws to fasten it with. =
Total cost to date is $7.50, not counting a new hacksaw blade. The =
bottom plate and the top and sides of the enclosure will be cut from an =
old broadcast video monitor cover, which is already perforated for =
ventilation. Pix of this effort can be found at =
www.lizcurtishiggs.com/images/special/side.jpg and =
www.lizcurtishiggs.com/images/special/underside.jpg. Still just an empty =
enclosure, and pix a bit fuzzy - sorry!

I don't know the exact gauge of the material, but it is thick enough to =
handle countersunk #6 screws, so I would guess that it is a bit heaver =
than average chassis material for this size unit. I will add a couple of =
braces, at least near the tuning mechanism.

Plans are to follow the HBR-16 architecture, but with a couple of tube =
changes. I'm going to try a 6eh7 as both RF amp and IF amps, a 6EJ7 as =
first mixer, and the 6U8A circuit from the HBR-13 as second mixer. =
Second IF is at 85kc (not Hertzes), using command set cans, possibly =
adding an extra can for additional selectivity (thanks, Walt!). The 6JH8 =
product detector from the "KCS Compactron" looks like it is worth trying =
(thanks for the schematic, Pat!).

Tuning will be with an old National 5:1 dial (yes, I know it's too slow, =
but I'm adding a small "clarifier" control in parallel. Also, rather =
than plug in coils, I'm going to try the "band imaging" concept, =
covering both 80 and 40 with a single VFO range. If I want the higher =
bands, I'll try an outboard converter . . .

Best wishes to all. I'll post some more pix as construction progresses.

Bill, NT4C 

--- StripMime Report -- processed MIME parts ---
multipart/alternative
  text/plain (text body -- kept)
  text/html
The reason this message is shown is because the post was in HTML
or had an attachment.  Attachments are not allowed.  To learn how
to post in Plain-Text go to: http://www.expita.com/nomime.html  ---