[HBR] HBR Receiver parts

[Sandy and Kees Talen]

The difficult to find parts for a HBR Receiver are the FM variable 
capacitor, the IF transformers, and the coil forms.

For the coil forms, an excellent solution is to use the 1-1/4" amber
pill containers or PVC. Attach a plug of your choice and only the 
osc coil socket should be ceramic for electrical stability. Testing 
(on the web site) has shown that the "Q" of coils wound on these 
forms is very close to that of the Amphenol coil forms. There ARE
other materials which are worse (ANY paper based product) or 
slightly better (ceramic). The winding adhesive DOES have an 
effect on "Q" (on the web site).

For the IF transformers, BC-453 85Khz IFs are great if you have
the room for the large cans. If you want to use the smaller 3/4"
cans, modified 262Khz IFs adjusted for more inductance and 
with 430pf padder capacitors seems to work well (previous 
discussions). 

For the tuning capacitor, the one offered by BG Micro was excellent
(three section with 7-27pf per section) but they are no longer
available from BG Micro. Since these are modern manufacture, it's
only a matter of time before someone finds a source of these again. 
There is another possible solution from the guy below. These are 
six section tuning capacitors. Section 3 and 6 are 5-21pf and 
section 4 can be modified to match sections 3 and 6 by removing 
one rotor plate and one stator plate. The range of 5-21pf will require 
some coil turn adjustment so the whole band can be covered. If 
you want more capacitance removing all the rotor plates except one 
between two stator plates on sections 1 and 2 provides 6-35pf 
each. Section 5 is a little more difficult due to the size of the plates
and gives 7-36pf if you remove all but two of the rotor plates ....but
the tracking will be different from sections 1 and 2. This will give
you more than an adequate tuning range for all bands, but I'd go
with the 5-21pf sections and adjust the coils if you can. The only 
drawback is that this capacitor has maximum capacitance fully 
clockwise, so the low end of the band would be to the right unless 
you design the dial drive. Both the BG Micro capacitor and this one 
are PC board mount variables and have 1/4" shafts.

Other subject........ 
How about a receiver based around some of the later articles (double
tuned frontend, low noise front end mixer, designed for 3-5-4Mhz with 
crystal converters for the other bands, etc), 262Khz IFs (retuned for 
256Khz), 256Khz Collins Mechanical filter #526-9700 (cheap, 
because no one knows what to do with a 256Khz filter), hang audio 
AGC, Q multiplier ....and naturally tubes (preferably no 7360s ....too
difficult to find for less than $25 and it won't decrease).

73s  Kees K5BCQ
  

-------- Forwarded message ----------
From: "I. Cannon" <ctrak04t@prodigy.net>
To: <windy10605@juno.com>
Subject: 1348464684 Large Multi Section Variable Capacitor (4)


Yes have more of these. Sold in pkgs/4 as listed on ebay at $16.00 for
first
pkg, and $15.00 thereafter. Ebay bid is not required, but please refer to
this same item number if ordering. Thanks.