[HBR] HB Receiver

[Hopperdhh at aol.com]

Byron,
 
Seems like it should work.  The first thing that jumps out at me  is your 
choice of oscillator frequency.  There will be a big birdy at  3990!  (Three 
times 1330 is 3990.)  If you go to the high  side, this won't be a problem.
 
For what its worth, I have used the 85 kc BFO can with a 6BE6 product  
detector, and it worked fine using the grid coil for the cathode.  Can't  remember 
if I had to open it up to change anything or not.  Would like to  here if the 
oscillator coil will work the same way with the 6BE6.  I have  always wanted to 
try that.
 
Dan Hopper
K9WEK
 
 
In a message dated 8/4/2006 6:46:52 P.M. Eastern Daylight Time,  
bjtatum at ev1.net writes:

Hello  All-
I have been thinking about a homebrew receiver design  and wanted to ask for 
opinions. I don't believe I am the first to propose this  design and I saw a 
HB receiver by a VK2 I believe that was similiar. Here it  is :
1. RF front end and first mixer -- A copy of sorts of  the Drake 2-B, whereas 
the RF amplifier covers all bands of interest and the  first mixer operates 
as another RF Amplifier on 80 meters, but as a frequency  converter for bands 
above 80 meters.
2. Variable IF -- The  variable IF will cover 80 meters as in the Drake 2-B. 
I plan to use the parts  from an R-25 ARC-5 set { a parts unit I cannabilized} 
to tune from 3.5 to 4.1  MC. My thoughts are to use the OSC. and RF sections 
of the tuning gang { after  pulling most of the plates} and fixed capacitance 
across the OSC. and RF coils  { from R-25} in order to get this tuning range, 
using a 6BE6 converter tube.  IF output to be 1415 KC as in R-25 receiver. Was 
thinking about placing  back-to-back 1415 KC IF transformers at output of the 
variable IF feeding into  one low gain stage at 1415 KC followed by another 
IF transformer. { This is a  departure from Drake 2-B where 80 meter variable 
IF is mixed down to 455  KC}
3. Third mixer -- The 1415 KC from IF amplifer would be  mixed down to 85 KC 
in a 6BE6 converter tube, using a L/C osc. at 1330 KC.{  Drake went in on low 
side of 455 KC IF in the 2-B using 405 KC  osc.}.
4. Final IF Amplifier -- Plan to use the 85 KC IF  transformers from R-23 
ARC-5 set. Thinking that one stage of IF using 6BA6  will be sufficient.
5. BFO / Product Detector / AM Detector --  Plan to use 85 KC BFO coil from 
R-23 receiver and have front panel BFO  control. Would like to have selectable 
detectors and decent AGC, etc. probably  borrowing from HBR receiver circuits.
These are  some thoughts of mine. One question regarding the IF transformers 
from the  ARC-5 sets : Some of them have taps on the coils, I noticed in 
schematics that  second IF transformer has a tap on input coil connected to plate 
of first  stage tube and tap on output coil of transformer connected to grid of 
second  amplifier tube. Are these taps to reduce the gain? When I use a 
higher gain  tube such as 6BA6 how should I connect these transformers?
Thanks, Byron.       
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