[HBR] Help with old home-brew receiver

[hbr@mailman.qth.net]

In a message dated 3/24/03 1:48:13 PM Eastern Standard Time, 
waltah@earthlink.net writes:

> I once converted a 3-6 Mcs command receiver to dual conversion 
>  using one of the original 1415kcs IFTs and two 85 Kcs ones.   It 
>  worked fine, tho just a little more gain would have been desirable.   
>  Actually, something along that line might also make a good HB 
>  project.   With the frame grid tubes you'd have plenty of gain.
>  
>  That could even be a way to go for a simple general coverage home 
>  brew receiver -- just have to add a converter in front of it for the 
>  successive bands.

OK, how about this......

Find some really hacked-up ARC-5 sets - BC-453, 454, 455. Pick the best 
chassis of the three and assemble an rx as follows:

Tuning gang - from BC-455
Tuning coils - from BC-454 (add low-Z link to RF coil)
New tuning gang will cover about 1 Mc. Suggest 3 to 4 Mc. range. Better dial 
readout and tuning rate.
IF cans - one from BC-454, two from BC-453
BFO - BC-453, remotely tuned with mini antenna trimmer from BC-454 or BC-455
Replace all canned bypasses with better types.

Tube Lineup:

12SG7 RF amp
12K8Y 1st mixer/osc
12K8Y or 12SA7 2nd mixer/xtal osc (need a 1500 kc. xtal, or reuse the BC-454 
BFO coil)
12SK7 IF amp
12SR7 detector/AVC/1st audio
12A6 Audio output (use dpdt switch to select cathode resistor and output 
transformer so that stage can drive 'phones or speaker).
12SQ7 BFO (mount in dynamotor socket)
1629 magic eye instead of S meter

With a little care, the original chassis will hold everything except the 
1629. 

An external converter can be built to cover the bands 40 thru 10:

~10.5 Mc. xtal permits coverage of 40 and 20 
~21.5 Mc. xtal permits coverage of 17 and 12
~25.0 Mc. xtal permits coverage of 15 and lowest mc. of 10
- 6.5 Mc. xtal permits coverage of 30

Lots of leeway in the xtal freqs and other combos possible because the tuning 
range is a full Mc.

73 de Jim, N2EY