[HBR] Help with old home-brew receiver

[hbr@mailman.qth.net]

In a message dated 3/23/03 12:22:31 PM Eastern Standard Time, K9HX@joink.com 
writes:

> Hi, I am brand new to the list and need some assistance. I recently picked 
up
>  a old tube type home brew receiver, and hope someone on the list can help 
me
>  identify it. The receiver uses plug in coils for band switching, and has 
>  several
>  parts that have been salvaged from an old command set including three 85KC
>  IF transformers, the 85KC BFO coil and several three section .05MFD caps.
>  
>  The rig uses an external power supply and the tube line up is:
>  
>  6AQ5
>  12AX7A
>  6AL5
>  6BY6
>  12AU7A
>  6BE6
>  6C4
>  6BJ6 x2
>  1 other 7 pin minature that I can't get the number off of.
>  
>  I was told that it was built from a QST article for the 1950's, and most 
of 
>  the
>  tubes have late 50's date codes on them. If anyone can help me locate the
>  original construction article and schematic I would be very grateful. TIA, 
>  and 73,

To my knowledge this does not match any design in QST. 

>From the tube lineup, it appears to be an adaptation of the HBR concept, 
using miniature tubes and an external supply. Here's my best guess on the 
tube lineup functions:

6AQ5 - Audio Output

12AX7A - 1st Audio

6AL5  Noise limiter & AM detector

6BY6 Product detector

12AU7A BFO

6BE6 2nd converter 

6C4 HF oscillator

6BJ6 x2  IF amplifiers

The unknown tube is probably the 1st mixer. What do its innards look like?

Some questions:

How many sections on the tuning capacitor?

What controls are on the front panel, and how are they labeled?

Any crystals in the receiver?

How many coil sets?

Does it have any meters?

What does the dial look like?

--

It IS possible to reverse-engineer a homebrew rx like this. First job is to 
trace out all the wiring - quite a task but very illuminating. 

Pix are a big help.

73 de Jim, N2EY