[HBR] HBR from Heath HR10B Question

[Walt Hutchens]

Steve said:

> I am looking at acquiring a HR10B for purposes of making it into my own
> HRB.  The question that I have relates to whether or not I can use a
> Hallicrafters SX140 just as well.  They both have approx a 1650 Khz IF
> and look like either one would work just fine.

The issues are:

1. Basically similar concept to the HBRs, for example a ham-band only design
using a three-gang tuning cap with mechanical reduction, two (or perhaps
three) IF stages, single conversion with a half lattice or better crystal
filter ...

2. Space on the chassis to arrange the three coils in a manner that allows
adequate shielding and keeps the osc. coil away from heat sources and nearby
metal or moving parts.

3. Adequate space for tubes and other parts -- basically plenty of chassis
area.

4. An adequate power transformer for the number of tubes you'll use.

5. A dial of usable quality (reduction ratio, freedom from backlash) that's
calibrated for the bands you have in mind.   (Since you'll probably want to
track your new receiver to the existing calibration.)

6. Suitable structure for a new front panel:  Few commercial receivers will
have a panel large enough for the type of cabinet you'll want to use for an
HBR.   The cabinet must be replaced because the usual commercial ham
receiver doesn't have a top you can open to change coils.   Also most ham
receiver cabinets and panels from the miniature tube era won't be tall
enough for the coils.

I've done the HR-10 to HBR reconstruction job so I know that one works.
While most of the requirements above are subject to some adjustment the big
advantage of the HR-10 is that VERY little of that is needed.  It is darn
near a perfect kit of major parts for an HBR, except for coils and front
panel.   Once you start saying, well ... I COULD use a different dial
mechanism (pick your part), the trouble goes up fast.

An added advantage of the HR-10:  It started life as a kit so the mechanics
and space on the chassis are appropriate for a home constructor.   (For
example, no tight corners, no riveted parts.)  Factory gear is often less
builder-friendly.  

The SX-140, I don't know about so that ground is waiting to be broken by
some HBR List adventurer!

Walt Hutchens
KJ4KV