[Milsurplus] RAV vs. RAX-1

[Mike Morrow]

Robert wrote:

>...I've always assumed the RAX/RAX-1 was an alternate to the
>RU's (meaning those RU models procurred without accompaning GF's)
>and therefore were countermeasures sets.

I've always considered the principle purpose of those RU sets without
an associated GF (RU-1, 4, 5, 6, 10, 11, 12, 18, 19) was to provide
the receiving component to go with non-GF transmitters like the GO-
and GP-series.  But these RUs supported two receivers in the system,
so perhaps the second receiver could provide some signals intelligence.

>And I assume that the RAT/RAT-1 and the RAV belong in the same 
>classification.

I agree that the RAV and the RAX were designed for the same roles.

Here's a listing of some similarities and differences:

The RAV contract date is 13 March 1940.
The RAX-1 contract date is 29 June 1940.

The eight RAV receivers cover 0.19 to 27.0 MC.
The three RAX-1 receivers cover 0.2 to 27.0 MC.

The RAV was designed for local control only.
The RAX-1 was designed for local control only.

The RAV is 28 vdc.
The RAX-1 is 28 vdc.

The RAX-1 system, compared to the RAV system, was notably lighter,
smaller, less complex, likely less expensive, and consumed less
resources to build and less power to operate.  (The RAV used 48
vacuum tubes, while the RAX-1 used 24.  That's a 50 percent 
reduction just by itself.)

The RAX-1 used a far more reasonable HV of 160 vdc, compared to
the RAV's 250 vdc.  The RAX-1 must have generated much less
waste heat, so possibly local oscillator stability was better.

The RAX-1 1.5 to 9.0 MC and 7.0 to 27.0 MC receivers had two
RF stages and three IF stages.  The RAV receivers all had one
RF stage and two IF stages.  One suspects that RF performance
of the RAX-1 above 1.5 MC was better than that of the RAV.

The RAX-1 receivers have much much better dial bandspread than the
RAV receivers.  The RAX-1 receivers have selectable AVC/MVC, while
the RAV receivers had no AVC.  There is much more panel area on the
RAX-1 for comfortably large controls.  Thus, the RAX-1 appears to
be much better suited to local operation than the RAV.

It appears to me that the RAV and the RAX-1 were designed from the
same set of requirements at about the same time.  Whatever the
rationale was for the RAV, it was the same for the RAX-1.  Comparing
the two, it's very easy to see why the RAX-1 won the competition, with
likely several thousand RAX-1 sets having been produced compared
to just 46 RAV sets.  I'd say that General Electric did a much better
job than did Aircraft Radio Corporation meeting the USN's requirements.

Mike / KK5F