[Milsurplus] Re: CMS Radio Again

[Hue Miller]

I have to assume that this and the Navy's MBM radio were designed, as Louis Mulstee's book
surmises, to be the Navy's equivalent of the PRC-1 and PRC-5. But why would the US Navy
need "suitcase radios" ??
I have no direct evidence of  the following genesis of these radios. However, we do know that
the US Navy was tasked with working with guerilla anti-Japan forces in China, to set up 
clandestine coastwatcher stations and weather reporting stations.  This organization was
named SACO, the "Sino-American Cooperation Organzation".  I am assuming t hat these
radios, with their more "sky wave frequencies coverage" ( 3-15 MHz CMS; 4-14 MHz MBM;
cw - altho the CMS has a practically unusable voice provision ), were commissioned by the
Navy for this deployment. ( Jeff Travis built the MBM; dunno who built the CMS, maybe
the Navy itself??)  But from the evidence, one photo and one citation in a book i quoted
a couple months back, it appears the only radio the reporting stations used was the off-
the-shelf TBX, and from the photo, as we'd expect, the particular production of the TBX
was the non-8. ( I wonder if the -8's ever actually saw action? )   Apparently the 4.5 MHz
top end of the TBX transmitter was sufficient for the moderate ranges required, add that
to the fact that these stations' reports were gathered, compiled, and retransmitted via a
central station with TBW transmitter, at Chunking and probably other sites, too. The 300
watt cw input of the TBW, up to 18 MHz, handled the ocean-spanning circuit to Hawaii
and possibly Australia. One of the books states "hundreds of stations" comprising
"thousands of radio personnel" - i don't know if that's quite true, or maybe the person
count was largely China nationals doing for the most part, assistance or apprentice work.
( I note also that a Navy "equipment maintenance reports manual" has a Navy approved
modification for raising the TBX transmitter frequency upper limit to 7 MHz. ) Anyway it
appears to me that the examples of the CMS and MBM seen here have been surplussed
( or five-finger "reallocated" ) in unused condition, and as these sets are quite rare, i have
to assume they never went into full production and in fact were most lilkely never used 
for their intended purpose.  In fact, it may be that the MBM was intended as an improve-
ment on the obvious shortcomings of the CMS, and then the idea to develop special 
radios was canned, and the move to off-the-shelf radios instead. Use of the TBX, already
in good supply and proven, possibly offered advantages in time and money- altho when
i'm not at all sure saving money was a criterion.  The MBM must have been quite expensive
to produce - why for example, produce a whole new handcrank generator when the TBX one
was already proven and in production? And why would the MBM, for example, have a 
an IF transformer with a machined cylinder can - why not use an off-the-shelf standard 
radio industry model? The other clandestine radios certainly did.  I kind of attribute that
to some weirdness in J-T's production methods - purely opinion, but i've long felt there 
is  some weirdness to Jefferson Travis's mechanical design. Hard to explain, but maybe
you have seen some J-T boat radios or portable consumer-market radios - before they
began just importing from orient in the late 1960s.   Actually, the CMS is weird enuff that
it could it be, J-T built that radio also? -Hue Miller
_____________________________________________________________________
----- Original Message ----- 
From: "Al Klase" <skywaves at webex.net>
To: "Old Tube Radios" <boatanchors at theporch.com>
Sent: Sunday, October 23, 2005 12:44 PM
Subject: CMS Radio Again


> Hi Gang,
> 
> Another example of the CMS (Spy Radio??) has surfaced.  See
> http://www.skywaves.ar88.net/SPY/spy.htm
> 
> We had a discuss of my set here a long time ago.  There wasn't much hard
> info, but someone said it was listed in a Navy book somewhere.
> In the mean time, a manual did come into my possession and is on the
> website.
> 
> In my estimation, this thing was intended to be an agent set, but it's
> kind of a stupid implementation.  I might be a redesign of something
> earlier.  The receiver uses 3S4 audio output tubes that are triode
> connected as if to substitute for something like a type 30.
> 
> Does anybody know anything or have any thoughts?
> 
> Regards,