[Milsurplus] Freq. Coverage of Navy Transmitters

[howard holden]

Hi Rob,

The TBW is not, as far as I know, a shipboard transmitter, rather a beach 
unit. Remember, it comes in the watertight cases, and is designed to be set 
up as a free-standing field unit. The TCS, on the other hand is a shipboard 
unit.

The puzzle to me is why did the TBW have the LF unit? Any antenna they could 
set up on the beach would be a pretty inefficient radiator in the LF range. 
The upper MF and HF would be far more useful and practical for shore-ship 
comms. Perhaps it was to be able to communicate with merchants involved in 
landings, who might have had only MF/LF rigs. That could explain the MCW 
capability on many Navy transmitters.

The other puzzle is why the Navy used suppressor-grid modulation instead of 
plate  mod on some transmitters? Typical power output with suppressor mod is 
about 1/4 of the CW output. Granted, the weight and space savings over plate 
mod on the TBW might mean something to the guys who had to muscle it ashore, 
but with a hulk like a TBL, at 700 lbs (not including the MG set), what 
would another 150 lbs mean, instead of the 75 lbs for the suppressor 
modulator.

Howie WB2AWQ



----- Original Message ----- 
From: "Robert Flory" <robandpj at earthlink.net>
To: "milsurplus" <milsurplus at mailman.qth.net>
Sent: Monday, November 01, 2004 11:40 AM
Subject: [Milsurplus] Freq. Coverage of Navy Transmitters


> Hi,
> The frequency coverage of WWII Navy HF transmitters has me scratching my
> head, especially at the low end.  Most of the shipboard units seem to go
> down to 2Mc.  Why do you suppose the TBW drops the 2-3Mc portion, yet the
> TCS goes down below 2Mc?
>
> Rob Flory
>
>
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