[Milsurplus] Re: ATB "LF" TU

[Mike Hanz]

Hue Miller wrote:

> I am wondering how often this 2.3 - 4.2 TU is encountered.


Good question.  Your thoughts on the "afterthought" status of that 
particular TU sounds plausible.  Sigh...still looking for a storage case 
for mine.

> Does your ATB have one?


Yup - http://aafradio.org/flightdeck/ATB.jpg .  Note that this photo is 
before I put the meter box braces on the top of the transmitter.  BTW, I 
placed a sketch of the braces at the bottom of 
http://aafradio.org/garajmahal/atbmnt.htm if anyone wishes to duplicate 
them.  You could actually use some .032" aluminum and tin snips if those 
are too complex to make.  Ask Jack Antonio about making the side rails 
for the transmitter, shown above these meter braces on the page above - 
he has some experience with that process....heh, heh....

> I encountered an ATB the other night (not in a dark alley ) with the
> LH position occupied by this TU. I was quite surprised to see this.
> This TU could probably be made to tune down to 1.8 MHz thus giving
> the transmitter 3 band capability, 160 80 40, retaining the other TU
> for the 2 higher bands. Or, it's kind of nice having the LF TU just kept
> as is for 80 and switching to the other TU for 40.


Looks like you could pad it down to 160 without too much problem, but 
then you might have to add some external inductance/capacitance to get 
it to tune up, depending on your particular antenna. 

> I suppose the reason this TU is less-common is that, per manual, it
> seems maybe to have been an accessory type unit, carried in its own
> carry case. Apparently many, most? proceeded back to the metal
> smelter.


Makes sense, especially since the coils were reportedly wound with solid 
silver wire to meet a whimsical Navy specification for Q that otherwise 
had little effect on actual performance of the transmitter.

> Interesting also, to me, that there was no real LF TU for this 
> transmitter,
> altho it is a more powerful transmitter than the (traditional) Command
> Sets - and from the manual, the ATB was clearly designed as not limited
> to Command Radio use, altho it does seem to have been quite rarely
> deployed. The only for-certain use i have seen is as the HF Command
> Radio in the PBY seaplane - a photo exists. 


As well as in the PB4Y-2 photos I posted a while back.

> Of Navy air radio veterans
> i have spoken to, around 5 or so, none of recognized the name or
> description.


Not surprising, given its capability duplication in other more common 
sets.  I have a feeling they may have been used more after the war than 
during...one of my TUs has an OH date of 1955!

73,
Mike