[ARC5] T-368

[millerke6f at aol.com]

Both the t-368 and the GRC-19 used the same design scheme to implement FSK for the RTTY mode.  The output of both unit's  low level RF sections are used to drive an external RTTY box that heterodyned a fixed oscillator (that could be frequency shifted by the RTTY data) against the incoming signal from the T-368 or GRC-9 transmitter to an IF frequency then down converted once again to the original incoming signal frequency which was sent back to the original transmitter for final amplification/multiplication as needed. In the T-368 scheme you could simultaneously transmit the low speed TTY signal and AM.  The downside to this scheme is that the process also generated a lot of broad band noise that could mess up the spectrum around the  desired signal.  The T-368 when used with the GRC-26D was quite a package to  behold, but a real handful to use given that it did drift a bit and operators had a lot of trouble dealing with the RTTY stuff when it was coupled with the KW-7 crypto box.  The  IF RTTY demodulators were also a bit of a handful, but ok if you kept the r-390A  on the desired idle mark frequency.  No point and shoot radio here.  I used these monsters in the Army Guard along with the GRC-46 ratt vans and later the GRC-142 ratt vans.   All of which could be replaced by a hand carried transceiver and a pooter tablet today. But no where near the excitement of these old beasts created.


Bob, ke6f



-----Original Message-----
From: Geoff <geoffrey at jeremy.mv.com>
To: Richard Knoppow <1oldlens1 at ix.netcom.com>; ARC-5 List <arc5 at mailman.qth.net>
Sent: Sun, Nov 25, 2012 1:18 am
Subject: Re: [ARC5] T-368




>
> ----- Original Message ----- 
> From: "Geoff" <geoffrey at jeremy.mv.com>
> To: "Richard Knoppow" <1oldlens1 at ix.netcom.com>; "ARC-5 List" 
> <arc5 at mailman.qth.net>
> Sent: Wednesday, November 21, 2012 12:48 PM
> Subject: Re: [ARC5] T-368
>
>
>> The story was in ER some time back, the index is on line.
>> As I remember it Bendix or some other outfit won the contract but had 
>> problems and B&W picked it up. I may be wrong; I read the article as a 
>> curiosity and not as an owner.
>>
>     A little further research indicates they were built by at least three 
> contractors, Bendix Radio, Barker & Williamson, and Crosley, there may 
> have been others.  I still have not found where the design originated.
>
>
> --
> Richard Knoppow
> Los Angeles
> WB6KBL
> dickburk at ix.netcom.com


Id say it was done by the Signal Corps and Bendix who was the initial 
contractor. Back then the SC at Fort Monmouth still had an EE/ME level 
design staff 

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