[Milsurplus] Fair radio

[Scott Johnson]

The 618S-1 = RT-311, the 618S-4 has 144 xtal positions, both were used 
by civil operators.  There is also confusion regarding the 618S-1MC SSB 
conversion, and the RT-594/ARC-38A.
I have examples of all these radios, but have not run across the 
618S-1MC manuals yet.  It seems that most USAF installations used the 
180-L3 couple, whereas the USN installations used the CU-351, which has 
a MS power connector, rather that the legacy K connector that dates back to
the 18S installations.  It would seem that this was done to simplify 
equipment upgrades.  This was evident later when the 618T-1 replace the 
618S-1 in C-130s (the 618T-1 used an external inverter supply to make 
400V 1500Hz, which was sent to the RT and stepped up to 1500 V and 
rectified for the PA, this allowed the use of original 618s-1 wiring.  
Make any sense, or am I rambling?

Scott
Mike Morrow wrote:
>> I have started to get into collecting "cold war" radios and ended 
>> up buying a 618S1/ARC-38 along with the matching head
>>     
>
> I like the cold war gear too.  But we collectors need to be careful with nomenclature.
>
> The Collins commercial 618S-1 and the USN RT-311/ARC-38 are NOT the same set at all.  The 618S is crystal-controlled.  The RT-311/ARC-38 uses a complex "stabilized master oscillator" to generate frequencies at 0.5 or 1 kc intervals, depending on frequency.  Likewise, the control heads are very different.  I don't know how the bad dope got started that the AN/ARC-38 was the military version of the 618S.  I guess someone must have thought that if the RT units looked about the same they must be equivalent.  The US military bought both sets, and many 618S name plates have a small "U.S." at the bottom.  But JAN nomenclature was never assigned to the 618S.  618S units are dogs on the market, with $50 price tags being typical.  The RT-311/ARC-38 is harder to find (most were converted to USB-mode RT-584/ARC-38A units) and usually bear more than twice the cost of a 618S.
>
>   
>> their were lots of the RT-618 and ARC series radios their 
>>     
>
> Likewise, the JAN RT-618 (actually RT-618/URC) is a USN shipboard HF unit, part of the AN/URC-35.  Not an airborne set.  An RT-618 is a lot harder to find and more expensive than a Collins 618S.
>
>   
>> Would think that if you plan to attend Dayton next year
>> consider planning coming early and going to their sale.
>>     
>
> I agree.  I used to give up Saturday at Dayton for a drive to Fair Radio at Lima.  It was always worth the opportunity to poke around the back rooms for unadvertised gear.  I like their new place better than the old, being just off I-75.  But ebay has proven to be far more useful to completing collections than any hamfest, even the biggest, so I've given up Dayton unless I have some other reason to be in the area that weekend.
>
> Mike / KK5F
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