[ARC5] Now for some AN/ARC-21 Info - Simplified Partial Re-posting

[D C _Mac_ Macdonald]

If I'm not mistaken, the AN/ARC-21 is (was) a relatively high-powered HF set.  If was later modified for SSB mode and renamed AN/ARC-65.  That is what I "went to war" with in B-52F. 
 
Mac in OKC

Sent from my iPhone

On May 30, 2016, at 15:07, Mike Morrow <kk5f at earthlink.net> wrote:

Some may have lost track of who is responsible for what text in a related thread.  So I am re-posting the AN/ARC-21 and AN/ARC-38 history that I composed in my last post today.  Any issues with the text below should be directed to me.

Mike / KK5F

Re-post:

The RCA AN/ARC-21 was a very unfortunate choice for the USAF and the US taxpayers.

March 1948 - Contract awarded to RCA for first prototype deliveries by June 1950. But that did not happen until December 1951.  In spite of the delay, the USAF decided to issue production contracts before any sets were available for service testing.
December 1950 to June 1952 - First production contract AF-33(038)-18325.  $54,021,975 for 3,915 sets, or $13,800 per set (equivalent to $124,600 in 2016).
April1953 - Second production contract AF-33(600)-24390.  $38,297,638 for 1,843 sets, or $20,800 per set (equivalent to $187,800 in 2016).  Contract terminated in June 1954.

There was also an un-pressurized version of the AN/ARC-21 to be developed as the AN/ARC-40, but it was canceled.

From the very beginning the AN/ARC-21 had massive in-service failure problems that resulted in MTBF in minutes rather than hours.  There was also very little training and maintenance support.  RCA civilian technicians had to be flown across the globe to service the set in the early days.  That's why the USAF purchased so many commercial Collins 18S-4 and 618S-1 sets to fill the roles for which the AN/ARC-21 had been intended.  Ultimately the RT-128/ARC-21 was re-worked to the RT-128A/ARC-21, which required an additional expenditure of more than $4,000 ($36,000 in 2016) per set that was already delivered.

In contrast, in 1947 the US Navy awarded a contract to Collins for a similar overly complex and heavy HF set called the AN/ARC-26.  The USN rejected it as impractical after $1,000,000 was spent for development.  Out of that came the well-known Collins AN/ARC-38 (similar to 618S-1, but with stabilized master oscillator and a few other improvements) which fulfilled the same role as the USAF AN/ARC-21 in a significantly lighter, less complex, much more reliable, much less expensive system...and no pressurization.  The AN/ARC-38 cost about $6,000 per set ($54,200 in 2016).  That's one-third what the AN/ARC-21 cost the taxpayers.

The USN did not use interim HF sets while awaiting the AN/ARC-38.  The USN continued use of the AN/ARC-25 (combo of AN/ART-13 and AN/ARR-15) until the AN/ARC-38 appeared in 1955.  However, the USN did buy some AN/ARC-59 sets, which were simply the Collins 18S-4A with a standard set of crystals and the RT-380/AR nomenclature.  These appear to have seen service mainly in non-combat logistics aircraft.  Mine is marked for Fleet Logistics Squadron VR-1, which is still in operation.

Mike / KK5F
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