[ARC5] "Geoff" on VHF vs HF

[Mike Morrow]

Mike/KK5F (aka "I") wrote in an earlier post (in lines with >>):
>> ...the UK helped get the USA away from attraction to its marginally
>> effective MF/HF command sets to VHF.

Carl/KM1H (aka "Geoff") responded (in lines with >):
> I think not as VHF has severe distance limits that only HF could cover.
> Both had their purpose and were widely used with excellent results by US
> forces.

I wrote:
>> What we've got here is...failure to communicate.

"Geoff" responds:
> Not really, there is a big difference between book reading and combat needs

The thread of this discussion is not 
             'HF vs. VHF for any aircraft communications',
just simply 
             'HF vs. VHF for aircraft **command** communications'.

The distinction in function and purpose between command sets and liaison
sets has always been very clear and unambiguous, surviving to this day.  

Carl, you do no service to the discussion if you can not recognize its
topic.  If you are going to argue against anyone's points, you must address
them in the original context of their declaration.

But...please pause a moment to explain how your declaration of a "big
difference between book reading and combat needs" applies to *any* discussion
in *this* thread, Carl?  Failing that, your statement is a non sequitur
that appears pointless, petulant and puerile.  I have the honor to point
out that reduces the statement's effectiveness. 

Now...back to thread topic: Your view appears to be that there is no 
important difference between command or liaison requirements and functions...
and that a MF/HF command set is valuable because it could possibly function
as some sort of long range liaison set.  However...the great majority of US
military aircraft during the past 65 years have lacked any HF capability.
Pilots in, say, Vietnam-era F-4s, A-37s, OH-6s, F-105s, etc. did not have
AN/ARC-94 or -102 HF sets installed, and there have been no new MF/HF command
set designs since the 1943 AN/ARC-5.  Were (and are) modern-era military
aircrews in these types of aircraft needlessly endangered because they
depend only on UHF or VHF?

I wrote:
>> My statement above clearly indicates its application to *COMMAND* sets,
>> not liaison sets.
>>
>> Command sets are used for plane-to-plane communication in formation,
>> and for short range communication to air fields on departure and
>> approach.

"Geoff" responds:
> As it says in the book

That is not a satisfactory response, Carl.  Do you dispute my statement, or
do you in fact agree with it but didn't wish it to appear obvious?

I wrote:
>> With respect to those "severe distance limits", the operating instructions
>> for many US VHF sets contain a graph of line-of-sight-to-ground range
>> at VHF frequencies.  The one in the 1944 AN/ARC-1 manual indicates the
>> range to be greater than 200 miles for an aircraft at 30000 feet.
>> Many of us have used two-meter FM HTs to talk with someone flying
>> at 30000 feet several states away.  It's not theory...it's real.

"Geoff" responds:
> Then I suppose all pilots stayed at high altitudes in your view of things.

That's a rather poor yet obvious attempt at a 'straw man' argument, Carl.

Command sets have *never* been designed to provide long range communications,
nor would such be desirable.  In WWII and later, enemy interception of VHF
communications from aircraft at altitude was a very real concern for which
cautions were frequently cited in applicable manuals.

In the ETO during the pre-VHF set era, enemy interception of HF command
set signals before and at the beginning of a flight was feared capable
of giving advance warning.  One of the desirable characteristics of VHF
command sets was the reduced probability of such early detection.

In short, for command communications, long range is *not* a positive
attribute.  VHF sets provide the aircraft in a flight or on approach or
departure the ability to communicate with each other or with terminal and
way points.  It should do nothing else.  Thus your earlier expressed
concerns about the "severe distance limits" of VHF command communications
is specious.

"Geoff" continues:
> What about crippled planes, those seperated [sic] from their group by
> weather or combat? Were they supposed to simply "deal with it"

Since most fighter and attack and similar aircraft for more than 60 years
now have flown without HF gear, the situation must now be pretty dire
and dangerous, then!

"Geoff" continues:
> I suppose that Spitfire pilot of the plane recently discovered in the desert 
> died happily knowing that he likely could have been rescued if a real radio 
> was available, and it wouldnt have been VHF.

His little **HF** set really helped him out, didn't it?  But what could the Brits
have otherwise installed?  The most common UK HF aircraft gear was the T1154/R1155,
or possibly a Bendix RA-10/TA-12 set...but there was no chance of either being
on board such an aircraft.  One could propose a VHF TR1143 or TR5043 (SCR-522-A)
instead.  That likely would not have been any better, but it could have not been
any worse than the 5 MHz battery powered TR9D that was on board.  Sometimes,
when you're screwed, you're screwed.

I wrote:
>> No one has ever cited a credible condition where, if VHF sets *had* been
>> available, they would not have better served the command set function than
>> MF/HF sets.  The UK helped to bring the US forces into that realization.
>> I challenge anyone to find a pilot's memoir that bemoans the replacement
>> of the SCR-274-N gear with the SCR-522-A.  Pilot praise for the SCR-522-A
>> and the later AN/ARC-3, expressed as great preference for the "push button"
>> rather than the "coffee grinder" command sets, can be found with little
>> difficulty.

"Geoff" responds:
> As long as pilots could communicate with their limited number of VHF 
> channels they were happy. Granted that changing frequencies on the fly with 
> ARC-5/SCR HF gear was no fun but if channelized sets had been available it 
> may have been a different story.
> Nothing was even close to ideal during WW2.

It was often ideal, for wartime of *that* epoch of technology.  War brings
out more than any other condition the advancement of technology and its
quick placement "in the field".  It would be nonsense to define, say, 2012
technology as ideal, and then bemoan its absence in WW2 as non-ideal.  In
2100, someone will be able to say "Nothing was even close to ideal during
2012".  But we get by thinking some of it is nearly so in present-day 2012.

An end with philosophical musings!  Carl, I think we've bonded.

Mike / KK5F