[ARC5] VHF Guard (121.5 MHz), and Other Guard Channels

[Bob Macklin]

Did US airports have UHF capability prior to the late 50's?

Bob Macklin
K5MYJ
Seattle, Wa.
"Real Radios Glow In The Dark"
----- Original Message ----- 
From: "D. Platt" <jeepp at comcast.net>
To: <arc5 at mailman.qth.net>
Sent: Friday, March 29, 2013 4:28 PM
Subject: Re: [ARC5] VHF Guard (121.5 MHz), and Other Guard Channels


> Order in the Court... The Monkey Wants to Speak.....  Or, something like 
> that.
> 
> Most of what you all have been saying, I believe is correct.  I'll 
> confirm that the URC-4 and URC-11 both worked on VHF and UHF Guard 
> (Emergency).  The military SAR aircraft, however, more often that not, 
> did not have VHF DF capability, except for the USCG.  They seem to have 
> kept up with both the civil and military arenas, from the get-go.  I'm 
> not sure when it was that the military started integrating full VHF comm 
> capability is most/all aircraft.  Given the whole gamut of A/G and A/A 
> scenarios, it became wholly necessary.  It was after my stint in the 
> USAF and in fighters (F-106's at KADW and KDOV).  In those days, fast 
> movers only had UHF.  With regard to civil airport and ATC having UHF 
> capability, most absolutely.  If one looks at either the civil or DOD 
> enroute supplements (IFR Supp) or any of the Joint Operations pubs, 
> you'll see the VHF and UHF frequencies listed.  That said, in the 
> "beginning" only ARTCCs in the CONUS and most of NATO countries had full 
> VHF/UHF capabilities.  Towers and other "outlets" like FSS's may have 
> only had UHF guard and a common UHF frequency.   With synthesized 
> equipment, and facility can and do, have the whole gamut.
> 
> Not to beleaguer a point, but has anyone noticed that the Europeans have 
> gone to 8.33 kHz channel spacing, vice the 25 kHz spacing we use in this 
> hemisphere.  That means there's a tremendous amount of gear in use that 
> won't homologate over there!   I do notice that some American avionic 
> companies are beginning to list that type of equipment, though.   God 
> help us if they mandate that here!!!
> 
> Jeep - K3HVG
> 
> PS:  In case anyone didn't know (or could have cared less), if you've 
> had occasion to hear an emergency beacon you'll notice that the mil 
> units sweep up in note and the civil beacons sweep down. That was an 
> "agreement" so that MIL assets could be readily identified by their the 
> "own" people, and of late, SARSAT.  Its all a moot point now as the new 
> 406 MHz burst beacons can't be readily heard and SARSAT ignores the old 
> frequencies.  CAP has retained both the SAR ability for both the old and 
> the new frequencies.  I wonder what the military is doing?   Probably 
> the USCG, bless their hearts, will keep it all.......
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