[Milsurplus] Re: [Repeater-Builder] ARRL Aiding Effort to MitigateRepeater Interference to Military Radars

Fri Apr 20 15:59:38 EDT 2007

There might still be a few SPS-40 shipborne radars out there that also 
operate in the 70cm band.

John WA4WDL,  former aircrew on E-2B Hawkeye and E-1B Tracer (Willy Fudd) 
aircraft.

----- Original Message ----- 
From: "Dick" <rertman at ix.netcom.com>
To: "Michael Vicari" <michael.vicari at verizon.net>; "MILSURPLUS" 
<milsurplus at mailman.qth.net>; "Larry Tighe" <larryradio at worldnet.att.net>; 
"Al AF6P Pantalone" <al at af6p.com>; "Louis OFFICE Strohacker" 
<louis.strohacker at L-3com.com>; "R. Dale KB7UB Piedfort" <kb7ub-5 at dxer.com>; 
"Harlan OFFICE Hicken" <hghicken at rockwellcollins.com>
Sent: Friday, April 20, 2007 3:35 PM
Subject: [Milsurplus] Re: [Repeater-Builder] ARRL Aiding Effort to 
MitigateRepeater Interference to Military Radars

> Only in a few geographical places.  I believe there are only two PAVE PAWS 
> radars operating now, so the Beale AFB, CA, and Otis AFB sites are the 
> only ones that might suffer 70 cm interference from amateur repeaters. 
> From what I hear, PAVE PAWS is being decommissioned one site at a time (I 
> sure would like to have one of their antennas for 70 cm SSB ops at my 
> QTH).
>
> The Navy still has radars in that band.  The AN/APS-138 series on the E-2C 
> Hawkeye AWACS airplane is one of them.
>
> 73,
>
> Dick
>
> ----- Original Message ----- 
> From: "Michael Vicari" <michael.vicari at verizon.net>
> To: "Dick" <rertman at ix.netcom.com>;Subject: Re: [Repeater-Builder] ARRL 
> Aiding Effort to Mitigate Repeater Interference to Military Radars
>
>
>> As secondary users, we might bite the big one.
>>
>> ----- Original Message ----- 
>> From: "Dick" <rertman at ix.netcom.com>
>> To: "MILSURPLUS" <milsurplus at mailman.qth.net>; "Larry Tighe" 
>> <larryradio at worldnet.att.net>; "Al AF6P Pantalone" <al at af6p.com>; "Louis 
>> OFFICE Strohacker" <louis.strohacker at L-3com.com>; "Mike Vicari" 
>> <michael.vicari at verizon.net>; "R. Dale KB7UB Piedfort" 
>> <kb7ub-5 at dxer.com>; "Harlan OFFICE Hicken" <hghicken at rockwellcollins.com>
>> Sent: Wednesday, April 18, 2007 1:56 PM
>> Subject: Fw: [Repeater-Builder] ARRL Aiding Effort to Mitigate Repeater 
>> Interference to Military Radars
>>
>>
>>> FYI:
>>>
>>> Dick W1NMZ
>>> =======================================================
>>> ARRL Aiding Effort to Mitigate Repeater Interference to Military Radars
>>>
>>> A PAVE PAWS radar facility. [US Air Force Photo]
>>>
>>> NEWINGTON, CT, Apr 17, 2007 -- The ARRL has been working with the US 
>>> Department of Defense to develop a plan to mitigate alleged interference 
>>> from 70 cm ham radio repeaters to military radar systems on both coasts. 
>>> Amateur Radio is secondary to government users from 420 to 450 MHz and 
>>> must not interfere with primary users. Citing an increasing number of 
>>> interference complaints, the US Air Force has asked the FCC to order 
>>> dozens of repeater systems to either mitigate interference to the "PAVE 
>>> PAWS" radars or shut down. The Commission has not yet responded. The 
>>> situation affects 15 repeaters within less than 100 miles of Otis Air 
>>> Force Base on Cape Cod, Massachusetts, and more than 100 repeaters 
>>> within some 140 miles of Beale Air Force Base near Sacramento, 
>>> California. ARRL Regulatory Information Specialist Dan Henderson, N1ND, 
>>> stresses that the Defense Department acknowledges Amateur Radio's value 
>>> in disasters and emergencies and is being extremely cooperative -- and a 
>>> wholesale shutdown of US 70 cm Amateur Radio activity is not in the 
>>> offing.
>>>
>>> "The ARRL Lab is working up calculations on each repeater system the Air 
>>> Force has identified to determine where interference-mitigation 
>>> techniques offer a reasonable chance of keeping the repeater on the 
>>> air," Henderson says. "In order for the amateur community as a whole to 
>>> succeed in this venture, it is going to require the cooperation of all 
>>> affected repeater owners."
>>>
>>> A US Air Force contractor identified the problematic repeater systems 
>>> last summer, but the situation didn't become critical until the Air 
>>> Force contacted the FCC a month ago. ARRL officials met with Defense 
>>> Department representatives in late March to discuss alleged interference 
>>> to the PAVE PAWS radar sites, and this week Henderson contacted Amateur 
>>> Radio frequency coordinating organizations in both affected areas -- the 
>>> Northern Amateur Relay Council of California (NARCC) and the New England 
>>> Spectrum Management Council (NESMC).
>>> PAVE PAWS is a missile and satellite detection and tracking system, and 
>>> its name is a half-acronym. "PAVE" is simply an Air Force program name. 
>>> "PAWS" stands for "Phased Array Warning System." Although PAVE PAWS has 
>>> been in existence since the late 1970s, the Cape Cod and Sacramento 
>>> sites are the only remaining operational facilities in the US.
>>>
>>> PAVE PAWS facilities occupy essentially the entire 70 cm band -- one 
>>> factor that makes mitigation difficult. Feeding upward of 1800 active 
>>> antenna elements, the broadband radar transmitters emit an average power 
>>> output of more than 145 kW.
>>>
>>> As a "first step" to mitigate the interference, the ARRL is recommending 
>>> that all affected repeater owners reduce power -- possibly to as little 
>>> as 5 W effective radiated power (ERP). "We understand the difficulty 
>>> this may cause to owners and users," Henderson said, "but the 
>>> alternative to operating with a smaller coverage area may be not 
>>> operating at all." Amateur Radio stations already must abide by a 
>>> maximum 50 W PEP power limitation in the areas around both Air Force 
>>> facilities.
>>>
>>> Henderson says the League is still seeking further information on the 
>>> problem. "Until the Defense Department accepts a mitigation plan, 
>>> repeater owners should exercise patience," he cautioned. "Once the ARRL 
>>> Lab has completed its propagation calculations, we will be in a better 
>>> position to provide advice for specific repeaters on a case-by-case 
>>> basis."
>>>
>>> Contact Dan Henderson, N1ND (860-594-0236), with specific questions or 
>>> issues associated with this situation.
>>
>>
>
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