[Elecraft] Elecraft Digest, Vol 269, Issue 8

[Andrew Lenton]

Hi, 
 
 
 
 
 I have heard this argument many timed although the ERP rises, the power does not. So if you have a 1Watt transmitter, even with a gain of 30dB, it is still 1 Watt, which your body can absorbed, it is just over a smaller area, and UHF wavelength is 1 metre to 30 CMs, so still a large area of body. 
 
 
 
 
 Now when you get to millimetric bands, the eyes is subseptable as it has a poor blood supply and can not cool the area, is so not look into waveguides. Or dishes. 
 
 
 
 
 Stay out of fields of 50V to 100V per meter. Or more 
 
 
 
 
 KR 
 
 
 
 
 Andrew 
 
 
 
 
 
 
 
 
 
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 Today's Topics: 
 
 
 
 
    1. Tower Climber RF Safety (Kurt Pawlikowski) 
 
    2. Re: Tower Climber RF Safety (Jim Brown) 
 
    3. Re: Tower Climber RF Safety (Wes) 
 
 
 
 
 
 
 
  
 
 
 
 
 Message: 1 
 
 Date: Mon, 7 Sep 2026 15:44:30 -0500 
 
 From: Kurt Pawlikowski <kurtt at pinrod.com> 
 
 To: "SKCC at groups.io Notification" <skcc at groups.io>, 
 
  "elecraft at mailman.qth.net" <elecraft at mailman.qth.net>, 
 
  metrodxclub at groups.io 
 
 Subject: [Elecraft] Tower Climber RF Safety 
 
 Message-ID: <eda1f866-a05c-45fc-a6dc-82d3e36b69ff at pinrod.com> 
 
 Content-Type: text/plain; charset=UTF-8; format=flowed 
 
 
 
 
 Hi! 
 
 
 
 
  ? ? I thought some of you might find this of interest. It applies  
 
 directly to Cell Tower climbers and RF safety, but might be a cautionary  
 
 tale for RF exposure for us (and maybe someone nearby our antenna!). Not  
 
 *exactly* amateur related. 
 
 
 
 
  ? ? kurtt WB9FMC 
 
 
 
 
 https://www.youtube.com/watch?v=DNvQo6JPO54 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 
 
 
 
 Message: 2 
 
 Date: Mon, 7 Sep 2026 14:26:41 -0700 
 
 From: Jim Brown <jim at audiosystemsgroup.com> 
 
 To: elecraft at mailman.qth.net 
 
 Subject: Re: [Elecraft] Tower Climber RF Safety 
 
 Message-ID: 
 
  <5ed63ad3-a4a6-42bf-9c22-3fd12a603272 at audiosystemsgroup.com> 
 
 Content-Type: text/plain; charset=UTF-8; format=flowed 
 
 
 
 
 On 9/7/2026 1:44 PM, Kurt Pawlikowski via Elecraft wrote: 
 
 
 
 
 The nature of UHF antennas is VERY different from those we use at HF.  
 
 They have very high gain, concentrating their energy in a narrow beam in  
 
 the horizontal plane, and which can focus a LOT of RF power into the  
 
 body of a climber who is in front of them. Much less below them,  
 
 although that can still be a lot if there are enough transmitters at the  
 
 site for the combined energy is great. 
 
 
 
 
 It's pretty hard to have significant RF exposure unless we're running  
 
 high power into an antenna that's very close to us (like a few yards). 
 
 
 
 
 73, Jim K9YC 
 
 
 
 
 
 
 
  
 
 
 
 
 Message: 3 
 
 Date: Mon, 7 Sep 2026 21:36:58 -0700 
 
 From: Wes <wes_n7ws at triconet.org> 
 
 To: elecraft at mailman.qth.net 
 
 Subject: Re: [Elecraft] Tower Climber RF Safety 
 
 Message-ID: <35bc7bb8-ee60-4fef-9689-d9d80ffa3133 at triconet.org> 
 
 Content-Type: text/plain; charset=UTF-8; format=flowed 
 
 
 
 
 Before my electronics career with Hughes Aircraft I worked for a time in the  
 
 automotive machine shop my dad managed.? Having an interest in VHF radio and  
 
 access to a machine shop, I built several high power 144 MHz amps both for  
 
 myself and a number of other local hams.? After moving to Hughes, I worked for a  
 
 time on TOW Missile and then moved on to the Phoenix Missile program. For folks  
 
 who haven't watched the Top Gun movies, (you really should) Phoenix and the F-14  
 
 were a marriage. 
 
 
 
 
 Phoenix had a feature called MOAT (Missile on Aircraft Test) wherein after (six)  
 
 missiles were loaded onto F-14s a quick functional test was performed on the  
 
 flight deck to verify that the system was ready to shoot. before launching the  
 
 aircraft. When F-14s were deployed on the Enterprise aircraft carrier there  
 
 started to be a lot of MOAT failures, necessitating the aircraft returning to  
 
 the hanger deck, the missile being downloaded and retested on an onboard test  
 
 set, where the failures couldn't be duplicated. 
 
 
 
 
 Someone a lot smarter than I hypothesized that the SCANFAR Radar system  
 
 (https://grokipedia.com/page/SCANFAR) was upsetting the MOAT.? The ERP of the  
 
 system was about 1.5 MW at about 225 MHz. The Phoenix Program Manager didn't  
 
 believe in calculating or simulating anything, he wanted lab testing.? With my  
 
 VHF background I was tasked with designing and building an amplifier that would  
 
 take the output of an HP-608 generator and develop 300+ watts to be used into a  
 
 10 dB Yagi pointed at a test missile, in a lab setting.? This was calculated to  
 
 be equivalent to the RF levels impinging on the missile on the flight deck.? I  
 
 agreed to build the amp but told them in no uncertain terms I didn't want to be  
 
 anywhere near this when testing.? All I could think of was all of those sailors  
 
 on the flight deck getting lit up by that radar. 
 
 
 
 
 Wes? N7WS 
 
 
 
 
  ? ps.? I'm as old as Jim and all is this is from failing memory so I can't be  
 
 held to any of it :-) 
 
 
 
 
 On 9/7/2026 2:26 PM, Jim Brown via Elecraft wrote: 
 
 
 
 
  
 
 
 
 
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 End of Elecraft Digest, Vol 269, Issue 8 
 
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