[TowerTalk] Smoking Rotor Box

[John]

I don't think I mentioned the PEP he was running.

In any event, it happens at 1KW or more.

-J
  ----- Original Message ----- 
  From: Chet Moore 
  To: jmltinc at aol.com 
  Sent: Monday, December 29, 2008 7:41 PM
  Subject: Re: [TowerTalk] Smoking Rotor Box


  keep the power under 1500 W


  ----- Original Message ----- 
  From: <jmltinc at aol.com>
  To: <towertalk at contesting.com>
  Sent: Monday, December 29, 2008 5:05 PM
  Subject: [TowerTalk] Smoking Rotor Box


  > Hello all,
  >
  > I have a friend (without computer) who has a Yaesu 2800 that has given him 
  > good service for a couple years. He works all bands from 160 meters 
  > through 10GHz. All of his amplifiers are QRO homebrew, of the highest 
  > quality.
  >
  > He recently constructed 2KW+ amp for 160 meters. All has been well since 
  > he put it on the air. The other day, he keyed up on 160 SSB and as he 
  > started to speak, he got a 'poof' from the Yaesu control box and a little 
  > puff of smoke. He immediately stopped. The rotor still works OK, so he 
  > opened it up and sees no visible burnt components (but has the tell-tale 
  > smell).
  >
  > He scoped each rotor cable wire at the control box and there is plenty of 
  > RF on each wire on 160 and 75 meters at 100 watts. The amplifiers are 
  > separate for each band. The (smoking) rotor is for the?10 GHz?dish and the 
  > only commonality is that all coax (there are dozens) and?rotor cables all 
  > are routed together to the outside. There is one other Yaesu 2800 and two 
  > Tailtwisters that are not affected.
  >
  > Our thought was to choke out the 160 (as no other band has any effect) 
  > using a toroid on the rotor cable before it enters the box.
  >
  > Any suggestions as to core and turns?
  >
  > All suggestions are appreciated.
  >
  > -John, N9RF
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