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Re: [TowerTalk] PL-259 to N Female Adapter on a Comet GP-9 Antenna

To: <>
Subject: Re: [TowerTalk] PL-259 to N Female Adapter on a Comet GP-9 Antenna
From: "David Calder" <>
Date: Mon, 19 May 2008 08:57:02 -0400
List-post: <">>

I use the exact same setup on my 2M repeater. I did the same thing the first
time. I used a cheap adapter with
the "ring" in it and it just came apart when I tightened it.

I bought a better adapter and the problem went away. I'm using 1/2" LDF4
hardline with mine. The antenna works
great on the repeater.

73 Dave

David Calder
DX cluster node 

-----Original Message-----
[] On Behalf Of
Sent: Monday, May 19, 2008 8:22 AM
Subject: [TowerTalk] PL-259 to N Female Adapter on a Comet GP-9 Antenna

I am trying to install a Comet GP-9 Antenna using LMR-400 Coax that has N
Males on each end.? I bought the Antenna from a reputable local dealer.? I
asked him for a Comet GP-9N, but, he did not have one in stock.? He told me
it would be no problem to use a PL-259 to N Female Adapter, and he gave me
one? to use? on the antenna. 

I? installed the adapter by tightening it firmly, and then firmly connected
the LMR-400 cable.? When I tried to? waterproof the cable with coax seal,
the adapter broke.? The PL-259 ring separated from the body.? I assumed I
had tightened the adapter too tight.? I obtained another adapter, and tried
again.? This time I carefully finger tightened the PL-259 ring.? I finger
tightened the N Male, and started to wrap the coax seal.? The adapter broke
again.? I figured out that it was due to the stiffness of the LMR-400.? The
leverage of the stiff cable rips the adapter apart.? Doe anyone have any
ideas for a fix?

The package brags that the GP-9 antenna is rated for 200 watts. As an
omni-directional antenna, it is obviously aimed at FM Simplex and Repeater
users.? However, the instruction sheet rates it at 200 watts SSB, not FM.?
It was my impression that SSB ratings are about 4 times that of a AM or FM
rating. I would then assume that a 200 watt SSB rating would give a maximum
FM power rating of about 50 watts.? Am I correct in this assumption?

I asked the US Distributor that type of question via email.? Their reply
email is below.? The only change I made in copying this email, was in my
changing my email address to protect me against spam.


-----Original Message-----
From: MickStwernik <>
Sent: Tue, 13 May 2008 2:07 pm
Subject: Re: GP-9 Data Sheet

The FM rating of the GP-9 is 100W FM, 200W SSB.


Depending on the duty cycle, 160W will probably 
damage the antenna.


Mick Stwertnik
NCG Company
15036 Sierra Bonita Lane
CA? 91710-8901

----- Original Message ----- 



Sent: 2008-05-12 07:27 PM

Subject: GP-9 Data Sheet

  is the FM Power Handling capability of the GP-9?? The data sheet says 200 
  Watts SSB, which is about 50 Watts FM power.?? I want to use the 
  antenna with a 160 Watt Mirage amplifier on FM Simplex at 146.58 Mhz.? Is 
  this wise, or will I be melting the antenna?

Noel Spears? 



  Plan your next roadtrip with America's #1 Mapping Site. 


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