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

[Roger (K8RI)]

n2oelspears at aol.com wrote:
> 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?
>   
A good quality connector should fix that.  I use N to UHF adapters in 
both directions. (M to F and F to M)
> 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?
>
>   
It was advertised as 200 watts, not 200 SSB. I run (at times) a Mirage 
160 watt amp for simplex and digital.  It was advertised as 200 and I 
expect it to run that regardless of what the manual says.  If it fails, 
I'll complain and pitch it and use someone else's stuff. OTOH I'm not 
going to try to feed it with the Henry 2002A<:-)).  However, we ran one 
of those antennas (or its predecessor ) for 3 or 4 years on a repeater 
at roughly 130 - 140 watts. It met an untimely end and I guess you could 
say it was due to too much power.  It took a direct hit by lightning. 
The top end looked like an exploded cigar and the end of the radiator 
(1/8" brass rod) was melted back about 6" to 8"  The radiator was 
salvagable, but the matching network was not.  The strike also blew out 
a section of 7/8" Heliax about 20' from the antenna which made it too 
short for anything useful.

73

Roger (K8RI)
> 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 <micks at cometantenna.com>
> To: n2oel at aol.com
> Sent: Tue, 13 May 2008 2:07 pm
> Subject: Re: GP-9 Data Sheet
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> The FM rating of the GP-9 is 100W FM, 200W 
> SSB.
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> ?
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> Depending on the duty cycle, 160W will probably 
> damage the antenna.
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> ?
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>
> Mick Stwertnik
> NCG Company
> 15036 Sierra Bonita Lane
> Chino, 
> CA? 91710-8901
> 800-962-2611
> 909-393-6133
> Fax? 
> 909-393-6136
> www.cometantenna.com
>
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>   
> ----- Original Message ----- 
>
>   
> From: 
>   n2oel at aol.com 
>
>   
> To: sales at natcommgroup.com 
>
>   
> Sent: 2008-05-12 07:27 PM
>
>   
> Subject: GP-9 Data Sheet
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> http://www.visradio.com/dwg/ncg/gp-9.gif
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> What 
>   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? 
>   N2OEL
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>   Plan your next roadtrip with MapQuest.com: America's #1 Mapping Site. 
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