The other (huge) thing not being mentioned is weatherproofing.
I have both weatherproof and non, and the diff in price between flavors is nil:
ie, REAL weatherproof PL259s are the same price as their N and BNC
counterparts.
The PL\SO239 connector is SO MUCH MORE healthy, though. I converted a 10 meter
vertical to N connectors before I discovered weatherproofPL\SOs. I get 3
inches of ice, and over 100 MPH winds here. Weatherproofing is a BIG deal.
The N males failed 3 times in 1 winter. The center socket wriggled around from
having the gamma direct mounted and would hollow out. The SO239 I'd replaced
had been in 3 complete winters here, and was over 30 years old. I put it back
after the 3rd N failure, gorilla snotted the SO connector, and used gasketed
PL259s since. NO more problems since.
REAL teflon PL\SO connectors are 12 \ each single lot qty, and they differ very
little, except in impedance match.
Transistors have ratings, tubes have guidelines!
--Shane
Kilowatt Delta Six Victor Xray India
-----Original Message-----
From: Steve Thompson <g8gsq72@gmail.com>
Sent: Tuesday, April 26, 2011 02:48 PM
To: amps@contesting.com
Subject: Re: [Amps] Power handling of an SMA
I suspect a lot of issues with 259s arise from the variation in
materials. I see lots with nylon and brown 'plastic' (bakelite or
SRBP?) insulation which I wouldn't trust under stress or with age.
Then there's the problem with the braid connection and the cold
soldered joints onto low grade plating. Even when that's ok, the
coupling ring is prone to working loose given time, mechanical
movement or thermal cycling etc. Most other connectors have some
form of spring fingering that maintains contact even when the
coupling nut isn't tight.
Where the non constant impedance isn't an issue, a good quality
well assembled 259 will handle a lot of juice - but it's a trap
waiting for the unwary.
Steve
Carl wrote:
> A 30 Ohm connector that is 1" long will not even show a bump thru at
> least 6M and they are still OK on 2M.
>
> Some UHF articles have stated they are a perfect 50 Ohms at 1296, dont
> know.I use them at low power on 2M FM gear including the 400W PP 4-125A
> FM amp for contest into an old commercial 22' collinear.
>
> Carl
> KM1H
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|