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Re: [TowerTalk] Coax

To: "'Tower and HF antenna construction topics.'" <>
Subject: Re: [TowerTalk] Coax
From: "Gary Schafer" <>
Reply-to:, "Tower and HF antenna construction topics." <>
Date: Tue, 13 Apr 2010 20:02:35 -0400
List-post: <">>
I too agree that PL type connectors are fine at HF.

Speaking of junk connectors; I used the MFJ 259B to try and measure a new
dummy load up thru 2 meters. A PL to N adaptor was used at the MFJ as the
load had an N connector. The return loss (SWR) was fine at HF but at 2
meters it did not look too flat. I discovered that the PL to N adaptor was
an off brand one. I replaced it with an amphenol and the return loss was
much better at 2 meters.

Gary  K4FMX

> -----Original Message-----
> From: [mailto:towertalk-
>] On Behalf Of Jim Brown
> Sent: Tuesday, April 13, 2010 6:18 PM
> To: Tower and HF antenna construction topics.
> Subject: Re: [TowerTalk] Coax
> On Tue, 13 Apr 2010 17:26:12 -0400, Roger (K8RI) wrote:
> >UHF connectors on HF have so little loss you'd never know they are
> there.
> Yup. I recently made up 1100 ft of very low loss RG8 in 100 ft lengths
> for the Iraq DXpedition. I measured their loss in series up to 500 MHz.
> That's 22 PL259s and 10 barrels. All real Amphenols, properly soldered,
> and real Amphenol barrels, not junk connectors. The loss at 500 MHz was
> slightly LESS than the mfr's spec for that length of cable at 500 MHz.
> The potential issue with PL259s is a MINOR impedance discontinuity that
> can cause a SMALL reflection at HIGH UHF. Think about it -- what's the
> wavelength at 1 GHz? How long is the connector?
> Martin said:
> "I take my information  from many articles that I have read"
> Like I said, actual measurements, not folklore. I'd bet that those
> articles are repeating articles that their authors have read. The
> historian and journalist Gene Lees wrote a long essay debunking the
> false story in a newspaper saying that Dizzy Gillespie had a drinking
> problem. Lees had known Gillespie and many of his friends for decades,
> and knew that he had always been a teetotaler, but this single newspaper
> story was picked up and quoted, and those quotes quoted, and that sloppy
> journalism became accepted as fact.
> Your time would be far better spent studying the fundamentals of how
> transmission lines work in the ARRL Handbook or Antenna Book. And we
> would all be better off if folks would not quote folklore as fact.
> 73,
> Jim Brown K9YC
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