Yup, very true. At HF frequencies, loss is not the issue. (Even at 144 MHz the loss is not significant if the connectors are mounted/installed correctly. Above that, at UHF frequencies, things go downhill pretty fast. That must be why they call 'em UHF connectors. Uh, yeah.)
The REAL problem with traditional PL-259 connectors (besides the need to weatherproof, but you better weatherproof the N connectors just as well!) is that they are oftentimes installed badly -- sometimes in such a manner that they malfunction intermittently. This can cause all sorts of havoc. It happened to me. The PL-259s were on either end of a short RG-8/X jumper connecting my rig to the antenna tuner, and (as I finally figured out) one of them would arc short whenever the RF voltage reached a certain point. On SSB, that was on voice peaks, of course. Whenever that would happen, the SWR would soar instantly, the TX SWR protection circuit would cut in, and the peak would be clipped off. Sounded just like a transmitter or mic connector problem. Took me a month to finally swap out that coax jumper, after trying everything else under the sun. Boy, was I embarrassed, as I had made the durn thing myself! This is about the time I got deadly serious about learning how to do these connectors right. There is much lore, folk wisdom, and mythology about how to properly install a PL-259 -- much of it bad -- but there is also a lot of really sound advice out there on the web. I've had the best luck installing it exactly as the manufacturer specifies. (Gee, imagine that!!) Complying with the specified cut dimensions is especially important. But you need HEAT CAPACITY, and lots of it. Other than outdoor water intrusion, the principle cause of PL-259 failure, indoors or out, is poor soldering, and this is often caused by inadequate soldering iron power. Inadequate soldering iron power leads to excessive time applying heat, which in turn causes heat to transfer excessively to the vulnerable inner dielectric and outer jacket material. You should be using a 100W iron (or larger) with a well-tinned chisel tip that fits in the "notch" where the solder holes are. You want maximum contact area. (Others have had good luck with other soldering tools, but this is what has worked best for me.) I hold the connector body still in a Vise-Grip, which pulls heat away from the shell of the connector where the outer jacket contacts it. Solder the connector in the shortest time possible consistent with correct results -- just long enough to get complete solder flow with good concave fillets in the solder holes (no balls or blobs). Quick, efficient soldering will minimize dielectric and jacket heating and deforming. It is somehow counter-intuitive to many hams that in order to minimize heat damage to the coax, you need to use more heat. But that's how it works. :-) Bill W5WVO ----- Original Message ----- From: "Michael Melland" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Tuesday, November 21, 2006 12:16 PM Subject: Re: [Elecraft] Fw: RG-213 BNC connector > I won't argue that the N connector may be a better choice for any number of reasons, but don't rush out to change out a PL259 fearing excessive signal loss... a PL-259 isn't in any way (especially at HF) "High Loss".... > > >From the Wirebook IV, pages 3.2 and 3.3.... Alan Bloom, N1AL, used an HP8753 RF network analyzer to compare losses of UHF vs. N connectors. > > Both connectors measured 0 db loss up to 100 MHz. > At 150 MHz, the N has 0 db loss, the UHF has .01 db loss. > At 450 MHz, the N has 0 db loss, the UHF has .09 db loss. > > Other studies show similar results ... > > -- > > Michael Melland, W9WIS > Redgranite, WI USA > "Non Sibi Sed Patriae" > _______________________________________________ > Elecraft mailing list > Post to: [email protected] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
