Is there anyone in the Livingston area that can help me with setting the SWR on a new 2 mtr antenna ?

Or going to be at the the Escapade ?

We stayed in Florida for Field Day but will be heading north on Tuesday. We do plan to attend the Fall Escapade. If you have not found someone to help you before then I will certainly be glad to assist. Hope to see you there in either case.

73

Thanks Roger, I may be hollering for you.

First, I am not near Livingston. Second I do not know what type antenna you are trying to tune-but since this is a mobile forum I will assume it is a vertical. Unless you wish someone to tune it for you I can give you some hints. Hopefully you, assuming a vertical, have mounted the antenna with some kind of ground plane-either over a metal area or radials. Next buy an swr bridge suitable for 2 meters-they are not expensive-radio shack or mfj, while certainly not the "best" will be sufficient. Start with the whip too long for the frequency you desire to tune and check swr. Keep shortening and checking until you reach some reasonable swr-say 2.5 to 1 or less. Swr does not have to be 1:1! The losses due to mismatch are a result of circulating current on the feed line. If the feed line is low loss then higher swr can be tolerated with little loss of radiated power. That is why on the lower bands open wire feed line is often used with swr of 15 or 20:1 with almost no reduction in power radiated because of the very low loss in the feed line. Most 2 meter installations use coax. Open wire feed line is not practical for most, if not all mobile installations so assume you are using coax. Buy the very best available-loss wise- at the frequency you operate because the only losses due to high swr are in the feed line. Of course if you are going to operate with considerable swr it will require the transmitter to have an output network capable of tuning the antenna to resonance. On the lower bands this is often done with an auxillary "antenna tuner" because most transmitters do not have sufficient matching ability although the oft used pi net-work output is nothing more than an antenna tuner. What it is doing is matching the output impedance of the transmitter to the input impedance of the antenna. Tube transmitters have a high output impedance and transistor transmitters have a low output impedance-in fact often in the 50 ohm range and that is why many have no matching net work at all-as I would guess is the case with your 2 meter rig. So-with no matching net work in the transmitter you MUST match by tuning the antenna to resonance mechanically since there is no electrical means to do so. Back to pruning the whip in small increments until you attain resonance or as will be indicated by your bridge-a low swr. And there you have it. An swr bridge, a pair of diagonal pliers to trim with, and a bit of patience and you will have tuned your antenna-and also know how and why it was necessary. I usually charge for this but I am feeling generous this evening-naw just kidding. Luck to you, jack