Power loss at antenna ?

[Slowmover]

If you change out the coax and your SWR goes up and you don't like it, put the old coax back on it.
The lowest SWR makes me feel better.

Paint the old coax with Liquid Plastic while the cheap stuff keeps the old lady warmed up?

.

 

[HomerBB]

Hmmm... I dunno.

 

[oldtymer]

If you change out the coax and your SWR goes up and you don't like it, put the old coax back on it.
The lowest SWR makes me feel better.

Lowest swr is not always the resonant point. I prefer to see the lowest reactance on the
analyzer even if swr is not the lowest reading.

 

[HomerBB]

Lowest swr is not always the resonant point. I prefer to see the lowest reactance on the
analyzer even if swr is not the lowest reading.

But that don't scratch my SWR itch. It gets worse when I break out in that horrible SWR rash.

When I get geeky then I love my Xs and 0s.

 

[Road Squawker]

Lowest swr is not always the resonant point. I prefer to see the lowest reactance on the
analyzer even if swr is not the lowest reading.

Agree, in fact the lowest reactance and lowest VSWR are almost always different.

 

[M0GVZ]

I took my meter out to the antenna, I hooked it up with 1 foot jumper. I calibrated meter and checked power and SWR. SWR went up to 1.25 from 1.1 the power went from 4 watts to 3 watts.

You've just had a demonstration that your antenna sytem has a completely inadequate RF ground and that the coax going from the antenna to the radio you bypassed was being used as one.

 

[Mark Malcomb]

Ok I guess what you mean is I need to ground my radio in the garage to a earth ground at a electrical box and recheck it? Thank you for the help, I need it.

 

[M0GVZ]

Ok I guess what you mean is I need to ground my radio in the garage to a earth ground at a electrical box and recheck it? Thank you for the help, I need it.

No, not that at all. You've described an electrical ground, not a RF ground. The two are completely different things and you implement them differently. What you need to do is to make/buy some radials and attach them to the antenna at the feedpoint. The Imax 2000 and Antron A99 for example have ground plane kits you can buy, antennas like the Sirio 827 or Sirio 2016 come with them built in. For those where no solution is available the easiest and cheapest way to implement it is four 9ft lengths of wire (reduce by 5% if using insulated wire) attached to the metal bracket of the antenna and brought out in a cross pattern, sloping downwards between 30-45 degrees. It'll affect tuning so you may need to adjust your antenna if it increases the SWR above 1.6 or so.

You also need to buy/make a RF choke to choke off the outside of the braid of the coax so it can no longer be used as part of the antenna. It needs to be done as close to the antenna socket as possible and can be done by simply making a coil from excess coax of 4.25" diameter with 5 turns.