Can my rig be giving me bad SWR readings?

[NeoHam]

I got my first OCF antenna and I don't understand the SWR readings. 10M = 1.8, 20M = 1.5, 40M = infinity, 80M = infinity.

I cut the LMR400 like coax and soldered on new fittings and checked it with a resistor. I am reading about 1/2 ohm resistance on the antenna balun. I do not have an analyzer.

This is my first and only rig. I can't swap anything out.

 

[W5LZ]

This isn't an answer for your question, but why are you using a balun at all? An OCF antenna is not a balanced antenna so a balun isn't needed.
- 'Doc

 

[Mudfoot]

Some of the commercial OCF's and windoms use a 4:1 current balun.

http://www.universal-radio.com/catalog/hamwire/1164.html

Dude at the last field day had one of these. I kinda liked it, but pricey. I think Princeton Windoms use the same. Get more "coverage" I suppose.

 

[WA8ZYT]

If you have good SWR on certain bands, it is how the antenna feed point is positioned, that is giving you bad readings on those other bands.

Problem with those OCF antennas is the have a lot sharp nulls in many directions. So, you might be missing out on DX in those directions.

 

[WA8ZYT]

Here is an interesting read for you on Windoms:
Radiation Patterns - HAMwaves.com

Maximum radiation appears to be off the wire ends, similar to a Beverage antenna. Just the opposite of a dipole.

 

[RatsoW8]

You really have to get a wire antenna up high to see any real directivity. Not too difficult at 10 meters but for 40 and 80 it's a different story. I don't have the vertical real estate for that so I imagine the simple OCFD I built is pretty much omnidirectional at 30 feet..

As for the OPS's swr. I wouldn't expect the antenna to show under 2:1 swr from 80 through 10 meters. You may have to do some trimming to get it low on the bands you use most and run a tuner for the rest. My OCFD is just under 2:1 on 40 meters and well below that up through 10. The height you have it installed at will probably affect it's performance on the lower bands.