9 Feb 2013

Par EF-10/20/40 Antenna and a comparison

This afternoon I decided to take down my 10m halo for a while and replace it with a lower antenna: the LNR Precision (was Par) EF-10/20/40 end fed wire antenna, which I've owned for some years but not used recently. As it suggests, it covers 10, 20 and 40m with a very low SWR, although it is a reasonable match on several other HF bands too.

See http://www.hamradio.me/antennas/lnr-precision-ef-102040mkii-test-data.html for an analysis of this antenna.  The antenna works very well and on 40 and 20m WSPR I was getting plenty of spots with 500mW to 5W.
Photo on http://www.hamradio.me website of the Par antenna
On 40m I did a comparison between the horizontal EF antenna and the earth-electrode antenna. A series of transmissions was made with each antenna in turn, then I compared WSPR spot S/N received from a number of stations.

The conclusion is the earth-electrode antenna is around 9-16dB down on the EF antenna on 40m, so averaging about 2.5 S-points down. The test is not too accurate as conditions change, the earth-electrode and EF have some directivity and the reports sample size was small.


Steve Wigg said...

VK3YE made an antenna based on similar design recently: https://www.youtube.com/watch?v=TV3Cj2J3T20

Roger G3XBM said...

Thanks Steve. Looks easy enough to build your own then. This antenna does work well and is ideal for portable use.

Graham Boor said...

Also some build info on this site Roger http://pa-11019.blogspot.co.uk/ next on the list of jobs to do for /p ops this year.

Graham G8NWC