|PAR END FED 10, 20 AND 40 METER EFHW wire antenna. by Earl Andrews VE3AB
This is the little Match Box for the feedpoint (at the end of the half wave wire
antenna). This little matchbox is only rated for 25 watts. If you are a qrper this
would be fine..or you could use it as a general listening antenna or SWL antenna.
This is the loading coil for 40 meters. The green tape is my tape to hold the antenna
loops after I roll it up. The full length of the antenna is about 39 feet overall. A good
100khz of 40 meters is covered without a tuner.
These Par antennas seem to work about the same as center fed dipoles. The SWR
curve is about the same and performance on the air seems about the same.
The main advantage with the end fed antenna is deployment. Here I used a mast I
keep around for stringing up portable antennas and I strung up a Par EF 10-20-40
meter end fed antenna in a matter of minutes. The other end of the 40 foot wire was
fastened to a fence on the other side of my yard. I checked the swr curves and they
were good except for 40 meters. I had to trim the antenna end a bit for 40. But after a
bit of trimming it was set to go for Field Day 2012..MY BACKYARD MINI SOLO FIELD
27 June 2012-- I strung the PAR 10-20-40 antenna back up in my backyard and I
took the time to plot some swr values vs frequency for each band. The antenna
at the feed point end was only up about 12 ft off the ground and sloped down
to about 7 ft high where I tied it to the fence in my yard.
When I was operating Field Day..I did not take the time to jot down enough
I made about a page of contacts on field day with this antenna. I tried using
reflectors behind it. I had a double half wave reflector strung up behind the
antenna for 10 meters..but a ten meter opening failed to materialize.
I did an Antenna A and Antenna B test with the 1/4 wave 20 meter mono band
(2inch diameter) over a ground plane in the backyard. See picture below of the
14 mhz vertical. It is a fat vertical that covers the band nicely.
Even though the PAR end fed 10-20-40 was only at a maximum of 12 feet high,
the signals I compared with both antennas on 20 meters (mostly local USA
signals) ..I could not tell the difference between one antenna or the other.
Maybe only a slight S meter advantage to the 20 meter vertical at times and I
think that was where the PAR was receiving the signal off the end of the
antenna. -- So certainly on receive anyways...the PAR is on par ..or just about
on par (excuse the pun) with the vertical ground mounted antenna with ground
If you are looking for a good receive antenna...Id say the PAR is a good one.
HMMM..I wonder what is in the box??? The little black box!! I did receive an
email from the fellow who owns PAR..and he said it would be a little more
difficult for the copy cats to duplicate this particular match box.
Im not about to cut it in half and try to reverse engineer it!
The pictures below show the Par antenna and my other antenna in the
backyard. The SWR curves were made with a 12 foot rgx coax feeder and an
MFJ antenna analyser.
Feedpoint matching box. Sorry the picture is blurred a bit but you get the idea.
The antenna is easy to tie off somewhere and feedpoint is near the operating
postion (quite often). Good for Field Day and portable operation.
This pole is a bit longer than 13 ft and I strapped it with wire to the side of my
garden shed. I untangled the wire and away it was ready to go.
|The coil is sufficient inductance to act as an isolator coil for 28 and 14 mhz thus
leaving the 33 ft or so radiator to be an active 1/2 wave on 14mhz and 1 wave on
10 meters. On 7 mhz..I'm not sure but I think it is equvilent to a 1/2 wave end fed
antenna by virtue of the loading coil and the short 4 ft or so of wire after the coil.
|Far end of the antenna tied to the fence about 7 ft off the ground. The whole antenna
is a temporary thing here..Im just stringing it up to get some swr curves.
|Shot looking down the wire. Dog Finnigan is taking in the sun!
|Another shot looking down the wire. The 14 mhz ground mounted vertical is also
in this shot.
|14 mhz vertical with the 4 by 4 wooden support post. Under the
vertical is a matrix of copper pipe tubing and wire.
|SWR curve for 10 meter band
|SWR curve for 20 meters. NOTE: I did no trimming to the 33 foot section of the Par
multiband antenna. Looks like it needs to be trimmed a few inches or so to get the swr
curve up higher in frequency. -- Looks like a good bandwidth on this antenna..but
remember ..it is only up 12 ft or so! The swr might change if the antenna was up higher.
|The swr curve is quite sharp on 40. This is to be expected with a
lower frequency antenna and especially one that is shortened. NOTE:
it is quite acceptable for me as I mostly operate the lower end of 40.
This article is under construction..27 June 2012. I will be finished it soon. 73 earl ve3ab
link back to my home page..www.earlandrews.com