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W3EDP test


#1

Dear all,

As today is the first day I’ve had off for a long time and the sun is beaming down, I dug out an old spool of wire and cut a W3EDP antenna. 84ft main element, 17ft “counterpoise”.

I took it out to the public gardens near my house in Bangor, taped it to my mast and bungeed it to a fence. Radio was an FT-817 at 5W, using an MFJ-901 travel tuner (T-match), which works just fine and the antenna will tune up happily on 80, 60, 40 and 20 as well as others. I can even get an acceptable match for 2m, hi! First contact was David MW6WOW/P on SW-028 on 3.666-lsb, followed by G0RQL and then Geoff (Dad) 2W0BTR/P who was also on SW-028. My received reports were encouraging, but I was struggling to hear all stations. I think that 80m is a bit flat today as I could only hear one CW station and no SSB other than those that came back to me, but the noise here varies between S3 and S7. I wonder if my close proximity to the sea (about 100m laterally, and about 10m ASL) helped with performance?

I shall take this antenna out on the hill with me next time and see how it performs from a summit. I think its worth experimenting with. Its another one of those maximum fun/minimum outlay designs.

Many thanks to all stations who patiently came back to me.

73,

Dave MW0MYA.


#2

Tnx for contact Dave,as you say 80mtr conditions very poor.
I have been struggling more so than ever the last couple of days on 80.
The W3EDP a well tried and tested aerial.
I have one made up in a box for use when required when out with the motor home.
The great thing about the W3EDP is you can chuck it out of the shack window or wherever, tie it to a post or tree or fence and the counterpoise laying on the floor or ground in any configuration will work.73 Don.


#3

In reply to M0MYA:

Hi, Dave, I have taken one of these out on several activations and it works very well. In my opinion it is a much better antenna than a linked dipole since you do not have to leave the operating position to change bands, which streamlines operation and reduces summit time.

I have been told that it will give an adequate performance on Top Band if you use a quarter-wave counterpoise, but I haven’t tried that, yet!

73

Brian G8ADD


#4

In reply to G8ADD:

Yes, thanks Don. I could hear you again today on 80m with the W3EDP from the Worcestershire QTH.

Brian: I have read some well argued posts of yours concerning the EDP before now. In fact, I first read one of your posts about it at about the same time I first happened to read about it in “Practical Wire Antennas” IIRC. I’m going to make a parallel tuner like yours at some point, which I’m hoping with give better performance than the T-network. I do have a homebrew Pi network tuner, but its huge and made of plywood!

The top band idea sounds interesting, seems funny having a counterpoise longer than the radiating element, but it is a common idea, using a 1/4 wave counterpoise for the band of interest with a W3EDP antenna, although IMO this stops it being a true W3EDP. I do fancy a bit of top band activating though.

Strangely, I am consistently finding that my received reports are better than my sent reports, and all with my tiny 5W! The W3EDP seems to be quite noisy in a built up area (which I think is contributing to this), but I am anticipating the usual calm on the hill. I have toyed with the idea of making removable spacers to keep the “counterpoise” next to the “radiator”, as I have heard that the “counterpoise” radiates too, and I’m keep to be getting as much of my 5W out as I can (rather than into the ground). However, I made the EDP so that I could have a super light and quick HF setup to take up the local high-spot in Bangor of an evening, and spacers will increase weight and fuss.

73,

Dave M0MYA


#5

In reply to M0MYA:

As today is the first day I’ve had off for a long time and the sun is
beaming down, I dug out an old spool of wire and cut a W3EDP antenna.
84ft main element, 17ft “counterpoise”.

It occurs to me that I use a half-size version (i.e. a 42ft wire) of this aerial on my lightest-weight trips . I use it with 2 x 5m radials and an ATU although it actually presents quite an acceptable match on 40m and 30m without one. I don’t think that it is as good as a dipole though because with a dipole the current is at the highest point on all bands. I don’t subscribe to the idea that linked dipoles are inconvenient either - I have never found getting up and walking a few metres to change bands, especially arduous.

73

Richard
G3CWI


#6

In reply to G3CWI:

I don’t think that it is as good as a dipole
though because with a dipole the current is at the highest point on
all bands.

I suspect this to be the case.

I don’t subscribe to the idea that linked dipoles are
inconvenient either - I have never found getting up and walking a few
metres to change bands, especially arduous.

Same. I think that a linked dipole with 80m as its lowest band cuts a very impressive figure on the hill (although I respect the opinion of those who do not), and I get a certain pleasure from stringing it up in the air and legging it around to change links when I QSY. My dipole serves me excellently on the hill. The 'EDP is my first foray into end feds and the mechanical benefits they bring.

73,

Dave M0MYA


#7

In reply to G3CWI:

I’m not sure that the high current point being at the apex will make a lot of difference for NVIS work, though I’m open to persuasion on that. Also, on many summits I would expect that the effective earth is well below ground level giving the effect that the antenna is higher than it actually is, but of course the dipole will benefit from that as much as the W3EDP. I rather enjoyed the convenience of not having to get up and work on the antenna on a couple of Cornish hills where the summit was a mass of boulders hidden in bracken, and like the time saving aspect when at any moment the XYL might tire of reading her “Woman’s Weekly” in the shelter of the summit cairn and say “I’m cold, time to pack up!” Still, as they used to say, different strokes for different folks!

When (if!) the sunspots return I intend to try out an OCF dipole, just for the hell of it!

73

Brian G8ADD


#8

In reply to G8ADD:

In reply to G3CWI:

that. Also, on many summits I would expect that the effective earth is
well below ground level giving the effect that the antenna is higher
than it actually is, but of course the dipole will benefit from that
as much as the W3EDP.

I’m not familiar with the concept of “effective earth”. Could you elaborate a little for me please?

73,

Dave M0MYA


#9

In reply to M0MYA:

Its been many years since I read up on that, Dave, and the terminology might have changed. On a rocky summit the conductivity of the rock is extremely low, and due to periglacial effects in the Ice Age it will often be severely fractured to a depth of as much as several metres. At some depth the water table will appear, and the conductivity at that depth will be much higher, the antenna system will tend to act as if that conductive layer is the earth plane. The situation is different on, say, a peat moor, the peat can be very acidic (I have actually measured pH values of about 3.0) and will be much more conductive, there the earth is effectively at ground level. Even in the average garden the electrical earth is below ground level.

73

Brian G8ADD


#10

In reply to G8ADD:

Fancy that! You learn something new every day.

73,

Dave M0MYA