Owen

My replies are in line.

On Nov 28, 2:56*pm, Owen Duffy wrote:
Tom,

The clever thing with the Arrow implementation is its dual band version where it is mechanically elegant. Does it lend itself to scaling up by near three times?

It isn't clear that you wanted a dual band version, though there are hints.

If you are looking for a single band antenna as implied in the subject...

Yes. I just want it to for six meters.

As you have noted, the total height of the J pole for 6m is a potential issue.

You could look at it as essentially an end fed half wave with a rather large impedance matching device (~1.5m).

There are other more compact ways to impedance match an end fed half wave.. The question for you is whether you can devise a robust implementation.

I'd love to hear about those other compact impedance matches. Two
different online articles claim that the matching stub can be at a
right angle to the radiating element without causing degradation in
performance. Can anyone give some authoritative reference that can
confirm or debunk that claim?

Is there advantage in using aluminium tube over wire? Well, obviously the wire needs support, but perhaps a telescoping fibreglass pole and wire with a matching network in a PVC box is another robust option.

Keep in mind that end feeding a half wave reduces the common mode current flowing to the feedline, the feed point voltage is highest at exactly a half wave. You might find a slightly shorter radiator to deliver most of the 'ground independent' feed, but with slightly less demands on the voltage rating of the matching network. It may be prudent to make your matching network adjustable to provide for locations where proximity to other things changes the tuning.

I said fibreglass (meaning literally glass reinforced plastic), and that doesn't include graphite or carbon fibre. A lot of these fishing poles are now made from graphite, and that introduces potential for loss.

BTW, I am not sure that your 'design' of the pattern is all that sound, however real antennas near lossy soil just don't have very low angle major lobes... so what you want happens for probably any low makeshift antenna.

You lost me on this one. Are you saying that the take off angles of
the half wave J-pole are not an effective way to get the signal up out
of the holes?

Owen

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Tom Horne, W3TDH