Spring Time and Antennas.

It has been a little while.

I have purchased a Cushcraft R6000 antenna, and it has to be assembled and set up this spring. This should enable me to work with a decent efficiency on all bands between 6m and 20m (yes, also 12 and 17m). The antenna is a shortened end-fed half wave antenna, so the current maximum should be a bit higher above ground than for a quarter wave ground plane.

The other day I had a little surprise. My HF dipole does not work at all on 10MHz. I decided to see if my 10m half wave vertical (without radials, of course) would match on 30m, and with the built-in tuner in the radio it turns out that it works much better than the dipole.
Now, since the antenna is too short, even for a quarter wave on 30m, and the impedance transformer at the bottom of the antenna is a *step-down* transformer, is is quite surprising that the unmodified antenna works on 30m.
I have been working a bit with this antenna, and DX is *very* difficult - no surprise there.
I suspect that the cable shield does its part of radiating my 30m signal, so who knows how the radiation pattern looks ? ...
I would like to work on a more regular basis on 30m, so I have been thinking of a few options :
1) Making a simple ground plane with a few radials above ground, a decent antenna
2) Making a half wave antenna, using a 15m long telescopic fibre-glass mast. This has the advantage that the current maximum goes up to 7.5m, and that the counterpoise only needs to be rudimentary, due to the high impedance of the antenna - this should prove an excellent antenna for 30m
3) Using the 15m mast with 3 wires for quarter wave resonators for 30, 40 and 60m. A little less efficient on 30m, but with the bonus of 40 and 60m operation - and a decent counterpoise is needed - a few radials for 30m and one or two for the 40 and 60m bands will have to do at my place.
4) Using the 15m mast with a single wire, then using a match box (e.g. an auto-tuner) and radials. This could be made to work on all bands form 30m to 80m, possibly, with low efficiency, on 160m.

All has its ups and downs - I may try several of the options over time.

Then there is 4m and 6m.
My only antenna till now is a 70cm/2m/6m vertical is off resonance, and will have to be fixed or replaced. Also, the cable is *very old* and should probably be replaced. For 4m I am considering an end fed half wave antenna - yes, I like those.

Right now I am looking forward to the summer sporadic E skip season, I intend to focus on 4, 6, and 10m. this year, and should I be able to work Es on 2m with the vertical, that would be a welcome bonus.

No comments:

Post a Comment