Exactly my thoughts, Fraser
The vertical does better for DX, and can get better low-angle radiation on the right hill, but needs the 7M fibreglass pole. The Carbon pole is too short and also detunes the antenna.
I think that the important factor is the azimuth radiation pattern. The 20m long antenna is two wavelengths long on ten, this means that its azimuth pattern has four lobes with some gain, and four deep nulls. This means that you will have four directions where it performs really well, and four directions where it performs very poorly. On the other hand it also produces four lobes in the vertical plane, two at a low angle suitable for DX, and two at a much higher angle that would be usefull during the sporadic E season when the skip is short. The two lobes are separated by a null at about 30deg which could be a disadvantage for some distances. A quarter wave vertical has no nulls so you can receive signals equally well from all directions, but it has less gain than the efhw. However it has just two broad lobes lobes in the vertical plane extending to a somewhat lower angle that would be a little better for long haul DX and with no null in the lobe so it would be better for sporadic E at intermediate distances.
My conclusion would be that if you are only operating on ten then the vertical is more convenient and has no directional disadvantages. The 20m inverted V has some disadvantages for ten but is conveniently multiband. The ideal is to have both!
In my case, at present I am chasing with a 40m long doublet. This has eight lobes in the horizontal plane, four of them with significant gain, but also has eight nulls with significant loss. It also is less useful for the higher angle sporadic E signals, so despite its gain in four directions it is not a satisfactory antenna for ten and when the weather inproves I shall erect a dedicated antenna for ten.
My information on the radiation patterns were taken from L.B.Cebik, W4RNL (SK).
Well, yes … and no. Now, understand I’m not speaking here as an expert, but the little I do know has been gleaned from online sources, such as those from L. Cebik whom you quote. A NEC-based program would show how a 20m long EFHW would perform in various configurations - I’ve used one of these to model such an antenna in two different configurations: as a flat-top, and as an inverted-vee similar to that used by Christoph DL1CR, and the results are presented here (the antenna is oriented 0°-180°, or E-W):
Both configurations - idealized of course - include a short (2m) horizontal counterpoise, and the antennas are 9 meters high at their highest point. As can be seen from the diagrams, the flat-top does indeed show the deep nulls in the propagation patterns you mention, with a low vertical first lobe, as would be expected from a dipole of this length operating on 10 meters. The inverted-vee (with legs at 40° from vertical), however, shows much different patterns, and indeed has just one vertical lobe at about 40° above the horizontal - not great for DX. These are, of course, results from just one (online) NEC-based tool - other such tools are available.
Hi Chris ! Thanks for the experiment. And I agree my “just using it” experience is that i get much better DX with 1/4 vertical, than an end fed in L / inverted V. But my end feds have been somewhat dubious
I can not tell the difference between 1/4 Vert with one radial or 3 radial. One radial works well for me, (no quantitive tests, just me gut feeling) and is super lightweight (78g) and super fast to put up. In these conditions i always carry it now.
It goes back to the argument of do you just want contacts, or do you want dx? As I said in my recent report, a 49:1, some RG-174 and an inverted V 40,20,15 & 10m EFHW will work, even with QRP. A dedicated antenna will work better.
However, when 10m is really open I don’t think you’d much difference. You could work dx with a telescopic whip.
A half-wave for 10m (without an auto-transformer) would need a decent radial field as well.
Just my take on this matter, I just made quick comparison between
Vertical - Xformer 3mtr agl EFHW10 wire tuned for 10m band
inv-V - Both ends at 2mtr agl apex at 10mtr EFHW4010 20.5mtr wire, end of antenna pointing North
inv-L - Xformer at 2.5mtr agl, apex at 10mtr EFHW4010 20.5 mtr wire, end of antenna pointing North
First IMO we should to consider propagation conditions on 10m band and most likely source of QSO
Not great for DX, as you say, but acceptable for Es. I remember about twenty years ago conducting tests during an Es opening on 6m with an Italian station who could tilt his beam at various angles above the horizontal. His signal showed a definate peak at about +30deg. Of course that is a single case, ISTM a lot depends on how extensive the Es reflecting area is, the localised nature of many Es openings suggests that the reflecting areas are often fairly small, but some days it is like the areas are huge.
My feeling is that for the purpose of the challenge it would be better to optimise for DX and full azimuth coverage to maximise the number of chaser or activator multipliers, but for ordinary SOTA it is more a matter of what is convenient.
I get the same azimuth patterns you get, Marek - here’s the elevation pattern for the (1/4-wave) vertical you have modelled:
with a main lobe at 15° - 18° above horizontal.
Of course, this just shows what we all know, viz. verticals are great for all-round DX, which is why they’re so popular with DXpeditions, but they tend to be noisy due to their picking up signals from every direction.
If so it’s interesting to see that it seems that EFHW10 (monoband) has slightly better gain and different radiation pattern. Which would give better performance at higher angles, when 10 is open, so anything is possible.