> The 40-2CD presents a reasonable match on 17M (<2:1 SWR)
> and seems to work as an effective rotary dipole on that band.
> The SWR on 12M is higher but can be tuned with most antenna
> tuners. I know many people who use this as their primary 17M
> antenna and a few who also use it on 12M. It should be possible
> to add a close spaced 12M parasleeve driven element if you want
> to achieve low 12M SWR without a tuner.
What design-type tuner would you recommend for this sort of application?
L, T, etc?
Each has strengths and weaknesses and I am interested in minimal loss and
noise. I am not up to adding a driven element ... yet! (Is the auto-tuner
in my TS-690SAT adequate for this task?)
> It would be a simple matter to add 12 and 17 meter reflectors
> (or a trapped reflector a la A3WS) to achieve 2 effective elements
> on each band. The fact that there are no elements in front of the
> driven element means that there will be NO destructive interference
> as experienced with 3 or more elements on lower bands. These
> additional elements for the WARC bands will NOT affect 40M
> operation.
OK, these would be approximately 18 and 25 foot reflectors inserted between
the director and 40m reflector? Hmmm. Perhaps I can recycle some tubing
from the TH6DXX I have laying around.
What sort of spacing would you suggest as a starting place? (I don't have
a 40-2CD ... yet ... so I don't have dimensions in hand.) Cushcraft is
only 25m north of me, perhaps I could beta test these mods for them!
> I have often thought such an option would make an interesting
> product enhancement for Cushcraft.
What do you suppose this does to wind load, balance at the mast, etc?
BTW: Someone mentioned here that the newest version of the 40-2CD (XM240)
has a reflector that is isolated from the boom. What would that offer?
Should the same be done for these added 12 and 17m reflectors?
Thanks! & 73, DavidC AA1FA
> 73 / GL, Tom N4KG
> .....................................
> >Over the past week several folks have told me that the 40-2CD tunes up
> >nicely and runs real well on 12 and 17, and that according to an
> >MFJ-259
> >shows a good swr and impedance on 6m (multiple wavelengths I guess!).
> >I would greatly value reports of actual experiences with this antenna
> >on these non-design frequencies as I move closer to finalizing my
antenna
> >plans.
> >
> >These are all secondary bands for me and if this beam will handle them
> >I will be able to settle on it as adequate for those bands and return my
> >focus to maximizing 10-15-20.
> >
> >This is a wonderful reflector, made so by all herein who love the
> >hobby and enjoy the sharing of knowledge and experience! Thanks & 73,
DavidC
> >AA1FA
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