Apparently a tribander & 40M beam combination works fine (I have a TH6
& 40-2CD here). The 15M & 40M monobanders are another story! Some
years ago we tried installing a 155BA above a 3 element 40 with full
size elements at W3GM. The 155BA had a severe degradation in gain &
pattern from it's stand alone conditions. We then tried a Cushcraft 4
el 15 above the 40. Same problems, the 15 was severely degraded. In
both cases the 40 appeared unaffected. Both 15M antennas showed
marked changes in VSWR indicating a high a mount of coupling to the
other antenna. Never tried this type of stack with a 40 with
shortened elements. FYI
73, Stew K3ND...
---Michael McCarthy wrote:
> Does anyone have any REAL data or experience with mounting a 15M beam
> 10' above a 40M beam? The concensus is that 15 and 40 interact too
> much. But all I have heard is opinion and conjecture. I know several
> who have put 40M beams above tribanders and the interaction does not
> seem to be much of a problem.
> I am considering a F12 EF-420/240 20M/40M interlaced beam and would
> like to add a 4L 15 about 10' above it on the same mast.
> Please, I have heard enough opinion and guesswork. I would like to
> hear from anyone with hard data or experience based on actual
> installations or accurate modeling.
> Tnx and 73 de Mike, W1NR
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