Ok... so here is my situation. I will have 6/6 on 15 with the top at 90. I will have the 40M4LLDD at 124 so just 34 above it (a good distance for stacking on 15!) I had asked for others with this ant
A full sized 40m dipole will have a high impedance on 15m and the SWR will be over 2:1 so the 2.7:1 SWR on your beam indicates that it is resonant. Is it hurting anything? Your model should show the
If some are seeing an SWR much closer to 1:1 ... then there WILL be interaction guaranteed. Is it hurting anything? Was that rhetorical? I ask because although I've done quite well in range testing t
1) WHY when I model a full size 2 element 40 does it not have a low SWR on 15 when I know in the real world people have said it should/does? At least to some extent, you're asking the wrong question.
Sorry Jim - you've misunderstood where I am going .... I'm using SWR as a 'worst offender" indicator. I am not at all worried about SWR, or at least not in it as a single indicator - but in all the m
I believe that K3NA did some nice work on this subject that was published a few years back in NCJ. I don't remember the details, but I remember concluding that you don't want your 40M beam and your 1
We all don't have unlimited budgets and space so we make compromises. Actually all antenna systems have compromises. I have homebrew 15m beams <20 feet above and below my lower 40m OptiBeam. I see no
the Optibeam is designed NOT to be resonant... funny how that works. One would think ALL antennas, if there is that likelihood, would be designed as such or at least an optional kit. Especially since
I don't think the Z is high.. I thought that 40m dipoles are close to resonant on 15m... 3/2 wavelength (21 Mhz vs 7 MHz) A quick model shows the SWR around 21 MHz of a dipole 1" aluminum, resonant
Why do you come to that conclusion, Gary? It's perfectly normal for a half-wave dipole resonant near the low end of 40M to also be resonant on 15M, which is its third harmonic! That alone does not im
Thanks Jim.... re the factors you mention: the antenna is 34' away, about 2/3 wave at 15 meters so quite close enough and an oft used stacking distance, it is in the same plane as the 15 ... and re t
On Thu,6/2/2016 5:07 PM, StellarCAT wrote: What I did to try to see if it would have an effect is this. I made the assumption that the linear loading wires would 'breakup' the element as it would pro
So we agree that the 15m SWR of a 40m dipole will be over 2:1. If it is not high impedance (100+ ohms) as I stated causing this, what is? John KK9A I don't think the Z is high.. I thought that 40m di
Well, to me, when someone talks "high impedance" in connection with dipoles, I think in terms of kOhms... (like a doublet that is a wavelength long). 100 ohms (compared to 72 ohms for an ideal dipol
Jim, But as noted before I can't get a model to work! Therein lies the issue. If I could get a model to do something close to reality I'd feel considerably more comfortable - I've heard several say t