Quote:
Originally Posted by boogie
From my experience (both deployed to Iraq as an 11B and Robin Sage as an 18E):
Body whips are mostly affected by terrain (emphasis on my personal experience)...both natural and man-made. that also includes your own personal body. What do I mean by personal body? Two things:
1: When you weave the coax cable up/down OR left/right through webbing of your kit, you have the potential of "cutting" the ANT. Knowing that we want a GOOD SWR (preferably 1:1 - 1:5) we must build the ANT to a specific length (Freq/234) (huh??)
If said ANT achieves that good SWR when stretched out, what happens to it if it is repeatedly woven at a close proximity? The potential of shortening our length happens, thus affecting the SWR. Our ANT is no longer resonant.
2: When woven, one can expect that you could potentially create a quasi-directional ANT. Example: woven on the back, the RF energy has to pass through the back plate, the kevlar of the body armor, your body itself, front kevlar, front plate, various steel/aluminum/metal mags/frags etc... then finally to the desired station.
Note, the ANT is still omni-directional, but it's distance is reduced towards the front due to the orientation of the ANT and your body's proximity.
How can one mitigate those 2 issues?
1: When weaving coax, skip over a couple of molle webbings, spread it out so it does not "cut" itself.
2: Depending on the the overall length of the coax, weave it back to the front to have some of the radiating element exposed in both directions. Also, if you have the radiating element actually touching your bare skin, your body will act as a ground and will drop the SWR 1-2 points.
Once again these are from my experiences, and what was taught to me from the Commo shed out at Sage. Overall, I've had better experience with the Blade ANT over a body whip.
If you have issues with a Blade check these things:
1: Is the Blade folded? That can be cutting the ANT making it not resonant to the Freq you're operating it on.
2: What is you PWR output? Pushing enough? I have made 35KM+ plus shots with a Blade ANT at .5 Watts numerous times
3: What is the orientation of the Blade is respects the desired station? Are the polarizations the same in respects to each other?
Having a working knowledge of HF helps alot when it comes to constructing ANTs.
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You sure about that?? (in bold)
Also weaving you're antenna will just physicaly shorten it, it will not electricaly shorten it, so, theoretically it's still "resonant" (if cut to a specific freq)
You are correct though, changing the physical characteristics will effect radiation patterns of any antenna.
What you think you're antenna is doing, is not what it's doing.
Not raggin on ya, just adding .02 worth...
otherwise, good advice..