maco v5/8, any reason to isolate it from a conductive mast? Any reason not to? Just wondering if anyone has a solid answer for this
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maco v5/8, any reason to isolate it from a conductive mast?
- Thread starter mr_fx
- Start date
B
BOOTY MONSTER
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if you're going to ground the antenna to earth you might as well use a conductive mast , either will be seen as a ground element . there are many threads here earth grounding
is there any reason to have a downward element? I mean there is 4 radials already
IMO, there are obvious reasons to use a good solid conductive mast, strength and durability, better static and lightning response, and maybe even a little better gain in some cases using the RF from a mast if it does not ill-affect the pattern too much. The last claim may be very hard to determine in real world testing however.
IMO, there may be particular heights that may present a worst case scenario in this regard also. I have suspected such while working my vertical CB antennas, but my modeling seems to be the best evidence that this might happen.
To this point, I tend to think 1/2 wave multiples in height can present such worst case issues, and that random heights, other than 1/2 wave to the feed point, tend to mitigate such problems. This flies in the face of the crowd that believes there is an advantage in placing your feed point at 1/2 or full wavelength, so plenty of disagreement will follow. On-the-other-hand, this idea is supported by the idea that 40'-42' feet for a dipole, mono or beam, is the best low height for antenna installations in 11 meters. I have never see isolation make enough difference to justify the trouble and the risk. Check out my models below and in the Workman V58 thread. The models also considers isolation with the antenna with radials and without.
View attachment Jazzsinger's idea comparing Imax with and without radials.pdf
Your mileage may differ due to location however.
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It's not real practical, but believe it or not Mac, such things have been used and tried back in the days. On big trucks it might have been thought of more as a safety factor however.
Maybe we don't disagree on this one. If I'm not just confused at your remarks Mac, I think my models and my experiences show that the typical 5/8 wave radiator, but maybe not the Imax, really needs radials, and isolation for such antennas probably is not necessary. Again, IMO that is what my models with a 5/8 wave radiator using horizontal radials...tends to show.
