Topband: Elevated Radials
zr at jeremy.mv.com
Fri Mar 1 18:25:16 EST 2013
> Hi Guys,
> Forgive me, please, if I'm re-hashing a bit of the "...same-old, same-old"
> here, but I am really curious as to any "real world" experiences that
> might be out there in the matter of elevated radials, vs. those that are
> simply laid atop the ground...
> My arthritic knees here are making the chore of rolling, & unrolling, my
> seasonal 24-radials-per-"L"-element radials (I have THREE of them here!)
> just that, i.e. a VERY painful chore...and barring the possibility of
> there being a new "bionic" knee replacement(s) in my future, pray tell me:
> (A) Is it true that a couple of elevated radials are just as effective as
> the "optimum" amount of buried ones...?
** Define "a couple". As Ive said on here umpteem times everyones
soil/ground conditions are different. Im on a hilltop with solid granite no
more than 2' down and mostly less than that, a couple defined as 2 wouldnt
fly here very well.
> (B) What is the "ideal" number of elevated radials that one should use...?
** When your antenna analyzer shows no change; in my case it was somewhere
between 16 and 32 as I simply doubled them and there was no change in 2:1
bandwidth or the impedance display.
> (C) How many elevated radials are "just enough"...?
** Same as B unless you dont mind seasonal changes or have great soil. I
probably could have done OK with 8 but I believe my success was by paying
attention to the details and not throwing away an unknown amount of power be
it some fraction of a dB or not. Watching the bandwidth narrow is an eye
> (D) How high should these radials be...?
** So you can drive a fire truck or 18 wheeler under them if necessary
otherwise 10-12' as a minimum.
> (E) Would it be a requirement that I raise the feedpoints of my "L's" to
> the same height as the elevated radials, or can I simply leave the bases
> where they are now (at ground level) & simply slant the radials upward
> with no effect upon performance...?
** Dont know. On mine I started at 10' and slanted to about 15' at a 45
degree angle as per Christman and then ran thru branches in the 15-20'
> (F) Is it OK to bend the elevated radials to fit property allotments...?
** I did, the West antenna was about 60' from the property line.
> (G) What is the desirable length of an elevated radial...?
** Resonant if only 2-4. Mine are approximately 130' of #16 insulated
copper but since they all go thru branches that lowers the resonance; I
didnt bother measuring it. Ive seen some suggest tying all the ends together
into one big loop but havent seen any model to indicate it helps.
> (H) Should any existing connections to real earth at the base of the "L's"
> (i.e. a ground pipe) be completed severed with a system of elevated
** Yes. It helps to have a close in ground screen but not connected. For
lightning you can connect them and a couple of rods after the ferrite
isolation choke but be sure you have sufficient isolation to not affect the
> This morning I happened to work a NJ station with elevated radials that
> almost pegged the S-meter on my 751A---the short distance between us
> notwithstanding, obviously something was working very well for him there!
> Thanks in advance & my vy
> ~73!~ de Eddy VE3CUI - VE3XZ
** Ive been an elevated fan since 1990, sure beats running on the ground
plus a screen and still not knowing if it really works as good as it could
as I had prior to that about 5 miles away and 500' lower.
> Topband Reflector
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