Hello all,
I have spent the better part of the day reading through the posts on this list
covering topics of radials and inverted-Ls (nearly 3,000 posts!). Great wealth
of information. I have, I believe, a few questions that I could not directly
find an answer for.
I am attempting to erect an inverted-L antenna for my shack mostly because of
trees/mounting points (making a little difficult for a dipole or similar). It
will be the only antenna that I have (my first shack!). The planned
arrangement is as follows:
Feedline comes from my second floor shack down to the ground. I will
(hopefully) use a remote antenna coupler, a Harris RF-601A. This tuner will be
grounded using radials (see next paragraph). From the tuner, a single wire
will emanate up the side of the house to a mast on my chimney. This should get
the height of the vertical portion of the antenna about 40' up. The wire will
then traverse across my front lawn to a tree about 140' away and still about
40' up. I would love to be able to get some signal out on 10-160.
The Harris tuner is designed for shipboard and shore installations and can
match 50 ohms to a whip of 15'-35' from 2-30Mhz. Now, I am not sure what this
implies as far as range of impedence matching capabilities. But perhaps
something can be derived from the height of the whip, probably using the ship
itself as the ground plane? More information can be found here:
<http://www.columbiaelectronics.com/an_ura_38a_antenna_coupler.htm>
<http://www.torontosurplus.com/com/harris/harris_rf601a.htm>
Here come the questions:
1. Most of the discussion I read about radials had to do with "vertical"
antennas. I am wondering if all those discussions could be more generalized to
pertain to all end-fed antennas such as the "L"? Is there anything different
about the use of radials (sizes, locations, numbers) as applied to L's vs
verticals?
2. I have an issue with the possible location of my radials. The vertical part
of the antenna is very close to my house, therefore My radials can be 180deg
_away_ from the direction of the horizontal wire, as the wire travels over the
house (not exactly, but you get the idea). In fact, I may only have some short
radials 180 deg away from the antenna, but can do longer ones +/- 90 deg from
the horizontal wire. Question is, with a long horizontal component, is there
any necessity to have the radials "beneath" the horizontal portion? For
example, if I can get 30 radials in the ground but none of them are beneath the
antenna is this terribly worse than 30 in the ground where some are beneath the
antenna?
3. With the heights and lengths described above, should I think about
shortening/lengthening the wire (perhaps to get onto 160?) Or should I let the
tuner do the work and just make the longest wire possible? Bands of interest
are primarily 160,80,40,20,15,10 (until I get my urt-23 running then its all
ham bands).
4. Connecting radials: I saw mention of one product for attaching the radials,
namely the lance johnson radials buss. Certainly, I could mimic this and make
my own, but does anyone have another product to suggest? Just trying to compile
my options
I am new to this stuff, so please be gentle with me!
Thank you all in advance.
Eugene
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