From: df9ox@gmx.de
Date: Sun, 06 Aug 2006 00:13:36 +0200
Subject: Re: Topband: Many Beverages on a small lot
GE/GA/GM all,
mni tnx for all the answers, very helpful, and I will change my design a bit.
my old idea:
http://www.df9ox.com/pics/_temp/GE_Jtorf_kpl_02.jpg
and my newest one:
http://www.df9ox.com/pics/_temp/GE_Jtorf_kpl_03.jpg
changes are:
- old F2 (85°) is gone, I will feed the 90°/270° Beverage now from both ends,
switchable. No longer bidirectional. (Jeff, right
u are!! And next winter with 100mW? Lsn
fr u also...:-)...)
- F1 (bidirectional 65°/245°) is longer now
- F4/5/6 got a common crossing-point (C1), that
will make it easier to fix the distance
between the wires.
- I added F8 as a bidirectional one (10°/190°).
But I don´t know, whether Polar-passes
are really of interest. No experience. But it covers SSW a bit more.
The whole coverage now on the worldmap from North-DL:
http://www.df9ox.com/pics/_temp/_JO53_bev_v01_80m.jpg
It is the coverage for 80m with Datas from ON4UN, 3dB beamwith for given wire
lengths. On 160m all will be brighter (or not? no experience).
-------------------------------------------------------------------------------------------
Some other aspects, questions:
1 - 2 wire beverages with one coax-feed (with an
transformer on the other end) might
be a problem here. It is a temporary installation
at all, I have to remove it in spring,
hopefully every spring...:-)...
Is the exact and constant distance between the two wires a critical point?
2 - Ground-rods: Is pur iron also ok, or is
developing corrosion/Oxidation a problem?
3 - the lot is not really fenced anymore against
animals. And yes, some deers, but small
ones are here. I will make the Bevs with visable
wire. The deers are used to it (white
electrical fence), I have seen them b4 jumping
above, not touching them. 1m agl they
were, and will be the Bevs. Uncommon, but I try to use my observation.
4 - well, I have some bidirectional bevs in plan,
so I will hold on >10m distance between
feedpoints. For an Option, might be I will give
them an extra relay for grounding unused
Bevs. Without that extra relay unused Bevs will
"flow" in the air. Should be ok?
5 - is it ok in practice to use a bunch of coal
1/2W resistors, a lot >10W at all, for
termination? Junk-Box needs free room!
----------------------------------------------------------------------------------------
Bill, yes, you have seen the probs in this small
country. All that past 6 years I have seen
that fantastic ground east of my garden, played
by horses. 2004/2005 I ran for only one
month a 160m long Bev WITHOUT transformer, E-W, unterminated, with vy good
results on 80 and 160 to east (9V1GO), but not
west. May be a prob of coupling on the
tower, which is direct in that west-QTF.
I have some 250m white electrical fence wire, but
will use it only for optical reasons.
Not sure, what I will use as wire. I have some
Kilometers of 0.6mm copper, but still
need something for optic. That 0.6mm is not
strong enough for deers and to dangerous
for visitors, because nearly unvisable.
Beldon 9907: mmmh, 300m are laying here, useless.
But u are right, CATV-cable is
cheap, well shielded, and 75Ohm do not play a rule. mmmh....
Ground-water: Yes, I know. plus/minus.... but no
choice. So the "Plus-point": maybe
short ground-rods are ok, but I will use 1.5m
long ones. They will be at the border of the
lot, I can leave them there (with flags on it to find them next autumn).
I will leave me always the option, to ground or
flow a Beverage or the Tower, with
relays. Not a big deal, but I can try to minimize or null interaction.
Mni tnx and vy 73, André DF9OX
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