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PE1OUD > TECH 13.03.22 22:20l 54 Lines 1783 Bytes #999 (0) @ WW
BID : 1885_PI8DHR
Read: GUEST
Subj: Diamond V-2000 50 MHz mod
Path: IW8PGT<IZ3LSV<I0OJJ<EA2RCF<LU9DCE<VE3CGR<PI8ZTM<PI8DHR
Sent: 220313/1605Z @:PI8DHR.#NH1.NLD.EURO #:1885 [Den Helder] FBB7.00e
From: PE1OUD@PI8DHR.#NH1.NLD.EURO
To : TECH@WW
SB ANTENA@WW
Mod on diamond V-2000
Hi, all
Here is brief report on how to modify a Diamond V-2000
triple-band vertical for 6 meters, 2 meters and 70 cm's.
The Diamond V-2000 comes in a number of varieties, such as:
- single piece with 90 degree short radials
- single piece with 90 degree single adjustable radial
- two-piece with 120 degree short radials
- two-piece with 120 degree two short, one long adj radial
I will be speaking about the latter.
I read on E-ham that the antenna could not really be circular
because the radiator along with the tuneable radial formed a
tilted dipole. I agreed with this amateur, Miguel - EA4EOZ,
who suggested the following modification:
Remove the original two short and one long tuneable radial, and
replace with three aluminium or (stainless) steel rods, 145 cm's
long and 5 mm diameter.
To do so, you need to cut M5 (metric!) thread on the ends of the rods.
You can also buy threaded rods but that doesn't look as nice.
My experience after the modification:
-2m and 70 cm's virtually unaffected.
SWR slightly improved, at a little lower frequency.
Still around the center of both bands.
-6m dip no longer adjustable ( not a surprise, really )
and it becomes clear that this vertical was meant to tune
around 51.4, well within the FM-part of the band.
SWR at 50.110 abt 1:2,5. Acceptable, since my rig, FT-950,
does not decreases power.
Main goal, to achieve a flat, omnidirectional radiation pattern has been
confirmed by testing 'before' and 'after' and showed 1-2 S-points
improvement.
Very worthwhile job, and if not satisfied it can be undone in a
matter of minutes, since no part is permanently altered.
Pictures at QRZ.COM
73, Gerard, PE1OUD (pe1oud@amsat.org)
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