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G8MNY > TECH 17.08.04 20:17l 48 Lines 1251 Bytes #999 (0) @ WW
BID : 5956_GB7CIP
Read: GUEST OE7FMI
Subj: A simple 3 ele yagi for 144Mhz
Path: DB0FHN<DB0RGB<DB0MRW<DB0HOT<DB0ERF<DB0FBB<DB0GOS<DB0ACC<DB0EA<DB0RES<
DK0WUE<HA3PG<JE7YGF<CT2GWY<GB7YKS<GB7PZT<GB7YFS<GB7CIP
Sent: 040817/1013Z @:GB7CIP.#32.GBR.EU #:5956 [Caterham] $:5956_GB7CIP
From: G8MNY@GB7CIP.#32.GBR.EU
To : TECH@WW
From: G0FTD@GB7SXE.#38.GBR.EU
Here is a simple 3 ele yagi for 2m /P work which I made up from
an old Band 2 FM antenna.
_______________________ 976 mm
Distance = 300 mm
___________o___________ 1000 mm
Distance = 590 mm
________________________ 1004 mm
Construction notes:
The reflector and director are touching the metallic boom in the centre.
A coaxial matching stub is used to match the driven element to 50ê due
to the coupling effect of the other elements. Attach a length of approx
20cm RG58 coax at the feedpoint of the dipole (in parallel with the
feeder cable and leave it open ended).
Some trimming will no doubt be needed of the matching stub for best match.
I find it best to star off with a slightly longer length than required
and trim by *5 mm* each time. It is essential to trim by 5mm because the
exact point of matching is quite narrow.
Expect 7db forward gain from the antenna.
You may vary the length of the driven element slightly and it will not
impair performance, but you will have a slightly different length needed
for the tuning stub.
- Emperor Andy -
Why Don't U send an interesting bul?
/QSL
73 de John G8MNY @ GB7CIP
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