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OE2TZL > TECHNIK 02.03.05 14:11l 27 Lines 1482 Bytes #999 (20) @ WW
BID : 235OE2XUM00C
Read: OE5AKM DL7ALE GUEST
Subj: Re:Isotron antenna test
Path: DB0FHN<DB0MRW<DB0RGB<OE5XBL<OE2XOM<OE2XUM
Sent: 050302/1143z @:OE2XUM.#OE2.AUT.EU [BayCom-Mailbox Untersberg ] BCM1.42
From: OE2TZL @ OE2XUM.#OE2.AUT.EU (Walter)
To: TECHNIK @ WW
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Hello Omīs
A serveral years ago I did tests with a isotron too. My results were
quite the same as on the F6EWX tests. s-results tended more to the -2 s
units.
measurements were taken with a JST-135 trx with calibrated s-meter.
But never believing in "miracle antennae", I did a compare to a feedline
consisting of RG58 coax shortened on the far end. Length was determined by
the point, when a perfect match on the trx side was found. Signal reports
were just 0.5 s-units fewer, than on the isotron. Both time the same cable
length. It was in the range between L/2 and L/4. Donīt remember the actual
length.
That certifies the statement of F8BOE, but he has an error in his idea
of replacing the isotron by a 50 ohm dummy load. a cable with z of 50 ohms
terminated by 50 ohms will not radiate at all!
A second test with a battery powered RX was done with an YU station, which
did extremely long qsoīs.
First I received him with S-9 in the shack, Then I went to the roof and used
just abt. 0.5 m of RG58. Signal dropped to S-2. I have to say, that this
receiver did not have a calibrated S-meter. But you can see the results very
much clearer with this second test. It does not matter, if the true result
were S-2, 3 of 4. This S-meter was surely not more unprecisely than 2
S-units.
Sorry to kill the illusions of many OMīs which believe in miracle antennae.
vy 73 OE2TZL Walter in Salzburg
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