Friends,
I have just now changed from a 6 el 6M quad to 7 el LAF2 WOZ Yagi by
Innovantennas These are my findings so far. As you will see to the end I
make some sweeping statements about Yagi vs quad. I may be wrong but they
are my observations for this situation. I hope this is not off topic and
that the ranting of a geezer does not annoy. It is not my intent and
hopefully no such thing occurs.
Thank you for the bandwidth.
73 Doug EI2CN
From: turnbull <turnbull@net1.ie>
Sent: Sunday 3 April 2022 15:24
To: Doug Turnbull <turnbull@net1.ie>
Subject: 7 el Pattern
Dear Friends,
These measurements are difficult and are carried out on a solid CW carrier
from EI0SIX at 50.004 MHz. You must allow for a 0.5 lsb error or perhaps I
might say +|- 1.5 dB, a quarter S unit.
Pk sig Az 153 -92.5 dB
2.5 dB Az 116 -95 dB
2.5 dB Az 170 ‐95 dB
5 to 6 dB Fwd lobe W 54
degrees approx
Turn Yagi 180 degrees
153 + 180 = 333 degree
@ Az 333 pk sig -116.5 dB
Thus FB ~ 24 dB
Front to Side
333 - 90 = 243 degrees
Az 243 pk sig = -130 dB
Thus FS ~ -37.5 dB
Now these measurements as previously stated have tolerances. Furthermore
they may differ from the computer model negatively because of proximity of the
house and terrain.
I am certain the pattern is tighter than that which I had with the 6 element
quad. Furthermore I bet the quad is no better at rejecting noise in general
and in particular from my neighbours PV panels. I expect no improvement in
forward gain which would be noticeable.
Previously I ran JA on six from EI like a madman perhaps 45 in 90 minutes. I
saw no difference on average with the two big GD stations. We each rivaled
the other more or less equally. The quad performed very well but was not
noticeably different from the performance of 'long john' Yagis.
I purchased the Yagi specifically to reduce EMI from a PV system.
The Yagi is infinetly easier to tune as well. In my case no tuning proved
necessary.
For me the case is closed. I agree a two element Yagi is the equal of a three
element Yagi and probably superior at rejecting noise. How much better in
numeric terms, I have never seen presented. Without numbers we are lost.
If this is confrontational well I was sensitized to claims made for the quad.
I a heard these claims since 1960 but hams overwhelmingly use Yagis. There
are reasons. Perhaps the full loop on the LFA Yagi for a driver and the
modified director largely eliminate the quad advantage at noise rejection?
Please forgive typos and lack of editing this is hell on a phone
73 Doug EI2CN
Sent from my Galaxy
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