Better gain bandwidth and better F/B bandwidth. I.e., .... (gain and
F/B) x (bandwidth). Possibly I could have written that more clearly.
Marginally less peak forward lobe gain.
Dave AB7E
On 8/1/2014 10:02 AM, Marsh Stewart wrote:
"Compared to even a full sized 2 element yagi, a properly engineered Moxon
will have better gain and F/B bandwidth, considerably higher F/B, a somewhat
broader front lobe, and only marginally less gain (0.5 db or so)."
So does it "have better gain" or "only marginally less gain"?
Marsh, KA5M
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of David
Gilbert
Sent: Friday, August 01, 2014 11:57 AM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] TowerTalk Digest, Vol 139, Issue 51
Rick's comment below is spot on ... all of it. Compared to even a full
sized 2 element yagi, a properly engineered Moxon will have better gain
and F/B bandwidth, considerably higher F/B, a somewhat broader front
lobe, and only marginally less gain (0.5 db or so). I don't remember how
front-to-side compares.
Anyone interested should check out the fairly exhaustive work on the
topic by Cebik (whose books, ironically enough, are periodically
promoted on this reflector).
73,
Dave AB7E
On 8/1/2014 9:15 AM, Richard (Rick) Karlquist wrote:
On 8/1/2014 8:38 AM, K7LXC--- via TowerTalk wrote:
I'm leaning towards buying a Cushcraft XM240 and then modify it
with a
Moxon modification as a few of you suggested.
Okay, what are the big advantages of a Moxon over a stock CC 2L
40?
The CC has 250 kHz of bandwidth and for a given boom length the gain
would be
the same or similar. Please elucidate.
Cheers,
Steve K7LXC
The 250 kHz of bandwidth is only SWR bandwidth, not gain or F/B, and it
is specified at the fairly high SWR of 2:1. We don't know what the
gain or F/B bandwidth is, and the manual recommends one of 3
settings: CW, low phone, or high phone. That is a red flag.
A Moxon, for several reasons, has a greater bandwidth both in terms
of gain and SWR, and has a F/B that is unobtainable with an ordinary
2 element Yagi. It is actually better than a full size 2 element
Yagi. It's the next best thing to a SteppIR. Actually, it
is better than the SteppIR when working large frequency splits (still
prevalent in contests), since the bandwidth is instantaneous.
It is amazing to me the amount of corporate inertia that must
be present to prevent Cushcraft from offering the modified version
of their XM240 as an off the shelf product. The engineering has
fallen into their laps.
Rick N6RK
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