[TowerTalk] Mosley....again

[Jim Thomson]

Date: Sat, 28 Jan 2017 19:05:48 -0600
From: Kelly Taylor <ve4xt at mymts.net>
To: Dave - AB7E <xdavid at cis-broadband.com>
Cc: w2gr at aol.com, Towertalk e-Goups <towertalk at contesting.com>
Subject: Re: [TowerTalk] Force 12 going away
I don?t think anyone has said Mosleys don?t work, merely there are others that work better.

Anything will radiate, it?s just by degrees how well. The data does favour other antennas and disfavour Mosleys. There are also sound engineering reasons to dislike Mosleys.

That?s not bashing, it?s just reality.

73, kelly, ve4xt 

ps: and no, the data are NOT the work of manufacturers? marketing departments, and none of the data supports Mosley?s exaggerated gain claims, either.

##  check out mosleys website, beyond absurd.   9.5 DBD  for a 3 el 40m yagi..... I dont think so,  maybe  5.2 max. 
8.5 DBD  for a 3el  20m monoband  yagi..again  absurd, 5.1  max.
10.5 DBD  for all their  5 el monoband yagis...somebody is drinking the coolaid, and then some.

## The 6063-T832 they use, doesnt work any better than the same 6063-T832 that everybody else uses, and bought from the same suppliers. 
##  Their tribanders should take wind pretty good, since the typ tribander trapped mosley uses 24-25 ft long eles.   Take a typ full sized 20M  REF, 
then lop off  5.5 ft  from each tip, then u end up with mosley length els.   Run that through the mech software, and u will see that the wind rating is
way up there.   Ditto with ice.

##  Stuff like their  33jr  tribander does have good FB, and also good FS.  It has directivity.  But it has next to no forward gain on 20M.   Its a full
10 db down from a 204BA, using proper test gear, and calibrated pads.   Been there, done that. 

##  beware, their power rating are bs.  I went through that with their engineer years ago.   Their bigger tribanders and other trapped yagis 
are  good for 600 w CCS rtty / FM... that’s it.   On cw they rate em at 2.5 kw.... which is  2.5 kw INPUT power,  1.5 kw out, they assume 60% eff,
and a 40% duty cycle on CW mode.  1500 x .4  = 600 watts average.   On ssb, they rate em for 5 kw.   Thats 5 kw pep input, and 3 kw pep output. 
They assume 20%  duty cycle on ssb....  so  3000 x .2 =  600 watts average.

## Dont do something stupid, like running 1.5 kw out on rtty contest, it will go up like a roman candle...larger tribanders and trapped yagis. 
1.2 kw pep out on ssb will melt the DE on any 33jr...and that’s with no speech processing. 

##  For a trapped yagi, they are  robust, short eles are a major factor there.   FS  + FB is pretty good on most bands.  Electrically, the forward gain
is way down though.   A 2 el  f12 will  eat their lunch. 
## and no, nobody has used 52 ohm coax,  since 1969.   Folks do like them, cuz they dont use full length els, one feedline, simple, and cover a lot of bands,
decent  swr and FS and FB.  Gain is what ever u manage to talk to that day.   So its a bunch of tradeoffs.  

VE7RF