Gary and others,
As I said losing 6 dB + on the 4-8 Pro by going to the smaller diameter
array down to 84.84 feet in diameter will be no problem whatsoever. There are
still many users using the arrays with the original Hi-Z amps which had a loss
of 6 dB. You are using amps with 6 dB more gain than those. In addition there
are several systems operating that use my dual band dual direction system. This
system loses another 3 dB of signal by splitting the signals to two combiners.
So, there are proven stations using the same combining system with much less
available system gain. I know for a fact they are hearing very well into the
noise. Especially on the system with the dual directions. He is a contester and
always on top of the heap. This user is still using the older style of amp with
6 dB of loss and the dual direction system with another 3 dB loss.
113.12 feet diameter or 80 feet on a 4 square side and 84.84 feet diameter
or 60 feet on a 4-square side are the only two stocked by DX Engineering.
Any other size systems would need a different set of delay cables.
Fear not Gary, Just cut your element cables for the widest spacing you think
you could ever use and then all you would have to do is move the elements and
change delay cables if you were still curious.
You will not be able to tell the difference between your ears.
The 84.84 foot system greatly improves 40 meters with only approximately a
0.2 dB loss in RDF on 160 meters. My original design goal was based on maximum
RDF on 160 meters period. Then the narrow spacing came later. I originally did
not expect I could get system accuracy good enough for the narrower arrays. It
paid off to pick the fly poop out of the pepper ( an engineering term) during
the original design as it ended up easily having the accuracy to implement that.
Lee K7TJR
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of StellarCAT
Sent: Wednesday, November 02, 2016 10:26 AM
To: n6bk@yahoo.com; topband@contesting.com
Subject: Re: Topband: 60' or 70' spacing on Hi-Z 4/8 element RX array
Thanks Bob,
70’ is what Lee use to offer ... I had a 4 sq with those dimensions (it was
stolen out of a self storage unit however). I believe Lee would do cabling for
either 70’ or 60’. My main focus is still 160 with 80 as the second ... but I
don’t want to neglect 40 as spring/summer/fall static can be horrendous. So the
total power isn’t an issue?.... please explain to me what exactly it means! So
ALL signals – noise and signal are reduced by this same amount – 6.6 db? And
assuming the preamp doesn’t add any noise then it would be – the same?
or put another way – say I have 2 of these – an 80’ on a side and a 60’ on a
side ... at the same location (but not interacting, or I can magically swap
them out)... what if any change is there in the headphones?! That to me is the
bottom line and what I’ve just not had an answer on yet.
g.
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