[TowerTalk] 4 square for 80

StellarCAT rxdesign at ssvecnet.com
Sat Sep 24 17:30:28 EDT 2016


Wayne,

Can you add more detail as to how it changed please - in the last scenario 
you have listed?

I have no idea what this means:  "DX reports =  antenna #1  (NE)  being the 
only one  detectable  ????  "   ?

Gary
K9RX



-----Original Message----- 
From: Wayne Kline
Sent: Saturday, September 24, 2016 1:46 PM
To: K1TTT ; towertalk at contesting.com
Subject: Re: [TowerTalk] 4 square for 80

I have been playing with 75/80 meter 4 sq. since I acquired a Colatcho  ( 
SP) unit back in the late 80's ... First were wire 14 ga  suspended from 
trees. This was on sloping ground and the radial were 1/4 wave laying  on 
the ground 8 per antenna . I choked the feed line at the antennas bases with 
slide over 43 mix, 8 pieces per feed line.   The performance was 
questionable  IMO because of the 18 ft. difference in antenna orientation 
NE/SE .
I moved to my now QTH in 99  and erected a 4 sq. out of modified Hi Gain 
high towers. I first used elevated radials 4 per base tuned and at first 1 
ft off the ground . talk about erratic performance from a RAIN to  DRY day 
.. RAIN = GOOD   Dry =POORboth  in FB and forward gain ... I then did the 
gull wing @ antenna base and 6 ft height. the dump power bandwidth 
narrowedand the pattern was not effected AS much from dry to wet
  I then bit the bulled and striped the area installed 14 ground rods ,  a X 
grid of 8 ga copper wire and 106  1/4 wave radials 20 ga insulated  silver 
soldered at the intersecting  8 ga  X grid .
WOW Stability  was achieved . The feed lines at first were NOT choked off at 
the base of the verticals  I then installed new feedline in the PVC emt  and 
choked off the base with 8  43 mix beads ..  the dump power lowered and the 
bandwidth  tightened up . with most  DX reports =  antenna #1  (NE)  being 
the only one  detectable
  ????  No NEC,    just real world  performance evaluation .  Could the 
choke  keep re reradiated RF out of the Comtec BOX ???But there was a 
noticeable difference with and with out the Beads.
Wayne  W3EA

> From: k1ttt at arrl.net
> To: towertalk at contesting.com
> Date: Sat, 24 Sep 2016 17:07:17 +0000
> Subject: Re: [TowerTalk] 4 square for 80
>
> Personally I have never choked the 4 feedlines to the verticals.  I fail 
> to
> see why the shield of the feedlines is different from the radials it is
> connect to at the base of the vertical.  On my raised 80m 4-square I have 
> 7
> radials from each base, starting with the one going to the adjacent 
> vertical
> they go outwards every 45 degrees using heavy aluminum wire, then the 8th
> one to complete the pattern is the shield of the coax going to the comtek
> box.
>
> David Robbins K1TTT
> e-mail: mailto:k1ttt at arrl.net
> web: http://wiki.k1ttt.net
> AR-Cluster node: 145.69MHz or telnet://k1ttt.net:7373
>
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Jim
> Brown
> Sent: Saturday, September 24, 2016 16:30
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] 4 square for 80
>
> On Sat,9/24/2016 7:15 AM, Steve London wrote:
> > How much better would the performance be with a multiturn choke ? Over
> > real ground, in the presence of real, possibly interacting structures
> > within N wavelengths, isn't there a finite limit to the performance,
> > regardless of your choice of "excellent" vs. "superb" common-mode
> > chokes ?
>
> Hi Steve,
>
> The primary reason for using common mode chokes in our antenna systems is 
> to
> reduce RX noise. A string of beads choke is NOT a good choke at HF for the
> reason cited -- it's effectiveness is strongly dependent on the electrical
> length of the feedline considering it as an antenna (that is, considering 
> it
> as a wire, not a transmission line). This is not a matter of "excellent" 
> vs
> "superb," it is whether it is effective at suppressing RX noise, and 
> whether
> signal pickup on the coax fills in the nulls a bit.
>
> 73, Jim K9YC
>
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