[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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