[TowerTalk] 4 square for 80

[Wayne Kline]

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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