[Top] [All Lists]

[TowerTalk] K8UR 4SQR modifications

To: <>
Subject: [TowerTalk] K8UR 4SQR modifications
From: (
Date: Thu, 15 Mar 2001 00:40:01 EST
After originally being somewaht satisfied with my K8UR style 40 meter 1/2 
dipole 4SQR,  I was becoming disillusioned and having trouble..the F/B seemed 
inconsistent and gain was not much over my Butternut HF2V.  Sometimes it 
worked ok, sometimes it seemed like a lot of work for nothing- 

For reference: the tower it hangs off of is 60 feet, with insulated guy 
wires, using a Comtek coupler ( 

 After a few modifications suggested by W1XE and K0RF, the antenna system is 
now working with some great comparison results working long haul (over 
3,500km) DX:

Antenna                    measured F/B to HF2V     measured gain to HF2V

Butternut HF2V                       na                                na

K8UR 4SQR                         5-15dB                          0-2dB

design                                  25-30dB                        3-5dB

The modifications made were simple.  All we did was move about 2/3rds of the 
top half of the dipoles vertically over the feed points vs having none of the 
top half of the dipole over the feedpoints on the K8UR design.  (None of the 
top or bottom portion of the dipole sits above or below the feed point on a 
K8UR style 4SQR because the dipoles are in a V shape pattern, with the ends 
tied closely to the tower. 

The tops of the dipoles on the modified 4SQR were tied 13 feet from the top 
of the tower. We then pulled the dipole down towards the ground with a rope 
tied to the feed point baluns at about a 45 degree angle.

Then using some very long bailing twine, we tied to the twine to the wire 
with a knot 10 feet from the top of the dipole.  Then, pulling out on the 
twine some 200 feet to a support post,  we created an angle in the wire so 
that the rest of the antenna's top portion, about 2/3rds of it, was sitting 
directly over the feed point.  (On a 40 meter 4 SQR, The feedpoint was pulled 
just about 25 feet from the center of the tower.)

Our dipoles went from a side ways V shape (K8UR style) to a sort of sideways 
square C pattern-                                               
To complete this square C shape, we took the bottom portion of each dipole 
and pulled it directly below the feedpoint, until it was about 6 feet from 
the ground. Then using ropes, we pulled the remaining end of the dipole 
(about 1/2 of it) back to the tower. With an opposing rope, we pulled the 
bent angle in the dipole out so that it made a right angle when pulled 
towards the tower.

Now, about 2/3rds of the top half of the dipoles sat directly above the 
feedpoints while around 1/2 of the bottom of the dipole was directly below 
the feed points. 

Some basic notes..........On the K8UR design, on a 60 foot tower, the tops 
and bottoms of the dipoles are tied much closer to the tower it self with 
about 5 feet of diagonal spacing between ends.....On the W1XE/K0RF design, 
the diagonal distance between the top ends of the dipoles is around 20 feet 
and around 6 feet on the bottom. 

The bottom of the dipoles on the K8UR antenna were about 4 feet off of the 
ground while on the W1XE/K0RF design, they were at least 6 feet off the 

What was really cool  was that my K8UR array had minimal resonance jump 
compared to where the individual dipoles were tuned.  But there was a huge 
140Khz jump experienced with the W1XE/K0RF design. Now thats a system acting 
like an array!  (K0RF had even more of a jump on his, but his dipoles are 
hanging a lot higher then mine-) 

The K8UR had little if any F/B on stateside signals compared to the Butternut 
HF2V. While the W1XE/K0RF designed had on average 15-20dB F/B stateside.

On stateside DX, the K8UR had little if any gain over the Butternut HF2V 
while the W1XE/K0RF had around 3-5dB's, even with stations as close as Texas 
and California.   

(refer to the table at the beginning of this posting for long haul DX 

Not a scientific study, but a good amount of time was spent testing these two 
styles of 1/2 wave dipole 4SQR's.  What seemed like minor modifications had 
huge results. 

If you have about an acre of land available, and you don't like having to put 
up huge towers, this modified W1XE/K0RF design will play well. 

If your short on space, the V shape 1/2 wave dipole version of the K8UR style 
works ok but you might be better off with a 40 shorty on a decent tower--

With a tall enough tower, you can suspend the tops of the dipoles directly 
above the feedpoints.  But I think you still need to fold back the bottom of 
the dipoles towards the tower to help eliminate unwanted high angle radiation 
.......I've never tried this so I don't really know what would happen but 
ON4UN talks about this in his 3rd edition of "Low Band DX'ing" Chapter 11, 
page 78.   

I played around with this array for about a year.  I got the idea on the 
modifications when W1XE and K0RF strung one up at K0RF's contest station.  I 
was told that the computer model showed this wider spaced version would blow 
away the K8UR design,  with it's sideway V shape dipoles,  and it was 

""""""""""Increasing the average spacing between the tops of the dipoles had 
huge results here!!!""""""""""""""

If anyone has a computer modeling program, and would like to better explain 
what is happening here, please let me know-  Also, if any past results were 
published by K8UR or by anyone else, on the effects of increasing spacing 
between the tops of dipoles in a 1/2 wave dipole 4SQR, I'd like to read up on 

E-mail photos of the K8UR style I built,  and/or the modified W1XE/K0RF 
version, are available- I'll be glad to send it-

Of note, I wrote about this last year, but since making more accurate spacing 
between feed points on both versions, and taking more time to better align 
the dipoles for 4SQR spacing, the differences between the two styles was even 
more dramatic than originally tested last year.

73  Paul  N0AH
Carpenter, WY   

FAQ on WWW:     
Administrative requests:

<Prev in Thread] Current Thread [Next in Thread>