Response from the hams on the list was great, thank you all for that. At the
end I decided to use the pipes and make another design of the antenna. It is a
modified version of a known 40m beam, on the position of the linear loading
there are coils now.
The result is perfect. 11,4dBi gain 22 meters above ground. 6,5dBi freespace,
20dB front/back. Here is the antenna description, if you need EZNEC file send
me an email, I cannot do the attachments here. The units are in meters.
73 & TNX all for sharing ideas.
Simon, S53ZO
--------------- ANTENNA DESCRIPTION ---------------
Frequency = 7,1 MHz
Wire Loss: Zero
--------------- WIRES ---------------
No. End 1 Coord. (m) End 2 Coord. (m) Dia (mm)
Segs Insulation
Conn. X Y Z Conn. X Y Z
Diel C Thk(mm)
1 W5E1 -1,8288, 0, 22 W2E1 1,8288, 0, 22 31,75
3 1 0
2 W1E2 1,8288, 0, 22 W3E1 3,9624, 0, 22 25,4
3 1 0
3 W2E2 3,9624, 0, 22 W4E1 5,6388, 0, 22 19,05
1 1 0
4 W3E2 5,6388, 0, 22 7,42, 0, 22 12,7
1 1 0
5 W1E1 -1,8288, 0, 22 W6E1 -3,9624, 0, 22 25,4
3 1 0
6 W5E2 -3,9624, 0, 22 W7E1 -5,6388, 0, 22 19,05
1 1 0
7 W6E2 -5,6388, 0, 22 -7,42, 0, 22 12,7
1 1 0
8 W12E1 -1,8288, 4,5, 22 W9E1 1,8288, 4,5, 22 31,75
3 1 0
9 W8E2 1,8288, 4,5, 22 W10E1 3,6576, 4,5, 22 25,4
3 1 0
10 W9E2 3,6576, 4,5, 22 W11E1 5,334, 4,5, 22 19,05
1 1 0
11 W10E2 5,334, 4,5, 22 7,25, 4,5, 22 12,7
2 1 0
12 W8E1 -1,8288, 4,5, 22 W13E1 -3,6576, 4,5, 22 25,4
3 1 0
13 W12E2 -3,6576, 4,5, 22 W14E1 -5,334, 4,5, 22 19,05
1 1 0
14 W13E2 -5,334, 4,5, 22 -7,25, 4,5, 22 12,7
2 1 0
15 W19E1 -1,8288, 8, 22 W16E1 1,8288, 8, 22 31,75
3 1 0
16 W15E2 1,8288, 8, 22 W17E1 3,3528, 8, 22 25,4
3 1 0
17 W16E2 3,3528, 8, 22 W18E1 5,0292, 8, 22 19,05
1 1 0
18 W17E2 5,0292, 8, 22 6,65, 8, 22 12,7
1 1 0
19 W15E1 -1,8288, 8, 22 W20E1 -3,3528, 8, 22 25,4
3 1 0
20 W19E2 -3,3528, 8, 22 W21E1 -5,0292, 8, 22 19,05
1 1 0
21 W20E2 -5,0292, 8, 22 -6,65, 8, 22 12,7
1 1 0
22 W26E1 -1,8288, 11,8, 22 W23E1 1,8288, 11,8, 22 31,75
3 1 0
23 W22E2 1,8288, 11,8, 22 W24E1 3,6576, 11,8, 22 25,4
3 1 0
24 W23E2 3,6576, 11,8, 22 W25E1 5,334, 11,8, 22 19,05
1 1 0
25 W24E2 5,334, 11,8, 22 6,56, 11,8, 22 12,7
1 1 0
26 W22E1 -1,8288, 11,8, 22 W27E1 -3,6576, 11,8, 22 25,4
3 1 0
27 W26E2 -3,6576, 11,8, 22 W28E1 -5,334, 11,8, 22 19,05
1 1 0
28 W27E2 -5,334, 11,8, 22 -6,56, 11,8, 22 12,7
1 1 0
Total Segments: 54
-------------- SOURCES --------------
No. Specified Pos. Actual Pos. Amplitude Phase Type
Wire # % From E1 % From E1 Seg (V/A) (deg.)
1 15 50,00 50,00 2 1 0 I
-------------- LOADS (RLC Type) --------------
No. Specified Pos. Actual Pos. R L C R
Freq Type
Wire # % From E1 % From E1 Seg (ohms) (uH) (pF)
(MHz)
1 2 0,00 16,67 1 Short 5,3 Short
0 Ser
2 5 0,00 16,67 1 Short 5,3 Short
0 Ser
3 9 0,00 16,67 1 Short 5,3 Short
0 Ser
4 12 0,00 16,67 1 Short 5,3 Short
0 Ser
5 16 0,00 16,67 1 Short 5,3 Short
0 Ser
6 19 0,00 16,67 1 Short 5,3 Short
0 Ser
7 23 0,00 16,67 1 Short 5,3 Short
0 Ser
8 26 0,00 16,67 1 Short 5,3 Short
0 Ser
-------- TRANSMISSION LINES ---------
No. End 1 Specified Pos End 1 Act End 2 Specified Pos End 2 Act Length
Z0 VF Loss Loss Freq Rev/Norm
Wire # % From E1 % From E1 Wire # % From E1 % From E1 (m)
(ohms) (dB/100 m) (MHz)
1 15 50,00 50,00 8 50,00 50,00 Actual
dist 75 1 0 0 R
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA ---------------
No. Cond. Diel. Const. Height R Coord.
(S/m) (m) (m)
1 ,005 13 0 0
> On 27 Apr 2020, at 16:17, Simon Ravnič <simon@hamradio.si> wrote:
>
> Hi!
>
> After 41 years of being on the tower it is time to upgrade the antenna. Has
> anyone made a modification of 40m 4el KLM - “Big sticker” and replaced linear
> loading rods with high Q coils?
>
> We are aware of M2 offer of coil replacement kit, but it is a bit expensive
> so we would like to do it on our own.
>
> 73
> Simon, S53ZO
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