Area 51 for Antenna Modelers & Builders (See Post #1)

423515 Views 1327 Replies 63 Participants Last post by majortom, Jun 20, 2020

stampeder

Discussion Starter · Apr 21, 2009 (Edited)

This thread has been created strictly for Antenna Modelers and Builders who like to live not just on the leading edge but on the bleeding edge of antenna research and development.

Area 51 is for posting and discussion of any computer model of any experimental antenna by Antenna Modelers and Builders

Area 51 is not for casual builders or newcomers to ask questions or look for useable home antennas. Participants here are expected to fairly well "know their stuff".

If an antenna design is shown to be worthwhile for general public consumption we will move it out of Area 51 into the main Antenna Research & Development Forum.

Just remember what the ancient map makers wrote when they had no further info to illustrate: "Beyond here be dragons!"

301 - 320 of 1328 Posts

300ohm

· #301 · Aug 21, 2009

found that the best gain was concentrated at one end of the UHF spectrum.

With corner reflector antennas, you basically design the corner reflector for the low end of the band, and the directors for the high end of the band. Thats supposed to even things out.
Try putting on one director first. The tricky/critical part is the first director placement. It should probably be about 2 to 3 inches in front of the element for the most gain.
Directors 2 thru N, are generally evenly spaced from then on(1), probably in the range of 4 - 5 inches for 700mhz.
The length of the directors should probably be about 7 inches for 700mhz.

(1 - This is from the commercial corner reflectors I have, although K7MEMs site has yagi director spacing slighty decreasing with each director)

holl_ands

· #302 · Aug 21, 2009

Although there may be a good reason to let the Gain fall off at the low end if you don't
have any channels at the low end (Land Mobile), it looks like you could SKALE
it slightly larger so that the Gain at 470 MHz is roughly the same as at 698 MHz
(or 803 MHz if that is your target).
This should flatten out the overall Gain curve.

holl_ands

· #303 · Aug 21, 2009

Although there may be a good reason to let the Gain fall off at the low end if you don't
have any channels at the low end (Land Mobile), it looks like you could SKALE
it slightly larger so that the Gain at 470 MHz is roughly the same as at 698 MHz
(or 803 MHz if that is your target).

HOWEVER, after trying it I see that there is a steep Gain dive at the highest freqs,
so not much help....

BTW: AutoGainTest=1.68 (2.25 dB) is way off.
I tried varying the SOURCE wire Radius with only limited success: AGT=1.47 (1.68 dB).
A narrower FEED separation (0.75 vice 1.0) helped a little more: AGT=1.43 (1.55 dB).
[It also might have lowered the SWR, but I didn't do a direct apples to apples comparison.]

I tried changing the SOURCE wire to 3 segments and running with AutoSegment: No help.
And I tried AutoSegment with various variables, but didn't stumble into a good result....

Perhaps someone else knows how to "fix" the AGT problem....

See less See more

wildwillie

· #304 · Aug 21, 2009

holl_ands looking at his setup 2 of the corner reflectors are acting like NARODS and 2 are acting like directors .

I need some help to get his NEC file to get me back to expert setup so i can run AGT test's i get lost on how to get back to that config.

anyways try moving his elements either directly under the last set of reflectors or right out in front by 1 inch or 1/2 inch.

I also get errors on the elements being to close

8-Whisker Bowtie with corner reflector.NEC wavelength=0.638 mtr.

Warn.: too sharp angle or too short/thick segment(s) for Wires 1 (tag 3) and 3 (tag 5)
Warn.: too sharp angle or too short/thick segment(s) for Wires 1 (tag 3) and 13 (tag 16)
Warn.: too sharp angle or too short/thick segment(s) for Wires 2 (tag 4) and 4 (tag 6)
Warn.: too sharp angle or too short/thick segment(s) for Wires 2 (tag 4) and 14 (tag 17)
Warn.: too sharp angle or too short/thick segment(s) for Wires 13 (tag 16) and 15 (tag 18)
Warn.: too sharp angle or too short/thick segment(s) for Wires 14 (tag 17) and 16 (tag 19)

Walter Dnes

· #305 · Aug 22, 2009

wildwillie said:
holl_ands looking at his setup 2 of the corner reflectors are acting like NARODS and 2 are acting like directors.

I think they're all reflectors. There's no rule that says a reflector has to do a 180 degree reflection.

wildwillie said:
I need some help to get his NEC file to get me back to expert setup so i can run AGT test's i get lost on how to get back to that config.

There are 2 ways to run AGT. In both cases, it starts off with...

F7
"* Far Field pattern" and "* Full"

If the expert menu is open, select options 1, 0, 0, 1. If not, simply check the "AGT" checkbox. Either way works.

wildwillie said:
I also get errors on the elements being to close

Is this after changing something? No log files here other than optimization logs.

I seem to be stuck at the high-value AGT stage. I can't reduce it either.

See less See more

wildwillie

· #306 · Aug 22, 2009

Walter Dnes no i ran it as you posted it and i got the errors
i manage to get the AGT down to 1.12 (0.48) but i had to remove 4 whiskers
and used 4 NARODS and corner Collinear Rods reflector
SWR <3 from 470 to 805
using 300 ohms was not sure if you were running 75 ohms or not so i went with 300 ohms but theres a dip have a look.

Code:

CM 4-Whisker Bowtie with corner Collinear Rods reflector
CM 2 NARODS 
CM Unoptimized
CM design by wildwillie
CM SWR <3 from 470 to 805
CE
GW	5	7	0	-1.75	0	0	-10.679907	3.97585079	0.05
GW	6	7	0	1.75	0	0	10.6799067	3.97585079	0.05
GW	7	7	-9.5	0.5	1.5	-9.5	8.5	1.5	0.05
GW	8	9	-7.70625	0.5	3.5	-7.70625	11	3.5	0.05
GW	9	9	-6.4125	0.5	5	-6.4125	12.5	5	0.05
GW	10	11	-5.11875	0.5	6.5	-5.11875	15	6.5	0.05
GW	11	13	-3.325	0.5	9	-3.325	18	9	0.05
GW	12	13	-2.03125	0.5	10	-2.03125	18	10	0.05
GW	13	13	-0.64375	-18	11.5	-0.64375	-0.5	11.5	0.05
GW	14	13	1.15	-18	12.5	1.15	-0.5	12.5	0.05
GW	18	7	0	-1.75	0	0	-10.679907	-3.9758508	0.05
GW	19	7	0	1.75	0	0	10.6799067	-3.9758508	0.05
GW	20	7	-9.5	0.5	-1.5	-9.5	8.5	-1.5	0.05
GW	22	9	-6.4125	0.5	-5	-6.4125	12.5	-5	0.05
GW	23	11	-5.11875	0.5	-6.5	-5.11875	15	-6.5	0.05
GW	24	13	-3.325	0.5	-9	-3.325	18	-9	0.05
GW	25	13	-2.03125	0.5	-10	-2.03125	18	-10	0.05
GW	26	13	-0.64375	0.5	-11.5	-0.64375	18	-11.5	0.05
GW	27	13	1.15	0.5	-12.5	1.15	18	-12.5	0.05
GW	1	3	0	-1.75	0	0	1.75	0	0.05
GW	43	13	1.15	0.5	12.5	1.15	18	12.5	0.05
GW	44	13	-0.64375	0.5	11.5	-0.64375	18	11.5	0.05
GW	45	13	-2.03125	-18	10	-2.03125	-0.5	10	0.05
GW	46	13	-3.325	-18	9	-3.325	-0.5	9	0.05
GW	47	11	-5.075	-15	6.5	-5.075	-0.5	6.5	0.05
GW	48	9	-6.4125	-12.5	5	-6.4125	-0.5	5	0.05
GW	49	9	-7.70625	-11	3.5	-7.70625	-0.5	3.5	0.05
GW	50	7	-9.5	-8.5	1.5	-9.5	-0.5	1.5	0.05
GW	51	5	-10.75	-7.7	0	-10.75	-0.5	0	0.05
GW	52	7	-9.5	-8.5	-1.5	-9.5	-0.5	-1.5	0.05
GW	53	9	-7.70625	-11	-3.5	-7.70625	-0.5	-3.5	0.05
GW	54	9	-6.45625	-12.5	-5	-6.45625	-0.5	-5	0.05
GW	55	11	-5.11875	-15	-6.5	-5.11875	-0.5	-6.5	0.05
GW	56	13	-3.325	-18	-9	-3.325	-0.5	-9	0.05
GW	57	13	-2.03125	-18	-10	-2.03125	-0.5	-10	0.05
GW	58	13	-0.64375	-18	-11.5	-0.64375	-0.5	-11.5	0.05
GW	59	13	1.15	-18	-12.5	1.15	-0.5	-12.5	0.05
GW	60	7	-7.70625	0.5	-3.5	-7.70625	10.5	-3.5	0.05
GW	61	5	-10.75	0.5	0	-10.75	7.2	0	0.05
GW	62	3	-0.25	-4	0.5	-0.25	-0.5	0.5	0.05
GW	63	3	-0.25	0.5	0.5	-0.25	4	0.5	0.05
GW	64	3	-0.25	-4	-0.5	-0.25	-0.5	-0.5	0.05
GW	65	3	-0.25	0.5	-0.5	-0.25	4	-0.5	0.05
GW	66	3	-0.25	-5	1	-0.25	-0.5	1	0.05
GW	67	3	-0.25	0.5	1	-0.25	5	1	0.05
GW	68	3	-0.25	-5	-1	-0.25	-0.5	-1	0.05
GW	69	3	-0.25	0.5	-1	-0.25	5	-1	0.05
GW	70	5	-0.25	-7	2	-0.25	-0.5	2	0.05
GW	71	5	-0.25	0.5	2	-0.25	7	2	0.05
GW	72	5	-0.25	-7	-2	-0.25	-0.5	-2	0.05
GW	73	5	-0.25	0.5	-2	-0.25	7	-2	0.05
GW	74	17	0	-11	-10	0	11	-10	0.05
GW	75	17	0	-11	10	0	11	10	0.05
GW	76	15	0	-9.5	-9	0	9.5	-9	0.05
GW	77	15	0	-9.5	9	0	9.5	9	0.05
GW	78	15	0	-9.5	-11.5	0	9.5	-11.5	0.05
GW	79	15	0	-9.5	11.5	0	9.5	11.5	0.05
GS	0	0	0.0254		' All in in.
GE	0
EK
EX	0	1	2	0	1	0
GN	-1
FR	0	1	0	0	177	0
RP 0 1 37 1501 90. 0. 0. 10. 0. 0.

See less See more

300ohm

· #307 · Aug 22, 2009

If the expert menu is open, select options 1, 0, 0, 1.

I always use 1, 5, 1, 1.

wildwillie

· #308 · Aug 22, 2009

The only way for me to get away from the errors is to make the bowties look
correctly to me. I even tried with a new NEC with out corner reflectors and still the same errors and AGT test resaults
Thanks guys i got her running AGT now

holl_ands

· #309 · Aug 22, 2009

To Run AutoGainTest (AGT): [SOURCE Wire is the one in the EX statement.]

1. Select Calculate/NECOutput-Data/FarFieldPattern (or simply hit F7 key)
2. Select FULL, 1001 (top to bottom) and Freq (e.g. 198 or 584 MHz, but isn't critical).
3. Generate
4. If the AGT is larger than 1.00, increase the SOURCE wire Radius, if smaller then reduce.
5. Save revised file.
6. OPEN the revised file and repeat from step #1....and repeat....and repeat....

TRICK: If you simply Save and repeat from step #1 (without reOPENing),
you'll have to reenter all of the parameters again....wasting a lot of time....

If you do both UHF and Hi-VHF runs, the SOURCE Wire Radius will probably be different.

Other things that affect AGT:
a. Whether SOURCE Wire has 1, 3 or more segments.
b. Length of SOURCE Wire.
c. Segmentation

I run AutoSegmentation while doing AGT runs and after AGT=1.0, I press F8 for NEC Output
and copy AutoSegmentation results into the file. Then turn off AutoSeg and retweak AGT.
AutoSegmentation parameter may be small for "simple" antennas and larger for
more complex jobs....and some are a real pain (like the Corner Reflector).
It is possible to have TOO many segments, resulting in additional warnings...

See less See more

holl_ands

· #310 · Aug 22, 2009

wildwillie said:
The only way for me to get away from the errors is to make the bowties look
correctly to me. I even tried with a new NEC with out corner reflectors and still the same errors and AGT test resaults
Thanks guys i got her running AGT now

I get same "too sharp" fat-end-overlap warnings in 4nec2 as WildWillie above.
This could probably be avoided by defining a small triangle (~1"?) where the bowties
come together and then AUTOSEGMENT again, cuz SOURCE wire would need more segments:

|\
|..\ ___[other half goes here]
|../
|/

and then attaching the four bowties to the outside vertical (with 3 wires, 1 seg each).
[Obviously, the triangle would match the line of the outer bowties.]
[Ignore the dots, the forum editor doesn't like spaces.....]

See less See more

wildwillie

· #311 · Aug 22, 2009

Ok i got the AGT down to 1.17 (0.68) more work neeeds to be done
and also have the errors fixed from 470 to 600 range as of this post.

because of the whiskers being so close together they needed to be opened up more and more added to lenght

holl_ands i have not made any ajustments to the wire Radius size as of this post everything is still the same.

Code:

CM 8-Whisker Bowtie with corner reflector
CM lowered AGT to 0.68db still needs more work to be done, by wildwillie
CE
GW	3	7	-1.6568047	-0.5	0	-1.6568047	-10	2.5	0.05
GW	5	7	-1.6568047	-0.5	0	-1.6568047	-7	7	0.05
GW	7	21	-7.90625	-13.8	1.725	-7.90625	13.8	1.725	0.05
GW	8	21	-6.6125	-13.8	3.45	-6.6125	13.8	3.45	0.05
GW	9	21	-5.31875	-13.8	5.175	-5.31875	13.8	5.175	0.05
GW	10	21	-4.025	-13.6	7	-4.025	14	7	0.05
GW	11	21	-2.73125	-13.841223	8.5	-2.73125	13.7587772	8.5	0.05
GW	12	21	-1.4375	-13.863314	10.4198399	-1.4375	13.7366864	10.4198399	0.05
GW	13	21	-0.14375	-13.8	12.075	-0.14375	13.8	12.075	0.05
GW	14	21	1.15	-13.8	13.8	1.15	13.8	13.8	0.05
GW	16	7	-1.6568047	-0.5	0	-1.6568047	-10	-3	0.05
GW	18	7	-1.6568047	-0.5	0	-1.6568047	-7	-7	0.05
GW	20	21	-7.90625	-13.8	-1.725	-7.90625	13.8	-1.725	0.05
GW	21	21	-6.6125	-13.8	-3.45	-6.6125	13.8	-3.45	0.05
GW	22	21	-5.31875	-13.8	-5.175	-5.31875	13.8	-5.175	0.05
GW	23	21	-4.025	-14.186391	-7	-4.025	13.4136095	-7	0.05
GW	24	21	-2.73125	-14.036687	-8.625	-2.73125	13.5633134	-8.625	0.05
GW	25	21	-1.4375	-14.265286	-10.5	-1.4375	13.334714	-10.5	0.05
GW	26	21	-0.14375	-14.2357	-12	-0.14375	13.3642996	-12	0.05
GW	27	21	1.15	-13.8	-13.8	1.15	13.8	-13.8	0.05
GW	1	1	-1.6568047	-0.5	0	-1.6568047	0.45	0	0.05
GW	2	21	-9.2	-13.8	0	-9.2	13.8	0	0.05
GW	28	7	-1.6568047	0.45	0	-1.6568047	10	2.5	0.05
GW	29	7	-1.6568047	0.45	0	-1.6568047	6.95	7	0.05
GW	30	9	-1.6568047	0.45	0	-1.6568047	10	-3	0.05
GW	31	7	-1.6568047	0.45	0	-1.6568047	6.95	-7	0.05
GS	0	0	0.0254		' All in in.
GE	0
EK
EX	0	1	1	0	1	0
GN	-1
FR	0	1	0	0	177	0
RP 0 1 37 1501 90. 0. 0. 10. 0. 0.

See less See more

holl_ands

· #312 · Aug 22, 2009

WildWillie: I calculated AGT=1.36 (1.34 dB) for the above file.
Also note one of the whiskers has 9 segs vs 7 for others...fixed it: not much help.

=======================================================
My Inner Triangle idea resulted in AGT=1.00 (0 dB) after adjusting SOURCE wire Radius
and rounding off to 2 or 3 decimal points after GeomEdit does it's crazy thing....
PS: And wouldn't hurt to add a Conductivity Card....esp. if Stainless Steel...
I would expect the BICT will add strength and might make it easier to fabricate
since the bowtie elements can meet at the apex and be tack welded (or whatever)
several times within the triangle.

Here's the file, along with all the FR and RP alternatives I copy/paste after GeomEdit:

CM 8-Whisker Bowtie with Corner Reflector, W. Dnes, Triangle Rev F, 22Aug2009
CM holl_ands RevF: Added Bowtie Inner Connection Triangle (BICT).
CM And Variable SOURCE Wire Radius to Adjust AGT. Resegmented & Reordered.
CM Raw Gain=10.0(470 MHz)-12.8(614 MHz)-11.4(806 MHz) dBi. SWR(300) under 1.8
CM F/B=24.9(470 MH)-37.1(578 MHz)-14.3(806 MHz) dB.
CE
SY Rsrc=0.0109 ' SOURCE Wire Radius. Adjust for AGT=1.0: UHF=0.0109
GW 1 1 0 -0.375 0 0 0.375 0 Rsrc
' Bowtie:
GW 2 13 0 -1 0.095 0 -9.46 1.384 0.05
GW 3 13 0 1 0.095 0 9.46 1.384 0.05
GW 4 1 0 -0.375 0 0 -1 0.278 0.05
GW 5 15 0 -1 0.278 0 -9.46 4.044 0.05
GW 6 1 0 0.375 0 0 1 0.278 0.05
GW 7 15 0 1 0.278 0 9.46 4.044 0.05
GW 8 13 0 -1 -0.095 0 -9.46 -1.384 0.05
GW 9 13 0 1 -0.095 0 9.46 -1.384 0.05
GW 10 1 0 -0.375 0 0 -1 -0.278 0.05
GW 11 15 0 -1 -0.278 0 -9.46 -4.044 0.05
GW 12 1 0 0.375 0 0 1 -0.278 0.05
GW 13 15 0 1 -0.278 0 9.46 -4.044 0.05
' Bowtie Inner Connection Triangle (BICT):
GW 14 1 0 1 -0.095 0 1 0.095 0.05
GW 15 1 0 1 0.095 0 1 0.278 0.05
GW 16 1 0 1 -0.095 0 1 -0.278 0.05
GW 17 1 0 -1 -0.095 0 -1 0.095 0.05
GW 18 1 0 -1 0.095 0 -1 0.278 0.05
GW 19 1 0 -1 -0.095 0 -1 -0.278 0.05
' Corner Reflector:
GW 20 43 -9.36 -14.04 0 -9.36 14.04 0 0.05
GW 21 43 -8.04375 -14.04 1.755 -8.04375 14.04 1.755 0.05
GW 22 43 -6.7275 -14.04 3.51 -6.7275 14.04 3.51 0.05
GW 23 43 -5.41125 -14.04 5.265 -5.41125 14.04 5.265 0.05
GW 24 43 -4.095 -14.04 7.02 -4.095 14.04 7.02 0.05
GW 25 43 -2.77875 -14.04 8.775 -2.77875 14.04 8.775 0.05
GW 26 43 -1.4625 -14.04 10.53 -1.4625 14.04 10.53 0.05
GW 27 43 -0.14625 -14.04 12.285 -0.14625 14.04 12.285 0.05
GW 28 43 1.17 -14.04 14.04 1.17 14.04 14.04 0.05
GW 29 43 -8.04375 -14.04 -1.755 -8.04375 14.04 -1.755 0.05
GW 30 43 -6.7275 -14.04 -3.51 -6.7275 14.04 -3.51 0.05
GW 31 43 -5.41125 -14.04 -5.265 -5.41125 14.04 -5.265 0.05
GW 32 43 -4.095 -14.04 -7.02 -4.095 14.04 -7.02 0.05
GW 33 43 -2.77875 -14.04 -8.775 -2.77875 14.04 -8.775 0.05
GW 34 43 -1.4625 -14.04 -10.53 -1.4625 14.04 -10.53 0.05
GW 35 43 -0.14625 -14.04 -12.285 -0.14625 14.04 -12.285 0.05
GW 36 43 1.17 -14.04 -14.04 1.17 14.04 -14.04 0.05
GS 0 0 0.0254 ' All in inches
GE 0
EK
EX 0 1 1 0 1 0
GN -1
' FR Freq Sweep choices in order of increasing calculation time:
FR 0 29 0 0 470 12 ' Freq Sweep 470-806 every 12 MHz - OLD UHF BAND
' FR 0 39 0 0 470 6 ' Freq Sweep 470-698 every 6 MHz - PREFERRED FOR UHF
' FR 0 77 0 0 470 3 ' Freq Sweep 470-698 every 3 MHz
' FR 0 153 0 0 470 1.5 ' Freq Sweep 470-698 every 1.5 MHz
' FR 0 71 0 0 300 10 ' Freq Sweep 300-1000 every 10 MHz - WIDEBAND SWEEP
' FR Hi-VHF choices:
' FR 0 15 0 0 174 3 ' Freq Sweep 174-216 every 3 MHz
' FR 0 29 0 0 174 1.5 ' Freq Sweep 174-216 every 1.5 MHz - PREFERRED
' FR 0 43 0 0 174 1 ' Freq Sweep 174-216 every 1 MHz - Hi-Rez
' FR 0 26 0 0 150 6 ' Freq Sweep 150-300 every 6 MHz - WIDEBAND SWEEP
' FR Lo-VHF choices:
' FR 0 35 0 0 54 1 ' Frequency Sweep every 1 MHz for Ch2-6
' FR 0 36 0 0 75 1 ' Frequency Sweep every 1 MHz for Ch5 + Ch6 + FM
' RP choices in order of increasing calculation time:
' RP 0 1 1 1510 90 0 1 1 0 0 ' 1D Gain toward 90-deg Azimuth
' RP 0 1 37 1510 90 0 1 5 0 0 ' 2D (Left only) Azimuthal Gain Slice
RP 0 1 73 1510 90 0 1 5 0 0 ' 2D Azimuthal Gain Slice - PREFERRED
' RP 0 73 1 1510 90 0 5 1 0 0 ' 2D Elevation Gain Slice
' RP 0 73 73 1510 90 0 5 5 0 0 ' 3D Lower Hemisphere reveals antenna
' RP 0 285 73 1510 90 0 5 5 0 0 ' 3D Full Coverage obscures antenna
' RP 0 1 37 1501 90. 0. 0. 10. 0. 0. ' fm Dnes
EN

See less See more

300ohm

· #313 · Aug 22, 2009

Whether SOURCE Wire has 1, 3 or more segments.

As a general rule in NEC2, you want the SOURCE wire to have more than 1 segment. And of course it has to be an odd number of segments to be centered.

Also, Arie has recently posted, you want to set the Resolution to 2 degrees from the default of 5 degrees for a more accurate AGT result. (within 5 degrees, you can have undetected lobes)

wildwillie

· #314 · Aug 22, 2009

WildWillie: I calculated AGT=1.36 (1.34 dB) for the above file.

holl_ands yes you would at 177 mhz

Code:

FR	0	1	0	0	177	0

holl_ands after looking at your NEC file now i see what you were talking about
nice
never thought of that
very nice work sir.

300ohm

· #315 · Aug 23, 2009

I get same "too sharp" fat-end-overlap warnings in 4nec2 as WildWillie above.
This could probably be avoided by defining a small triangle (~1"?) where the bowties
come together and then AUTOSEGMENT again, cuz SOURCE wire would need more segments:

|\
|..\ ___[other half goes here]
|../
|/

and then attaching the four bowties to the outside vertical (with 3 wires, 1 seg each).
[Obviously, the triangle would match the line of the outer bowties.]
[Ignore the dots, the forum editor doesn't like spaces.....]

Actually, that approximates the real life old style vhf bowtie connector.

See less See more

bokakob

· #316 · Aug 23, 2009 (Edited by Moderator)

X-316 VQuad

Hello, everyone! I would like to submit for criticizing a something what I think is to be unusually sweet. Please, don't be too harsh if it happens to be some nonsense. Thank you!

CE VQUAD by BOKAKOB (c) 2009-08-23
GW 1 3 0 0.022 0 0.05273204 0.124 0.0873346 2.e-3
GW 2 7 0.05273204 0.124 0.0873346 0.16673204 -0.104 0.28478837 2.e-3
GW 3 7 0.16673204 -0.104 0.28478837 0.26173206 0.086 0.4493332 2.e-3
GW 4 5 0.26173206 0.086 0.4493332 0.33773205 -0.066 0.58096907 2.e-3
GW 5 3 0.33773205 -0.066 0.58096907 0.369 0 0.63912675 2.e-3
GW 6 3 0.369 0 0.63912675 0.33426795 0.066 0.58296907 2.e-3
GW 7 5 0.33426795 0.066 0.58296907 0.25826795 -0.086 0.45133321 2.e-3
GW 8 7 0.25826795 -0.086 0.45133321 0.16326795 0.104 0.28678838 2.e-3
GW 9 7 0.16326795 0.104 0.28678838 0.04926795 -0.124 0.08933459 2.e-3
GW 10 3 0.04926795 -0.124 0.08933459 0 -0.022 0 2.e-3
GW 11 3 0 -0.022 0 0.05273204 -0.124 -0.0873346 2.e-3
GW 12 7 0.05273204 -0.124 -0.0873346 0.16673206 0.104 -0.2847884 2.e-3
GW 13 7 0.16673206 0.104 -0.2847884 0.26173205 -0.086 -0.4493332 2.e-3
GW 14 5 0.26173205 -0.086 -0.4493332 0.33773205 0.066 -0.5809691 2.e-3
GW 15 3 0.33773205 0.066 -0.5809691 0.36899998 0 -0.6391268 2.e-3
GW 16 3 0.36899998 0 -0.6391268 0.33426795 -0.066 -0.5829691 2.e-3
GW 17 5 0.33426795 -0.066 -0.5829691 0.25826795 0.086 -0.4513332 2.e-3
GW 18 7 0.25826795 0.086 -0.4513332 0.16326795 -0.104 -0.2867884 2.e-3
GW 19 7 0.16326795 -0.104 -0.2867884 0.04926795 0.124 -0.0893346 2.e-3
GW 20 3 0.04926795 0.124 -0.0893346 0 0.022 0 2.e-3
GW 21 1 0 -0.022 0 0 0.022 0 2.e-3
GW 1000 3 0.27107695 -0.35 0.70951905 0.27107695 -0.25 0.70951905 5.e-3
GE 0
EK
LD 5 0 0 0 5.8e7 0
EX 0 21 1 0 1 0
GN -1
FR 0 1 0 0 470 0
RP 0 1 61 1001 90 0 3 6 10000 0
EN

I cut some of the input file to make it fit in the post. Oops...
Please be nice to me as I am a beginner in this field...
Thanks for your input!

See less See more

3

Xauto

· #317 · Aug 23, 2009

bokakob: OK. By bending, what did that do for you? Can you show how it differs from flat.

bokakob

· #318 · Aug 23, 2009

Here is the picture of the straight allignment.

I think someone with more experience could say something more meaningfull than me.

See less See more

wildwillie

· #319 · Aug 23, 2009

bokakob I ran what your nec file as you had posted it and your AGT resaults were at 1.24 (0.95 db ) to bring the AGT resaults down i widened the fed piont gap and lenghtened the 4 wire elements connected to the fed point gap to 7 inches this brought the AGT down below 1 to around -0.98 .

300ohm

· #320 · Aug 23, 2009

I cut some of the input file to make it fit in the post. Oops...

You can spread it out over a couple of posts if need be. We really need the whole thing. The reflector has a big influence on the AGT and SWR too.

It looks like youre on the right track if you have the lobes spread out like that on a flat reflector.

301 - 320 of 1328 Posts

This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.