Posts by nikiml

nikiml · Mar 9, 2010

this is a modification of the JED's GH10 (rev2),
with bent NARODs and 3 narod reflectors.

Chart:

Numerical gain data (VHF-hi):

Code:

Ch		7	8	9	10	11	12	13
swr		1.63	1.69	2.24	2.2	1.84	1.34	1.17
Net Gain	9.06	9.33	8.9	8.78	8.83	8.81	8.29

Numerical gain data (UHF):

Code:

Ch		14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31	32	33	34	35	36	37	38	39	40	41	42	43	44	45	46	47	48	49	50	51	52	53	54
swr		1.22	1.27	1.36	1.45	1.52	1.55	1.47	1.38	1.35	1.35	1.36	1.37	1.38	1.38	1.39	1.39	1.4	1.4	1.41	1.42	1.44	1.48	1.53	1.57	1.6	1.62	1.64	1.67	1.69	1.72	1.75	1.78	1.8	1.83	1.85	1.87	1.91	1.95	2.01	2.09	2.18
Net Gain	13.59	13.9	14.14	14.29	14.35	14.33	14.43	14.59	14.65	14.66	14.65	14.61	14.58	14.55	14.51	14.5	14.49	14.47	14.43	14.38	14.27	14.13	14.05	14.1	14.27	14.46	14.61	14.76	14.88	14.99	15.11	15.22	15.32	15.41	15.47	15.47	15.39	15.18	14.86	14.39	13.74

nec code

Code:

CE
SY radius=0.003175
SY hat_rad=0.003175	'0.0010265
SY l1=0.381
SY g1=0.019
SY z1=0.037
SY l2=0.280
SY g2=0.009
SY z2=0.137
SY l3=0.556
SY g3=0.0055
SY z3=0.262
SY l4=0.511
SY g4=4e-3
SY z4=0.414
SY l5=0.270
SY g5=4e-3
SY z5=0.592
SY x=-0.081
SY a1=0.196
SY a2=0.192
SY a3=0.190
SY b=0.120
SY feed=0.0548348
SY a1ma2=a1-a2
SY a1pa2=a1+a2
SY a1ma2pa3=a1ma2+a3
SY a1pa2pa3=a1pa2+a3
SY n_l=0.449369
SY n_top_l=0.223443
SY n_b_l=(n_l - n_top_l)/2
SY n_z_sp=0.012
SY n_h=0.04795
SY n_b_z=a1pa2pa3*.7071+n_z_sp+hat_rad-radius
SY n_top_z=n_b_z+n_h
SY n_back=-0.25325
SY n_refl_size=0.404294
SY n_refl_z=0.367714
SY n_refl_size1=0.447082
GW	1	23	0	-feed	0	0	-feed-0.70711*a1	0.70711*a1	radius
GW	2	23	0	-feed-0.70711*a1	0.70711*a1	0	-feed-0.70711*a1ma2	0.70711*a1pa2	radius
GW	3	23	0	-feed-0.70711*a1ma2	0.70711*a1pa2	0	-feed-0.70711*a1ma2pa3	0.70711*a1pa2pa3	radius
GW	4	15	0	-feed-0.70711*a1ma2pa3	0.70711*a1pa2pa3	0	-feed-0.70711*a1ma2pa3-b	0.70711*a1pa2pa3	radius
GW	5	45	x	g1	z1	x	l1+g1	z1	radius
GW	6	33	x	g2	z2	x	l2+g2	z2	radius
GW	7	65	x	g3	z3	x	l3+g3	z3	radius
GW	8	61	x	g4	z4	x	l4+g4	z4	radius
GW	8	33	x	g5	z5	x	l5+g5	z5	radius
GW	13	7	0	-n_top_l	n_top_z	0	-n_top_l	n_b_z	hat_rad
GW	14	13	0	-n_top_l	n_b_z	0	-n_top_l-n_b_l	n_b_z	hat_rad
GX	20	010
GW	10	53	0	n_top_l	n_top_z	0	-n_top_l	n_top_z	hat_rad
GW	15	95	n_back	-n_refl_size	n_refl_z	n_back	n_refl_size	n_refl_z	radius
GX	40	001
GW	100	13	0	-feed	0	0	feed	0	radius*.8675
GW	16	105	n_back	-n_refl_size1	0	n_back	n_refl_size1	0	radius
GE	0
LD	5	0	0	0	24900000
GN	-1
EK
EX	0	100	7	0	1			
FR	0	0	0	0	800	0
RP	0	60	73	1001	0	0	3	5		
EN

nikiml · Mar 9, 2010

The curved top hat NAROD may eliminate that.

Are talking about smoothing (arc-ing) the bents on the narods?

nikiml · Mar 10, 2010

I started with a top hat narod and ended up with the model above. no curving though.
And although I have not triede all possible configurations i order to be certain, from those that I tried the above gave the best results.
(of cource best is relative)

I can try curving.

nikiml · Mar 10, 2010

Well,

I had a top hat narod, like that

Code:

   ___________________
  |___             ___|
______|           |______

Had all parameters open for the optimizer and it turned it to:

Code:

        ___________
    ___|           |___
___|                   |___

So I decided to change it into the simpler to build version above and it looked good to me.

nikiml · Mar 10, 2010

which makes me think that I should try this

Code:

     ___________
    /           \
___/             \___

nikiml · Mar 10, 2010

I think the key for getting the gain dip out is to have more wire in the NAROD, yet still having it resonate in the vhf hi range within the element stubs

well I started with more wire, but the optimizer insisted...

nikiml · Mar 10, 2010

I also wanted to put the dip into numbers.
So here is the difference of the net gains between the original JED's GH10 rev 2 and the model in this thread.

Code:

Ch	14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31	32	33	34	35	36	37	38	39	40	41	42	43	44	45	46	47	48	49	50	51	52	53	54
Diff	0.56	0.43	0.33	0.26	0.24	0.32	0.37	0.29	0.2	0.14	0.11	0.09	0.09	0.1	0.12	0.13	0.15	0.21	0.26	0.37	0.52	0.72	0.86	0.88	0.78	0.66	0.58	0.51	0.46	0.42	0.38	0.33	0.26	0.18	0.12	0.07	0.04	0.08	0.15	0.25	0.39

the maximum difference is at channel 37 and is .88 db

nikiml · Jun 2, 2010

GH8 with top hat narods and 3 narod reflectors

Here is another model with good vhf-hi gain.
This one is based on the jed's GH8.
And again the jed's parameters are not modified,
the antenna is equivelent to the Jed's GH8 but has narods and
narod reflectors added.

Here is the model:

Code:

CM model segmentation is derived from autosegmentation 22 at 800Mhz	
CM for VHF AGT of 1 set the radius multiplier of the souce wire to 1
CM 
CE
SY radius=0.003175
SY hat_rad=0.003175	'0.0010265
SY l1=0.314
SY g1=0.018
SY z1=0.083
SY l2=0.340
SY g2=0.0305
SY z2=0.258
SY l3=0.417
SY g3=0.0425
SY z3=0.439
SY l4=0.302
SY g4=.054
SY z4=0.620
SY l5=0.270
SY g5=4e-3
SY z5=0.592
SY x=-0.081
SY a1=0.193
SY a2=0.193
SY a3=0.183
SY b=0.121
SY feed=0.0725
SY a1ma2=a1-a2
SY a1pa2=a1+a2
SY a1ma2pa3=a1ma2+a3
SY a1pa2pa3=a1pa2+a3
SY n_top_l=0.214173
SY n_b_l=0.120877
SY n_z_sp=0.012
SY n_h=0.048478
SY n_b_z=a1pa2pa3*.7071+n_z_sp+hat_rad-radius
SY n_top_z=n_b_z+n_h
SY n_b_ystart=-n_top_l	'-feed-0.70711*a1ma2pa3-n_b_ysp
SY n_b_yend=n_b_ystart-n_b_l
SY n_back=-0.29961
SY n_refl_size=0.406309
SY n_refl_z=0.43301
SY n_refl_size1=0.479869
GW	1	23	0	-feed	0	0	-feed-0.70711*a1	0.70711*a1	radius
GW	2	23	0	-feed-0.70711*a1	0.70711*a1	0	-feed-0.70711*a1ma2	0.70711*a1pa2	radius
GW	3	21	0	-feed-0.70711*a1ma2	0.70711*a1pa2	0	-feed-0.70711*a1ma2pa3	0.70711*a1pa2pa3	radius
GW	4	15	0	-feed-0.70711*a1ma2pa3	0.70711*a1pa2pa3	0	-feed-0.70711*a1ma2pa3-b	0.70711*a1pa2pa3	radius
GW	5	37	x	g1	z1	x	l1+g1	z1	radius
GW	6	41	x	g2	z2	x	l2+g2	z2	radius
GW	7	49	x	g3	z3	x	l3+g3	z3	radius
GW	8	35	x	g4	z4	x	l4+g4	z4	radius
GW	11	7	0	-n_top_l	n_top_z	0	n_b_ystart	n_b_z	hat_rad
GW	14	15	0	n_b_ystart	n_b_z	0	n_b_yend	n_b_z	hat_rad
GX	20	010
GW	10	51	0	n_top_l	n_top_z	0	-n_top_l	n_top_z	hat_rad
GW	15	95	n_back	-n_refl_size	n_refl_z	n_back	n_refl_size	n_refl_z	radius
GX	40	001
GW	100	17	0	-feed	0	0	feed	0	radius*.8675
GW	16	113	n_back	-n_refl_size1	0	n_back	n_refl_size1	0	radius
GE	0
LD	5	0	0	0	24900000
GN	-1
EK
EX	0	100	9	0	1			
FR	0	0	0	0	800	0
RP	0	60	73	1001	0	0	3	5		
EN

Here is the predicted gain/swr:

Code:

Channel		7	8	9	10	11	12	13			14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31	32	33	34	35	36	37	38	39	40	41	42	43	44	45	46	47	48	49	50	51	52	53	54
Raw gain [dBi]	9.71	9.77	9.56	9.33	9.13	8.97	8.85			13.81	13.92	14.01	14.09	14.15	14.22	14.27	14.33	14.38	14.39	14.37	14.32	14.26	14.21	14.18	14.16	14.15	14.15	14.15	14.16	14.17	14.18	14.19	14.2	14.21	14.26	14.33	14.42	14.53	14.64	14.76	14.87	14.98	15.07	15.15	15.2	15.21	15.16	15.03	14.78	14.39
SWR		1.69	1.56	1.82	1.83	1.75	1.68	1.67			1.66	1.44	1.28	1.17	1.1	1.09	1.12	1.16	1.2	1.24	1.28	1.32	1.35	1.38	1.41	1.43	1.46	1.49	1.51	1.54	1.57	1.6	1.63	1.67	1.71	1.75	1.8	1.83	1.86	1.88	1.89	1.9	1.89	1.87	1.84	1.8	1.75	1.69	1.63	1.59	1.59
NetGain[Dbi]	9.42	9.56	9.18	8.94	8.79	8.68	8.57			13.53	13.77	13.94	14.06	14.14	14.21	14.26	14.3	14.34	14.34	14.3	14.24	14.16	14.1	14.05	14.02	14	13.98	13.96	13.96	13.95	13.94	13.93	13.92	13.9	13.92	13.96	14.03	14.12	14.21	14.32	14.43	14.55	14.65	14.75	14.83	14.88	14.87	14.77	14.55	14.16

a graph:

the top hat narod looks like that:

Code:

           -----------a-----------           
           |                     |             a = 0.4283m
           b                     |             b = 0.0485m
           |                     |             c = 0.1209m
-----c-----                       -----------

and it is mounted at 12mm distance form the active element's legs

The narod reflectors:

Code:

           ------------L1------------

                                          L0 = 0.9597m
          -------------L0-------------    L1 = 0.8126m
                                          L1_z = 0.433m
                                          X = 0.3m
           ------------L1------------

X here is the distance between the active element and the narod reflectors plane

and 3d image:

nikiml · Jun 4, 2010

GH6 with top hat narods and 3 narod reflectors

A Jed's GH6 mod this time.
Again, as the previous two, it can be build from and existing GH6
by adding narods and narod reflectors.

Model:

Code:

CM model segmentation is derived from autosegmentation 22 at 800Mhz	
CM for VHF AGT of 1 set the radius multiplier of the souce wire to 1
CM 
CE
SY radius=0.003175
SY hat_rad=0.003175	'0.0010265
SY l1=0.322
SY g1=0.022
SY z1=0.085
SY l2=0.328
SY g2=0.036
SY z2=0.299
SY l3=0.312
SY g3=0.0495
SY z3=0.590
SY x=-0.075
SY a1=0.184
SY a2=0.205
SY a3=0.171
SY b=0.124
SY feed=0.0755
SY a1ma2=a1-a2
SY a1pa2=a1+a2
SY a1ma2pa3=a1ma2+a3
SY a1pa2pa3=a1pa2+a3
SY n_top_l=0.200532
SY n_b_l=0.128128
SY n_z_sp=9.849e-3
SY n_h=0.054536
SY n_b_z=a1pa2pa3*.7071+n_z_sp+hat_rad-radius
SY n_top_z=n_b_z+n_h
SY n_b_ystart=-n_top_l	'-feed-0.70711*a1ma2pa3-n_b_ysp
SY n_b_yend=n_b_ystart-n_b_l
SY n_back=-0.3055
SY n_back1=-0.3055
SY n_refl_size=0.408133
SY n_refl_z=0.44513
SY n_refl_size1=0.493491
GW	1	23	0	-feed	0	0	-feed-0.70711*a1	0.70711*a1	radius
GW	2	25	0	-feed-0.70711*a1	0.70711*a1	0	-feed-0.70711*a1ma2	0.70711*a1pa2	radius
GW	3	21	0	-feed-0.70711*a1ma2	0.70711*a1pa2	0	-feed-0.70711*a1ma2pa3	0.70711*a1pa2pa3	radius
GW	4	15	0	-feed-0.70711*a1ma2pa3	0.70711*a1pa2pa3	0	-feed-0.70711*a1ma2pa3-b	0.70711*a1pa2pa3	radius
GW	5	39	x	g1	z1	x	l1+g1	z1	radius
GW	6	39	x	g2	z2	x	l2+g2	z2	radius
GW	7	37	x	g3	z3	x	l3+g3	z3	radius
GW	11	7	0	-n_top_l	n_top_z	0	n_b_ystart	n_b_z	hat_rad
GW	14	15	0	n_b_ystart	n_b_z	0	n_b_yend	n_b_z	hat_rad
GX	20	010
GW	10	51	0	n_top_l	n_top_z	0	-n_top_l	n_top_z	hat_rad
GW	15	95	n_back	-n_refl_size	n_refl_z	n_back	n_refl_size	n_refl_z	radius
GX	40	001
GW	100	17	0	-feed	0	0	feed	0	radius*.8675
GW	16	113	n_back1	-n_refl_size1	0	n_back1	n_refl_size1	0	radius
GE	0
LD	5	0	0	0	24900000
GN	-1
EK
EX	0	100	9	0	1			
FR	0	0	0	0	800	0
RP	0	60	73	1001	0	0	3	5		
EN

Predicted gain[dBi]/swr

Code:

Channel	7	8	9	10	11	12	13		14	15	16	17	18	19	20	21	22	23	24	25	26	27	28	29	30	31	32	33	34	35	36	37	38	39	40	41	42	43	44	45	46	47	48	49	50	51	52	53	54
Raw gain	9.66	9.62	9.38	9.15	8.96	8.81	8.7		13.6	13.68	13.72	13.76	13.78	13.8	13.82	13.84	13.83	13.79	13.72	13.65	13.59	13.56	13.55	13.55	13.57	13.58	13.6	13.61	13.62	13.64	13.65	13.68	13.73	13.8	13.88	13.97	14.06	14.16	14.25	14.35	14.44	14.52	14.59	14.65	14.68	14.68	14.61	14.46	14.21
S W R		1.63	1.26	1.43	1.46	1.46	1.52	1.66		1.45	1.24	1.11	1.06	1.11	1.17	1.21	1.25	1.28	1.31	1.34	1.36	1.38	1.4	1.43	1.46	1.49	1.52	1.55	1.58	1.61	1.64	1.68	1.71	1.74	1.78	1.81	1.83	1.86	1.88	1.89	1.89	1.89	1.88	1.86	1.82	1.77	1.7	1.62	1.52	1.42
Net Gain	9.4	9.56	9.24	9	8.8	8.62	8.42		13.45	13.63	13.71	13.76	13.77	13.77	13.78	13.79	13.76	13.71	13.63	13.55	13.48	13.44	13.41	13.4	13.4	13.39	13.39	13.39	13.38	13.37	13.36	13.37	13.4	13.45	13.5	13.58	13.65	13.74	13.82	13.92	14.01	14.1	14.18	14.27	14.33	14.38	14.36	14.27	14.07

gain/swr graph:

the top hat narod dimensions:

Code:

           -----------a-----------           
           |                     |             a = 0.4011m
           b                     |             b = 0.0545m
           |                     |             c = 0.1281m
-----c-----                       -----------

and it is mounted at 10mm distance form the active element's legs.

The narod reflectors dimensions are:

Code:

           ------------L1------------

                                          L0 = 0.987m
          -------------L0-------------    L1 = 0.816m
                                          L1_z = 0.445m
                                          X = 0.306m
           ------------L1------------

X here is the distance between the active element and the narod reflectors plane

nikiml · Jun 5, 2010

One question because of the downward gain pattern, are you optimizing the NARODs just for channel 7 and 8 or for 174 to 216 mhz ?

Not being careful enough I was optimizing for 174-210, but I'll change it to 174-216 from now on.

Also, just to keep all the graphs identical, can you put in the numbers for the original GH6 here :
http://www.digitalhome.ca/ota/superantenna/design.htm
optimizing the original GH6 with your top hat narods and 3 narod reflectors, but use a 89mm feedpoint instead of the 44mm one ?

Are you asking me to do with the original GH6 the same thing I did with the jed's models?
Just change the feed point?

I could do that.

The Jeds GH4 is also on my pipeline. It too should be stackable to something not too big.

nikiml · Jun 5, 2010

300ohm said:
knocking the top and bottom pairs of uhf reflectors off the GH6 above, making it an unoptimized GH4, looks pretty darn good

It is certain that better configurations exist,
since I was optimizing with the Jed's parameters intact,
in order to enable people that already have the jed's antennas
to just add narods.

nikiml · Jun 5, 2010

Just out of curiosity: why do you want the feed gap doubled?

nikiml · Jun 5, 2010

the uhf swr gets quite high at both ends of the range (3+) is that ok?
For comparison the vhf-hi swr is < 1.8

nikiml · Jun 5, 2010

Original GH6 with tophat narod

Check this out:

Code:

CM model segmentation is derived from autosegmentation 22 at 800Mhz	
CM 
CE
SY radius=0.003175
SY hat_rad=0.003175	'0.0010265
SY l1=0.295
SY g1=0.01
SY z1=0.0635
SY l2=0.306
SY g2=0.01
SY z2=0.1905
SY l3=0.306
SY g3=0.01
SY z3=0.381
SY x=-0.1
SY a1=0.180
SY a2=0.180
SY a3=0.180
SY b=0.142
SY feed=0.0445
SY a1ma2=a1-a2
SY a1pa2=a1+a2
SY a1ma2pa3=a1ma2+a3
SY a1pa2pa3=a1pa2+a3
SY n_top_l=0.2171
SY n_b_l=0.124
SY n_z_sp=0.0117
SY n_h=0.0492
SY n_b_z=a1pa2pa3*.7071+n_z_sp+hat_rad-radius
SY n_top_z=n_b_z+n_h
SY n_b_ystart=-n_top_l	'-feed-0.70711*a1ma2pa3-n_b_ysp
SY n_b_yend=n_b_ystart-n_b_l
SY n_back=-0.303
SY n_refl_size=0.4138
SY n_refl_z=0.4331
SY n_refl_size1=0.4805
GW	1	21	0	-feed	0	0	-feed-0.70711*a1	0.70711*a1	radius
GW	2	21	0	-feed-0.70711*a1	0.70711*a1	0	-feed-0.70711*a1ma2	0.70711*a1pa2	radius
GW	3	21	0	-feed-0.70711*a1ma2	0.70711*a1pa2	0	-feed-0.70711*a1ma2pa3	0.70711*a1pa2pa3	radius
GW	4	17	0	-feed-0.70711*a1ma2pa3	0.70711*a1pa2pa3	0	-feed-0.70711*a1ma2pa3-b	0.70711*a1pa2pa3	radius
GW	5	35	x	g1	z1	x	l1+g1	z1	radius
GW	6	37	x	g2	z2	x	l2+g2	z2	radius
GW	7	37	x	g3	z3	x	l3+g3	z3	radius
GW	11	7	0	-n_top_l	n_top_z	0	n_b_ystart	n_b_z	hat_rad
GW	14	15	0	n_b_ystart	n_b_z	0	n_b_yend	n_b_z	hat_rad
GX	20	010
GW	10	51	0	n_top_l	n_top_z	0	-n_top_l	n_top_z	hat_rad
GW	15	97	n_back	-n_refl_size	n_refl_z	n_back	n_refl_size	n_refl_z	radius
GX	40	001
GW	100	11	0	-feed	0	0	feed	0	radius*.8675
GW	16	113	n_back	-n_refl_size1	0	n_back	n_refl_size1	0	radius
GE	0
LD	5	0	0	0	24900000
GN	-1
EK
EX	0	100	6	0	1			
FR	0	0	0	0	800	0
RP	0	60	73	1001	0	0	3	5		
EN

vhf-hi raw-gain/swr:

Code:

174	9.72	1.78
180	9.54	1.39
186	9.3	1.43
192	9.07	1.4
198	8.88	1.37
204	8.72	1.39
210	8.58	1.5
216	8.45	1.71

nikiml · Jun 6, 2010

Well, the sweeps, even when autosegmentation is used, are done with the same segmentation for all frequencies.

I chose this one segmentation to be the one that the autosegmentation generates at 800Mhz with 22 seg per half-wave.
I then fix this segmentation into the nec file, turn the autosegmentation off and I do AGT test at 174, 195, 216, 470, 585 and 710 Mhz.

If you use autosegmentation 22 for the AGT test you'll get quite different results, because for every frequency a different segmentation will be used.

nikiml · Jun 7, 2010

Karyudo,

Those models are mods of the JED's antennas.
You can just use his dimensions
and I have posted dimensions for the additional elements for two of the three models
in the thread.
Check out the 3d view to get an idea of how the dimensions are to be applied.

nikiml · Jun 10, 2010

GH4 with top hat narods and 3 narod reflectors

A slightly conservative mod. This is because I fixed the horizontal legs length to be the same and I fixed the spacing between the active element and the narods to be 12mm. I believe this model won't produce the unequal segmentation warning.

Nec code:

Code:

CE
SY radius=0.003175
SY hat_rad=0.003175	'0.0010265
SY l1=0.300
SY g1=0.018
SY z1=0.128
SY l2=0.312
SY g2=0.045
SY z2=0.444
SY x=-0.084
SY a1=0.196
SY a2=0.202
SY a3=0.171
SY b=0.122
SY feed=0.075
SY a1ma2=a1-a2
SY a1pa2=a1+a2
SY a1ma2pa3=a1ma2+a3
SY a1pa2pa3=a1pa2+a3
SY n_top_l=0.20747
SY n_b_l=0.122
SY n_z_sp=0.0105
SY n_h=0.053322
SY n_b_z=a1pa2pa3*.7071+n_z_sp+hat_rad-radius
SY n_top_z=n_b_z+n_h
SY n_b_ystart=-n_top_l	'-feed-0.70711*a1ma2pa3-n_b_ysp
SY n_b_yend=n_b_ystart-n_b_l
SY n_back=-0.3034
SY n_refl_size=0.424505
SY n_refl_z=0.459371
SY n_refl_size1=0.475897
GW	1	23	0	-feed	0	0	-feed-0.70711*a1	0.70711*a1	radius
GW	2	25	0	-feed-0.70711*a1	0.70711*a1	0	-feed-0.70711*a1ma2	0.70711*a1pa2	radius
GW	3	21	0	-feed-0.70711*a1ma2	0.70711*a1pa2	0	-feed-0.70711*a1ma2pa3	0.70711*a1pa2pa3	radius
GW	4	15	0	-feed-0.70711*a1ma2pa3	0.70711*a1pa2pa3	0	-feed-0.70711*a1ma2pa3-b	0.70711*a1pa2pa3	radius
GW	5	35	x	g1	z1	x	l1+g1	z1	radius
GW	6	37	x	g2	z2	x	l2+g2	z2	radius
GW	11	7	0	-n_top_l	n_top_z	0	n_b_ystart	n_b_z	hat_rad
GW	14	15	0	n_b_ystart	n_b_z	0	n_b_yend	n_b_z	hat_rad
GX	20	010
GW	10	49	0	n_top_l	n_top_z	0	-n_top_l	n_top_z	hat_rad
GW	15	101	n_back	-n_refl_size	n_refl_z	n_back	n_refl_size	n_refl_z	radius
GX	40	001
GW	100	17	0	-feed	0	0	feed	0	radius*.8675
GW	16	113	n_back	-n_refl_size1	0	n_back	n_refl_size1	0	radius
GE	0
LD	5	0	0	0	24900000
GN	-1
EK
EX	0	100	9	0	1			
FR	0	0	0	0	800	0
RP	0	60	73	1001	0	0	3	5		
EN

Numeric results:

Code:

Ch.	Freq	RawGain	R-in 	X-in 	SWR	NetGain
	171	9.69	428.61	-240.2	2.1	9.1
	174	9.61	415.59	-123.24	1.61	9.37
7	177	9.5	417.9	-57.03	1.44	9.35
	180	9.38	423.34	-18.55	1.42	9.25
8	183	9.27	427.45	4.69	1.43	9.13
	186	9.17	429.21	20.15	1.44	9.03
9	189	9.08	429.2	32.33	1.45	8.93
	192	9	428.61	43.71	1.46	8.85
10	195	8.92	428.7	55.54	1.47	8.76
	198	8.86	430.59	68.28	1.5	8.68
11	201	8.8	435.29	81.99	1.54	8.6
	204	8.75	443.7	96.48	1.6	8.51
12	207	8.7	456.79	111.34	1.67	8.42
	210	8.66	475.69	125.91	1.76	8.32
13	213	8.63	501.76	139.13	1.86	8.22
	216	8.6	536.72	149.19	1.98	8.1
	219	8.57	582.52	152.98	2.12	7.97
						
	467	13.15	204.81	-65.08	1.59	12.92
	470	13.24	222.9	-46.48	1.41	13.11
14	473	13.29	241.94	-34.18	1.28	13.22
	476	13.31	261.25	-26.23	1.18	13.28
15	479	13.33	279.84	-22.58	1.11	13.32
	482	13.33	296.69	-22.82	1.08	13.32
16	485	13.32	310.97	-26.21	1.1	13.31
	488	13.31	322.14	-31.78	1.13	13.29
17	491	13.29	330.03	-38.46	1.17	13.26
	494	13.26	334.83	-45.28	1.2	13.22
18	497	13.24	337	-51.48	1.22	13.2
	500	13.21	337.1	-56.54	1.24	13.16
19	503	13.18	335.75	-60.18	1.25	13.13
	506	13.16	333.51	-62.32	1.25	13.11
20	509	13.14	330.85	-63.03	1.25	13.09
	512	13.12	328.13	-62.44	1.24	13.07
21	515	13.11	325.63	-60.74	1.23	13.06
	518	13.1	323.53	-58.13	1.22	13.06
22	521	13.1	321.96	-54.8	1.21	13.06
	524	13.1	320.99	-50.92	1.19	13.07
23	527	13.11	320.66	-46.65	1.18	13.08
	530	13.11	320.98	-42.13	1.16	13.09
24	533	13.12	321.95	-37.48	1.15	13.1
	536	13.14	323.55	-32.79	1.14	13.12
25	539	13.15	325.76	-28.16	1.13	13.13
	542	13.16	328.54	-23.66	1.13	13.14
26	545	13.18	331.88	-19.37	1.13	13.16
	548	13.19	335.73	-15.35	1.13	13.17
27	551	13.2	340.04	-11.64	1.14	13.18
	554	13.22	344.78	-8.3	1.15	13.2
28	557	13.23	349.91	-5.36	1.17	13.2
	560	13.24	355.37	-2.87	1.18	13.21
29	563	13.25	361.11	-0.85	1.2	13.21
	566	13.25	367.09	0.68	1.22	13.21
30	569	13.26	373.26	1.71	1.24	13.21
	572	13.26	379.58	2.23	1.27	13.2
31	575	13.26	386	2.24	1.29	13.19
	578	13.26	392.49	1.74	1.31	13.18
32	581	13.25	399.03	0.73	1.33	13.16
	584	13.25	405.59	-0.79	1.35	13.15
33	587	13.24	412.17	-2.83	1.37	13.13
	590	13.24	418.75	-5.4	1.4	13.12
34	593	13.23	425.32	-8.55	1.42	13.1
	596	13.22	431.86	-12.31	1.44	13.08
35	599	13.22	438.34	-16.74	1.47	13.06
	602	13.22	444.69	-21.93	1.49	13.05
36	605	13.22	450.82	-27.93	1.51	13.04
	608	13.22	456.61	-34.81	1.54	13.02
37	611	13.24	461.88	-42.6	1.56	13.03
	614	13.25	466.48	-51.28	1.59	13.02
38	617	13.27	470.21	-60.81	1.61	13.03
	620	13.3	472.91	-71.08	1.63	13.04
39	623	13.33	474.39	-81.96	1.66	13.06
	626	13.36	474.56	-93.27	1.68	13.07
40	629	13.4	473.3	-104.83	1.7	13.1
	632	13.43	470.56	-116.42	1.72	13.11
41	635	13.47	466.32	-127.85	1.74	13.14
	638	13.5	460.58	-138.89	1.76	13.16
42	641	13.54	453.38	-149.33	1.77	13.19
	644	13.58	444.8	-158.99	1.79	13.22
43	647	13.61	434.93	-167.66	1.8	13.24
	650	13.65	423.9	-175.19	1.81	13.27
44	653	13.69	411.84	-181.43	1.82	13.31
	656	13.72	398.93	-186.24	1.82	13.33
45	659	13.76	385.32	-189.53	1.83	13.37
	662	13.79	371.21	-191.23	1.83	13.4
46	665	13.82	356.76	-191.27	1.82	13.43
	668	13.85	342.17	-189.64	1.82	13.47
47	671	13.87	327.6	-186.33	1.81	13.49
	674	13.89	313.23	-181.33	1.79	13.52
48	677	13.9	299.21	-174.67	1.78	13.55
	680	13.91	285.71	-166.39	1.76	13.57
49	683	13.91	272.85	-156.52	1.73	13.59
	686	13.9	260.79	-145.12	1.7	13.6
50	689	13.87	249.64	-132.23	1.67	13.59
	692	13.82	239.54	-117.91	1.63	13.56
51	695	13.75	230.6	-102.21	1.59	13.52
	698	13.66	222.95	-85.18	1.55	13.45
52	701	13.54	216.72	-66.88	1.52	13.35
	704	13.38	212.04	-47.37	1.48	13.21
	707	13.19	209.05	-26.71	1.46	13.04
	710	12.95	207.91	-4.96	1.44	12.8

Top hat dimensions:

Code:

           -----------a-----------           
           |                     |             a = 0.4149m
           b                     |             b = 0.0533m
           |                     |             c = 0.122m
-----c-----                       -----------

The top hat is mounted at 12mm distance form the active element's legs.

And the narod reflectors dimensions:

Code:

           ------------L1------------

                                          L0 = 0.9518m
          -------------L0-------------    L1 = 0.849m
                                          L1_z = 0.4594m
                                          X = 0.303m
           ------------L1------------

X here is the distance between the active element and the narod reflectors plane

nikiml · Jun 10, 2010

A note to the DBGH builders who try to stack two of those.

It seems that the narod reflectors can be moved closer with no much gain loss,
as long as the top and bottom narods are also are aslo moved away from the middle ( the optimizer knows exactly by how much).

Thus one could may be try to have 5 narod reflectors for the whole DBGH...

nikiml · Jun 10, 2010

A simple mod of GH4

With just the middle reflector. It has lower VHF gain and a small dip at ch 17-21. But the SWR is ok.

Code:

CM model segmentation is derived from autosegmentation 22 at 800Mhz	
CM for VHF AGT of 1 set the radius multiplier of the souce wire to 1
CM Wire	15	95	n_back1	-n_refl_size	n_refl_z	n_back1	n_refl_size	n_refl_z	radius				
CE
SY radius=0.003175
SY hat_rad=0.003175	'0.0010265
SY l1=0.300
SY g1=0.018
SY z1=0.128
SY l2=0.312
SY g2=0.045
SY z2=0.444
SY x=-0.084
SY a1=0.196
SY a2=0.202
SY a3=0.171
SY b=0.122
SY feed=0.075
SY a1ma2=a1-a2
SY a1pa2=a1+a2
SY a1ma2pa3=a1ma2+a3
SY a1pa2pa3=a1pa2+a3
SY n_top_l=0.183474
SY n_b_l=0.129366
SY n_z_sp=0.012
SY n_h=0.051536
SY n_b_z=a1pa2pa3*.7071+n_z_sp+hat_rad-radius
SY n_top_z=n_b_z+n_h
SY n_b_ystart=-n_top_l	'-feed-0.70711*a1ma2pa3-n_b_ysp
SY n_b_yend=n_b_ystart-n_b_l
SY n_back=-0.317
SY n_back1=x
SY n_refl_size=0.4146
SY n_refl_z=0.726
SY n_refl_size1=0.442318
GW	1	23	0	-feed	0	0	-feed-0.70711*a1	0.70711*a1	radius
GW	2	25	0	-feed-0.70711*a1	0.70711*a1	0	-feed-0.70711*a1ma2	0.70711*a1pa2	radius
GW	3	21	0	-feed-0.70711*a1ma2	0.70711*a1pa2	0	-feed-0.70711*a1ma2pa3	0.70711*a1pa2pa3	radius
GW	4	15	0	-feed-0.70711*a1ma2pa3	0.70711*a1pa2pa3	0	-feed-0.70711*a1ma2pa3-b	0.70711*a1pa2pa3	radius
GW	5	35	x	g1	z1	x	l1+g1	z1	radius
GW	6	37	x	g2	z2	x	l2+g2	z2	radius
GW	11	7	0	-n_top_l	n_top_z	0	n_b_ystart	n_b_z	hat_rad
GW	14	15	0	n_b_ystart	n_b_z	0	n_b_yend	n_b_z	hat_rad
GX	20	010
GW	10	43	0	n_top_l	n_top_z	0	-n_top_l	n_top_z	hat_rad
GX	40	001
GW	100	17	0	-feed	0	0	feed	0	radius*.8675
GW	16	105	n_back1	-n_refl_size1	0	n_back1	n_refl_size1	0	radius
GE	0
LD	5	0	0	0	24900000
GN	-1
EK
EX	0	100	9	0	1			
FR	0	0	0	0	800	0
RP	0	60	73	1001	0	0	3	5		
EN

Numeric gain results:

Code:

Ch.	Freq 	RawGain	R-in	X-in	SWR	NetGain
	171	5.31	458.77	61.19	1.58	5.09
7	177	5.89	473.08	12.08	1.58	5.67
8	183	6.27	409.56	-33.25	1.38	6.16
9	189	6.51	334.91	-15.11	1.13	6.49
10	195	6.67	290.98	37.68	1.14	6.65
11	201	6.78	277.93	102.23	1.43	6.64
12	207	6.85	292.55	171.94	1.77	6.5
13	213	6.89	339.51	245.61	2.14	6.28
	219	6.9	436.62	317.89	2.52	6.01
						
						
	467	12.38	212.36	-5.77	1.41	12.25
14	473	12.38	257.52	29.49	1.2	12.34
15	479	12.24	307.96	48.56	1.18	12.21
16	485	12	358.84	48.96	1.26	11.94
17	491	11.77	401.6	30.3	1.36	11.67
18	497	11.66	427.16	-0.43	1.42	11.53
19	503	11.69	434.26	-31.35	1.46	11.53
20	509	11.81	429.11	-54.77	1.47	11.65
21	515	11.95	418.52	-69.16	1.47	11.79
22	521	12.09	406.84	-75.91	1.45	11.94
23	527	12.22	396.34	-76.95	1.43	12.08
24	533	12.34	388.09	-73.96	1.4	12.22
25	539	12.45	382.58	-68.27	1.37	12.34
26	545	12.55	380.02	-60.92	1.35	12.45
27	551	12.64	380.49	-52.77	1.33	12.55
28	557	12.72	383.97	-44.59	1.32	12.64
29	563	12.8	390.39	-37.1	1.33	12.71
30	569	12.87	399.6	-31.04	1.35	12.77
31	575	12.93	411.31	-27.17	1.38	12.82
32	581	12.98	425.01	-26.26	1.43	12.84
33	587	13.03	439.96	-29.03	1.48	12.87
34	593	13.06	455.08	-36.02	1.53	12.86
35	599	13.08	469.03	-47.44	1.59	12.85
36	605	13.08	480.28	-62.95	1.65	12.81
37	611	13.07	487.46	-81.49	1.7	12.77
38	617	13.04	489.8	-101.41	1.74	12.71
39	623	12.99	487.55	-120.9	1.78	12.64
40	629	12.93	481.86	-138.85	1.81	12.55
41	635	12.88	473.98	-155.34	1.84	12.48
42	641	12.86	464.16	-171.29	1.87	12.44
43	647	12.88	451.38	-187.14	1.9	12.44
44	653	12.94	434.29	-202.03	1.93	12.48
45	659	13.03	412.39	-214.03	1.96	12.55
46	665	13.13	386.4	-221.13	1.98	12.63
47	671	13.23	357.9	-221.97	1.99	12.73
48	677	13.32	328.69	-215.94	1.97	12.83
49	683	13.38	300.46	-203.1	1.94	12.91
50	689	13.41	274.62	-183.85	1.89	12.98
51	695	13.39	252.25	-158.74	1.81	13.01
52	701	13.29	234.27	-128.34	1.71	12.98
53	707	13.09	221.47	-93.16	1.6	12.85
	713	12.75	214.67	-53.65	1.48	12.58

top hat dimensions:

Code:

           -----------a-----------           
           |                     |             a = 0.3669m
           b                     |             b = 0.0515m
           |                     |             c = 0.1294m
-----c-----                       -----------

the middle reflector length is .8846m and it is in the plane of the regular reflectors.

nikiml · Jun 10, 2010

Having not built it, all I can say is:
I hope so!
Post feedback.

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