Area 51 for Antenna Modelers & Builders (See Post #1) - Page 79 - Canadian TV, Computing and Home Theatre Forums

kgb · 2012-04-19, 01:07 AM

and rest of it

HTML Code:

GW	4	9	0.0622254	-0.051	-0.0622254	0.04454773	-0.051	-0.0445477	2.5e-3
GW	4	9	0.0622254	0.051	-0.0622254	0.04454773	0.051	-0.0445477	2.5e-3
GW	4	9	0.0622254	0.153	-0.0622254	0.04454773	0.153	-0.0445477	2.5e-3
GW	4	9	0.0622254	0.255	-0.0622254	0.04454773	0.255	-0.0445477	2.5e-3
GW	4	9	0.07990307	-0.255	-0.0799031	0.0622254	-0.255	-0.0622254	2.5e-3
GW	4	9	0.07990307	-0.153	-0.0799031	0.0622254	-0.153	-0.0622254	2.5e-3
GW	4	9	0.07990307	-0.051	-0.0799031	0.0622254	-0.051	-0.0622254	2.5e-3
GW	4	9	0.07990307	0.051	-0.0799031	0.0622254	0.051	-0.0622254	2.5e-3
GW	4	9	0.07990307	0.153	-0.0799031	0.0622254	0.153	-0.0622254	2.5e-3
GW	4	9	0.07990307	0.255	-0.0799031	0.0622254	0.255	-0.0622254	2.5e-3
GW	4	9	0.09758074	-0.255	-0.0975807	0.07990307	-0.255	-0.0799031	2.5e-3
GW	4	9	0.09758074	-0.153	-0.0975807	0.07990307	-0.153	-0.0799031	2.5e-3
GW	4	9	0.09758074	-0.051	-0.0975807	0.07990307	-0.051	-0.0799031	2.5e-3
GW	4	9	0.09758074	0.051	-0.0975807	0.07990307	0.051	-0.0799031	2.5e-3
GW	4	9	0.09758074	0.153	-0.0975807	0.07990307	0.153	-0.0799031	2.5e-3
GW	4	9	0.09758074	0.255	-0.0975807	0.07990307	0.255	-0.0799031	2.5e-3
GW	4	9	0.11525841	-0.255	-0.1152584	0.09758074	-0.255	-0.0975807	2.5e-3
GW	4	9	0.11525841	-0.153	-0.1152584	0.09758074	-0.153	-0.0975807	2.5e-3
GW	4	9	0.11525841	-0.051	-0.1152584	0.09758074	-0.051	-0.0975807	2.5e-3
GW	4	9	0.11525841	0.051	-0.1152584	0.09758074	0.051	-0.0975807	2.5e-3
GW	4	9	0.11525841	0.153	-0.1152584	0.09758074	0.153	-0.0975807	2.5e-3
GW	4	9	0.11525841	0.255	-0.1152584	0.09758074	0.255	-0.0975807	2.5e-3
GW	6	33	0.15061374	-0.255	0.15061374	0.15061374	-0.153	0.15061374	2.5e-3
GW	6	33	0.15061374	-0.153	0.15061374	0.15061374	-0.051	0.15061374	2.5e-3
GW	6	33	0.15061374	-0.051	0.15061374	0.15061374	0.051	0.15061374	2.5e-3
GW	6	33	0.15061374	0.051	0.15061374	0.15061374	0.153	0.15061374	2.5e-3
GW	6	33	0.15061374	0.153	0.15061374	0.15061374	0.255	0.15061374	2.5e-3
GW	6	33	0.18596908	-0.255	0.18596908	0.18596908	-0.153	0.18596908	2.5e-3
GW	6	33	0.18596908	-0.153	0.18596908	0.18596908	-0.051	0.18596908	2.5e-3
GW	6	33	0.18596908	-0.051	0.18596908	0.18596908	0.051	0.18596908	2.5e-3
GW	6	33	0.18596908	0.051	0.18596908	0.18596908	0.153	0.18596908	2.5e-3
GW	6	33	0.18596908	0.153	0.18596908	0.18596908	0.255	0.18596908	2.5e-3
GW	6	33	0.22132442	-0.255	0.22132442	0.22132442	-0.153	0.22132442	2.5e-3
GW	6	33	0.22132442	-0.153	0.22132442	0.22132442	-0.051	0.22132442	2.5e-3
GW	6	33	0.22132442	-0.051	0.22132442	0.22132442	0.051	0.22132442	2.5e-3
GW	6	33	0.22132442	0.051	0.22132442	0.22132442	0.153	0.22132442	2.5e-3
GW	6	33	0.22132442	0.153	0.22132442	0.22132442	0.255	0.22132442	2.5e-3
GW	7	33	0.15061374	-0.255	-0.1506137	0.15061374	-0.153	-0.1506137	2.5e-3
GW	7	33	0.15061374	-0.153	-0.1506137	0.15061374	-0.051	-0.1506137	2.5e-3
GW	7	33	0.15061374	-0.051	-0.1506137	0.15061374	0.051	-0.1506137	2.5e-3
GW	7	33	0.15061374	0.051	-0.1506137	0.15061374	0.153	-0.1506137	2.5e-3
GW	7	33	0.15061374	0.153	-0.1506137	0.15061374	0.255	-0.1506137	2.5e-3
GW	7	33	0.18596908	-0.255	-0.1859691	0.18596908	-0.153	-0.1859691	2.5e-3
GW	7	33	0.18596908	-0.153	-0.1859691	0.18596908	-0.051	-0.1859691	2.5e-3
GW	7	33	0.18596908	-0.051	-0.1859691	0.18596908	0.051	-0.1859691	2.5e-3
GW	7	33	0.18596908	0.051	-0.1859691	0.18596908	0.153	-0.1859691	2.5e-3
GW	7	33	0.18596908	0.153	-0.1859691	0.18596908	0.255	-0.1859691	2.5e-3
GW	7	33	0.22132442	-0.255	-0.2213244	0.22132442	-0.153	-0.2213244	2.5e-3
GW	7	33	0.22132442	-0.153	-0.2213244	0.22132442	-0.051	-0.2213244	2.5e-3
GW	7	33	0.22132442	-0.051	-0.2213244	0.22132442	0.051	-0.2213244	2.5e-3
GW	7	33	0.22132442	0.051	-0.2213244	0.22132442	0.153	-0.2213244	2.5e-3
GW	7	33	0.22132442	0.153	-0.2213244	0.22132442	0.255	-0.2213244	2.5e-3
GW	8	33	0.26375083	-0.255	0.26375083	0.26375083	-0.153	0.26375083	2.5e-3
GW	8	33	0.26375083	-0.153	0.26375083	0.26375083	-0.051	0.26375083	2.5e-3
GW	8	33	0.26375083	-0.051	0.26375083	0.26375083	0.051	0.26375083	2.5e-3
GW	8	33	0.26375083	0.051	0.26375083	0.26375083	0.153	0.26375083	2.5e-3
GW	8	33	0.26375083	0.153	0.26375083	0.26375083	0.255	0.26375083	2.5e-3
GW	8	33	0.30617724	-0.255	0.30617724	0.30617724	-0.153	0.30617724	2.5e-3
GW	8	33	0.30617724	-0.153	0.30617724	0.30617724	-0.051	0.30617724	2.5e-3
GW	8	33	0.30617724	-0.051	0.30617724	0.30617724	0.051	0.30617724	2.5e-3
GW	8	33	0.30617724	0.051	0.30617724	0.30617724	0.153	0.30617724	2.5e-3
GW	8	33	0.30617724	0.153	0.30617724	0.30617724	0.255	0.30617724	2.5e-3
GW	9	33	0.26375083	-0.255	-0.2637508	0.26375083	-0.153	-0.2637508	2.5e-3
GW	9	33	0.26375083	-0.153	-0.2637508	0.26375083	-0.051	-0.2637508	2.5e-3
GW	9	33	0.26375083	-0.051	-0.2637508	0.26375083	0.051	-0.2637508	2.5e-3
GW	9	33	0.26375083	0.051	-0.2637508	0.26375083	0.153	-0.2637508	2.5e-3
GW	9	33	0.26375083	0.153	-0.2637508	0.26375083	0.255	-0.2637508	2.5e-3
GW	9	33	0.30617724	-0.255	-0.3061772	0.30617724	-0.153	-0.3061772	2.5e-3
GW	9	33	0.30617724	-0.153	-0.3061772	0.30617724	-0.051	-0.3061772	2.5e-3
GW	9	33	0.30617724	-0.051	-0.3061772	0.30617724	0.051	-0.3061772	2.5e-3
GW	9	33	0.30617724	0.051	-0.3061772	0.30617724	0.153	-0.3061772	2.5e-3
GW	9	33	0.30617724	0.153	-0.3061772	0.30617724	0.255	-0.3061772	2.5e-3
GW	10	17	0.11525841	-0.255	0.11525841	0.15061374	-0.255	0.15061374	2.5e-3
GW	10	17	0.15061374	-0.255	0.15061374	0.18596908	-0.255	0.18596908	2.5e-3
GW	10	17	0.18596908	-0.255	0.18596908	0.22132442	-0.255	0.22132442	2.5e-3
GW	10	17	0.11525841	-0.153	0.11525841	0.15061374	-0.153	0.15061374	2.5e-3
GW	10	17	0.15061374	-0.153	0.15061374	0.18596908	-0.153	0.18596908	2.5e-3
GW	10	17	0.18596908	-0.153	0.18596908	0.22132442	-0.153	0.22132442	2.5e-3
GW	10	17	0.11525841	-0.051	0.11525841	0.15061374	-0.051	0.15061374	2.5e-3
GW	10	17	0.15061374	-0.051	0.15061374	0.18596908	-0.051	0.18596908	2.5e-3
GW	10	17	0.18596908	-0.051	0.18596908	0.22132442	-0.051	0.22132442	2.5e-3
GW	10	17	0.11525841	0.051	0.11525841	0.15061374	0.051	0.15061374	2.5e-3
GW	10	17	0.15061374	0.051	0.15061374	0.18596908	0.051	0.18596908	2.5e-3
GW	10	17	0.18596908	0.051	0.18596908	0.22132442	0.051	0.22132442	2.5e-3
GW	10	17	0.11525841	0.153	0.11525841	0.15061374	0.153	0.15061374	2.5e-3
GW	10	17	0.15061374	0.153	0.15061374	0.18596908	0.153	0.18596908	2.5e-3
GW	10	17	0.18596908	0.153	0.18596908	0.22132442	0.153	0.22132442	2.5e-3
GW	10	17	0.11525841	0.255	0.11525841	0.15061374	0.255	0.15061374	2.5e-3
GW	10	17	0.15061374	0.255	0.15061374	0.18596908	0.255	0.18596908	2.5e-3
GW	10	17	0.18596908	0.255	0.18596908	0.22132442	0.255	0.22132442	2.5e-3
GW	11	17	0.11525841	-0.255	-0.1152584	0.15061374	-0.255	-0.1506137	2.5e-3
GW	11	17	0.15061374	-0.255	-0.1506137	0.18596908	-0.255	-0.1859691	2.5e-3
GW	11	17	0.18596908	-0.255	-0.1859691	0.22132442	-0.255	-0.2213244	2.5e-3
GW	11	17	0.11525841	-0.153	-0.1152584	0.15061374	-0.153	-0.1506137	2.5e-3
GW	11	17	0.15061374	-0.153	-0.1506137	0.18596908	-0.153	-0.1859691	2.5e-3
GW	11	17	0.18596908	-0.153	-0.1859691	0.22132442	-0.153	-0.2213244	2.5e-3
GW	11	17	0.11525841	-0.051	-0.1152584	0.15061374	-0.051	-0.1506137	2.5e-3
GW	11	17	0.15061374	-0.051	-0.1506137	0.18596908	-0.051	-0.1859691	2.5e-3
GW	11	17	0.18596908	-0.051	-0.1859691	0.22132442	-0.051	-0.2213244	2.5e-3
GW	11	17	0.11525841	0.051	-0.1152584	0.15061374	0.051	-0.1506137	2.5e-3
GW	11	17	0.15061374	0.051	-0.1506137	0.18596908	0.051	-0.1859691	2.5e-3
GW	11	17	0.18596908	0.051	-0.1859691	0.22132442	0.051	-0.2213244	2.5e-3
GW	11	17	0.11525841	0.153	-0.1152584	0.15061374	0.153	-0.1506137	2.5e-3
GW	11	17	0.15061374	0.153	-0.1506137	0.18596908	0.153	-0.1859691	2.5e-3
GW	11	17	0.18596908	0.153	-0.1859691	0.22132442	0.153	-0.2213244	2.5e-3
GW	11	17	0.11525841	0.255	-0.1152584	0.15061374	0.255	-0.1506137	2.5e-3
GW	11	17	0.15061374	0.255	-0.1506137	0.18596908	0.255	-0.1859691	2.5e-3
GW	11	17	0.18596908	0.255	-0.1859691	0.22132442	0.255	-0.2213244	2.5e-3
GW	12	19	0.22132442	-0.255	0.22132442	0.26375083	-0.255	0.26375083	2.5e-3
GW	12	19	0.26375083	-0.255	0.26375083	0.30617724	-0.255	0.30617724	2.5e-3
GW	12	19	0.22132442	-0.153	0.22132442	0.26375083	-0.153	0.26375083	2.5e-3
GW	12	19	0.26375083	-0.153	0.26375083	0.30617724	-0.153	0.30617724	2.5e-3
GW	12	19	0.22132442	-0.051	0.22132442	0.26375083	-0.051	0.26375083	2.5e-3
GW	12	19	0.26375083	-0.051	0.26375083	0.30617724	-0.051	0.30617724	2.5e-3
GW	12	19	0.22132442	0.051	0.22132442	0.26375083	0.051	0.26375083	2.5e-3
GW	12	19	0.26375083	0.051	0.26375083	0.30617724	0.051	0.30617724	2.5e-3
GW	12	19	0.22132442	0.153	0.22132442	0.26375083	0.153	0.26375083	2.5e-3
GW	12	19	0.26375083	0.153	0.26375083	0.30617724	0.153	0.30617724	2.5e-3
GW	12	19	0.22132442	0.255	0.22132442	0.26375083	0.255	0.26375083	2.5e-3
GW	12	19	0.26375083	0.255	0.26375083	0.30617724	0.255	0.30617724	2.5e-3
GW	13	19	0.22132442	-0.255	-0.2213244	0.26375083	-0.255	-0.2637508	2.5e-3
GW	13	19	0.26375083	-0.255	-0.2637508	0.30617724	-0.255	-0.3061772	2.5e-3
GW	13	19	0.22132442	-0.153	-0.2213244	0.26375083	-0.153	-0.2637508	2.5e-3
GW	13	19	0.26375083	-0.153	-0.2637508	0.30617724	-0.153	-0.3061772	2.5e-3
GW	13	19	0.22132442	-0.051	-0.2213244	0.26375083	-0.051	-0.2637508	2.5e-3
GW	13	19	0.26375083	-0.051	-0.2637508	0.30617724	-0.051	-0.3061772	2.5e-3
GW	13	19	0.22132442	0.051	-0.2213244	0.26375083	0.051	-0.2637508	2.5e-3
GW	13	19	0.26375083	0.051	-0.2637508	0.30617724	0.051	-0.3061772	2.5e-3
GW	13	19	0.22132442	0.153	-0.2213244	0.26375083	0.153	-0.2637508	2.5e-3
GW	13	19	0.26375083	0.153	-0.2637508	0.30617724	0.153	-0.3061772	2.5e-3
GW	13	19	0.22132442	0.255	-0.2213244	0.26375083	0.255	-0.2637508	2.5e-3
GW	13	19	0.26375083	0.255	-0.2637508	0.30617724	0.255	-0.3061772	2.5e-3
GW	50	47	0.299	-0.075	0	0.299	0.075	0	0.001
GM	0	5	0	0	0	0.01	0	0	50
GW	52	47	0.299	-0.075	0	0.308	-0.075	0	0.001
GM	0	4	0	0	0	0.01	0	0	52
GW	53	47	0.299	0.075	0	0.308	0.075	0	0.001
GM	0	4	0	0	0	0.01	0	0	53
GE	0
LD	5	1	0	0	58000000
GN	-1
EK
EX	0	1	3	0	1	0	0
FR	0	0	0	0	470	0
EN

For some reason my computer wrote reflector all in numbers. I had it as copy/ move. But for some reason it rewrote all thing. What did I touch

O MY

300ohm · 2012-04-19, 02:00 AM

Quote:

Did anybody try those antennas what I put here???

Sorry, Ive been busy playing around with Win8 preview and some new ram and video card cooler, and a new WMC remote control, heh.

It looks and performs like a plain old fashioned corner reflector with a wide director in front. A nice wide pattern, easy to aim.

You need to adjust AGT so that AGT = 1.0 (0db). You do that by adjusting the wire size on the wire that is referred to in the EX card.
To increase AGT, increase the wire radius and vice verse to decrease AGT. Its a trial and error thing that gets easier in time.

Quote:

I mainly focus on impedance and j. but ,,, e'm I mistaken??? Is that most importing thing??

Digital is more sensitive to a high SWR than analog TV was. Basically, you want to shoot for a SWR less than 2.7 max. It looks fine and very low in your model. Is the gain enough for your area ?
Gain for digital TV is actually a bit less important than it was for analog TV. If youre already getting say 85 on the meter and the threshold for a lock on is 60, there's really not much point to having a higher gain antenna to push it to say 95. With analog TV, it was always more gain, less snow.

Quote:

Should I give up and start some different hobby

Heck no. Like in plumbing, its mostly a matter of learning the terminology.
When I first started with 4nec2, I had a serious brain freeze about the whole segment concept, heh.
It looks like you're doing well with Geometry Edit. I hope you realize you can do copy, paste, delete, rotate, rescale also in Geometry Edit. That makes drawing things quick.

About the antenna, are you planning to use variable spaced mesh, like garden rabbit wire to make the reflector ?

kgb · 2012-04-21, 12:28 PM

Hi there. Thank you for reply. It looked like, that I'm talking here to myself

. I agree, to figured out this program is a struggle and must be great to master it, I just hope that is not like CAD program and won't take 20 years to do so

. For reflector in corner antenna I was going to make it from scratch. Just for some reason I thing I will try make it slightly bigger. I'm not happy with gain. 12 dBd will be nice.SWR come surprisingly low. I'm not complaining. Just all those errors in reflector. I don’t know if I should bother or not. It seems to that straight rods do better in this program, but is harder to tune it up. O well,,,,

300ohm · 2012-04-21, 03:25 PM

Quote:

Just for some reason I thing I will try make it slightly bigger

Yeah, the basic rule of thumb for the width of corner reflectors is 1.2 times the width of the driven element as a very minimum. Right now, yours is 1.16 times. I personally like to go 2 times the width of the driven element. Youll definitely see a gain increase.

kgb · 2012-06-26, 01:30 AM

ooo those antennas

we need better program for modeling ,,, some that you can just takl to,,do this and tel me when you are done

here is my version of 91x but so complicated to build.

HTML Code:

CM 91x yagi	
CM KGB 2012
CM 
CM 
CM 
CM 
CE
GW	1	9	0	-0.018	0	0	.018	0	.004	
GW	2	9	0	-0.205	0.07	0	-0.018	0	.004
GW	2	9	0	-0.205	-0.07	0	-0.018	0	.004
GW	2	9	0	0.205	0.07	0	0.018	0	.004
GW	2	9	0	0.205	-0.07	0	0.018	0	.004
GW	6	9	.045	-.075	0	.045	.075	0	.00635
GW	7	9	0.065	-.2	0	0.065	-.055	0	.004
GW	8	9	0.065	.2	0	0.065	.055	0	.004
GW	9	9	0.115	-.2	0.055	0.115	-.055	0.035	.004
GW	10	9	0.115	.2	0.055	0.115	.055	0.035	.004
GW	11	9	0.115	.2	-0.055	0.115	.055	-0.035	.004
GW	12	9	0.115	-.2	-0.055	0.115	-.055	-0.035	.004
GW	9	9	0.17	-.2	0.075	0.17	-.055	0.055	.004
GW	10	9	0.17	.2	0.075	0.17	.055	0.055	.004
GW	11	9	0.17	.2	-0.075	0.17	.055	-0.055	.004
GW	12	9	0.17	-.2	-0.075	0.17	-.055	-0.055	.004
GW	9	9	0.22	-.2	0.115	0.22	-.055	0.095	.004
GW	10	9	0.22	.2	0.115	0.22	.055	0.095	.004
GW	11	9	0.22	.2	-0.115	0.22	.055	-0.095	.004
GW	12	9	0.22	-.2	-0.115	0.22	-.055	-0.095	.004
GW	9	9	0.285	-.2	0.05	0.285	-.055	0.03	.004
GW	23	9	0.285	.2	-0.14	0.285	.055	-0.12	.004
GW	24	9	0.285	.2	0.05	0.285	.055	0.03	.004
GW	25	9	0.285	-.2	-0.14	0.285	-.055	-0.12	.004
GW	26	9	0.285	.2	-0.05	0.285	.055	-0.03	.004
GW	10	9	0.285	.2	0.14	0.285	.055	0.12	.004
GW	9	9	0.285	-.2	0.14	0.285	-.055	0.12	.004
GW	12	9	0.285	-.2	-0.05	0.285	-.055	-0.03	.004
GW	10	9	0.45	.2	0.14	0.45	.055	0.12	.004
GW	11	9	0.45	.2	-0.14	0.45	.055	-0.12	.004
GW	12	9	0.45	-.2	-0.14	0.45	-.055	-0.12	.004
GW	9	9	0.45	-.2	0.14	0.45	-.055	0.12	.004
GW	9	9	0.36	-.2	0.14	0.36	-.055	0.12	.004
GW	10	9	0.36	.2	0.14	0.36	.055	0.12	.004
GW	11	9	0.36	.2	-0.14	0.36	.055	-0.12	.004
GW	12	9	0.36	-.2	-0.14	0.36	-.055	-0.12	.004
GW	9	9	0.55	-.2	0.14	0.55	-.055	0.12	.004
GW	10	9	0.55	.2	0.14	0.55	.055	0.12	.004
GW	11	9	0.55	.2	-0.14	0.55	.055	-0.12	.004
GW	12	9	0.55	-.2	-0.14	0.55	-.055	-0.12	.004
GW	42	9	1.04	-.2	0.14	1.04	-.055	0.12	.004
GW	43	9	1.04	.2	0.14	1.04	.055	0.12	.004
GW	44	9	1.04	.2	-0.14	1.04	.055	-0.12	.004
GW	45	9	1.04	-.2	-0.14	1.04	-.055	-0.12	.004
GW	9	9	0.66	-.2	0.14	0.66	-.055	0.12	.004
GW	10	9	0.66	.2	0.14	0.66	.055	0.12	.004
GW	11	9	0.66	.2	-0.14	0.66	.055	-0.12	.004
GW	12	9	0.66	-.2	-0.14	0.66	-.055	-0.12	.004
GW	9	9	0.78	-.2	0.14	0.78	-.055	0.12	.004
GW	10	9	0.78	.2	0.14	0.78	.055	0.12	.004
GW	11	9	0.78	.2	-0.14	0.78	.055	-0.12	.004
GW	12	9	0.78	-.2	-0.14	0.78	-.055	-0.12	.004
GW	9	9	0.91	-.2	0.14	0.91	-.055	0.12	.004
GW	10	9	0.91	.2	0.14	0.91	.055	0.12	.004
GW	11	9	0.91	.2	-0.14	0.91	.055	-0.12	.004
GW	12	9	0.91	-.2	-0.14	0.91	-.055	-0.12	.004
GW	13	9	1.17	-.2	0.14	1.17	-.055	0.12	.004
GM	0	8	0	0	0	.14	0	0	13
GW	14	9	1.17	.2	0.14	1.17	.055	0.12	.004
GM	0	8	0	0	0	.14	0	0	14
GW	15	9	1.17	.2	-0.14	1.17	.055	-0.12	.004
GM	0	8	0	0	0	.14	0	0	15
GW	16	9	1.17	-.2	-0.14	1.17	-.055	-0.12	.004
GM	0	8	0	0	0	.14	0	0	16
GW	9	9	2.42	-.191	0.14	2.42	-.055	0.12	.004
GW	10	9	2.42	.191	0.14	2.42	.055	0.12	.004
GW	11	9	2.42	.191	-0.14	2.42	.055	-0.12	.004
GW	12	9	2.42	-.191	-0.14	2.42	-.055	-0.12	.004
GW	95	9	-.2	-.255	0.002	-.2	.255	0.002	.008
GM	0	6	0	0	0	0	0	.071	95
GM	0	0	0	12	0	0	0	0	95
GW	96	9	-.2	-.255	-0.002	-.2	.255	-0.002	.008
GM	0	6	0	0	0	0	0	-.071	96
GM	0	0	0	-12	0	0	0	0	96
GE	0
GN	-1
EK
EX	0	1	5	0	1	0	0	'Voltage source (1+j0) at wire 1 segment 5.
FR	0	0	0	0	470	0
EN

300ohm · 2012-06-26, 08:39 PM

Not bad. Did you also play around with a DAT-75 type design ?

http://www.hdtvprimer.com/ANTENNAS/DAT75.html

ToolMan78 · 2012-11-22, 09:07 AM

I live in northern Costa Rica and a lot of my neighbors are using all sorts of homemade antennas that range from damaged bicycle rims to a bunch of random wires jammed into a PVC pipe. Needless to say the reception they get is terrible.
Some have antennas that they bought and they get the low VHF channels 2-11 reasonably well. So I built a Stealth Hawk and got OK reception from Ch7 up. I was wondering if there is a simple design that will get channels down to ch2. If I can build something that works well I'll show some of the locals how to build it so that they have a cheaper alternative to store bought ones that many can't afford.
We are in a rural area. Upper UHF isn't important because I don't think there are any signals strong enough to use. The antennas are generally mounted on wood poles about 15 ft. high. They will probably use 1/4" rebar as a material because it's cheap and plentiful. They hook them up with a cheap balun with about 20 ft of coax cable.
Any advice would be appreciated.

Ndnile · 2012-11-22, 04:18 PM

For channel 2.... have you tried using a basic dipole (rabbit ears)? There are articles on the web about using basic 300ohm twin lead wire to make low VHF antennas. check this link it might help you.

http://www.wfu.edu/~matthews/misc/dipole.html

Even if you don't use twin lead you should be able to make this out of conductive (aluminum / copper) wire. This article also explains directors and reflectors to help add gain if needed.

300ohm · 2012-11-22, 07:25 PM

Quote:

Some have antennas that they bought and they get the low VHF channels 2-11 reasonably well.

Vhf-low covers channels 2 - 6 54- 88 Mhz, and vhf-hi covers channels 7 - 13 174 - 216 mhz, so what they bought was vhf-hi-low combo antennas.

Because of the low frequencies, vhf-low antennas are big. We have some vhf-low Wade Delhi models in this thread :
http://www.digitalhome.ca/forum/show...e+delhi&page=2

We also have some vhf-low-hi combo antenna models, like stampeders CM1111 and my CM1221 and some of the Radio Shack VU models scattered throughout this forum. Do a search on vhf-low and you should come up with them.

Vhf-low-hi combo antennas are mostly LPDAs due to the high bandwidth needed at such low relative frequencies.
Holl_ands has zig-zag lpda that can be made cheaply using wire on a wooden frame here:
http://imageevent.com/holl_ands/zigz...igzagboomwedge
Somewhere on this forum, I have a vhf-low-hi zig-zag model from a 70's Popular Electronics article. Also heres Mother Earth News plan directions for their uhf-fm-vhf-hi-low zig zag antenna, on thread #5:
http://www.digitalhome.ca/forum/showthread.php?t=99138

Vhf-Low only or Vhf-hi only antennas are also popular in the Yagi style antenna.

Another popular vhf-hi-low antenna (popular in the 1950's but still works well) is the large bowtie.
Holl_ands has a vhf-hi model for it here:
http://imageevent.com/holl_ands/dipoles/hivhfbowtie

ToolMan78 · 2012-11-22, 08:42 PM

Thanks for the quick responses. I'm busy with the farm right now so I don't have time to do much more than check my e-mail. But I'll get around to checking your suggestions this weekend. They sound promising.
A couple of quick questions regarding general antenna building. Would changing from 1/4" steel rebar to 1/8"x3/4" aluminum flat stock make much of a difference? I know a place that sells the aluminum. Also, if I use the rebar and paint it to keep it from rusting, would the paint block the signal? And finally I used steel screws to fasten the wire to a 2" square post for the Stealth Hawk, do small pieces of metal like 3/4" long screws touching the wire hurt the reception?
I hope I'm posting these questions in the right forum. Thanks again for your help.

ota_canuck · 2012-11-23, 12:55 AM

The #289 Stealth Hawk [see post #289 in the Stealth Hawk thread] should be mounted to the mast only @ the area of the balun feedpoint. Mounting the element to the mast at any other points of the wire may interfere with resonance.

Yes.// that 1/8" flat aluminium should perform better than the steel rods. Painting the steel rod material should not reduce performance as long as it does not coat [insulate] the metal to metal electrical connection points at the balun connection screws.

For better lo-VHF reception using the #289 Stealth Hawk you can simply lengthen the two lower lengths to 17". the upper diamond shaped section above the feedpoint will still work well for UHF but the gain at the higher UHF frequency range will drop slightly. See the driven element dimensions here http://www.digitalhome.ca/forum/show...&postcount=277

For more gain you could build a simple reflectorless version using the driven element dimensions of the Super Stealth Hawk.

You should post your tvfool results in the reception thread that is dedicated to your viewing area for further discussion.

300ohm · 2012-11-23, 03:21 AM

Quote:

Would changing from 1/4" steel rebar to 1/8"x3/4" aluminum flat stock make much of a difference?

Big difference in terms of total weight, plus aluminum is a better conductor.

The zig zag LPDA antennas above all use wire around a pvc or wood frame, preferably something like common copper or aluminum house wiring.

300ohm · 2012-11-23, 05:24 PM

Quote:

Somewhere on this forum, I have a vhf-low-hi zig-zag model from a 70's Popular Electronics article.

Here it is, NEC file on post # 11 and the picture of the 1.5" X 1.5" frame I had for it on post #21.
http://www.digitalhome.ca/forum/showthread.php?t=99138

holl_ands · 2012-11-23, 06:33 PM

Tollman78: I understand Costa Rica uses SAME 6 MHz wide channels as USA,
although it appears that only Ch2-13 are currently used (NO UHF stations):
http://en.wikipedia.org/wiki/Template:Costa_Rica_TV
I also understand Costa Rica is changing from our ATSC to ISDB, but has
probably not completed the change over:
http://www.tvtechnology.com/news/011...tandard/205979

ATSC (and probably all new high speed digital systems) are degraded when
SWR is not minimized (preferably below 2.7, iffy if above 3.0). The many
reflections bouncing up and down a long coax appear as short delay type
multipath...which Generation1-3 ATSC Demodulator chips have been
found to have a difficult time decoding when tested. I have yet to see
any data newer than about 2006 for current Gen5+6 chips. More info
can be found here:
http://www.digitalhome.ca/forum/show....php?p=1303957
http://www.digitalhome.ca/forum/show....php?p=1343247
I'll have to look at the skimpy ISDB test summaries to see if they have
any information on this vulnerability.....

I've been cranking out Ch2-13 response curves for numerous candidate DIY
antennas and will be posting them as I finish analyzing and uploading them.

I'll start with what are POOR choices (Folded Dipole Twinlead & Rabbit Ears)
and will progress to some SO-SO choices and eventually will present some
alternatives providing minimally acceptable SWR and Gain across ENTIRE Band,
however, it's going to take more than this weekend to run nikiml's scipts to
find the Optimized element sizes and locations.

VHF Folded Dipole:
http://imageevent.com/holl_ands/loops/vhffoldeddipole
Twinlead is cheap, although no longer readily found in USA stores anymore.
It is frequently used for the FM Band, where SWR is relatively unimportant.
However, acceptable SWR can't be maintained for more than one channel,
shown here for Ch6 (Twinlead is 1/2-in wide, AWG24):
http://imageevent.com/holl_ands/loops/vhffoldeddipole
And lower channels will be even narrower bandwidth....

Below the results for various element diameter sizes optimized for Ch6 are
larger lengths for Elements using 1/2-in Copper Tubing that will provide
minimally acceptable performance across Ch3-6 and barely acceptable
performance across Ch2-6. Hence these would be need to be combined
with a Hi-VHF Antenna using a HLSJ Hi-VHF/Lo-VHF Band Combiner.

VHF Rabbit Ears:
Rabbit Ears also suffer from being too thin to provide good SWR across
either the Ch2-6 and certainly not the entire Ch2-13 Band....unless you
get up and readjust the lengths for "best" reception:
http://imageevent.com/holl_ands/circ...zed/rabbitears

More to come.....

nikiml · 2012-11-23, 07:14 PM

I just could not help myself but try this. Higher gain is possible but the SWR also goes up. May be couple of reflectors will help with both.
Also a lot more carefull adjustment is needed on the gain target levels to better control the SWR.

The antenna is about 2.6m high and 2.2 m wide.

Code:

CM 
CM Sweep ranges:
CM R0 = (54 3 7) with target levels (6 6)
CM R1 = (76 3 5) with target levels (6 6)
CM R2 = (174 6 8) with target levels (6 6)
CM SWR target: 2
CM Target function: max(max_swr_diff .2*ave_max_gain_diff +.8*ave_gain_diff)
CM Autosegmentation: 21 per 0.75
CM 
CM Score 1.3518
CM 
CM 
CM GH0n - optimized by nikiml for VHF - lo/hi
CE 
GW 1 10 0 0.0780208 0 0 0.320088 0.242067 0.003175
GW 2 6 0 0.320088 0.242067 0 0.158397 0.403758 0.003175
GW 3 24 0 0.158397 0.403758 0 0.76169 1.00705 0.003175
GW 4 8 0 0.76169 1.00705 0 1.04922 1.00705 0.003175
GW 11 8 0 0.766423 1.28138 0 0.829452 1.01848 0.003175
GW 12 8 0 0.829452 1.01848 0 1.11699 1.01848 0.003175
GX 20 010
GW 13 43 0 -0.766423 1.28138 0 0.766423 1.28138 0.003175
GX 40 001
GW 100 7 0 -0.0780208 0 0 0.0780208 0 0.00275431
GE 0
LD 5 0 0 0 24900000
GN -1
EK 
EX 0 100 4 0 1
FR 0 0 0 0 200 0
EN

the gain /swr data :

Code:

Freq sweeps: [(54, 3, 7), (76, 3, 5), (174, 3, 15)]
Autosegmentation: 21 per 0.75


  Freq  RawGain  NetGain     SWR     F/R     F/B     Real     Imag    AGT(corr)
==================================================================================
  54.0    5.273    4.530   2.314   0.000   0.000   260.15  -238.05  0.97(-0.123)
  57.0    5.183    4.733   1.915   0.000   0.000   170.44   -74.50  0.97(-0.123)
  60.0    5.163    4.650   2.002   0.000   0.000   150.68    19.43  0.97(-0.123)
  63.0    5.183    4.529   2.194   0.000   0.000   152.75    90.00  0.97(-0.123)
  66.0    5.253    4.457   2.385   0.000   0.000   167.96   151.97  0.97(-0.123)
  69.0    5.353    4.431   2.554   0.000   0.000   196.07   211.74  0.97(-0.123)
  72.0    5.463    4.432   2.702   0.000   0.000   241.21   272.29  0.97(-0.123)
  76.0    5.620    4.462   2.875   0.000   0.000   344.69   352.74  0.98(-0.090)
  79.0    5.770    4.526   2.992   0.000   0.000   478.10   398.12  0.98(-0.090)
  82.0    5.930    4.606   3.104   0.000   0.000   682.64   381.72  0.98(-0.090)
  85.0    6.100    4.696   3.216   0.000   0.000   917.87   196.85  0.98(-0.090)
  88.0    6.260    4.773   3.333   0.000   0.000   962.72  -179.91  0.98(-0.090)
 174.0    3.142    2.557   2.101   0.000   0.000   624.28   -53.46  0.98(-0.082)
 177.0    4.112    3.202   2.539   0.000   0.000   735.87  -126.45  0.98(-0.082)
 180.0    4.932    3.766   2.886   0.000   0.000   713.43  -304.61  0.98(-0.082)
 183.0    5.692    4.376   3.093   0.000   0.000   564.91  -412.04  0.98(-0.082)
 186.0    6.422    5.028   3.202   0.000   0.000   408.64  -416.90  0.98(-0.082)
 189.0    7.132    5.706   3.247   0.000   0.000   292.12  -369.12  0.98(-0.082)
 192.0    7.802    6.373   3.251   0.000   0.000   213.59  -303.98  0.98(-0.082)
 195.0    8.395    6.984   3.226   0.000   0.000   162.25  -236.22  0.98(-0.075)
 198.0    8.875    7.492   3.186   0.000   0.000   129.43  -170.72  0.98(-0.075)
 201.0    9.195    7.841   3.146   0.000   0.000   109.48  -108.56  0.98(-0.075)
 204.0    9.305    7.967   3.123   0.000   0.000    98.98   -49.37  0.98(-0.075)
 207.0    9.195    7.852   3.130   0.000   0.000    95.92     7.65  0.98(-0.075)
 210.0    8.875    7.502   3.172   0.000   0.000    99.31    63.50  0.98(-0.075)
 213.0    8.375    6.951   3.243   0.000   0.000   108.95   119.22  0.98(-0.075)
 216.0    7.745    6.258   3.333   0.000   0.000   125.35   175.84  0.98(-0.075)

2012-06-26, 08:39 PM	#1176
300ohm Veteran Join Date: Mar 2008 Location: Somewhere in Delaware on the flat side Posts: 7,002	Not bad. Did you also play around with a DAT-75 type design ? http://www.hdtvprimer.com/ANTENNAS/DAT75.html __________________ My builds/plans (not the latest models) are located here.

2012-11-22, 09:07 AM	#1177
ToolMan78 Rookie Join Date: Nov 2012 Posts: 2	New to this forum I live in northern Costa Rica and a lot of my neighbors are using all sorts of homemade antennas that range from damaged bicycle rims to a bunch of random wires jammed into a PVC pipe. Needless to say the reception they get is terrible. Some have antennas that they bought and they get the low VHF channels 2-11 reasonably well. So I built a Stealth Hawk and got OK reception from Ch7 up. I was wondering if there is a simple design that will get channels down to ch2. If I can build something that works well I'll show some of the locals how to build it so that they have a cheaper alternative to store bought ones that many can't afford. We are in a rural area. Upper UHF isn't important because I don't think there are any signals strong enough to use. The antennas are generally mounted on wood poles about 15 ft. high. They will probably use 1/4" rebar as a material because it's cheap and plentiful. They hook them up with a cheap balun with about 20 ft of coax cable. Any advice would be appreciated.

2012-11-22, 04:18 PM	#1178
Ndnile Join Date: Jun 2011 Location: Victoria BC - shelbourne Posts: 273	For channel 2.... have you tried using a basic dipole (rabbit ears)? There are articles on the web about using basic 300ohm twin lead wire to make low VHF antennas. check this link it might help you. http://www.wfu.edu/~matthews/misc/dipole.html Even if you don't use twin lead you should be able to make this out of conductive (aluminum / copper) wire. This article also explains directors and reflectors to help add gain if needed. __________________ victoria: 2 H-stack xg91, 2 H-stack mod cm4228hd's , 2-YA-1713's, cm7777,cb trap,fm trap,hpf,33,38,22 notch filters

2012-11-23, 12:55 AM	#1181
ota_canuck Veteran Join Date: Mar 2009 Location: Dunnville, Ontario on the Grand River, North shore Lake Erie Posts: 2,405	The #289 Stealth Hawk [see post #289 in the Stealth Hawk thread] should be mounted to the mast only @ the area of the balun feedpoint. Mounting the element to the mast at any other points of the wire may interfere with resonance. Yes.// that 1/8" flat aluminium should perform better than the steel rods. Painting the steel rod material should not reduce performance as long as it does not coat [insulate] the metal to metal electrical connection points at the balun connection screws. For better lo-VHF reception using the #289 Stealth Hawk you can simply lengthen the two lower lengths to 17". the upper diamond shaped section above the feedpoint will still work well for UHF but the gain at the higher UHF frequency range will drop slightly. See the driven element dimensions here http://www.digitalhome.ca/forum/show...&postcount=277 For more gain you could build a simple reflectorless version using the driven element dimensions of the Super Stealth Hawk. You should post your tvfool results in the reception thread that is dedicated to your viewing area for further discussion. __________________ 3D SSH III with ZZ4 refl. http://imageshack.us/user/jmsdigital

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2012-04-21, 12:28 PM	#1173
kgb Join Date: Apr 2009 Location: South Surrey BC Posts: 81	Hi there. Thank you for reply. It looked like, that I'm talking here to myself . I agree, to figured out this program is a struggle and must be great to master it, I just hope that is not like CAD program and won't take 20 years to do so . For reflector in corner antenna I was going to make it from scratch. Just for some reason I thing I will try make it slightly bigger. I'm not happy with gain. 12 dBd will be nice.SWR come surprisingly low. I'm not complaining. Just all those errors in reflector. I don’t know if I should bother or not. It seems to that straight rods do better in this program, but is harder to tune it up. O well,,,,

2012-11-22, 08:42 PM	#1180
ToolMan78 Rookie Join Date: Nov 2012 Posts: 2	Thanks for the quick responses. I'm busy with the farm right now so I don't have time to do much more than check my e-mail. But I'll get around to checking your suggestions this weekend. They sound promising. A couple of quick questions regarding general antenna building. Would changing from 1/4" steel rebar to 1/8"x3/4" aluminum flat stock make much of a difference? I know a place that sells the aluminum. Also, if I use the rebar and paint it to keep it from rusting, would the paint block the signal? And finally I used steel screws to fasten the wire to a 2" square post for the Stealth Hawk, do small pieces of metal like 3/4" long screws touching the wire hurt the reception? I hope I'm posting these questions in the right forum. Thanks again for your help.

2012-11-23, 06:33 PM	#1184
holl_ands Veteran Join Date: Nov 2008 Location: San Diego, CA Posts: 1,592	Tollman78: I understand Costa Rica uses SAME 6 MHz wide channels as USA, although it appears that only Ch2-13 are currently used (NO UHF stations): http://en.wikipedia.org/wiki/Template:Costa_Rica_TV I also understand Costa Rica is changing from our ATSC to ISDB, but has probably not completed the change over: http://www.tvtechnology.com/news/011...tandard/205979 ATSC (and probably all new high speed digital systems) are degraded when SWR is not minimized (preferably below 2.7, iffy if above 3.0). The many reflections bouncing up and down a long coax appear as short delay type multipath...which Generation1-3 ATSC Demodulator chips have been found to have a difficult time decoding when tested. I have yet to see any data newer than about 2006 for current Gen5+6 chips. More info can be found here: http://www.digitalhome.ca/forum/show....php?p=1303957 http://www.digitalhome.ca/forum/show....php?p=1343247 I'll have to look at the skimpy ISDB test summaries to see if they have any information on this vulnerability..... I've been cranking out Ch2-13 response curves for numerous candidate DIY antennas and will be posting them as I finish analyzing and uploading them. I'll start with what are POOR choices (Folded Dipole Twinlead & Rabbit Ears) and will progress to some SO-SO choices and eventually will present some alternatives providing minimally acceptable SWR and Gain across ENTIRE Band, however, it's going to take more than this weekend to run nikiml's scipts to find the Optimized element sizes and locations. VHF Folded Dipole: http://imageevent.com/holl_ands/loops/vhffoldeddipole Twinlead is cheap, although no longer readily found in USA stores anymore. It is frequently used for the FM Band, where SWR is relatively unimportant. However, acceptable SWR can't be maintained for more than one channel, shown here for Ch6 (Twinlead is 1/2-in wide, AWG24): http://imageevent.com/holl_ands/loops/vhffoldeddipole And lower channels will be even narrower bandwidth.... Below the results for various element diameter sizes optimized for Ch6 are larger lengths for Elements using 1/2-in Copper Tubing that will provide minimally acceptable performance across Ch3-6 and barely acceptable performance across Ch2-6. Hence these would be need to be combined with a Hi-VHF Antenna using a HLSJ Hi-VHF/Lo-VHF Band Combiner. VHF Rabbit Ears: Rabbit Ears also suffer from being too thin to provide good SWR across either the Ch2-6 and certainly not the entire Ch2-13 Band....unless you get up and readjust the lengths for "best" reception: http://imageevent.com/holl_ands/circ...zed/rabbitears More to come.....