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Gizmotchy Antenna Review
- Thread starter Happy_Hamer
- Start date
i plan on finishing the review,
times are tough so i am working as many hours as i can to stay off the layoff boat. Im in Milwaukee this week and kansas city all next week then st louis then back to kansas, so i MUST survive my job however i can
sorry folks,
times are tough so i am working as many hours as i can to stay off the layoff boat. Im in Milwaukee this week and kansas city all next week then st louis then back to kansas, so i MUST survive my job however i can
sorry folks,
Keep toughing it out there Hammer! 
A friend of mine had an old Gizmotchy and it was in use for years, must have cheapened it up on the newer ones... :headbang
73 mechanic
A friend of mine had an old Gizmotchy and it was in use for years, must have cheapened it up on the newer ones... :headbang
73 mechanic
Any up dates on this beam ?....
Ive been doing some research on the Giz beam, but I may just have to look at another type of small beam.....Ive been looking at the G31 due to it having a small boom length, since I dont have the room for a bigger beam...
Ive been doing some research on the Giz beam, but I may just have to look at another type of small beam.....Ive been looking at the G31 due to it having a small boom length, since I dont have the room for a bigger beam...
I used one some 30 years ago during a high sunspot cycle.
Here is what I saw using it.
This antenna design has a very high side null/rejection but poor front to back ratio.
On local area topo contacts at distance with the other stations using PDLs, neither Giz polarization would show any signal advantage.
If the PDL was switched it to showed no difference in signal strength at either end.
The reason is the GIZ pattern is at an angle to the PDL normal horiz or vertical patterns so neither polarity selection would provide any advantage.
However on DX where the signal polarization from the upper layer can be anything at anytime the GIZ will respond very often better than a PDL.
BTW, the antenna should be at a height of 50 + feet to be proper.
Reason is the height above ground affects any 11m beam type antenna's angle of radiation pattern both for tx and rx.
A vertical has it's own radials to work against and has a natural low angle of radiation 'somewhat' independent of height above ground but still needs height for local tropo distance use to get above obstruction.
Hams have all the same things to deal with.
A good study of antenna theroy will point this out.
Good luck.
Here is what I saw using it.
This antenna design has a very high side null/rejection but poor front to back ratio.
On local area topo contacts at distance with the other stations using PDLs, neither Giz polarization would show any signal advantage.
If the PDL was switched it to showed no difference in signal strength at either end.
The reason is the GIZ pattern is at an angle to the PDL normal horiz or vertical patterns so neither polarity selection would provide any advantage.
However on DX where the signal polarization from the upper layer can be anything at anytime the GIZ will respond very often better than a PDL.
BTW, the antenna should be at a height of 50 + feet to be proper.
Reason is the height above ground affects any 11m beam type antenna's angle of radiation pattern both for tx and rx.
A vertical has it's own radials to work against and has a natural low angle of radiation 'somewhat' independent of height above ground but still needs height for local tropo distance use to get above obstruction.
Hams have all the same things to deal with.
A good study of antenna theroy will point this out.
Good luck.
I know this is an old thread and apparently the review was never finished. I am currently building one of these and was a little concerned about some of the comments on the 2nd director length and spacing. The directions that came with the booster kit does clearly state that the element length is to be 100" and spacing the same 3'8" as between the driven and 1st director. One thing that confused me even more is that Kens website (a distributor) states the the 2nd director in the 4 element configuration should be 97" ?? wish I knew which to use, may have to call Tom Charles this week and see if he can clear that up for me.
Now I am looking at the picture in this post #11 and something does not look right to me at all... then looking at the measurements from the quote above it appears to me that this beam was assembled improperly if it was assembled for 11 meter. (I almost did the same thing)...
"SPACING FROM REFLECTOR TO DRIVEN = 3 FOOT 8 INCHES"
"SPACING FROM DRIVER TO FIRST DIRECTOR = 5 FOOT 2 INCHES"
I have read my instructions over and over thinking I misread something but it seems that Hamer got these backwards as the instructions that came with mine are clear for 10/11 meters that from reflector to driven is 5'2" and driven to director is 3'8" perhaps this is the cause for some of the issues?
FYI: My boom length is 12'9"
The saga continues...
Response from Tom Charles of Gizmotchy antenna's as follows
Reflector element 109
Driven element 105
1st director 100
2nd director 99
The rule of thumb for Gizmotchy antennas is after the first director shorten each on 1" So if you had a 2nd director you should make it 99"
Element spacing
Reflector to driven 62"
Driven to 1st director 44
1st director to 2nd director 45
So now we see he is giving me different measurements for the "booster" than is written in their instruction sheet, 1 in wider spacing and 1 in shorter elements.
Response from Tom Charles of Gizmotchy antenna's as follows
Reflector element 109
Driven element 105
1st director 100
2nd director 99
The rule of thumb for Gizmotchy antennas is after the first director shorten each on 1" So if you had a 2nd director you should make it 99"
Element spacing
Reflector to driven 62"
Driven to 1st director 44
1st director to 2nd director 45
So now we see he is giving me different measurements for the "booster" than is written in their instruction sheet, 1 in wider spacing and 1 in shorter elements.
they are a fantastic antenna,the head of midwest control in Time Beach Missouri had a 8 el at 100 ft...worked the world
Maybe if you spent some money with him he may have given you different numbers. Just Sayin
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Just an update... Tom Charles sent me an email with a correction to spacing between the 1st and 2nd directors, it is 44" not the 45" he previously stated. Now if I could just find out what the conflicting information is all about on the 2nd director length I would feel better about the assembly process.
Manufacturers written directions say 100", manufacturer tells me via email to make them 99" and I'd like to go with that but he did initially make a mistake on the spacing. A distributor for them says 97" on their website which makes more sense but then again these are not a typical beam.
7 years later...I would like to ask what was his findings....no reviews on the g31....and all these threads are open ended....