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Using a small satellite dish as an 11 meter antenna

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  #17  
Old 04-29-2010, 11:17 AM
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I took the receiver module off of the small satellite dish and mounted a small center loaded mobile antenna on the existing bracket by drilling a 3/8" straight down.

It works so well around Carson City, Nevada that everybody wants me to build them one.

Dick Baublitz KI7YF
blitz@pyramid.net

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Old 04-29-2010, 11:56 AM
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No pictures from King Mudduck or Baublitz (an extra class no less) = more CB bullsh*t.

Last edited by Marconi; 04-29-2010 at 05:37 PM.

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Old 04-29-2010, 02:28 PM
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Quote:
Originally Posted by baublitz View Post
I took the receiver module off of the small satellite dish and mounted a small center loaded mobile antenna on the existing bracket by drilling a 3/8" straight down.

It works so well around Carson City, Nevada that everybody wants me to build them one.

Dick Baublitz KI7YF
blitz@pyramid.net
Only in the bizarro world of CB radio could this happen...very amusing.

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Old 04-29-2010, 04:03 PM
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Just because you see some directional characteristics and a good SWR does not mean the antenna is working well. As has been already said any directional effect is due to shielding from the dish and has nothing to do with the dish acting like a parabolic reflector that would add forward gain. The dish is about 100 times too small. But more important is the orientation of the driven element (4 foot whip) with respect to the dish. First of all for the dish to be able to reflect energy back onto the driven element, the driven element should be parallel to the dish, not perpendicular. Second the driven element must be properly spaced out in front of the dish so that it's placed in the focal point of the dish. Not with it's feedpoint on the dish.

I won't argue that it doesn't work, it just doesn't work well and the dish is doing little more then acting like an insufficient ground plane. The signal would also be horizontally polarized and tend to talk broadside of the driven element. It could have some rejection on the back because it's not a balanced dipole and the ground plane would shield some signal from the back. Whatever signal you could produce with this dish would easily be surpassed by even the cheapest base ground plane. It's a 4 foot loaded 1/4 wave ground plane with a ground plane that's too small. That places it more then 2 db behind a simple half wave. That's not even including the major loss in cross polarization. This could be as much as a 20 db loss!

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Old 04-29-2010, 04:21 PM
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i would not have thought a 2 foot or less diameter ground plane would be capable of tuning to 1.2 vswr on 11 meters with a 1/4 wave verticle radiator .

i also cant understand why the 1/4 wave firestick would have more gain out the top than off to the sides . i can see it on a full wave length verticle since the strongest lobes come out the end of the top of it .

i certanly have a lot left to learn about antennas though .

ill add another request for pics .
KingCobra_CDX882 likes this.

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Old 04-29-2010, 04:46 PM
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Quote:
Originally Posted by BOOTY MONSTER View Post
i would not have thought a 2 foot or less diameter ground plane would be capable of tuning to 1.2 vswr on 11 meters with a 1/4 wave verticle radiator .

i also cant understand why the 1/4 wave firestick would have more gain out the top than off to the sides . i can see it on a full wave length verticle since the strongest lobes come out the end of the top of it .

i certanly have a lot left to learn about antennas though .

ill add another request for pics .
The dish is not big enough to mimic a ground plane and produce the 1.2:1 SWR. You can be sure the coax and or the mast is acting as the counterpoise to reach the match. I would also expect maximum signal to occur off to the sides and not the dead front of this dish. The back may be the weakest signal but the front is not going to be the strongest. Check it again and you'll find there are two spots, one on each side that show the highest signal. Not one high spot right in front.

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Old 04-29-2010, 05:30 PM
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Quote:
Originally Posted by King Mudduck View Post
I have been playing around with this thing to today and i actually got it to work. What i did was drill out the center of a direct TV dish and mounted a 4 foot fire stick antenna there. I have it up about 10 feet right now as i am still working the bugs out but after figureing out the ground for this antenna i have the SWR down to 1.2. It's seems to receive and transmit very well and it is very directional with great rejection which is what i wanted from the start of this little project. The only reason i tried this was out of boredom but i was wondering if any of you have tried something like this.

The reason i posted this here was because most hams like to experiment and i thought that some of you may have tried this in the past.
King Mudduck, based on the experimental aspect of your claim, can you tell us what you figured out regarding the ground, and then how or what did you do to the ground to get the SWR down to 1.2 as noted.

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  #24  
Old 05-01-2010, 04:30 AM
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There aren't any pics cause it probably does not exist except in someones imagination.
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antenna engineering, experimental antenna, home made antenna, loop antenna, magnetic loop antenna
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