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Discussion Starter #1
Howdy,
First, my thanks to all for your work. The information and assistance you are providing here is greatly appreciated.

I am a newbie to this site and have just built my first antenna, SBGH. The plans and instructions found in this forum made it easy. I built off of the plan posted by "300ohm".

I have questions about optimizing this antenna for my area; element dimensions, element separation, separation from reflector, etc...

I am posting a pic of my build and a link to my tvfool data.

Any help and/or suggestions would be apprecieted.

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id=da32123aa090bc

;
 

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The plans and instructions found in this forum made it easy. I built off of the plan posted by "300ohm".
The mesh model ?

If so, you should have posted here first before building, as we would have told you to build a rod reflector with NARODs model. You have some vhf-hi channels as well as uhf. Unfortunately for obvious reasons, NARODs dont work with the mesh reflector models.
 

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Discussion Starter #4
Yes, i built the mesh model. Thought my pic would post...evidently I failed.
I had looked at the rev1 & rev 2 models as well. I just picked the mesh model because I had materials for it. The frame is 1/2" sched40 and just pressed fit. The mesh is zip tied on. Any modifications will be quick.

Correct, I should have posted first. However I like to jump in, do it all wrong and generally make a mess of things.....Then ask, figure out a fix and make it happen. Thats how I do it. I learn that way. Much to my better halfs' dismay.

I have not had cable or satellite tv for over ten years. I subscribe to netflix and that has been my only source. The area where I reside facilitates very poor reception and store bought antenna have not worked worth a hill a beans.
I have chatted with my neighbors about it for years. They have all given up and subscribed to cable or dish providers. I have done fine without, untill.....
One of my neighbors bought a new flat screen, a nice HD3D model and I installed it for them. The very next day, they decided it wasn't big enough for them(46"). They purchased a 55 and asked if I would be willing to take the 46 off of their hands. I did. It replaced an old 26" inch jvc that weighed a ton.

So... now I have a very nice tv and only use it for netflix, although downloading to the tv is cool, it just ain't right. The tv and I both deserve local programming. Why not get it for free as it was intended to be.

Hence the search for reception.

I could modify the GH or start something new.

If you can point me in the right direction, I'm game.

Thanks
 

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Discussion Starter #6
Much to my surprise I picked up 9 channels. Unfortunately none of them are on my wish list. I'm lookin to get KING, KOMO, KSTW, KCPQ, etc...

I have an over abundance of large tall trees. There are some openings but I think I may need more than one antenna to get all I can.
 

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Discussion Starter #8
No I didn't. Antenna positioned at 90.
I am going to put up a mast that might get me closer to 30' elevation. I will experiment with some tilt.
Before I do, I would like to know that I am putting up an antenna or array, that will do the best job.
I am concerned with the mechanical aspects of my antenna. Do I have the correct element separation, etc.. and what about 300ohms' suggestion of NORADS and ditching the mesh reflector?
 

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and what about 300ohms' suggestion of NORADS and ditching the mesh reflector
Well, for any of KCTS, KSTW, KCPQ and K08OU (all that are listed as VHF-hi in the lower table) you need to.
Your current antenna filters those away.

The array or antenna question is trickier and I would first experiment with a tilt to see if there is any chance of getting those 2 edge channels.

And please post your current results in more detail, what channels are you getting and with what (relative) strength. we need as much detail as possible to make a reasonable conclusions. Otherwise one can only guess...
 

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I'm lookin to get KING, KOMO, KSTW, KCPQ, etc...
The antenna you built has more than enough gain in theory to be able to get KING, KOMO per TVFool, but because of the trees and the iffy 2 edge signal bounce over the mountains, the signal may just not be there. KSTW, KCPQ will require a NAROD GH model, as they are vhf-hi.

So, if you cant get KING or KOMO at least almost locking on, I would say the signal is completely blocked from that direction for you and that no antenna would get those channels. In that case, then youre stuck with the LOS channels, and what you have built already is overkill for them.
 

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Regarding gearhead's location, keep in mind that the SeaTac area has the same geographic issues as we in the Vancouver area face: the presence of so many tree-covered hills in such a wet area can make OTA reception quite counter-intuitive due to all the signal-shadow zones. Unfortunately TVFool is only a general yardstick for us... :)
 

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Discussion Starter #13
I think a couple of the channels I picked up were subs, however I didn't write them down. I haven't permanently installed the coax run yet, and the Mrs. didn't appreciate it running across the floor and out the window. I'll reconnect and post the list of channels I'm receiving, later this evening.

Evidently my tv does not have a signal strength meter. Any suggestions?
samsung 8000 series
 

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Discussion Starter #15
Too cold and icy to go up on the roof tonight. I did hook up and just set the gh out on my back porch (northerly azimuth). I get 33,42,46 and 51(plus several subs) no matter how I turn it. Thats the worst spot on my place (high bank and the most trees and at ground level.

Should warm up tomorrow, so I'll get it back up top and try shooting the seattle station azimuths.

My elevation is around 350'. There's a fella a couple of miles up the road from me who claims he gets KING, KOMO, etc. OTA. He's only about 60' higher than me. He had some professional outfit install an antenna (with a rotater) for him.

Seems like years ago when we tried, we could pick up channel 4 or 5 and a couple other ones, but they were pretty fuzzy. I will remain optimistic .

I would like to verify that I have built my GH to the right specs. What's the trick to posting pics?
 

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The frame is 1/2" sched40 and just pressed fit. The mesh is zip tied on. Any modifications will be quick.
Offhand it looks good. :) But it looks like electrical tape is used instead of black UV resistant wire ties. Electrical tape doesnt last all that many years outside before unraveling.
White pvc should be given a light coat of flat spray paint for use outdoors. Its OK to paint the mesh reflectors, but remove the driven elements before spray painting. A light covering coat will last longer than multiple heavy coats.
On later builds, I used single slanted pieces of pvc pipe for the stub holders. You can save the use of 4 tees and 2 caps that way. (lowers the material cost by $1.50+)
Similar to this :

I cant tell from the picture, but after attaching the mesh, a 1" vertical (up and down) gap is cut in the middle of the mesh reflector. This gives an additional .5+ dbi increase in gain. Although, because of your strong LOS signals, the .5 dbi increase isnt going to do anything, I would in your case leave the mesh intact as is.
It looks like you have the 89mm feed point, and as long as all the legs are 7" and all the stubs are 5.6" and a reflector to driven element distance of from 95mm to 115mm and you have a good balun on it, it should work great for uhf.

Oh yeah, drill some 1/8" - 1/4" weep holes in the bottom rail for water to get out.

and just pressed fit
I used tiny #4 X 1/2" wood screws (after assembling) to hold the joints in place. Much better than gluing, as the fittings can be easily reused.
 

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Discussion Starter #19
300, Thanks for the tips. I had a few zip ties on it but it was rattlin in the wind and I wasn't sure I had all the dimensions right, so the temporary taping. The measurements you posted are what I was looking for to confirm I had it right. From all the different posts, I saw different values for element separation and element to reflector depth.

I stopped at my local electronics supply today and picked up some phenolic lam to fab some element clamps like your pic shows. Also figured up my loss in the coax run from what will be this antennas permanent location. I didn't realize the run would be so long, (25' from ant. to amp and another 75' to the TV). I picked up a good quality adjustable 25 db amp, combiner and enough Quad4 to do the job.
I'm curious as to what kind of gear some of you are using and welcome any suggestions.

If all goes well and I get the Seattle stations I'm after, I think I might try building one of the revised GH models with NORADs. If I'm understanding the info correctly, that should enable me to pick up some of the stations to the North of me as well.

Thanks again
 

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I stopped at my local electronics supply today and picked up some phenolic lam to fab some element clamps like your pic shows.
Free vinyl siding samples or free corian samples from Lowes or Home Depot also work fine.
What I used in that picture was thick 1/8" - 3/16" black plastic from a shipping pickle barrel (it originally contained sweet gerkins). I had that piece of plastic left over when I sliced the side of the pickle barrel open, making a 60 gallon aquarium tank for my goldfish. I silicone sealed the barrel lid on. The barrel cost me $6 and so far has lasted as an aquarium for about 15 years, heh.
Black plastic from the larger size (ie thicker) plant/tree containers also lasts a long time outdoors.

I picked up a good quality adjustable 25 db amp, combiner and enough Quad4 to do the job.
I'm curious as to what kind of gear some of you are using and welcome any suggestions.
Whats the make of the preamp ? Hopefully not Radio Shack. Channel Master and Winegard generally give the best performance and quality for the buck.
Quad shield RG6 isnt necessary unless youre running the coax next to noisy electrical lines. Regular RG6 is fine and is lower loss (but a preamp makes up for coax losses) and is cheaper.

I personally use a CM0264 preamp (as does mclapp) which has a 300 ohm uhf input, a 300 ohm vhf input and one 75 ohm output. That eliminates the use of a balun. Unfortunately the CM0264 is very hard to find any more. And of course the CM0264 isnt good for use with a NAROD model. For the NAROD models, a single combined 300 ohm vhf/uhf input and one 75 ohm output preamp would be the ideal.

And I neglected to ask you the most important question. How does it make you feel to build a high gain antenna on your own ?? Without using MasterCard, I think its priceless, heh.
 
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