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Discussion Starter #1
Hi all,

I had a 4' tripod on a flat top roof with a 8' pole & channel master rotor and another pole for the antenna (just a bit longer than the 4228). Along with a 7777 pre-amp. Total height around 15' off the roof.

Channel 14 was always dropping out along with 33, 32, 39

I ventured to build a DBGH with a mesh reflector (1/2" grid spacing hardware cloth). I followed the measurements to a tee on the main website:
http://www.digitalhome.ca/ota/superantenna/design.htm

The DBGH is now mounted on the same tripod (shorter bottom pole - 4' + 7' pole out of the rotor and the 7777 pre-amp. I'm not worried about wind as from the north & west I have huge houses blocking pretty much all the wind. I'm pointing towards grand island, through some old maple trees (they are about 300' south). I estimate the antenna height to be around 30' off the ground.

All these readings are at night between 7pm and 11pm. During the day weird stuff happens (signal loss on almost all channels except locals from CN Tower and such).
- 14 is amazing now 82%+ signal.
- 32 is pretty good at 75%
- 33 is weak... between 55% and 75% at nights
- 38 is very good actually - +75%
- 39 is hit or miss between 51% and 70% or so

- ALL local channels are 95%-100%.

33 & 39 are hit or miss, they drop out on a regular bases at night time - weather conditions I guess. During the day I'm not concerned about as I do not really watch tv. Channel 43 PBS I have never been able to get, I do not know why.

I figure my entire issue is related to the trees and there's probably nothing that can be done. But I'm hoping for some ideas.

I'm using an HD Homerun - I do not have a TV with a built in tuner only a Benq w5000 projector - so everything is running from my PVR using the HDHR.

Here's a link to TV Fool:
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id=9fbe615233814a

Any ideas how to improve 33 & 39? Besides cutting down my neighbours trees - as I do not think they would approve of that :)

Thanks in advance,

Ben
 

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33 I can understand you having issues with - you're starting from a -12 NM via a 2-edge path. You don't have quite enough antenna gain to protect fully from the extra randomness of WGRZ's signal having to scatter twice before it reaches you. How is reception of WPXJ (RF 23)? I don't know what to say about WIVB.

You might be overloading the 7777. CBLT 5 and CFTO 9 are monster hot!
 

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What is your nearest major street corner in Toronto? Others need to know about these issues with such a powerful antenna.
 

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33 I can understand you having issues with - you're starting from a -12 NM via a 2-edge path.
Yeah, RF 33 is pretty much a lost cause except for tropo days, no matter what the antenna.

RF 39 is strong, so you should be able to get that with a slight amount of maple trees in the way on a dry night. If too thick a grove, then maybe not.
You may want to try adusting the antenna height. A foot higher or lower can make a difference.
 

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If you're in the horseshoe than WGRZ shouldn't be a problem (for most people). Remember TVFool is not always right.



Looking at the above map, most parts of Toronto/GTA are in the light-blue and WGRZ should be in the yellow-orange zone for most parts and quite recievable. You might have gotten an abnormally low NM for WGRZ if your location happens to be in the very isolated, scattered spots with no colour around the Don and Humber River valleys. Moving the marker even slightly saw WGRZ's NM shoot back up into around +15 to +20 dB NM.

That said I would take such instances with a grain of salt. If you're getting some signal, you should be okay.

I have the opposite situation for WGRZ. TVFool gives it a reading of +13.6 dB, I am in a darker-blue area to the southwest of you (Clarkson). It continues to be my most troublesome station.

You can also adjust the height of the antenna like 300ohm suggested. That said I would try avoiding using a preamp as you will ineviatbly overload the blowtorch that is the CN Tower. It doesn't help that Toronto and Buffalo are in the same compass direction. WNLO on 32 is also a blowtorch and could be causing issues with 33.

If however by chance TVFool is right, and you in fact do live in a hole, then your best bet would be John's extended Hovermans (click here). They peak at around 18+ dB around RF35, but you can try scaling them back for 33.
 

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Discussion Starter #6
Wow thanks for all the replies.

The locals at 100% seem to be fine, I don't know what an overloaded station looks like. But they all appear to be great!

I originally got the 7777 pre-amp when 14 kept dropping out. So I wonder if it's causing issues with 32 being so close. The amp seemed to help a bit but I really don't know.

The nearest intersection is 401 & Avenue Rd... I'm right in the top left of the 2nd bubble little-infinity posted above.

According to TVfool increasing the pole height from 35-45' would greatly increase the chances but there's no way I can do that as I do not have a mast. So I guess I'll try moving it up and down in small amounts. I'll check out the extended hoverman.

There is a tree right above the antenna, but clear sight to the southern direction (except for the neighbours tree(s) down the block)

Here's some pictures of the antenna:




 

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I wouldn't put too much faith on the TVFool data then. I pegged your location (Avewnue/401 area). It does seem to be in an area devoid of colour, but moving it so slightly WGRZ showed 18.4 NM. Moving it slightly made it go down again to around -12. Play around. The fact that signal is there is a very good sign for you :) It could be as simple as tilting your antenna or doing a stack for increased reliability.

I think your 7777 is just way too much amplification though. Even in Mississauga I tried that and CBLT analog overloaded. Perhaps you can try switching the 7777 to be separate to filter out the strong analog VHF. You might have a better chance.

I wouldn't rule it out to be honest. I'm going a bit offtopic though. I feel your pain, WGRZ is a PITA. Even my stacked 4221HDs + 7778 mast mounted will not pull it in proper, and I'm in the blue areas where (theoretically) it should be stronger.
 

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Overall, your build looks nice. :)

But one thing I noticed from the pictures above is that you have the balun connection screws on the inside of the phasing lines. Try moving them to the outside of the phasing lines, that may help matters a bit. Or try spreading the phasing line out to 2 inches in the middle where the balun connection is.
 

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Discussion Starter #10
300ohm - So 2" (50mm) just in the centre ? So the wires would bow out from 20mm top and bottom to 2" (50mm) in the middle balun connection point with the screws on the outside? I guess with the screws on the inside it is in effect bringing the phasing lines together at that point... Kinda like when I bent one by mistake when I put it up. Reception was very poor with only 10mm gap between them. I had to take the antenna down to correct that!

I forgot to mention the entire antenna is made from PVC sch40 fittings and sch40 electrical conduit. It's also hard to tell from the pictures but the balun exits behind the mesh with the RG6 cable behind the mesh not in front. Not sure if that matters or not. The antenna is attached to a 1.25" fence top rail - with 3 .. 2" stainless pipe clamps. It's actually much more solid than I thought it would be.

ota_canuck. Distance from the elements to the mesh is exactly 100mm. I spent a ton of time making the antenna to spec. I do agree from the pictures it looks like they are very close :eek:
 

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300ohm - So 2" (50mm) just in the centre ? So the wires would bow out from 20mm top and bottom to 2" (50mm) in the middle balun connection point with the screws on the outside?
Yep, try that and see if it helps.
Kinda like when I bent one by mistake when I put it up. Reception was very poor with only 10mm gap between them. I had to take the antenna down to correct that!
With the connection bolts on the inside, it still looks like a 10mm gap between the phasing lines, heh. Its much better if wider in the middle than at the top/bottom, instead of vice-versa.

The best way to tweak phasing lines IMO would be in real time. That way, the balun and the coax would be included in the tweak process.
 
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