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Discussion Starter · #1 ·
OK, I'm about 40 miles from the tower and most HD stations use UHF here in the Dallas area (but one does not).


I plan to get a RS double bowtie, and apply the 300 ohm to 75 ohm fix (remove the 300 ohm wire and replace it with a coax and twin lead connector). It HAS to sit in my attic (by order of my wife!).


But what about the one station that transmits HD over VHF? I still need my BIG (10 feet long..about as wide) RS antenna for that, but this guy is also UHF (just not as good at it as the double bow tie).


How do I connect these two together (exactly how....I'm no antenna guru for sure!)?


Can I even get these two to work with each other since the VHF antenna is also UHF?


:(
 

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If your big old antenna does UHF as well, why bother with the RS Double Bowtie, then? You may as well just use the big one---I'm sure it'll do a better job than the little old RS DBT.
 

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Discussion Starter · #4 ·
Well I was assuming that the double bow tie might do a better job.


Last evening I bought one of the little RS DBTs and tried it. Down starirs by the TV with the 300 Ohm wire leads, it was about as good as my attic mounted RS antenna for UHF stations (not too good on VHS obviously).


I figure amplified and with the 300 Ohm wire removed (did that last night after I tested) this thing will do just fine.


Maybe I'll couple it with a dedicated VHF antenna unless someone can tell me how to reuse my big RS VHF/UHF antenna along with it!


BTW, can annyone suggest a good amp to go with this that is fairly inexpensive?


Thanks!
 

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Quote:
Originally posted by darrinps
Well I was assuming that the double bow tie might do a better job.


Last evening I bought one of the little RS DBTs and tried it. Down starirs by the TV with the 300 Ohm wire leads, it was about as good as my attic mounted RS antenna for UHF stations (not too good on VHS obviously).


I figure amplified and with the 300 Ohm wire removed (did that last night after I tested) this thing will do just fine.


Maybe I'll couple it with a dedicated VHF antenna unless someone can tell me how to reuse my big RS VHF/UHF antenna along with it!


BTW, can annyone suggest a good amp to go with this that is fairly inexpensive?


Thanks!
For an inexpensive amp, try the 10db cylindrical (cigar tube) inline amplifiers that they have at RatShack. They seem to work fairly well for me as line extenders, after splitters, etc. Looks pretty clean on a spectrum analyzer also (I have one). Otherwise avoid their 20db amplifier of the same variety - very tempermental and prone to spurious oscillations/intermod artifacts etc, especially depending on the input termination Z. I dont know off hand what the noise figure is on these, but it isnt terrible, and if what you have right now sort of works, then I dont see this as being an issue.


Otherwise if you know for certain that you need a really low noise amplifier, the Channel Masters and Winegards do publish believable specs - but at a higher $$$.


Nice thing about the RatShack 10db amps is that they can be cascaded in series for more gain if needed, like putting one at the antenna, and then another at the TV right where you might then split things off to multiple recievers, etc. The gain on the ones I have actually seems to be closer to 16 db in the UHF band, at least according to my spectrum analyzer. Its probably 10 db up around 2 gigahertz, which is what these things top out at.
 

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I seem to remember in one of your older posts you had a problem with antenna size. The problem with VHF antennas is they are BIG. You will have a boom length of 9 feet or more.
 

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Discussion Starter · #7 ·
Yes, I know. I measured the antenna and it is over 10 feet long but I think I might just have enough room for it over the garage.


I'd like to be able to reuse it for VHF, but I don't know if it is possible since both it also sends out UHF.


Does anyone know if these two antennas can be combined?
 

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If you use your big RS antenna do you think you will need the double bow tie? I would suggest you try it first over the garage and see what sort of signal you get - you may be able to return the DBT.
 

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Discussion Starter · #9 ·
Too late to return it as I have applied the "fix" to it, but at $17.99, I don;t care too much.


Still, it seems to have a lot more potential than did the big antenna for UHF. I guess I'll try what you suggest and see what the big guy does. If I have problems with its size or ability, then I'll put up the bow tie and buy a dedicated VHF antenna.


Still, I would have thought there would be a way to combine a UHF to a VHF-UHF antenna.
 

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Quote:
Originally posted by darrinps
Does anyone know if these two antennas can be combined?
I hate to say it, but "it depends"...


I currently have 2 of Radio Shack's big UHF-only antennas (can't recall the model off hand) combined and it works great. One is in my attic, the other on the roof. In my case I needed to point one south and the other north. I have amplifiers at each antenna, and combine the signals just before they go into my tuner. I bought spliter/combiners from parts express. I'm not sure if they are any better/worse than the ones at Radio Shack...


Combining the antennas is going to cause signal loss. But if you can use amplifiers at the antennas, before any long cable runs, and before they get combined, then you should have enough signal strength to survive the loss from combining.


The biggest problem you risk is that both antennas pick up the same UHF stations. In my case because the antennas are pointed in different directions this isn't an issue at all. Without actually trying the antennas, I don't think you can really predict the outcome with any accuracy (unless perhaps you are like me and need to point them in completely opposite directions and are a long way from both sets of stations).


One point you should probably keep in mind about that old VHF antenna is that using a large antenna pointed the wrong way will likely be worse than a smaller antenna correctly aimed. So if your space is too small to be able to fully rotate the antenna it may not be a good choice. People don't talk about them much anymore, but rotors used to be really popular for off-the-air reception. Now with cable and DBS, antenna installation seems to be a bit of a lost art.


Good luck,


-- Doug
 
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