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Discussion Starter · #1 ·
I've had a Radio Shack VU-75 VHF/UHF combo antenna on the room for some time, and have become very annoyed with the poor reception of UHF DTV stations. The prime problem seems to be multipath -- although I've no idea where it's originating (nearby trees, perhaps?).


The general recommendation for an antenna to combat multipath seems to be the ChannelMaster 4248 UHF-only, deep-fringe yagi. Although this antenna might help with the multipath issues, I'm worried that it'd result in overload (too much signal) due to my close proximity -- less than 4 miles -- to the transmitting towers.


I've seen some recommmendations for the ChannelMaster 4221/4228 (4/8-bowtie) models. However I've also found quite a few reports that state that these aren't good choices in high multipath areas.


Are there any similar UHF antennas with less gain than the 4248 but which are still multipath 'friendy'? Anything else I should consider?
 

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The gain of an antenna and its ability to reject off-axis signals (multipath) is the same thing, directionality. You can't have one without the other. The 4228 and 4248 have very similar performance despite what has been posted elsewhere. As long as you don't use a pre-amp I see little probability of overload. An attenuator between the antenna and receiver is a cheap and easy fix though if there is too much signal and it won't compromise the multipath rejection. Remember that the higher the antenna gain the more carefully it needs to be pointed.


The problem with 4 miles is the transmitt antenna pattern might be going right over your head placing you in a shadow zone. You will need to do alot of experimenting with antenna direction to combat that.
 

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Discussion Starter · #4 ·
Thanks for the replies. I think I'll order one of the 8-bay bowties (model 4228) and hopefully that'll help with the multipath problems.


Those tiltable antennas from A-Tech do look interesting, though...
 

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I might suggest the Channel Master 3021. It should solve some of the "overload" issues. However, the Multipath issue may present. Either way I would suggest the Channel Master products. Here is a link to the 3021:
http://www.solidsignal.com/prod_disp...oom=zoom#xview


You might even buy both - the cost of the 3021 is small. Save you time in developing a solution.
 

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Discussion Starter · #7 ·
As indicated in my prior post, I ordered an 8-bay bowtie from Channelmaster (model 4228). I finally installed it today.


I've only had a very short time to check out signal strength and multipath, so it's possible these results will vary on subsequent days. So far, though, both items seem to be improved by a small amount.


The signal strength (reported by my MIT MDP-100 receiver) for most of the local stations is now a steady 70-75%, and dropouts seem less frequent on most channels.


Oddly, there are two stations with much better signal strength than the others -- and they're the two local PBS stations. Channel 16 is the second-lowest power station in the area at 50KW, and it's coming in at 85-90%. The other PBS station, Channel 34, is at a steady 100%. Both stations broadcast from the same tower as most of the other local stations -- so I'm uncertain why the signal strength on these two is so much better than the others. This seems a bit too unusual to be explained away as simple chance. Perhaps the transmission pattern of the other stations is different, creating the 'shadow zone' issue that NightHawk described.


Not all is perfect, though. Channel 44 (KSTC) is still plagued by continuous dropouts (every few seconds) despite a steady 70-75% signal strength. And WB is still non-existant, probably due to the miniscule transmitter power (are they even putting out 100 watts?).


I'm not aware of any way to tilt this antenna. And I have not tried raising the antenna by using a longer pole, although I may eventually try that. I'll probably need to add another metal strap to the chimney mount before I can try a longer pole.
 
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