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Old 20-Jun-2017, 7:06 PM   #50
rabbit73
Retired A/V Tech
 
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,747
Quote:
Originally Posted by jrgagne99 View Post
In my latest experiment, I combined a Stellar Labs 30-2476 VHF yagi with a DB8e 8-bay using a UVSJ combiner (Stellar labs 33-2230 UVSJ). Real channel 25 (WNNE) is strong enough that it is separately received by both antennas, even though I point them 90-degrees off from the Real-25 tower to pick up Burlington stations. I confirmed this by separately removing UHF and VHF feeds to the UVSJ, and I receive Real-25 in both cases. Strangely, when both feeds to the UVSJ are populated, the UVSJ does not allow Real-25 to pass through to the output.
You are expecting too much and not giving even the best UVSJ a chance. When you aim your DB8e at Burlington, you are placing WNNE perfectly in the antenna null, making it much weaker. That is what you would do if you wanted to reject WNNE, not receive it.



As ADTech said, their UVSJ is the only one currently available with known performance.





There are a few Radio Shack 15-2586 UVSJs still left; the last one I measured did well.





I opened up the MCM 33-2230 and wasn't impressed, but haven't measured it yet. They are using an all purpose board modified for use as a UVSJ, with a lot of empty pads for components.





Attached Images
File Type: jpg jrgagne99nullWNNE.jpg (158.5 KB, 1831 views)
File Type: jpg ADEU385CS-1Sfront.jpg (157.8 KB, 1806 views)
File Type: jpg RS 15-2586previous.jpg (144.6 KB, 2366 views)
File Type: jpg RS_15-2586_UVSJinside.jpg (216.2 KB, 2518 views)
File Type: jpg MCM33-2230UVSJ.jpg (145.1 KB, 1824 views)
File Type: jpg MCM33-2230boardtop.jpg (167.3 KB, 4854 views)
File Type: jpg MCM33-2230boardbottom.jpg (174.2 KB, 4935 views)
File Type: jpg ADEU385CF-1Sinside.jpg (172.8 KB, 2333 views)
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Last edited by rabbit73; 20-Jun-2017 at 11:26 PM.
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