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Old 5-May-2021, 3:12 AM   #1
bobsgarage
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Digitek SX91 X Element Antenna

I've been playing around with the AD 91XG and the Extreme Signal HDB91X. Something about those antennas I think just a great design. A lot of questions have come up about durability in the past guys finding X elements and their yard after a windstorm etc etc....

I discovered this antenna. It's made in China but sold by an Australian company DigiTek.

SX91(D-1648-HA)



The interesting thing about that antenna is,
it looks like the active element is actually an X element too



Ness Electronics out of Minnesota was selling these for a very, very reasonable price plus shipping. So I bought six of them. I just want to experiment. I'm probably going to make an extra long version and then try ganging four of them.







I put one completely together and I am documenting with pictures how this antenna is constructed.. it appears to be a 91XG clone but only in appearance. First of all the Boom is only two sections not including the mounting brace. The Boom is also constructed from Steel and is powder-coated. It almost looks like the old finish they put on typewriters "back in the day"..Note the finish. I believe it's powder coating but it's textured also:



Cross section. I believe there's a little bit of powder coating hanging over the edge but it does look a bit wavy:



Here's the kit. Four bags of 5 X elements + one bag of two elements. 2 booms plus the mounting support. Also some screws were loose in the bag. Did I mention that this doesn't come in a box?




This is how they come. I'm not so sure I agree with the packaging. Obviously this is a package for mass shipment. Maybe when they're sold individually in Australia they come in a box?




Another unique thing about this antenna where the X elements mount, there is a plastic mount riveted to the steel boom. For the life of me I can't figure out why they just don't clamp them to the Boom unless it's some sort of patent infringement? :



In the next couple of posts, I'll post some close up pictures of the X elements and the driven element and later I'll assemble one.
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Last edited by bobsgarage; 5-May-2021 at 3:33 AM.
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Old 5-May-2021, 8:55 AM   #2
bobsgarage
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SX 91 More Pics















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Last edited by bobsgarage; 5-May-2021 at 12:06 PM.
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Old 5-May-2021, 12:39 PM   #3
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SX 91 Driven Element

So, what about the driven element? This is a departure from the typical 91XG clones. It just appears to be a larger X element. Food for thought. It'd be nice to get a bunch of these to experiment with to see if a larger element would pick up the lower channels better!


















Attached Images
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Old 5-May-2021, 1:08 PM   #4
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SX 91 Boom and Reflector Detail

Here's where things really get different with the 91 XG and the SX 91. The DigiTek version has steel booms. It also has mounting lugs for the X element directors. Not sure why that is. Seems like it cost a lot more to do it that way so it must have been either an afterthought some sort of correction factor. Each plastic mount is installed with a heavy duty pop rivet.



Side by side comparison of the rear most part of the boom sections for both antennas. The aluminum boom is the antennas direct design, note that the spacing is different between the two so it's not a direct copy:










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Last edited by bobsgarage; 8-May-2021 at 11:10 PM.
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Old 7-May-2021, 12:23 PM   #5
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DigiTek Antenna clamp

Here's some close-ups of the antenna clamp. There are a couple possible ways of mounting it.







Here is the Stellar labs HDB91X (which is the same antenna as the Stellar Labs 30 - 2370) Mast clamp:





I'll post a 91xg cramps when I get a chance
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Last edited by bobsgarage; 7-May-2021 at 12:26 PM.
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