Laryn Lohman wrote: > The landlord is installing a new tower about 150ft away from the > existing tower at one of our sites. We have a remote receiver and > backup 2M repeater located there. We're thinking it is wise to > replace the 16 year old Diamond F23 with this move to the new tower. > Our timeframe is 2-4 weeks max to acquire a new quality antenna. > > I know that this topic comes up often, but times and antennas change. > I'm comparing a Telewave 150D3 and Sinclair SD212. If possible I > want recent experience and opinions about these two models and brands. > The antenna needs to be suitable for duplex work. > > Thanks all. > > Laryn K8TVZ
http://www.sinctech.com/catalog/resources/pdf/SD212-DI.pdf http://www.telewave.com/pdf/TWDS-7045.pdf You can compare the data sheets side by side for your preferences. We have a Sinclair SD212 at a 8000' MSL/roughly 2000' AGL site that just rocks the boat, seriously. I have no idea what kind of a bounce we're taking, but that site is down in a valley, and the signal from that machine climbs right out of the valley (Boulder, CO) and into Denver since we switched from Sinclair 4-bay to the 2-bay. (Site owner needed us to move tower spots, and the new spot needed a shorter antenna.) The current theory is that the "backdrop" of the Front Range mountains are reflecting the signal with the wider vertical beamwidth of the 2-bay... similar to using a 1/4 wave on mobiles in mountainous terrain with the repeaters up above them, instead of 5/8 wave antennas. But no matter how it works, it does! It really booms out of "Boulder Hole" as we call it, since the antenna switch. I would happily recommend any Sinclair antenna product. The Sinclair is also made in a "low-PIM" (PIM = Passive Intermod) model that's better joined at seams and things like that, which can be both a benefit to you and your neighbors if the tower has a lot of high RF transmitters on it. They also make an "HD" model that's heavy-duty if you expect insane wind speeds/loads. I like the HDs and we've never ordered a low-PIM that I know of, but that's a nice option. Looking at the photo, I see something I don't like about the Telewave... but I've never used one. The external harnesses and black coating. UV from the Sun up here at 6000' MSL (and much higher) eats things alive. The internal harnesses of the Sinclairs are out of the direct sunlight. That black coating maybe makes sense for the cold winter months of the year to keep ice/snow off of it, but I can't imagine it'll be too fun to grab a black antenna on a hot day in the remaining 6-9 months out of the year when it's just gathering heat -- if you have to work on it for any reason. Nate WY0X
