Advice on channel cut yagi

[mc510]

Hi everyone, just moved to a new house (zip 94530), put my Eagle Aspen DB2 knockoff on the roof and pointed at Sutro tower. So far so good. But there's also 2 distant stations in different directions that I'm interested in, and I'm having idle thoughts about adding a yagi to get one or the other. I have no idea if this is really feasible and hope the experts here can advise.

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d9fbe50e97590e9 is my tvfool plot. The stations that I'm interested in are KRCB (with NM 22.1) and KTEH (with NM 13.6). I've got about 75 feet of RG59 running from the DB2 to one TV (Samsung LNT3242). With this setup, the weakest station that I get from the Sutro direction is KTSF (NM 32.3). The next (weaker) station down the list in this direction (which I don't receive) is quite a bit weaker, so I don't really know where my bottom limit is.

Stuff that I'm wondering about: is it likely that I could pull in either KRCB or KTEH with a frequency-appropriate yagi of a reasonable size (say, no longer than 1.5 meters)? Could I combine the feed from the DB2 and the yagi with a simple combiner (rather than a join-tenna filter)? If I put them both on the same mast, how much vertical separation is needed? And, perhaps most importantly, is there a better way than what I'm thinking about? Thanks!

[tigerbangs]

Your problem will not be in finding an appropriate antenna, but rather in how it integrate the signal from that antenna into the signals from a broadband antenna. Using a simple joiner can and will lead to issues with multipath, co-channel interference and channel suck-out. In analog, these issues were easy to to identify: in digital, they manifest as a no-reception condition.

It is fairly easy to add one channel from a different direction by using an antenna aimed in that direction, and using a join-tenna device that filters out all but the one channel that you are looking for. Channel Master used to make these devices, but no longer does, however, there are other, smaller companies that still make them on special order. receiving multiple signals from different directions is another matter, and requires a join-tenna device for each channel desired.

[mc510]

Well, shoot. From what I can tell, a custom join-tenna type device is a bit more spendy than what I had in mind. If anyone has a used Ch 23 or Ch 50 jointenna for sale, I'm your buyer.

Is there a better way to approach this reception challenge? I suppose I could just use one big antenna with a rotator. Any other way to slice this beastie?