I'm interested in trying to get a bit more gain out of a 91XG by adding one or more boom segments cannibalized from a second 91XG. I'm wondering what spacing I should use for the directors?

Motivation is that I want to reduce the occasional dropouts on a distant channel 36 (there are other stations I want to continue to receive on channels in the upper 20s to 50, so I don't want a channel-specific setup for 36). I just spent most of the weekend experimenting with ganging two 91XGs and got consistently worse signal strength with two antennas than I had with one. Tried over/under and then side by side on a fiberglass pole, with about 40" spacing. Lots of work and complexity and I finally got frustrated with that approach.

Thanks in advance for any suggestions.

Andy

I'm interested in trying to get a bit more gain out of a 91XG by adding one or more boom segments cannibalized from a second 91XG. I'm wondering what spacing I should use for the directors?

Motivation is that I want to reduce the occasional dropouts on a distant channel 36 (there are other stations I want to continue to receive on channels in the upper 20s to 50, so I don't want a channel-specific setup for 36). I just spent most of the weekend experimenting with ganging two 91XGs and got consistently worse signal strength with two antennas than I had with one. Tried over/under and then side by side on a fiberglass pole, with about 40" spacing. Lots of work and complexity and I finally got frustrated with that approach.

Thanks in advance for any suggestions.

Andy

Take the center section out of one unit and add it to either side of the current center section.

Relocate the U-support a bit more forward and try to bridge at least one of the forward segment joints to lessen the "Concorde" effect.

My installation showed a tiny increase in the actual signal strength (measure with my Sencore) but several dB improvement in the carrier-to-noise ratio.

Adding the extra section increases the directivity a bit and narrows the beam width a little.

A few of us have been discussing this on the Digital Home Canada board (I haven't had time to do more testing on mine yet). Terrestrial Digital will send you an additional middle boom section if you call them and tell them what you're trying to do (and that you're following the various message boards).

See http://209.29.131.153/forum/showthread.php?t=111116 for previous discussion...

Thanks for the replies, and thanks to whoever relocated this to the right forum. :-)

Adding another middle section is appealing because it would be so easy, but the director spacing within the middle section gets larger as you move away from the driven element, so the two-middles arrangement wouldn't fit the general pattern of increasing spacing between directors moving from back to front. Would that matter? If it does matter, maybe there's an optimal spacing pattern for a lengthened 91XG that could be achieved by drilling new holes in the top of the boom to hold the directors in new positions?