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wideband antenna construction question

Posted: Mon Mar 12, 2007 11:27 pm
by LarryB
This is probably way off topic, but would it be possible to buy a wideband rf amp off of ebay and connect it to an antenna that resembles a stove pipe except smaller so that it would have a broader bandwidth than a whip? if so what diameter and length of pipe? Would this just cause severe overload? thanks, Larry.

Posted: Tue Mar 13, 2007 7:54 pm
by Jim1348
Is this for a transceiver or just a scanner radio receivers? What frequencies ranges are you interested in? Is this for use in a mobile environment or at a fixed station?

Posted: Tue Mar 13, 2007 9:30 pm
by LarryB
Thanks for the reply Jim, would like to have a wideband receive only VHF/UHF antenna with considerable gain. would like to have one for vhf air band, one for vhf public safety, and one for military uhf air band. fixed station use. thanks. Larry B.

Posted: Tue Mar 13, 2007 10:22 pm
by Jim1348
My experience has been that you really can't have both wide band performance AND gain at the same time. Since you want wide band performance, concentrate on a good wideband antenna AND very good feedline. I happen to think most scanner owners ought to at least give some consideration to a good quality discone, but they are not the only wide band antenna out there. I have a Nil-Jon also, but kind of had mixed results. At the very least consider 9913 feedline or better. As far as wideband RF amplifiers go, my personal recommendation is don't waste your money on one. Again, at the risk of sounding like a broken record:

-get a good discone

-get good feedline

-forget the amplifier

You may want to consider a directional antenna like a log-periodic dipole array, but they are more money and effort than many people want to spend on the hobby.

Posted: Wed Mar 14, 2007 12:37 am
by LarryB
Thanks again for reminding me what actually works. As long as I have been playing with scanners, radios and antennas, you would think that I would quit searching for a "magical" antenna that could not possibly exist, the coaxial cable is one thing which can actually make or break an antenna or radio. I do have a wide band discone I just have not gotten around to re-installing it yet. It worked very well with my Icom R7000 about ten years ago. this antenna just overloaded a normal scanner with pager signals when connected to it. That proves an amplifier definitely would not work in this high rf area. Larry B.