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On Thu, 19 Feb 2004 13:01:33 GMT, Ken wrote:
Actually, I have some discontinued big megawatt (!!) "truck mirror mount" CB whips Ooops. Before I get inundated with derisive emails, that should have been "kilowatt." I just added half a gig of memory to my PC to handle Bill's bloatware and must have lost perspective of prefixes. The fact that I have received no comments shows that no one is surprised that some CB'ers are operating at the megawatt level! Ken KC2JDY Ken (to reply via email remove "zz" from address) |
Ken wrote:
The fact that I have received no comments shows that no one is surprised that some CB'ers are operating at the megawatt level! Some of them think all that forward power is being accepted by the antenna. :-) -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
"Cecil Moore" wrote in message ... Ken wrote: The fact that I have received no comments shows that no one is surprised that some CB'ers are operating at the megawatt level! Some of them think all that forward power is being accepted by the antenna. :-) I sometimes stop into CB shops, just for the comic relief. 500W amplifiers, with big heavy cables, and 10A fuses... 5000W antennas, with RG-58 coax in the package.. "ground plane" extenders, consisting of three 3" stubs that screw in to the antenna near the base.. Just the antenna names are worth a laugh, "Penetrator", "Intruder", "Dominator".. Still, I run a CB on long trips, because I've never had any luck getting road info on the ham bands. Lately, there's a big trend to tilt the antennas on trucks forward by 20-45 degrees. Not sure what that's about. |
"Dave VanHorn" wrote in message ... .... Lately, there's a big trend to tilt the antennas on trucks forward by 20-45 degrees. Not sure what that's about. They're going for vertical at highway speeds... s'what I've been told, anyway... __ Steve KI5YG .. |
" Stephen Cowell" wrote in message om... "Dave VanHorn" wrote in message ... ... Lately, there's a big trend to tilt the antennas on trucks forward by 20-45 degrees. Not sure what that's about. They're going for vertical at highway speeds... s'what I've been told, anyway... Then they've overshot it by about 40 degrees. |
The only real way is to try it and see what happens. But it isn't guaranteed.
While adjusting the length of the whip alters the resonence, the base loading coil has two parts, or is a tapped inductor (although some use a capacitor instead). The "matching" part of the inductor, between the coax and ground, may or may not be correct for large excursions in frequency so altering the length of the whip may or may not work. Nothing to lose by trying, it's fun to learn! |
Steve Silverwood wrote in message et...
[This followup was posted to rec.radio.amateur.antenna and a copy was sent to the cited author.] In article , says... I have an old mag mount RS CB antenna with a 24" (approx.) telescopic whip. It is fitted with an integral audio cable (as the feedline) terminating in (what else?) a male RCA jack that plugs into the CB's antenna jack. The CB is rated at 5 watts FM. The whip can be shortened quite a bit. Is there any reason it wouldn't resonate on 10M? Audio cable ain't RG-8/U, but is it enough to handle 30 watts FM on 10M? No reason why it shouldn't. I used a RS mag-mount antenna for several years with a couple of different 10m radios (HR-2600 from Uniden, and HTX-100 from RS). As noted elsewhere in the discussion, I'd be careful putting a lot of power into it, but certainly there should be no trouble running up to 25 watts into it. I'd look into replacing the feed line with coax, though, if possible. Once you're ready, set your rig on VERY low power (under a watt). Select a frequency in the middle of the range where you plan to operate. Tune the antenna for minimum SWR for that frequency and you should be good to go. Don't expect it to perform spectacularly, though -- remember, you're dealing with a vertical antenna with a loading coil, so it's not going to be the best thing in the world. But with a similar setup as described above, I was able to make some decent contacts during my morning and afternoon commute in Los Angeles back in the late 80s. (In fact, a buddy of mine and I used to chat with one another on the morning drive, and were joined by a Russian station for a few minutes!) My experience has been very similar to Steve's. I have several from Radio Shack and they work just fine on 10 Meters, after a little adjustment. I used one of their little 3 Ft mag-mounts with a HTX-100 on my vehicle for years and never had any trouble talking to anyone I could hear. I regularly talked from Phoenix to the mid-west and east coast. And, if I remember correctly, there were instructions with the antenna for CB and Amateur use. I also have one of their full size verticals. Coax is fed up the center of the bottom element to the center. Effectively it's a vertical dipole. The antenna works great. There were no real adjustments for 10 Meters but it was wide banded enough to use on the low end of 10 Meters. I also agree that you should change the cable. It may just be some type of cheap unmarked coax and would be better off replaced. Martin |
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