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DoctorZ

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  • Website URL
    https://www.youtube.com/user/MisterPersuasion/

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  • Location
    Twin Cities, MN
  • Interests
    Ham Radio, Storm Chasing, Meteorology, Cars/Trucks, Genealogy, Star Trek, Astronomy, Creation-Science, and Garden Railroading.

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  1. You guys and your Larsen antennas......I guess whatever other type of antenna I buy, it wouldn't be a Larsen. Speaking of antennas, my new GMRS Repeater antenna came yesterday! I won't be able to put it into operation until Spring though. Too much snow on the ground right now.
  2. I live in the woods, but trim my trees when the antennas start clipping them. I've also done a fair amount of four-wheeling, but take the antennas off for that. If I'm upside down, I can then put them on the undercarriage and call for help. LOL. I mainly use my radios for Storm Chasing and SkyWarn Spotting, hense I need a little bit of gain. So where do you find a commercial equivlent to the 2x4SR?
  3. Here is a little diagram taken from a very old book I have called, "The Big Dummy's Guide To C.B. Radio." I realize that 11-meters is not the same as UHF 400Mhz, but the same principles still apply:
  4. I guess antenna preference is a matter of personal taste. I have tried Larsen monoband antennas because others swear by them, and they have been the WORST pieces of junk I've ever tried. No matter if you like them, that's great. I'm glad you're happy with them. I do question your testing techniques though, considering after close examination of your pictures, the Comet CA2x4SR seems to be buried down about half way below your roof line, while your precious 1/4 wave is mounted at the prime location top-center of your vehicle. Do you think it's a fair test to compare those two antennas this way? Assuming the SWR is still within acceptable range being the radiating element is so close to all that metal, I'd say about 50% of your signal is getting absorbed by your vehicle's metal roof, not to mention the strange take-off angles your transmissions must make from the Comet.
  5. First off, let me state that no wide banded antenna will perform as well as one cut for a specific frequency range. However, I find the performance of my CA2x4SR to be excellent! It even tunes up great on my favorite VHF band, 220Hhz, and it's not even rated for that band!
  6. Well since we're showing off our antennas of choice, here's mine: http://www.hamradio.com/detail.cfm?pid=H0-001424
  7. From the OP's post I gathered that he/she wanted the maximum gain out of a mobile antenna. No antenna that isn't grounded to the vehicle's metal is going to meet that spec.
  8. A general question deserves a good general answer..... In a nut shell, the antenna is only 1/2 of the system; the other half is the ground plane. In the case of your vehicle, it acts as the ground plane. Placement of your antenna on your vehicle will also affect your transmit and receive. If you mount the antenna on the rear of the vehicle, you will have a directional (or beam) system. Your transmit and receive will work better in the direction of the most metal, or in your vehicle's case, towards the front if mounted on the rear. For the best all around performance, mount the antenna in the middle of the vehicle and make sure it has a good contact with the metal of your vehicle. Fiberglass bodies, vinyl tops, etc., will greatly reduce your antenna's performance not to mention possibly damage your transmitter. If you have a fiberglass body, you will need to drill through it to the frame or roll cage and attach it to there. As for wavelengths, they say the best is a 5/8 wave, or a .64 wave if you can find or make one. 5/8 = .625. A full wave antenna tends to radiate most of it's signal up in the sky. At 5/8 you have the "flatest" take off angle of your signal, which in theory helps it cover the distance the best. As for power, for every doubling of power you will gain 3dbs. Each number on your radio's S-Meter (if it has one) is 6dbs. So if you are giving someone 3 S-units on his radio's meter at 25W of transmit power, you will need to increase your transmit power to 100W to give him 4 S-units on his meter, given you don't change anything else. With all that said, my best advice is for you to buy an antenna that is designed for the frequency band(s) you wish to talk on (450-470) for GMRS, and mount it as close to the center of your vehicle as you can, making sure it has good contact with the sheet metal of your vehicle's body. A good ground and matched SWR on your antenna system will do more for you than anything else.
  9. It's been a very long time since that tower was put up. The base is composed of a welded steel cage with rebar reinforcements cemented into a 4' x 4' x8' deep hole. The total cost of the tower was around $4,500 in 1992. That's about $40,000 now days!
  10. Here is a video I shot of CP Rail's Christmas Train pulling into the Union Depot in downtown St. Paul, MN, last Friday night: https://www.youtube.com/watch?v=GSBSINSFs14&hd=1 Enjoy!
  11. Well I guess better late than never to reply to a post. What would you like to know? What info can I give you on the tower?
  12. Check out my YouTube video of my custom built 80-foot Tip-Tower: https://www.youtube.com/watch?v=cY-7VgZNypk
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