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Hands down best 2 meter base vertical antenna

Discussion in 'General Technical Questions and Answers' started by KI4RVY, Jan 10, 2007.

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  1. KI4RVY

    KI4RVY Ham Member

    Im needing a good antenna to mount on top of a 20 foot tower that is should also do 440.

    I was looking at the Diamond X700HNA

    Much feedback welcome because I am new to ham.
    Also I plain on running 150 to 300 watts depending on the antenna and amp.

    Thanks
     
  2. AI4IJ

    AI4IJ Ham Member

    How much are you willing to spend?  For around $100, you can get a Tram 1481 that will give you a claimed 8.3dBi of gain on 2M and 11.7dBi of gain on 70cm.  But, you could spend more, or less, and still get a decent dual band antenna.  So, how much do you want to spend?

    73
    Richard
    AI4IJ
     
  3. WA2ZDY

    WA2ZDY Guest

    Hands down best? Think "more than $100." Think Stationmaster by Celwave.
     
  4. KI4RVY

    KI4RVY Ham Member

    I will spend more than $100 but I dont think that more than $500 wont have any benifits but that is why Im here asking
     
  5. AI4IJ

    AI4IJ Ham Member

    If all you've got to spend on your 2M/70cm vertical base antenna is $100, the Tram 1481 IS the "hands down best."   [​IMG]

    73
    Richard
    AI4IJ
     
  6. K0RGR

    K0RGR Premium Subscriber

    I'm really not an expert, but I will tell you to check the power ratings on the Diamond. I used to run a 200 watt amplifier on occasion on FM, to work some very distant machines. 200 watts to a vertical is usually a very bad idea, anyway - you will bring up every repeater on that channel pair for hundreds of miles when the band conditions are right. But nonetheless, I managed to 'fry' my Diamond slightly. It's rated at 100 W and it means it. I am not sure what the rating is for the antenna you mentioned.

    For the kind of money you're talking about, consider a small beam and a TV antenna rotator to turn it on top of a 25 foot TV mast. 50 watts into a 10 dB gain yagi yields an ERP of 500 watts, and it will greatly help your receiving, too, by making the distant station seem 10 X as strong. Cushcraft has two dual-band yagis. The bigger of the two gives you 5 elements on each band for $129. AES sells a light duty rotor for $69. You'll want some good coax to feed it with - LMR-400 (DON'T USE CHEAP COAX!) 83/92 cents a foot + connectors.

    For working distant stations, this will beat the heck out of a vertical.
     
  7. AI4IJ

    AI4IJ Ham Member

    It occurs to me to mention to you that, while a good antenna is important, height above average terrain is even more so, when it comes to 2M and 70cm.

    Given a choice between a 20 foot tower with a 24 foot antenna, like the Diamond X700HNA mounted on top of it, and a 45 foot tower with a homemade 1/4 wave ground plane mounted on top of it, I would choose the 45 foot tower with the homemade 1/4 wave ground plane.  Why?  Because, the 45 foot tower with the smaller antenna will have the primary radiation lobe higher above the ground than the primary radiation lobe of the bigger antenna at the lower height.

    I recently built a one 1/4 wave element over eight 1/2 wave elements collinear vertical for the 1.25M band out of 8 gauge copper wire (about 19 feet tall).  For testing purposes, I used some rope to pull the antenna up into one of the pine trees in my back yard.  I got the feedpoint of the antenna up to about 50 feet above the ground.  The antenna had an initial SWR of 1.3:1 at the design frequency of 223.520; so, I didn't have to make any adjustments.

    Now, I had been using a 5/8 wave ground plane for 1.25M pulled up into the same tree; but, because the antenna was considerably shorter, I was able to get the feedpoint up another 15 feet, or so, higher above the ground than I could get the feedpoint of the collinear above the ground.

    The application for this antenna is in a 1.25M to 2M crossband repeater setup.  I use it while mobile to talk with my buddies who are too far away for me to work from my vehicles.  And, I have had a few months experience with the shorter antenna and know where many of the weak and strong spots are in the area.

    What was interesting to discover was that the smaller antenna performed significantly better than the much higher gain (about 9dB over 1/4 wave) collinear antenna I just built.  But, of course, its primary radiation lobe was located higher above the ground.

    Now, had I been able to get the feedpoint of the collinear antenna up to the same height as the smaller antenna, I have no doubt that the collinear would simply blow the little 5/8 wave ground plane away in terms of performance.

    So, my point is that your money and/or efforts would be better spent in acquiring a higher support for your antenna than to get a better antenna.

    Of course, having said that, I must also say that even this rule isn't hard and fast.  For example, if your 20 foot tower is already 5500 feet above the surrounding terrain on top of a mountain, an extra 25 feet isn't going to provide as much benefit as a bigger, higher gain antenna with a better pattern would provide.

    The main thing is to get the antenna as high and in the clear as possible.  If you can do that easier with a smaller antenna pulled up into a tree, you might save yourself some money and get better coverage at the same time.

    73
    Richard
    AI4IJ
     
  8. KI4RVY

    KI4RVY Ham Member

    Im moving into a house that alread has a 20 foot tower that I would have thought to be used for TV. I would like to make the best of it with a great antenna and not install a new tower. Just trying to make the best with what I aready have to work with.

    I like the idea on a dual-band yagis. this could also keep me from having to buy a amp.. Good point guys. Now Im probably heading in the right direction
     
  9. N0NCO

    N0NCO Ham Member

    KI4RVY,

    The Diamond X700HNA or Comet GP-9 will work quite nicely for a home VHF/UHF FM station.

    Remember - for VHF/UHF work, the antenna's height above average terrain (HAAT) and your coax choice will make the most difference in your station's performance - not antenna gain, or transmitter power. In other words - a high-gain antenna won't make up for a poor location and/or a long run of lossy coax. Neither will an amplifier. A rule of thumb I use is to keep my system losses below 1 dB if possible - main coax & jumpers included. Of course, if one has no choice as to location, a high-gain antenna in a poor location is still better than a low-gain antenna in a poor location. But never, ever skimp on coax for VHF/UHF/SHF work.

    With this above in mind - I suggest using 1/2" hardline (not SuperFlex) or Times-Microwave LMR-600 for your main coax run, if you can afford to. At bare minimum, use LMR-400. At VHF and especially UHF, coax losses can easily ruin the performance of an otherwise great station. Also, don't use an SO-239 to N adapter to connect to the antenna's N connector, rather, terminate your coax with an N connector on the antenna end.

    Don't forget to have a good VHF/UHF SWR/Power meter connected to your station - especially if you run an amplifier.

    Hope this helps - and good luck with your station! If you have more questions, I will be happy to help, if I can.

    73...

    Joel - N0NCO
     
  10. KG6YTZ

    KG6YTZ Ham Member

    Claimed. Just out of curiosity... Has anyone been able to confirm these numbers with their own tests? Sounds like a decent antenna, at least on paper...
     
  11. K9KJM

    K9KJM Ham Member

    I agree that coax feedline is VERY important at VHF/UHF.
    Generally speaking, Times LMR-400 for up to a maximum of 70 or so feet........    At 70 feet or more, Better coax is a must. While Times LMR-600 IS good stuff, It is kind of expensive, AND connectors are Very expensive!  For less money, Usually a person can find some good used Heliax complete with connectors at a swapfest.... (1/2" or even better, 7/8")
     
  12. VY1JON

    VY1JON QRZ Member

    I dont know if that would be the best ever but i had very good results with the famous Comet GP-9. It is a dual-band antenna, mine had been up in the air since 2000 and is still strong going. Look-it up online if you wish, on 2 meter it is a 5/8 wavelength x3. 73's
     
  13. N0NCO

    N0NCO Ham Member


    K9KJM,

    Good point.

    For my more permanent station setups, I've usually used 1/2" Heliax. The thought of using 7/8" Heliax for a home station makes me drool.

    Wow, did I really just say that? I guess I really am a geek. [​IMG]

    73..

    Joel - N0NCO
     
  14. WB2WIK

    WB2WIK Premium Subscriber

    Impossible, based on size. All these "amateur radio" VHF-UHF colinear vertical models have impossible gain figures. The standing joke is they're based on "dBgcl," which is "dB over a garbage can lid."

    That doesn't mean they're bad antennas. It just means the gain claims are ridiculous.

    I've installed and used a lot of the Diamond (brand) VHF-UHF vertical colinears and they're pretty good. They're not Stationmasters, or in that league, but of course they're much lighter and less expensive.

    The only "weakness" I've found with the Diamond antennas (and this applies to Comet - Tram and any of the other lightweight fibreglas antennas) is that they won't hold up very long under very high winds, or being hit by a large bird. No kidding. I had the X500HNA installed on my tower a couple of years ago and one day found it snapped in half, with the upper half dangling, supported by the internal "radiator" wire. Since there aren't any neighborhood vandals who are 65 feet tall, I figured a big bird probably flew into it. That kind of stuff does not happen with a Stationmaster! But then, the 2m Stationmaster weighs about 25 lbs, and the Diamond probably weighs about 2 lbs.

    Not a bad choice, but the "tall" (long) models won't last forever. The shorter, lower-gain models probably last longer because there's less stress on the fibreglas tubing.

    WB2WIK/6
     
  15. KD8Z

    KD8Z Ham Member

    I simply hate "best" hands down threads! [​IMG]

    Almost as much as I dislike little, yellow smiley faces!
     
  16. KD4MZM

    KD4MZM Ham Member

    Hello,
    I use the CATV hardline for my 50mhz and up stuff. Works great and the SWR is not a problem ether. I use a homemade connector too. I get my CATV hardline from the guy next door to me. To them a 50 to 150 foot spool end is useless, but to me it's just right. You might try looking into that if you can find a local CATV hardline installer. Around here they will give it to you as they have to pay to get rid of those spool tails.

    Eric...KD4MZM...
     
  17. VE6WTF

    VE6WTF Ham Member

    I use 5 watts FM for 200 miles?
    how distant do you think you are gonna get 200watts for?
     
  18. N3ATS

    N3ATS Ham Member

    I use a Diamond X50A, with RG-213 and with 50 watts I can work repeaters 100 miles out. That is with the base of the antenna at a mere 25'.
     
  19. WB2WIK

    WB2WIK Premium Subscriber

    Very possible. Remember, the repeater's doing most of the work!

    It's how far you can work on simplex that is more an indication of antenna performance.

    I can work repeaters in Baja California (XE2) that are 150 miles away, with an HT from my living room couch. They're just very well sited repeaters!

    WB2WIK/6
     
  20. KI4RVY

    KI4RVY Ham Member

    Station Master huh? I searched but I cant find any dealers or prices.
     
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