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Thread: New to 10 meter what radio features are most important

  1. #1

    Default New to 10 meter what radio features are most important

    I'm new to ham radio and have a dual band 2m 70cm radio in base. Antenna in attic J pole.
    I want to buy a hf radio now and was thinking of 10m. I see a lot of radios with watts up to 200 in my price range. But some of them don't have fm or ssb. Should I go for a lower power radio that has these features or go for the power. If I go for the higher power I will have to get another power supplied that goes up to 50 amps.
    I am thinking of a antenna on my den roof which is about 12' off the ground at the peak. I am thinking of a vertical 5/8 wave Hygain Spt 500 or similar. Mounted on a tripod with a mast of 8' or so. It would be 30' to the top of antenna. My J pole is about 15' feet away in attic and would be about same height.
    Thanks for any info

  2. #2

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    Go for the features. on 10m, skip is easy to shoot with low wattage.

    Unless very expensive, really high power radios are generally lacking in their output filtering.
    The most important thing (in my opinion) is the radios selectivity and sensitivity. Radios nowadays have tiny little sideband filters that suck and you hear lots of air noise. When it comes to power, you dont really need it on 10m. 10m ground wave on a 5/8 vertical in northern minnesota terrain averages 30 miles. We have 3 locals that run 11m cb. one of us runs 12w, another runs 100w, and the third guy runs 1500w. Each of us have the same antenna, the Sirio 827. The 1500w guy doesnt do much better locally. He is 45 miles away and we hear him just as often when he runs low power. High power helps on the dx side of things, but for the most part, you will simply walk on more people and get through pileups better. But theres plenty of skip for the barefoot radios given a decent antenna!

    If output power is a concern, then it is useful to talk about what differences more power has. Radiation intensity, as it travels away from the antenna, is inversely proportional to the square of the distance. This means power vs distance is a logarithmic thing. if you want to be twice as strong at the receiver, you need 10*log(2) more dB. About 3 more dB.

    Each time you double the power, you add 3.01dB. If you had a 20w radio and added a 600w-output amplifier, you just added 10*log(600/20) dB, 14.77dB. This is why I just laugh when I hear people running 1500w amplifiers, you only have about 4dB over a 600w amp. Pay an extra $1000 for 4dB more??? Why? 4dB is easy to get from a simple beam that costs a fraction of the savings.

    Imagine if you put a 9dB beam on a 20w radio... your signal using the beam will the same as if you used 158w into the isotropic antenna.
    same scenario using a 100w radio... EIRP is 794 watts!
    now connect that 600w amp to a 9dB beam.... EIRP is 4765 watts!
    compared to a 1500w amp on an isotropic antenna... 1500w
    and running that 20w radio into a 1500w amp into a 9dB beam.... almost 12,000 watts EIRP.

  3. #3

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    If you do just want a vertical antenna for 10FM, say, then why not do what I and all the local guys (and girls) did back in the 80s. We all got 11m CB antennas ("Silver Rod") in my case, the got out the calculator and shortened it slightly to work on 10m. Darned sight cheaper than the 'equivalent' 10m verticals (which were probably the same anyway) and of all the antennas that sat unused over the house for 25 years, it's the only one that survived intact.

    Of course, if you want more than the 30 miles or so you usually get, then Brandon makes some good points. Of course, if conditions are right, then 3000+ miles is possible on 10 watts and the aforementioned Silver Rod. Worked some Caribbean stations on 10 and 11 (tsk, tsk!)
    Current radios: VHF/UHF: 2 x Baofeng 2/70 Handhelds. VHF: Kenwood TR9130 2m multimode. HF: Kenwood TS930S-AT
    Home antennas planned: G5RV / G7FEK / end fed wire. 1/2 wave vertical for 10m. 6 element beam for 2m. Vertical collinear for 2/70
    Website for the 'day job': www.andrew-gilbert.com

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