AA6XA, but also KN6REU.

  • 18 Posts
  • 53 Comments
Joined 1 year ago
cake
Cake day: June 13th, 2023

help-circle








  • A j-pole is a half-wavelength vertical with a quarter-wavelength matching section on the bottom.

    It turns out that the 70cm band is about 3x the frequency of the 2m band (150MHz * 3 = 450MHz, close enough to each band). So the 2m the long leg of the j-pole is 3/4 wavelength (1/2 + 1/4 matching section), and on 70cm the long leg is 2.25 wavelength (3/2 + 3/4 matching). Both are an odd number of quarter waves, as we expect. The ham who made that briefing probably discovered in their testing that the matching stub wasn’t good for both bands, so they added a second one for 70cm.

    This is not a novel design, Arrow Antennas has been selling one like it for years (https://www.arrowantennas.com/osj/j-pole.html)









  • ham_bitious@lemmy.radioOPMtoVHF+@lemmy.radio10GHz and Up Contest
    link
    fedilink
    English
    arrow-up
    2
    ·
    1 year ago

    Yes. Usually one person is on a mountain top, and the other is on a different mountain or the valley. Microwaves are mostly LOS, but can and do go farther. Mt Diablo to Frazier Mountain is a popular path here in CA. Last year I heard people coordinating contracts from Frazier to somewhere near Quartzite.

    This weekend might provide a lot of rain scatter opportunities for the SoCal hams.


  • ham_bitious@lemmy.radioOPMtoVHF+@lemmy.radio10GHz and Up Contest
    link
    fedilink
    English
    arrow-up
    2
    ·
    1 year ago

    Yes, it is ham radio. I think some people were planning to go up Potosi, but changed their plans with the incoming hurricane. That’s too far and too many mountains for NorCal, so I haven’t been watching their plans closely.

    Theoretically you could listen in, but you’d need to be somewhere in the beam of the stations. At 10GHz an 18" dish had a beamwidth of only a few degrees, so if you’re even a little off you’ll hear nothing.

    I believe there are LNBs people have used to get on the band. Those are probably the cheapest. SBMS is probably the closest microwave club, is check out their website.

    I have a video on YouTube of last year’s contest: https://youtu.be/Ch_j_zfCYgI





  • My gear load really depends on the hike.

    Short easy hike? I’ll bring the KX3 and amplifier. Long hike? Just the MTR3B and lightweight antenna. Crowded or densely wooded summit? I’ll bring an antenna with a small footprint. Having options is nice.

    And of course all the jackets, water, food, and other stuff one needs to be safe in the woods.