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1

The HM-98 uses a couple resistors for the up/down buttons, while the 133 uses digital signalling along with the rest of the keypad. It is MOSTLY compatible. For normal operation, it will work just fine. The only issue will be when it comes to putting the radio in programming mode. The HM-98 uses a couple resistors for up/down, while the 133 uses digital ...


4

Troposcatter is the common mode for beyond line of sight on the 10 GHz ham band when the band is not otherwise open, good for 100's of miles. A radio with just a few watts output power and a moderate sized dish (60cm or more) gets enough ERP for troposcatter. For a few random references, check out: Pages 64-70 of http://www.mike-willis.com/Tutorial/RT%...


-2

IC-2730A is a nice full duplex radio that will not break the bank.


1

The optimal length for a HT whip antenna would be ¼ λ. The smaller rubber ducky, with its comparable performance, would win hands down for its convenience and ease of use. The performance of either would be enhanced by adding a ¼ λ flexible-wire counterpoise, popularly known as a 'rat tail' or 'tiger tail'. A ring-type lug, attached at one end of the ...


2

It depends on the type of the antenna. Mobile antennas are often monopoles. A monopole is self-resonant when it's a quarter wavelength long. A quarter wavelength is good: smaller, and the feedpoint impedance will be capacitave and may require a matching network. Matching networks introduce loss. larger, and the radiation pattern grows lobes that go up ...


3

To directly answer your question, the ideal antenna length for maximum radiation is dependent on the wavelength. For example, CB wavelength is approximately 11m. The ideal antenna is half of that for a dipole antenna. However, most CB (and HT) antennas are monopoles, which split the antenna in half and use its mount as the other half, so the ideal CB ...


1

I had a 15" whip for my 2m HT that I thought performed quite well. Unfortunately I dropped my radio and that managed to snap the antenna. I have yet to replace it. You're gain isn't really proportional to the length. Rather, it's about the electrical resonance of that length. Think about humming an A really loudly next to a guitar. You can make the A string ...


0

Typical HT antennas are very much a compromise. What would be considered a "basic" antenna at other bands would be a half-wave dipole, or a quarter-wave vertical with a ground plane or quarter-wave elevated radials. Polarization for FM is vertical, so a horizontal dipole won't work. Ordinary vertical dipoles are not very practical for portable use (the ...


0

In my opinion either a ¼ λ ground plane antenna or a ½ λ J-pole antenna, cut for the centre of the Airband, would be a better choice for reception of ground stations.


2

Ask the radio shop to show you the VSWR of the antennas at the frequencies you use. Have them do it in front of you. That will likely tell you whether the antennas are suitable or not. To ensure an accurate measurement, the antenna must be plugged directly into a VHF (not CB) SWR meter with no coaxial cable jumper between the antenna and the meter. A ...


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