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any HAMS? antenna tuning question.
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and no, not you dave.

for the most part i'm a new ham. i've put this diamond NR73B on my jeep, i'll be running a yaesu HT, FT3D. the antenna is a dual band antenna.
to tune this antenna will the only adjustments made be at the base, at the element holder?
or, will one band be tuned by making adjustments at the element holder? and the other band adjusted
by the phase inductor?

if tuning can be accomplished for both bands by only one adjustment then that's pretty efficient. and if that is the case i'd have to ask how. i'd speculate that it's due to the ratio of the antenna length to wavelength of those two bands are such that this is why one antenna is able to work with 2 bands.

i could prob wait and call the shop i bought it at monday and they'll have the answer, but i'd like to work on this tomorrow, sunday. i havent hooked up an SWR meter yet, so, it may be tuned pretty good from the factory. tomorrow i'll be going down the road to get away from buildings and into an open space so i'd prefer to know how to make adjustments ahead of time in case some tweaking needs to be done.

thanks for taking a look here.

73




ΜΟΛΩΝ-ΛΑΒΕ
we're doomed
Last edited by: Madduck: Sep 19, 20 21:19
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Re: any HAMS? antenna tuning question. [Madduck] [ In reply to ]
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Hi There,

It`s been a long time since I was on the air. Usually these type of antennas are half wave dipoles and will be resonant at their fundamental frequency and odd harmonics of that fundamental frequency. The inductor probably just reduces the overall length of the antenna - it seems that this antenna is designed for 2m/70cm therefore 3x 144MHz = 433MHz So, if I understand your situation correctly you should have good resonance on both bands just based on the design of the antenna and you should not have to adjust anything. That being said I would hook up the SWR meter first and see how the antenna performs on both bands - I would guess that the match with your rig will be good but better to know for sure. You might also want to get yourself an antenna tuner which will help you dial in the antenna but you may also be able to squeeze another band from your vertical.

73 and enjoy!

EI9GDB
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