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Old 03-19-2017, 04:33 PM
Squidly-Diddly Squidly-Diddly is offline
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stupid question about what "2 meter" and 70cm bands mean VS freq.

https://www.youtube.com/watch?v=bFC1quZJGs8

I've got some vague idea that freq = speed of light/wave length, and that by some electronic wizardry a little radio can broadcast on a wide range of freq without needing to physically shorten or lengthen its antenna.

So what do they mean when they say this radio is "2m and 70cm"?

Any good links to radio basics? I just got my HAM lic but I'm not getting a few concepts.

I've got time to watch youtubes but not time to join any clubs at the moment.
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Old 03-19-2017, 06:21 PM
jehardiman jehardiman is offline
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2m or 70cm is the wave length. Speed of light (i.e. effective speed of em emissions) is 299,792,458 m/s. So 2m wave length would be 149896229 Hz ~ 149.8 MHz. (i.e. Hz =Speed of light (c)/ wave length (lambda)

http://www.translatorscafe.com/unit-...velength/27-1/
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Old 03-19-2017, 06:36 PM
jehardiman jehardiman is offline
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Sorry, didn't realize the actual question. Basically the discussion of wavelength for a particular xmitter/receiver is more in line towards the antenna size/length than the frequency. All xmitters are tuned for a particular frequency and are expecting a particular sized antenna for maximum effect. Receivers are more tolerant but suffer from gain effects. Sorry, but antennae design is a little out of my field.

https://www.electronics-tutorials.co...nna-basics.htm
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Old 03-19-2017, 10:28 PM
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philSweet philSweet is offline
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https://en.wikipedia.org/wiki/2-meter_band

https://en.wikipedia.org/wiki/70-centimeter_band
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Old 03-20-2017, 03:52 AM
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CDK CDK is offline
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Quote:
Originally Posted by Squidly-Diddly View Post
I've got some vague idea that freq = speed of light/wave length, and that by some electronic wizardry a little radio can broadcast on a wide range of freq without needing to physically shorten or lengthen its antenna.
It is very simple. For maximum performance an antenna must resonate at a particular frequency. If you are satisfied with less than maximum and/or want a shorter antenna, a coil is added in the base, if you want to cover two frequency bands, two different coils are added.
In your example the radio works reasonable well in the 2 meter and 70 cm band.
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