[AMRadio] 75 or 80m?


W5OMR/Geoff w5omr at satx.rr.com
Thu Dec 8 20:17:42 EST 2005


Jose HF Silva wrote:

>Hi ALL,
>
>I wonder why it is beeing mostly mentioned 75m, when
>in fact it is supposed to be 80m?
>
>The (old) sets and books and tables and slang were
>always referring 80m band (3.5 - 3.8 MHz).
>
>The 75m correspond to 4.0 MHz: is this a new band or a
>new trend?
>
>Thanks for clarification on this :-)
>
>73
>
>de Jose - ct1axg
>  
>

in the US, the entire band is from 3.5 ~ 4.0Mc.

a half-wave antenna on 80m is (of course) 40m, and therefore roughly 1m 
= 3.14 feet.

3.14 * 40 = 125'.

a half-wave dipole on 75m would be roughly 37.5m, or 117.5 feet.

The higher in frequency you go, the shorter the antenna.

The low end of the band has always been (for the 47 years I've been 
around Ham Radio) 80m, and the upper portion has always been 75m.

Hope that helps.

---
73 = Best Regards,
-Geoff/W%OMR





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