[BC] Re: Cutting Vs Matching Antenna Vs no code

[Larry Bloomfield]

Richard:

What your are saying is true. I can't argue with that. There are many TV 
transmitter sites with common antennas for all the transmitters. Antenna 
design is a fascinating discipline. Most hams that I know of don't have 
nor can afford those kinds of antennas and basic theory is still 
important to know and understand. It is an avenue where a guy who wants 
to design an antenna that is broad banded can really learn from the 
experience. Most ham radio that I'm familiar with is experimentation. 
Many things that hams have developed, especially in the earlier years of 
ham radio, have found their way into commercial use. I believe ham radio 
is a valuable service for many different reasons.

+++++++++++++++++++++++++
Larry Bloomfield, KA6UTC
Bloomfield Enterprises, LLC
dba - Tech-Notes
1980 25th St., Florence, OR  97439-9717
(541) 902-2424 - Home/Office/Cell
WWW.Tech-Notes.TV  -- See you on the Road Show.




Richard Fry wrote:

> Larry Bloomfield:
>
>> As for Antennas, we all know that an antenna is resonate at one
>> frequency only. If you intend to change from that frequency, you MUST
>> change the electrical length so the transmitter thinks it is the correct
>> length - shorter or longer as the frequency you're putting to it is
>> higher or lower.
>
> _________________
>
> This can be true-ish for a simple wire dipole or whip, but even then 
> they have an acceptably low VSWR over a small range of frequencies 
> with no physical change to the antenna, or needing a "matcher."   And 
> even a simple dipole can have a fairly wide VSWR bandwidth if the 
> radiator outer diameters are suitably large.
>
> Other radiator designs can have a very wide VSWR bandwidth.  Recall 
> that FM broadcast Master antennas can have a measured VSWR of 1.1:1 or 
> less across the whole FM band (20% bandwidth), using radiators with 
> fixed mechanical dimensions.  Some UHF TV transmit antennas cover the 
> whole UHF TV band with low VSWR.
>
> RF
>
>
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