In message Tue, 12 Aug 1997 11:30:48 -0400, bames@mecasw.com writes:
>
> Well, then the point is that I can buy an amp that has 50 out for 10 or so
> in. Now why dosen't that violate
> the FCC rules?
>
>
> Bill Ames
> KB1LG
>
Because--they didn't want to ban amplifiers wholesale. They just wanted to
make it impractical to build/sell one that would amplify or could be
modified to amplify a 5W CB rig. To do this the regulations state
That when operated at it's full output power it must be driven with at
least 40W. AND it must not be capable of amplifying the input RF driving
signal by more than 15db, unless the amplifier has a designed transmitter
power of less than 1.5KW (in such a case, gain must be reduced by the same
number of dB as the transmitter power relationship to 1.5KW).
SO that would mean it we wanted an amplifier with 100 W power output it
could not have a gain of more than 3.24db. 100W is 11.76Db less than 1500W
leaving 3.24db of the 15db allowed. To drive a 100W amplifier with the
maximum allowed gain of 3.24db requires 47.42 watts. So we're back to the
requirement that the amplifier not be able to be driven to full output with
less than 40 watts and therefore it can't be driven with a qrp rig (ARGO).
Now as you surmised you can buy a large power amplifier and since it's
linear, drive it with a 5 watt rig legally. Let's say you bought the legal
limit amplifier, 1500W. It has a gain of 15db, if you put 5 watts into it
you would get 158W output. Even with a 500W amp with a legal gain of 10.25db
if you drive it with 5 watts you will get slightly over 50W output. No, it's
not practical (economically) to purchase a legal linear to amplify a 5 watt
rig. BUT once again it's legal and the only way to do it.
73 Jim K4CGY
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