[AMRadio] Source Broadcast Xmtrs

[Ron Youvan]

Jim Tonne wrote:

>> Commercial AM broadcast transmitters have
>>   more bandwidth than this. Close to +/- 5KC.

> Total fiction.

>>   The new digital systems require at least a
>>   30 kilohertz audio response.

   That is not what HAMs are rescuing.  Such systems must bandwidth limit audio somehow or they will 
exceed the spectral mask.

> And they are FLAT out to there.  But most
> AM BC rigs will do 15 kc without too much
> trouble.

   Is your MIC is flat to 15 kc?  And your voice goes out to 15 kc?

> And speaking of hi-fi, that is nonsense about
> two ham signals closer than 10 kc to each
> other causing a heterodyne to both.   I routinely
> listen to AM on my Collins 51J4 using the
> 3.1 kc mechanical filter.   I have yet to hear
> a heterodyne over about 4 kc.

   Naturally, try it on a wide-band receiver, the heterodynes ARE there, right there in your IF. 
Two carriers 6 kc apart (or closer) will whistle on my FT-990 with the BW set to 6 kc.  Set BW to 
2.3 kc and there is no point to have two sidebands.

> And it is treacherous to use a ricebox to make
> an AM signal and follow it by a linear.   The
> linear has to be adjusted   *just right*   or it will
> cause splatter.

   Never, if the amplifier splatters it is NOT LINEAR amplifier!  (obviously)
25 to 30 Watts of drive is all a SB-220 needs.
-- 
    Ron  KA4INM - You can't fool me ...
                       ... I'm a moron.