[SixClub] 6 meters AM

[donroden at hiwaay.net]

Some early analog TV transmitters ( AM modulation ) used filters and  
antennas that were frequency shifted to pass USB and attenuate LSB,  
producing a quasi-single sideband signal.

Don WA4NPL



Quoting "Roger K4RW" <k4rw at lowcountry.com>:

> George,
>
> As I'm sure you're aware, this mode has 3 distinct components of the signal.
> Two distinct sidebands of modulation component (USB & LSB), and a carrier
> are present during transmit. This requires antennas that are capable of
> radiating each component. The best arrangement is using either a 2 antenna
> stack or a 3 antenna stack. The latter is considered the best choice as it
> will equally radiate the two modulation components, each from its own
> antenna, plus the carrier from its own antenna. The 2 antenna stack works
> well but you will have some degradation of the signal levels on the two
> sidebands. This is due to only one antenna of the stack sharing the
> radiation of 2 sidebands while the other antenna is radiating the carrier.
>
> If you have a Shure 444 or 450 microphone, place the extendable neck of the
> microphone in the middle of its length of travel. These microphones are
> designed to be fully extended for USB and fully lowered for LSB. Using the
> middle will allow for the use of both sidebands and provide better audio on
> AM.
>
> So there you have it. My secrets are out.
>
> All kidding aside, the antennas used for SSB or CW also work quite well on
> AM mode. No special "mode based" antenna is required. However, the
> polarization does make a difference if you want to talk with someone close
> to you. Then your respective polarization should match for best signal
> strength.
>
> Roger, K4RW
>
>
>
> -----Original Message-----
> From: sixclub-bounces at mailman.qth.net
> [mailto:sixclub-bounces at mailman.qth.net] On Behalf Of George Clark
> Sent: Sunday, May 24, 2009 11:11 AM
> To: undisclosed recipients:
> Subject: [SixClub] 6 meters AM
>
>   Those that run AM on 6 meters. What do you use for an antenna?
> Beam,Dipole? I've never tried it. Those that use dipoles,Could you give the
> measurements for it?
>                                                    George
>
>
>
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