Motorola MRF 454's ????

[Switch Kit]

I've heard it said over the years that MRF 454's are a true side band transistor .........Can someone explain to me why this is ? ........are they any truer then the Toshiba's or any other transistors along those lines ? Is there something that makes the MRF 454's special when it comes to SSB compared to others ? Thanks

 

[linearone]

I've heard it said over the years that MRF 454's are a true side band transistor .........Can someone explain to me why this is ? ........are they any truer then the Toshiba's or any other transistors along those lines ? Is there something that makes the MRF 454's special when it comes to SSB compared to others ? Thanks

I heard they had more audio

 

[nomadradio]

.are they any truer then the Toshiba's or any other transistors along those lines ?

No. A transistor that was meant for FM land-mobile radios would not have fixed base bias applied to it, as a rule. But a sideband power stage requires a steady trickle of collector current for a clean signal. A steady trickle of current into the transistor's base terminal is how this gets arranged.

Pretty sure every RF transistor Motorola sold was meant to work properly in a sideband amplifier.

Only exception I remember going by was the SD1446 formerly made by ST Micro. The data sheet showed it being used for 50 to 80 MHz FM transmitters. But they still sounded okay on sideband with proper base bias.

73

 

[Switch Kit]

No. A transistor that was meant for FM land-mobile radios would not have fixed base bias applied to it, as a rule. But a sideband power stage requires a steady trickle of collector current for a clean signal. A steady trickle of current into the transistor's base terminal is how this gets arranged.

Pretty sure every RF transistor Motorola sold was meant to work properly in a sideband amplifier.

Only exception I remember going by was the SD1446 formerly made by ST Micro. The data sheet showed it being used for 50 to 80 MHz FM transmitters. But they still sounded okay on sideband with proper base bias.

73

Thank you much Nomad , I guess somebody just wanted to label them as a true Sideband transistor .

 

[unit_399]

I'm not certain, but I think that one of the Motorola Engineering Bulletins written by Helge Granberg was for an SSB amp that used 454s. Maybe this is where the notion that 454s were for SSB got started. . Then again, maybe not.

- 399