sd-1446's. Appears to be in like new condition. I think it's of old
manufacture, due to the quality of the work and size of the heatsink. It
also has a fan on a temp switch(clik-on type). Brand is apache...says' "450
swing".

Sounds like too much from a 4 pill 1446.

Thoughts?

Don

On Sun, 22 Aug 2004 19:12:14 -0400, "M-Tech"
wrote in :

sd-1446's. Appears to be in like new condition. I think it's of old
manufacture, due to the quality of the work and size of the heatsink. It
also has a fan on a temp switch(clik-on type). Brand is apache...says' "450
swing".

Sounds like too much from a 4 pill 1446.

Thoughts?

Don



It might push 450 watts PEP (not 'swing'), although 400 watts PEP is
more realistic (or 100 watts AM carrier power). The important things
to remember are that your input power may be as high as 30 watts PEP
(7.5 watts AM) for full output, and the peak DC current draw will be
at least 60 amps. Most important, the SD1446 is not a transistor you
want to over-volt -- it is recommended for operation at 12.5 VDC and
has a Vceo of only 18 VDC, so you might be taking some risk even if
you run it at normal alternator voltage (13.8 VDC). Instead, find a
nice, big deep-cycle battery to run this amp. Something around 100
Amp/hrs should give you about 4-5 hours of talk time per charge.






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Hello M- Tech:

I had a old 4 pill SD1446 Messenger 3V (class Ab1) that did around 380
to 390 when whistling in it, when driven with a Motorola Radio doing
about 16 watts PEP. This was on a Bird Model 43 watt meter so the
measurement should be pretty close. It indicates the RMS value of the
peak power voltage, or Peak Envelope Power, abbreviated PEP.

I am sure with a little more drive it will do more, but your at about
the end of its power output capability with 380 to 400 watts. Any more
output and you will be close to smoking the transistors, and it won't be
any louder or get any more significant range.

I am sure the "450 Swing" is just a CB type hype term or rating.

The Messenger 3V Amp smoked off the 130 pF capacitor in the base loading
coil in my K-40 antenna, so did the Messenger 3V Amp go south.

I replaced the cheap burnt up 130 pF capacitor with a Mica Type
transmitting capacitor rated at 1000 Volts, again at 130 pF. And that
bullet proffed the K-40 Antenna.

I replaced the SD1446 Transistors with MRF 453 transistors, as I bought
a few at the TRW Swap Meet near the Los Angles Airport, for a song.

The SD1446 Transistors where rated at 80 watts out I believe, and the
MRF453 Transistors had a 60 watt output rating. I believe the MRF 453
Transistors had a higher input impedance marking the input impedance
match much closer. The amp didn't put out as much but sounded great on
both SSB and AM. About 100 watts less but sounded great, and no one
could tell the difference in signal strength.

Jay in the Mojave

M-Tech wrote:

sd-1446's. Appears to be in like new condition. I think it's of old
manufacture, due to the quality of the work and size of the heatsink. It
also has a fan on a temp switch(clik-on type). Brand is apache...says' "450
swing".

Sounds like too much from a 4 pill 1446.

Thoughts?

Don

Thanks Frank/Jay!! Great info. I figured the "450" on the front was all
hype:-)

Don

"M-Tech" wrote in message
...
sd-1446's. Appears to be in like new condition. I think it's of old
manufacture, due to the quality of the work and size of the heatsink. It
also has a fan on a temp switch(clik-on type). Brand is apache...says'
"450
swing".

Sounds like too much from a 4 pill 1446.

Thoughts?

Don