[Elecraft] RE: Speaker for K2 - Low audio

Bruce Thompson [email protected]
Mon Feb 3 11:29:00 2003


I've struggled with low audio on my K2 for a long time.  I use it in two
modes:  1) mobile in an SUV and 2) portable, in the same SUV, but with a
beam on a mountain top. =20

The best thing I did to improve my audio?  Got a better antenna.  When I
run a 2 element Fluid Motion beam on the back of my truck, I have plenty
of audio.  Even have to turn it down a little bit.  However, when I'm
running a screwdriver off the back, I have to run it full audio, full RF
gain, with the preamp on, which includes the modification to add even
extra gain to the preamp.  I had the screwdriver mounted at the trailer
hitch level and it was pretty useless on receive.  A hamstick on the
roof did 2-3 S units better (yes, S units!)  I have since still have it
mounted off the trailer hitch but raise it so the base is level with the
roofline.  Now on par with the hamstick on receive but much better on
transmit.

I just completed all the modifications to bring my K2 up to rev B level,
including a brand new SSB board and new matched crystals. However, I
have NOT made the smoothing audio pot mod.  I don't have the scratchy
pot problem since I almost always leave the RF turned full blast.

I use a clearSpeech speaker pointed directly at me less that 2 feet
away.  I'm experimenting with routing the audio through the SUV's stereo
system but I'm finding it picks up too much RF at the higher power
levels, even with lots of ferrite.  Also, when I operate portable, I
like to have the truck's ignition off to cut down any noise.  Looks like
if I find a small audio amp, I should be able to put in inside the
speaker.  Anyone know of one?  A new Elecraft kit option? =20

I've done very extensive debugging of the rig.  Rewound torroids just
for fun.  I've posted details in the past.  About the only thing I
haven't done is acquire a calibrated signal generator to trace the
signals through the receiver and compare it to another K2.  Initial
indications of measurements I've done seem normal. =20

Don't get me wrong.  There's nothing like sitting on a mountain top with
a K2, a beam and 500 watts at your disposal.  It just doesn't work very
well in my mobile environment.  Your mileage may vary=85

No flames please.  I've got them already.

73,

Bruce KG=D8SH
Golden, CO





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