Just don't try replacing it with a 1/4"-20 "no-blow".

Not familiar with that amp, but if the internal wiring is short and straight (no sharp bends, etc), I'd think UHF signals should pass through it when it's turned off - just like a 2 meter sig.

As usual, Steve is right on, both with the likely description of the shunt, and the likely condition of the meter.

If you have to replace the meter, find out the precise resistance value of the coil (out to at least 3 decimal places) and the full-scale current it requires.  We can do basic Ohm's Law calculations to find out what the shunt resistance should be, and then hit the books to find out how much copper wire of what size and length we'll need to make a precision shunt just for that meter.

Seems like an unreasonably large voltage drop from unkeyed to keyed, and I don't know what the plate voltage is "supposed" to be.  Can you change your amplifier's transformer taps to boost the voltage, perhaps?

The best band to use for listening to ARRL is the band on which you can best hear ARRL. This will change from hour to hour on any given day.  As far as a receiving antenna goes, don't reinvent the wheel.  A simple piece of wire, 50-100 feet long and up as high as you can get it will work wonders if you have a decent receiver.  Don't worry about SWR and resonance just yet; receivers operate off voltage, not power.

Try this link:

http://www.radioera.com/mall/manuals.asp

Enter 30K1 in the second line.  They appear to have the manual...if you have $42 plus shipping.

The 30K1 is a transmitter, not an amplifier.  Do you mean 30L1?

Try here:  http://www.radioera.com/mall/dynamic-results.asp

MFJ-247??? Is that a brand new model?

Even as an electrical engineering student, he only had to answer 70 per cent of the questions correctly...

SWR doesn't change with power unless there's something wrong with the antenna, feedline or transmitter.  It's a RATIO, not an absolute value.

I was a radioman in the Navy, but I stood some signalman watches from time to time.  10 WPM was a good "average" speed.  A "fast" speed would have been around 12-13 WPM.  The chief criterion was that you didn't "bang" the shutters on the searchlight.  Takes a bit of practice and getting used to the large swivel motion your wrist must take, rather than the short up-and-down motion when using a J-38.  But I bet I can still do 12 WPM on flashing light!  Or maybe more.

Why not try it out and see for yourself?

738.476 Hz or so.

Build it.  Let us know how it works.

I don't think this is a "stereo" amplifier; from what I've been able to find on the internet is that it's for PA use, which implies only one speaker.

Stay away from the 70V terminal - that's for speakers especially designed for line input.

I'd try one speaker, connected to the proper terminals depending on the speaker's impedance (you'll have to determine that).  Then maybe connect two identical speakers in parallel across the next-higher-impedance terminals.  You might have to reverse connections to one speaker to get the phasing correct.