wire a Shure 577B mic

I know one near me that can....and did.....but you'd have to mail it to him.....pm me for contact info. (I've got one that is simply awesome.....a little added mod of the RK 56 step-up transformer as well...look close at the pic)

 

It's so painfully obvious that those early galaxy radios are based on 148F GTLs...

 

Email sent.....

Mike

 

The email I sent you came back "undeliverable"?????

Never mind, got an "out of office" email so guess it made it.

 

Not to a technician who fully comprehends the circuitry. If you study the 146GTL you will see the design was given a new synthesizer with binary half adders to generate the bands as well adding other features which evolved over the years through many models to the Export class of radios today. Wireless marketing also used the same base design in the 90's but used a PIC processor instead of the standard 145106 plus half adders to create the Northstar line. Even the RCI 2950/70 used the same base design of the 146GTL but opting to use a more complex computer and synthesizer. Today many models exist with varying computer designs yet you can still see the similarities in the receive and transmit sections to the old 146GTL. The heart of the 148GTL is very different and the 'F' was merely the addition of a frequency counter. The counter itself was taken for use in various export models so you are right in that for some of them but the base radio design is quite different. Ironically if one studies the most advanced Johnson models back in the day one can tell it was used as a template for many of the circuit blocks in the 146GTL by the designers of that era. Johnson was the source of much the new equipment the CB crowd grew to love. The switch in the stock Johnson microphone was taken for the Roadking and Astatic model mics with Astatic using the crystal element in its M6D104 series. Nothing new under the sun.

 

1=shield
2=audio
3=transmit
4=receive

I usually hardwire one element wire to shield, the other element wire connects to the audio wire, and only switch transmit and receive.
when you key, transmit connects to shield.
unkey, receive connects to shield.
One wire from element can be permanently soldered to shield.
color code means nothing.
Audio wire is the only one shielded regardless of color.
one wire from element solder to shield.
the other wire from element solders to audio wire.

 

My 577B has the RoadKing circuitry wired into it for a little more punch. Best mic I ever had!