D-104 F base? (and Icom 718)

[K7WXO]

Hi All,

I picked up an old Astatic D-104 off E-bay a few years back. It was only like $10, and I only bought it at the time because I thought it would look nice on the shelf. But now I've decided I would like to try and use it. The problem is, I can't seem to find anything about this particular base. Seems to be an F model? The connector is just 2 pins. I've attached some pictures if it helps.

Is this just an un-amplified version or what?

Thanks for any info you might have!

73

Bryan K7WXO

[K9STH]

The way to be certain if this is an amplified base is to take off the bottom cover. There are screws inside the 3 rubber feet. Take these loose and the bottom cover will come off. If there is a circuit board inside then the base is amplified.

Also, virtually all of the amplified bases have a hole in the bottom cover to access a level control.

Glen, K9STH

[K7WXO]

Thanks Glen I will check. I know I looked before and don't recall seeing a circuit board, but maybe a resistor or two on the terminals. I don't believe there is a hole in the bottom either, but good thing to check, I will see.

Thanks!

Bryan K7WXO

[K7WXO]

So I pulled off the base, it's just a terminal strip, couple wires connect to the microphone, 2 to the PTT switch, and then running out to the connector.

Any ideas how I might be able to use this on a IC-718? All of the instructions I've found were using an amplified base.

Thanks and 73,

Bryan K7WXO

[KC8VWM]

Looking at the photos it appears this microphone has been modified.

There's a control knob installed on the base and I don't see a metal PTT bar attached to the side of the microphone.

So without knowing how it was modified, it would be difficult to guess how it should be wired. A schematic won't show you anything about how it was modified.

If it were mine, I would rewire it back to basics, similar to how the stock microphone on my rig is wired up.

Any idea why there's no PTT key on it? Perhaps it was connected to a PA system?

[K9STH]

Looks like a push operated switch on the base to me.

Glen, K9STH

[KB4QAA]

http://members.cox.net/n4jk/d104.htm

http://www.fredspinner.com/W0FMS/micpreamp/

The authoritative site:
http://www.qsl.net/wa2mzf/d104.html

You will probably need to build a simple amplifier to bring the mic level up to that needed by modern low impedance (Low-Z) rigs. You can find all the parts you need at Radio Shack for a small amount. Here are some sites with info. Bill

[AG3Y]

See this thread:
http://forums.qrz.com/showthread.php?t=260570
for a good looking single IC interface that might work with your mic.

The only thing you need to be concerned about is the fact that the mic element in D-104s is very high impedance. The IC may have to have some resistor values juggled around in order to get the right amount of gain for the radio.

Also, remember that many D-104 elements have gone bad over the years, due to rough handling and/or humidity. They are a crystal element, and don't stand much abuse.

Good luck! 73, Jim