Any One Use a Military Surplus M-80 Microphone???

[Onelasttime]

I picked up 3 of them really cheaply but have not had the time to even unwrap one. I know them well from sight because my Dad was int he Army from 1972 to 1993. I grew up an Army Brat. I have no experience with them. I mostly wanted the durable plastic/composite/nylon body what ever it is. I also figured the ptt switch should be durable. The official freq. response is listed as 350Mhz to 3500Mhz if I recall properly. It was listed as noise cancelling.

1) Does anyone know if it is the element that limited noise by limiting freq. response?

2) Does it use any components to reduce freq. response?

3) Anyone use one of these as a donor body for an electret condenser mic element?

I have considered using it for SSB only. I think I paid $7 or $8 for each one still sealed in the orignal wrapping dated 1992 the same year I graduated High School!

 

[rabbiporkchop]

I picked up 3 of them really cheaply but have not had the time to even unwrap one. I know them well from sight because my Dad was int he Army from 1972 to 1993. I grew up an Army Brat. I have no experience with them. I mostly wanted the durable plastic/composite/nylon body what ever it is. I also figured the ptt switch should be durable. The official freq. response is listed as 350Mhz to 3500Mhz if I recall properly. It was listed as noise cancelling.

1) Does anyone know if it is the element that limited noise by limiting freq. response?

2) Does it use any components to reduce freq. response?

3) Anyone use one of these as a donor body for an electret condenser mic element?

I have considered using it for SSB only. I think I paid $7 or $8 for each one still sealed in the orignal wrapping dated 1992 the same year I graduated High School!

I have a few of them and even with a matching transformer, the audio is weak although sounds nice. I plan on retrofitting one with a noise cancelling electret in the next couple weeks.

Noise cancelling is achieved by sound entering both the front and rear of the microphone.

frequency response isn't too impressive.

ANM-5254L-R electret is what I plan using.

 

[RatsoW8]

Those microphones aren't designed to sound nice and have a wide freq response, they are designed to pass the most effective voice frequencies for readable radio communications.

 

[Robb]

The element is fairly linear; but far from having a flat response. It is down -15db @ 100hz and +10db @10khz.

Have you used this element before - RPC?

Kinda reminds me of the D-104 response - IIRC . . .

 

[rabbiporkchop]

The element is fairly linear; but far from having a flat response. It is down -15db @ 100hz and +10db @10khz.

Have you used this element before - RPC?

Kinda reminds me of the D-104 response - IIRC . . .

View attachment 20465

It sounds really good but the audio level is a little on the weak side even with the matching Transformer added to it.
just out of curiosity where did you find that specification?

 

[Robb]

It sounds really good but the audio level is a little on the weak side even with the matching Transformer added to it.
just out of curiosity where did you find that specification?

http://www.puiaudio.com/pdf/ANM-5254L-R.pdf

 

[rabbiporkchop]

http://www.puiaudio.com/pdf/ANM-5254L-R.pdf

Sorry, I thought you were talking about the M80-C/U.
I'm still trying to get the mic gain turned down to the proper level with my new mic I just built. It seems to be kinda decent and I had a good audio report with it this morning.
I epoxied one of those elements into an EV 603t housing and this is what I plan on using from now on in the mobile.
here is a pic and a sample of the line level audio. No over the air recordings yet though.

Keep in mind I'm still trying to figure out the levels.


Once I figure out the levels, I'll be putting one of those electrets in the M80-C/U

 

[rabbiporkchop]

Mic gain was too high here...These ANM-5254L-R electrets are ungodly loud with 5 volts of phantom power. Gotta choke that mic gain way back to compensate.

 

[rabbiporkchop]

The element is fairly linear; but far from having a flat response. It is down -15db @ 100hz and +10db @10khz.

Have you used this element before - RPC?

Kinda reminds me of the D-104 response - IIRC . . .

View attachment 20465

If you're looking for a flat response you should check out the Panasonic WM-61 or it's closest replacement.
http://www.taydaelectronics.com/condenser-microphone-2-2k-ohm-1-5v.html

 

[Onelasttime]

Those microphones aren't designed to sound nice and have a wide freq response, they are designed to pass the most effective voice frequencies for readable radio communications.

Yes well I got 3 of them NOS still in the OEM Miltary Wrappings for $8 each. They have a bakalite construction and are made by Electrovoice so you know the PTT is built to last. I just want the body and the PTT the cord, plug and dynamic mic element can all be ditched. I am not operating a manpack radio or in a HMV being shot at I just want the body and the switch! Even at $50 a pop you can not buy a mic today built that well let alone for $8.

 

[Onelasttime]

If you're looking for a flat response you should check out the Panasonic WM-61 or it's closest replacement.
http://www.taydaelectronics.com/condenser-microphone-2-2k-ohm-1-5v.html

I will check into that. I got some Gentex Call Center Electrets off ebay that I am going to try. 50hz-16000hz but the numbers alone do not tell you how it will ultimately sound. They make mic elements for miltary and aviation so I am hoping they will sound good. The pattern rolls the sound off anything off-axis by a large amount so I am hoping it will eliminate the need for true dual phasing noise cancellation. I have seen it done but it rather seems like voo-doo and does not seem to work a lot of the time.

 

[rabbiporkchop]

I will check into that. I got some Gentex Call Center Electrets off ebay that I am going to try. 50hz-16000hz but the numbers alone do not tell you how it will ultimately sound. They make mic elements for miltary and aviation so I am hoping they will sound good. The pattern rolls the sound off anything off-axis by a large amount so I am hoping it will eliminate the need for true dual phasing noise cancellation. I have seen it done but it rather seems like voo-doo and does not seem to work a lot of the time.

Depending on what the output level is you might need to build an attenuator pad to reduce the output level To 45 millivolts or less.
Here is a handy calculator to calculate the necessary dampening Factor.
http://www.sengpielaudio.com/calculator-amplification.htm
Here's a handy calculator to calculate the values that you might need to build your attenuator pad.
http://www.nu9n.com/tpad-calculator.html