[Milsurplus] Gilbert MRCA Event AAR - MEP-025 noise

[Ray Fantini]

What we have been doing is running the generator every hour or so for ten or fifteen minutes to charge the batteries on board the mutt. That tends to keep everything running. The M151, GRC-106 and other radios are all somewhat the same generation so wanted to keep with something like the MEP-025 but that noise can be an issue.

Ray F/KA3EKH

-----Original Message-----
From: Kenneth G. Gordon [mailto:kgordon2006 at frontier.com] 
Sent: Monday, September 30, 2019 2:24 PM
To: 'Military Surplus Mail List' <milsurplus at mailman.qth.net>; Ray Fantini <RAFANTINI at salisbury.edu>
Subject: Re: [Milsurplus] Gilbert MRCA Event AAR - MEP-025 noise

On 30 Sep 2019 at 17:34, Ray Fantini wrote:

>     Noise suppression for the MEP-025, the generator has a fifty foot cable that connects it to the 
>     slave connector on the mutt. But the generator itself is so noisy (acoustic not electrical) that it is 
>     annoying.

Ray:

First of all the MEP-025 is a 3600 RPM generator, and that alone makes for lots of noise. If it turned at half that RPM it would make a big difference, but you can't change that.

Secondly, most of the noise from small generators comes from mechanical engine noise, valve clatter, and such, and very little from the exhaust. Adding an easily removeable car-muffler can modify the exhaust noise, making it less "sharp" but doesn't really quiet it much.

The only real way to quiet such a generator is pretty much as the manual says: "bury" it. At a recent field day, we stuck my small 2200 watt genny down in the bottom of a nearby ditch and that made a huge difference on apparent noise from it.

Some of us have had some success building a sound-proofed box around our generators with the top open so that the noise goes pretty much straight up into the air rather than "sideways", but even that is kind of a PITA to do.

You might consider using a pair of series connected HUGE batteries like are used in diesel trucks or large busses. I don't know what is the  24-28 VDC load you have, but a pair of those MIGHT suffice. At least you could charge them periodically from the MEP-025 rather than having to have the genny running continuously.

The batteries I am thinking of usually weigh near 100 lbs each, and are 18" to  24" long, a foot high, and 12" to 18" wide or so.

Ken W7EKB