WB0SMX

  MMR40 Chassis Work (Con’t) Filed in Kits on Dec.20, 2009 I was able to get a little more chassis work done on the MMR-40. Here is what the faceplate looks like now.  I’m still debating on whether to put in a jack for headphones on the front.  This will end up with a laminated photo overlay for a nice looking finish. MMR-40 Faceplate Ace Hardware had some nylon screws an nuts that I used to mount the PC board.  This prevents any shorts that might occur due to some traces being really close to the screw holes. Mounting Hardware So the board is bolted to the perfboard, with the controls sticking out the front panel just enough to tighten the nut on the microphone jack to add some stability. MMR40 Mounted in the chassis Here is a wide view of the board and external wiring.  All connections to the board are on headers, so it may easily be unplugged to work on it out of the chassis.  I haven’t tied up all of the wires yet, as it’s still a work in progress. MMR-40 Overh

  MMR-40 Front Panel Filed in Kits on Dec.14, 2009 Here are just a couple more pictures I had in the camera of the MMR-40 Box Up… The plan is to put a piece of red acetate over the display, then the front panel image over the whole thing.  That should cover up any rough edges in the hole I cut out for the display. I replaced the incandescent light in the meter with a white LED that draws about 20 ma.  It gives it a nice color, and should never need replacing. I plan on putting both the digital display and the meter backlighting on an electronic switch that will light for about 1 minute when I momentarily press a button.  That will save batteries when I don’t need to know what’s going on at all times. Front Panel with displays powered up Here is the back of the front panel.  The KD1JV Digital Dial is on the left, and the S-meter/Power Meter is on the right. The Digital dial is held in place by two countersunk flathead screws through the front panel, but under the PC boa

  The Haul – (Superstition ARC Swapfest 2009) Filed in homebrew on Dec.11, 2009 I got up at my normal work wake up time on Saturday morning to attend the Superstition Amateur Radio Club’s 2009 Swapfest at Mesa Community College. I was expecting more of the same as I had seen in the last few years, with dwindling attendance, mostly computer stuff, and bad weather. I’m happy to say I was wrong on all counts. Progressive Receiver Start This year, I found more good parts and part radios than I had seen in several years.  I was mostly hoping to find some variable capacitors at reasonable prices, as they cannot hardly be found new anymore.  They are necessary for a lot of the older projects I have been interested in building. I found a box of variable caps, with a tube socket and a microphone thrown in.  I offered $20 for the whole box, and was happy to have it accepted. Variable Capacitors There are a couple of transmitting caps in there and lots of receiver type caps.  I

  Boxing up the MMR-40 – Part 2 Filed in Kits on Dec.11, 2009 Once the faceplate was started, I went on fitting it to the front of the radio. It’s a little short on the sides, as the CB face was just a little longer than 6″, and I didn’t want to waste a bigger piece of pc board on this.  It will look fine in the end… Fitting the Faceplate I used my pocketknife to trim down the little bumps around all of the holes in the old faceplate. This will allow the new faceplate to sit flush on a flat surface. Bumps Shaved Off Next, I went to work cutting out the various holes that would be necessary for the controls to fit through the old faceplate. While I was working on it, it became apparent that there was a thin sheet of aluminum covering the old faceplate. This had to be removed, as it was loose, and I didn’t want the new faceplate to lift off of the face. I just grabbed it with pliers and pulled it off. It was just glued on… Aluminum Sheet removed The CB chassis wasn’t

  Boxing Up the MMR-40 Filed in Kits on Dec.11, 2009 I’ve been told that the site is getting a little stale, so I better get another post on.  I usually wait until I have more progress, but here’s what’s been happening lately. I’ve seen a couple of examples of people packaging up their QRP kits into old CB Radio Chassis.  I was able to locate a used CB through Craig’s List.  It cost $10.00, but I think just the parts alone are worth that.  It has the SO239 antenna connector, a speaker, microphone, meter, several switches and potentiometers, and a few RF transistors for salvage.  So I’ll try to put the MMR-40 into the chassis, and include metering circuits and a digital frequency readout. Here is what I’m starting with (excuse the fuzzy pictures, I had low light while doing some of this): Cobra CB to start with Here is a top view of the complete CB.  Notice the nice RF final that should come in handy someday! Cobra Top View And it has a nice, big speaker that should enh