Battery Welder:

 Did yuh ever want to replace those NiCad or NiMH batteries in your HT, then you find out they are welded together with a small strip of metal.  You can try to solder the new batteries, but more times then not you will destroy the battery or the solder joint will be too big to allow the batteries to fit back in the case. Well, here's a solution. It only takes a few components and a big capacitor.  These capacitors are what the Big Booming car amps use to keep the battery supply from dropping with they hit a big base note!  These things are measures in Farads.  The one I used is 1.5 farads, and seems about right. I got mine off e-bay.  The key is to charge the cap up and then quickly discharge it to spot weld the connection to your battery. It works great.  Of course we are talking about a heavy duty amount of current in a short amount of time. So use as heavy cables as you can find, and still be flexible. The circuit uses two LM-317's..  The first one is a current limiter so the cap don't just blow up the power supply when charging.  This limits the charging current to about an amp or so. That's more then enough to charge the cap rather quickly.  The other 317 is to adjust the voltage.  I found about 10 volts is perfect.  Anyway,  once the 'spark' of the weld discharges the cap, it will recharge quickly. Just watch for the voltage to get up to 10 volts again. That should be no more then a second or two.

Click here for welder schematic

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Vertex vxr-7000 issues:

 The vertex 7000 repeater might be a fine repeater, but it has difficulity with PL tones.  There is an option that says it will allow the transmitter to be locked unless it receives a carrier and PL tone. Sounds perfect to me to allow for normal PL operations.  Well, it does sort of work. But has a bad habit of locking out people in conversations because it appears it take the carrier to be inactive for 3 seconds before it will unlock the transmitter.  That's crazy and drove me nuts.

 To get around this problem I came up with this hardware solution that seems to work great.  It involves a off box PL detector and some digital logic to make sure we don't insert a COR unless we have both PL and COR from the repeater receiver.  Once we have BOTH we insert COR to the controller and away we go.  I also took the opportunity to add led's on the COR, PL and PTT lines. This really helps in trouble shooting.  Our controller happens to be a CAT-1000 and I was able to hijack the needed leads from the H4 connector.  Click the link for a schematic of this solution.  

Click for Vertex 7000 -- CAT-1000 PL interface solution

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Pine Cone Christmas Tree.

This is a fun project that allows you to build a small blinking Christmas tree out of a Pine Cone and a few electronic parts.  Besides having fun, you will learn about LED's, resistors and soldering. Not to mention allowing your imagination to run wild.  The Pine Cone forms the body of the tree and we mount a bright white steady LED at the top. The other LED's are blinking types that randomly change between red, green and blue.  They are also bright LED's but we cut down a little on the brightness for better affect and also to allow the 9 volt battery to last longer.

Click on this link to check out our latest (November 2010) meeting project.

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Joe Loucka  (AG4QC)