DXPeditions Page...

I can't say enough good stuff about NG3K's Announced DX Operations page on the web. It has really helped me keep up with DXPeditions and raise my country count. There's a link under most calls listed, that will automatically take you to DX spots for them, info on where to find more info, the approximate schedule dates, and loads of other info. If you're into DXing, be sure to bookmark it, and keep the page pulled up in the background...lots of info in one spot for DX hunting. I have it linked in the [DX Tools] section of my personal site, but you can get to it directly at https://www.ng3k.com/Misc/adxo.html . 

Dave WB4IUY

http://www.WB4IUY.net

Cushcraft A3 Trap Tips...

I've rebuilt a number of Cushcraft A3 and A3S antennas over the years. (The "S" just means Stainless Steel hardware). Like a dummy, I once totally disassembled an antenna without marking the traps. Cushcraft marks them with invisible ink (just kidding), so you're on your own if you mix the traps up on an older antenna. Turns out it's not too tough to figure out. Also, those crazy little plastic caps that go on the ends of the traps don't hold up very well, and I've found that 2" heat shrink seems to last a lot longer (and is cheaper to boot!). 

I've uploaded a few bits and tips to my site that might help, in case you find yourself trying to identify the traps or rebuild one of these. One is a .pdf from Dale KG5U, one is a .txt file with my tips, and a .jpg pic of a trap with the heat shrink end caps. Hope that helps some of you!!

Go to my website at http://www.WB4IUY.net , mouse over [Workshop]. and select "Schematics Manuals". Scroll down to the Cushcraft section and you'll find it. 

Dave WB4IUY
http://www.WB4IUY.net

Repairing a Tripp-Lite PR-40 DC Supply

TrippLite power supplies are well made, high quality supplies, but that negative lead regulation is a little odd and difficult to wrap your head around when it comes time to repair them. This supply to me inoperative, so I had to dig in deep to see what was wrong. 

First: TrippLite keeps the schematics for these close to their chest, so it took a bit of searching online to locate someone with an electrical schematic. FYI, there's a great site on yahoogroups for power supplies,  you should join it if you think you'll ever need a schematic or info on a power supply. The link to it is:

https://groups.yahoo.com/neo/groups/powersupplies/

I also uploaded a copy of the schematic in the [Schematics & Manuals] section of my website at:

http://www.WB4IUY.net

I discovered the remaining insulators on the output terminals had failed, and the rest were totally missing, shorting the output/crowbar board to the chassis. This took out all of the pass transistors and a few other bits. I replaced the pass transistors, fabricated new feed-thru insulators to protect the output studs from shorting to the case again, and rebuilt the crowbar circuit. Now, it'll go from no load to 40 amps @ 13.8 VDC with only 0.2 VDC shift. Solid supply! 

 Just cracking it open to take a look...

 Output / Crowbar board removed for inspection...

 Broken insulator...

 The only insulators left... There should be a feedthru insulator and a backup insulator in each stud...

 The PR-25, PR-40, and PR-60 use the same schematic... 2 pass transistors for the 25, 4 for the 40, and 6 for the 60.

 One pass transistor tacked in and boards jumped in place for testing...

 New insulators fabricated...the outside insulator is T-shaped and passes through the chassis, the inner parts are counter bored so they fit together. 

 Outside view with the new insulators in place...

All finished and ready to rock!!


Dave WB4IUY
http://www.WB4IUY.net

2 Computers, 1 Mouse/Keyboard!

I run two computers at my operating position in "studio A". Two keyboards and two mice really clutter up the table in front of the radio gear. I stumbled across a piece of free software that allows me to seamlessly slide my cursor from one screen to the other, and the keyboard input follows the mouse. You can copy things to the clipboard in one computer and paste it on the 2nd computer, and even drag single files from one box to the other (only one file at the time, with a 100meg file size limit)

The software was easy to install and ran without a hitch on my junk computers (one old XP Pro box, and an old Dell Optiplex 260 Win7 box). Now, one mouse and 1 mini-keyboard runs both computers at once, I love it! The software is called "Mouse Without Borders". The latest version is on Microsoft and doesn't support XP. I found an older version that does support XP over on cnet. Oh, it'll run up to 4 computers at the same time, too.

I ran multiple monitors on a single computer about 10 years or so ago with a graphics card and some software. In my situation, I'm running multiple 15+ year old boxes at home to share the load, so it looks to be a good answer to my problem. I could buy something new and much faster that would do everything, but I'm a tightwad and am always looking ways to keep old stuff working. It's neat to not to toggle between screens on my primary applications, and everything is fast by each computer running with less overhead. 

Here's a link to the new version for Win7 and newer: 
Mouse-Without-Borders-NEW

Here's a link to the older version that includes Win XP: 
Mouse-Without-Borders-OLD


Dave WB4IUY

http://www.WB4IUY.net

Blast from the past...

A cool snippet of an advertisement from 1940, and this tube is still in operation at many ham stations! I love these old promotional bits. 

Dave WB4IUY

http://www.WB4IUY.net

I miss the Radio Shack Project Boxes...

Wow...sure miss the days when Radio Shacks were all around, and I could grab one of these cool cabinets to build things in. I've built a ton of stuff in these things...keyers, receive preamps, T/R Switches, Power Supplies, Amps, you name it! Lots of stuff, I wish these were still available.... 

 Later, before Radio Shack closed up, these cheapie plastic boxes came out. They're cool for stuff, but nothing like those nice metal cabinets with the wrinkle finish. I wonder if anyone still sells the metal cabinets above?? Here's a few pics of the plastic stuff I also built things in...

Oh well, I guess times change, but I still like to live in the past!! Email me if you know of a source fo rthe metal cabinets in the first picture group. Thanks!

Dave WB4IUY

http://www.WB4IUY.net

A Few Bits From JARSfest...

I headed up to a hamfest put on by the Johnston Amateur Radio Society (JARS) on Sunday 11/18/18. We had a chilly start for the tailgate area, but it warmed up quickly. BIG turnout! There was loads of stuff outdoors by the tailgating crowd, and all tables were sold out inside. Here's a few pics I took...

You can tell by the photos above, that I like the vintage stuff :-)  I picked up two bags full of components for various projects, only spent abt $30! Shrink tube for trap caps, piles of capacitors (HV, ceramics, electrolytics, etc), zener diodes, transistors, switches, project boxes, a huge RF plate choke, rubber feet, spacers, nicad battery packs, binding posts, etc.

 

 I saw lots of old friends I had not seen in years, met several new friends, got to look at tons of stuff, and had the most fun I've had at a hamfest in years. 

Dave WB4IUY

http://www.WB4IUY.net

"Sealed" Lighting Repairs...

OK, this isn't ham radio related, but it is electrical :-) On a recent fishing trip with our little JonBoat, Debbie spotted the rear driver's side tail lamp module on our boat trailer had failed. These are sealed incandescent units, without any possible access to replace the lamp. They're not very expensive, but being the tightwad that I am, I had to set about to attempt a repair. 

These have a dual filament 1157 lamp inside, with the wiring soldered to the bulb, the bulb mounted in a glob of silicon rubber adhesive, and the red lens literally glued in place. Using my Dremel tool and a carbide cutoff disc, I cut around the junction where the red lens was attached to the white plastic housing. 

With the red lens removed, I scraped off the melted plastic, pulled the lamp out, and peeled the old silicone adhesive out. A new 1157 lamp (costing about a buck!) was re-soldered to the wiring, a new glob of silicone adhesive (bathtub caulking) was squirted into the middle of the white plastic base, and the new lamp was nestled down into the adhesive. Once that cured, I applied a thick bead of silicone caulking around the perimeter of the lens, and the lens was pressed back into place onto the base. The excess caulking was wiped off, and the assembly was allowed to cure.

Once cured, the light assembly was reconnected to the trailer wiring harness, and the light assembly snapped back into the gasket of the trailer. A quick test showed all to be well. Gotta love a cheap repair!

Dave WB4IUY

http://www.WB4IUY.net

Converting More Switching Supplies...

Building a few more 20A DC 12 VDC bench power supplies from old computer supplies. Those things make great 12VDC power sources for projects, radios, to run R/C battery chargers, etc!

Dave WB4IUY
http://www.WB4IUY.net

2M SSB, a sad state of affairs...

I remember, in the not too distant past, when 2m SSB was a blast to operate. One could easily work 3+ states any night of the week, and very often it sounded like 75m SSB at night, what with so many stations operating up and down the band. Seriously, this was in the early-to-mid 90's. I could call CQ from my very modest station on 144.200, and have to move off of the calling frequency to work folks, to free up the calling frequency for others...

Now, in 2018, it's crickets. Static. No one EVER calls CQ in my area. I listen on my station with a 13 element antenna up at 111', nothing but static. Even when the contests are running, there's only a handful of the same players that pop on from time to time. I hear beacons 200+ miles out at night, but no live humans. Where did all the 2M SSB ops go??

I recently spent a lot of time and effort building and replacing my 2m SSB antennas that were damaged in a storm, but it seems to have been wasted time.  I recently asked a question about this on an internet forum, and other hams replied with the same experience. What a shame, 2M SSB can be such great fun, but not like this. Even the VHF contests yield such a pitiful response, it's just not worth the effort, I might as well be looking for microwave activity. Where is everyone??

Dave WB4IUY
http://www.WB4IUY.net

Rebuilding the old Diamond X-500 Antenna...

The old Diamond X-500 2m/70cm vertical is finished, reassembled, and up on the test mount. This one had a rough life... Back in 2016, the antenna had quit working. When the tower fell in April '16, the fiberglass portion also got snapped off just above the aluminum mount. I tossed it in the scrap antenna pile until a later date. Fast forward to May of 2018, I finally got to it while rebuilding all the damaged antennas,

The metal base had to be cut away with tubing cutters to gain access to the base loading coil, as the threaded section had become seized. During disassembly, I discovered the series and shunt capacitors in the base were toasted. Closer examination revealed the top part of the fiberglass enclosure was split and the metal cap was smutty black...I'm guessing it had taken a lightning strike. The condensate drain hole was also plugged up with _stuff_, so that was cleaned out for proper drainage. 

The capacitors were originally some low voltage style. I replaced the series cap in the feed with a nice 10pf 2.5 kv version, and fabricated the 1.5pf shunt cap by twisting two pieces of wire with 600v insulation, while reading the value with a capacitance meter. It was all cleaned up, the contaminated foam removed from the coils, the stacking couplers were sanded to remove crud, the top fiberglass section was repaired with fiberglass resin, a pvc sleeve / splice was installed over the broken section at the bottom of the fiberglass enclosure (radome) and 'glassed, and the bottom aluminum section was brazed back together with low temp aluminum brazing rod and a propane torch.

I got it up on the test tower this morning and ran some tests, and all was well. SWR match is good, and some on the air tests proved that it was working pretty good. I'm ready to install the decoupling elements, and get it up on the tower on a sidearm (I'm not top mounting it, these things seem to be lightning magnets when put on top of tall towers!).

 Parts of the antenna are in this pile of scraps...

  Internals out of the radome, partially cleaned up...

 Nasty couplers...

 Damp contaminated foam on the coils had to be removed...

 

 Had to use a tubing cutter to cut the bottom off, to gain access to the base loading coil.

 Yuk... corrosion and ratty looking caps...

 Shunt cap blown apart...

 Shunt cap...

 I split a piece of pvc pipe to stretch over the fiberglass tubing, made clean cuts on the broken fiberglass, wetted the parts with fiberglass resin, and assembled...

 Fiberglass resin applied to all parts...

 

  Fiberglass cloth laid over the splice...

 Fiberglass CSM (chopped strand matte)

  Base cleaned up, ready for reassembly...

 1.5pf cap (dicky) fabricated and installed (in red).

 

  10pf series cap installed... I slipped a piece of thick heat shrink over this assy, before reinserting it into the aluminum housing...

 All reassembled, I used GE silicone caulking to seal all of the joints, and bolted it to the top of the test stand in my back yard. SWR was good, and it seem to work OK. Another antenna resurrected from the scrap pile

Dave WB4IUY
http://www.WB4IUY.net