Wednesday, May 30, 2018

Repairing the IC-211 Receiver, again...

This isn't my first rodeo with this 40+ year old rig from the mid-70's. It uses a dual gate N-Channel FET for the 1st RF amp... It's very sensitive (single tone detectable down below .01uV!), but it is also easily blown. I think this was knocked out when lightning struck a tree about 100' away. I repaired it last back in 2015, when I fried it while operating full tap on the 160 m band, when the 160m antenna was only about 10' away from the 2m SSB yagi :-)





I snatched the case off of it to have a look...it was only hearing about 3uV minimum, but when I injected a signal on the output of Q47, it came alive. Yep, bad FET.

This is Q47 after I removed it. I dug around in the junk box a bit, but didn't have any more of those. This was a ELM222, but the original was a 3SK40. 

 



Well, I scratched around in my spare parts and found a RCA 148085, similar to a NTE222, and decided to give it a try. Sure enough, the receiver sprang to life and has a really sensitive front end, now.




Q47 as seen on the schematic...




This is the bag of the one FET I found in the workshop with a suitable operating frequency range.




Here's the IC-211, back in it's operating position and ready to go. I was able to work Alex KC4PHJ over in Apex and was hearing him fine, so combined with the rebuilt 2M SSB antenna I put up last weekend, my 2M SSB station is back on the air!

Dave WB4IUY
http://www.WB4IUY.net









Sunday, May 27, 2018

More of the yagi's back up on the tower...

It was a long, tiring day, but what a great feeling to look up and see it all beginning to come back together. It's been over 2 years since the storm took my antennas and tower down. Today we got more antenna work finished, and it's much closer to being completed. 
 

The 5 element yagi for 6 meters and 13 element yagi for 2 meters SSB (horizontal) are now installed at 108' and 111' respectively, feedlines installed & terminated, and other tower maintenance done. Still have to install stuff for 2m / 220 / 440 FM, and raise the 160, 80, & 40 meter antennas from 65' to abt 100', and 30 meters to about 90'.

 The 13 element 2M SSB yagi propped up against the house, waiting to be pulled up the tower.

 Looking to the NW at about 80'. You can see the top guy wire coming down from above in the photo.
 
 The view as I was climbing up the tower. The work / tool bucket was already tied to the tower near the top...

  Looking down from the rotator shelf at about 100', at the 2m SSB yagi to be installed with horizontal polarization at about 111' on the tower.

 Looking up at the mast where the yagi's will be installed...

 Looking to the west from under the 2M SSB yagi at about 111'.

 Looking up through the HF, 6m, and 2m yagis while on the tower.

 Looking to the west at about 105', just below the Force-12 HF Yagi...

 View to the east at about 105', under the Force 12 HF yagi


 
 Looking straight up the tower at the yagi stack. More antennas coming to fill that space :-)

 An opening in the trees frames the view of the new yagi stack from the back yard.

 Looking up at the tower and yagi stack from the rear deck.. More tower work coming soon!


Dave WB4IUY
http://www.WB4IUY.net














Thursday, May 10, 2018

Rebuilding a Cushcraft A3S HF Yagi...

This is one of the Cushcraft A3 Antennas I had, this one was on the tower when it came down in the storm on April of 2016. It was bent up and broken pretty bad, but considering they're selling new for $600 + freight these days, it's certainly worth rebuilding. I started by sorting through the wreckage, and trying to figure out what parts went where...


It was pretty bent up and broken, but I was able to kinda sort it all out. Some parts were removed from the trees, some parts were still attached to the mast, and some parts were broken off and scattered across the back yard. I located the boom, removed all of the brackets and such, and put it to the side...


Next, I gathered up the various bits and grouped them together by element... reflector, driven element, and director parts. I bundled it all up in groups, and stored it away for later. After all, I had another HF yagi to put on the tower and bigger fish to fry first, but planned to come back to this and rebuild it later. 



Well, 2 years passed, and I've rebuilt all of the other antennas for the tower. I have installed a Force 12 6 element HF yagi, and the others I recently rebuilt are ready to go back up. Now the time has come to get this beast rebuilt and find a new home for it. I restarted this rebuild by first cutting out the bad and broken sections, and straightened the other parts (elements and boom sections). I will order some aluminum tubing to splice or replace the damaged sections where necessary (not that many places, surprisingly!). 

I decided to disassemble every trap, clean them out, check the internal connections, and replace all of the plastic end caps on them. The real chore was to sort the traps and label them, since there are no permanent markings on them... the TB & TC traps all look the same. I found a chart on the web that told the approximate resonant frequency of each trap, built a simple coupler for my MFJ antenna analyzer to use it as a dip meter, and checked each trap. They're now tested, tagged, and waiting for new end caps...





That's it for this blog, I'm waiting on some aluminum tubing, new stainless steel hardware, and replacement end caps for the traps / elements / boom. I'll probably build a new and stronger center insulator for the driven element, next...

Dave WB4IUY
http://www.WB4IUY.net











Sunday, May 6, 2018

Building a 7 EL 220 mhz Yagi from the Scrap Pile...

Another of the antenna that was destroyed in the tower crash was my 11 element 220 mhz yagi... It was originally installed with vertical polarization, as I used it mostly for FM simplex with some friends about 30 miles away, and for some of the local repeaters. It was really torn up... a section of the boom and 4 elements were crunched up and broken so badly, there was no hope for that part of the antenna.

I decided, rather than spend $$ to put it back like it was, to salvage when I could and build a 7 element version from the wreckage. That should be more than adequate for my 220 mhz FM needs without spending any money for materials or hardware.By salvaging the materials and hardware from the scrap pile, this yagi cost my $0...my kinda price!

 This was all of the materials and usable parts left from the once 11 Element Long Boom Yagi...

 I disassembled the antenna, straightened the boom and element sections in my redneck tubing straightener (see previous blogs about that), and began measuring the boom for the proper element locations (based on info I found on the web for a 7 element 220 mhz yagi).

 The boom was reassembled, and redrilled for proper element placement. Once reassembled, I had to find a new balance point for the boom-to-mast clamp.

 The antenna was clamped to my test tower section for tuneup. It's installed upside down in this pic (matching rod down, should be above the boom)...

 The antenna tuned up OK, and it ready for installation on the primary tower...

Another look down the boom from the front of the antenna. All finished and ready to go!


Dave WB4IUY










Saturday, May 5, 2018

Completing a 13B2 2M SSB Yagi (re)build...

The 2nd evening of work on this antenna went pretty quickly...mostly just assembly of the parts that had been straightened, cut to length, salvaged, etc. This antenna went together well, and I got it bolted up to the test tower section for tuneup. The SWR match was great, and adjustment went right by the Cushcraft instructions. Here's a few pics and info...

 All parts and hardware, ready to go together...

 Bolting the elements to the boom....

 Assembly almost completed...

 Checking for element alignment...

 Bolted to a piece of tower, set up to test the antennas I'm rebuilding...
 
Ready to install on the primary tower!  This was totally built without sending a penny, just by salvaging all needed and materials and hardware from the wreckage. Time to start the next antenna (re)build from the scrap pile :-)


Dave WB4IUY
http://www.WB4IUY.net












Thursday, May 3, 2018

Building a 13B2 from 2ea 13B3 Yagi's...

Wow, the storm of April 2016 that wrecked my tower, converted 17 antennas into scrap metal. I kept what I could in a big pile, with plans to eventually rebuild as much as possible from the wreckage. I had a 13B2 on 2m FM, and a 13B3 on 2M SSB. I was able to salvage enough elements and boom tubing to build a 13B2 for 2M SSB :-) Let's get started...

I can't find the photo of the original pile, but it makes this pic look like new antennas :-) I picked and saved as much as I could, some of the parts were so smashed up that there was no way to use it for anything.

Here, I began to lay out what I had from this and another antenna that could possibly be straightened, repaired, and reused. It became obvious that there was probably only enough good or repairable parts to build a 13 element 2 meter yagi. At 112' with good feed line, that'll still do a good job for me. Being a tightwad, I try to build or restore as much as possible.

This is a section of boom stock that I think I can repair in my redneck tubing straightener. Read my previous blog on the 6m antenna rebuild for more info on that hi-tech device.

Boom stock after being reworked in my redneck tubing straightener.

Here's a pile of parts I have salvaged from the two antennas. Elements of various lengths, element mounting hardware, driven elements, etc.

Boom straightening and assembly almost finished here, just a little tweak here or there neeed for a perfectly straight boom, now...

  Back in the shop, I sorted the elements, cut them to the required lengths where needed, and labeled them for re-installation on the boom. Enough for today...time to call it quits on the project and return later to finish it...


Dave WB4IUY