Showing posts with label 15m. Show all posts
Showing posts with label 15m. Show all posts

Monday, September 30, 2024

Cycle 25 is Kicking Butt

Don't know why I didn't write about this when it happened.

August 9th, the daily Sunspot Number (SSN) was 382. That seemed enormously high. I couldn't remember a single time when the SSN was that high. So, I did some digging.

I downloaded all the SSN data, converted into an Excel spreadsheet and did some analysis. The SSN hasn't been that high since 1991. That's 33 years ago!

The SSN has only been this high a total of ten times in my lifetime (since February 1961) -- Five in 1979, Twice in 1989, and Three times in 1991. 

Of course, none of this compares with Cycle 19, where daily SSN values were well over 500 for many days. But those values all happened 1956-1959, well before I was born.

Cycle 25 is shaping up to be much better than Cycle 24, which was really lousy, and possibly better than Cycle 23.  The smoothed SSN has already exceeded the maximum value for Cycle 24, and it is far from over. 

We've already seen a huge change in the bands in the last couple of years. 20m is open 24 hours, and 15m much of that time. 12 and 10m is open every day. I'm hoping we might see some 6m F2 openings. Enjoy it while you can. We should have two more years of these conditions before the cycle starts back down.

Monday, December 28, 2020

A3S/A743 Refurbished - Rotating Once Again

A3S/A743 QRV @ 15m
Since I took it down back in October, the A3S/A743 is once again proudly back at the top of my tower. It's been something of a long ordeal.

Refurbishing the antenna was delayed when I had to wait eight weeks to get traps out of MFJ -- they, like many companies have been greatly affected by the Coronavirus. Indeed, their biggest problem is getting parts from their suppliers, who are likewise affected.

Even after getting the parts, I had a lot of trouble tuning the A3S somewhere close to the bands. That required a lot of jockeying on the tower. It did give me a lot of time at the top of the tower, something that is always a confidence-builder.

I had a little trouble with the rotator yesterday -- one of the connector lugs came off the pigtail. This meant that while the rotator was in place, it wouldn't turn. I was tired from the long climb yesterday, and fixed it today. 

The good news is the antenna seems to be working correctly. I haven't worked a lot with it, but I'm sure I'll get a chance during the RTTY Roundup this next weekend. 

Hopefully, this antenna should serve me well for many years to come -- the initial installation worked for over fifteen years. Fifteen more would be fine by me.

Next project will be to fix the WARC trap dipole and put it back up.


Saturday, December 19, 2020

Tuning the A3S/A743

Adjusted A3S/A743, ready for rotator.
After adjusting the A3S/A743 on the ground and getting it back on the tower, I was very disappointed to find the SWR dips for each of 10, 15, 20 and 40m were all outside the band. They were all too low. This surprised me. When I measured the antenna with the beam facing upward, the dips were very close to the band. Now that the antenna was on the tower, it was going to be more difficult to adjust.

Rick Dougherty, NQ4I, gave me an important tip. Always measure horizontal antennas horizontally. Don't attempt to make measurements with the antenna vertical. With the antenna 6-8 feet off the ground, you can get a good sense of the measurements, knowing that the antenna will rise in frequency as it moves away from the ground. Generally by about 100-300 kHz at the 30 or 40 foot level. As you move further from the ground, the effect lessons. 

Rick knows his stuff -- he built a superstation in Griffin, GA, and has experienced this phenomena putting up dozens of antennas. 

OK, I didn't follow Rick's belated but sage advice - what should I do now? I didn't want to take the antenna off the tower again, it was a lot of trouble to get it up there in the first place. I decided I could make adjustments similar to how I added the A743 option originally - by tipping the Driven Element (DE) vertically and climbing down the tower.

On the tower adjusting
the now vertical DE.
One the first climb to make adjustments, I could already see part of the problem - some of the DE joints had slipped outward while the antenna was waiting to be installed pointed vertically. The extra weight of the A743 parts probably had something to do with this. 

Loosening the U-bolts for the DE and the support mast, the DE tipped over easily and I was able to climb down the tower and adjust. I had to make some of the adjustments somewhat blind, since I could not easily put a measuring tape against the elements. 

I ended up with the 10m traps out about 83.5" (A), the 10 and 15m traps spaced as 6" (B), and the 15 and 20m traps at 18.75" (C) -- this was the lower limit, since the tubing ends were contacting each other inside the support tube. the 40m portion I extended to about 66". These measurements are for each side of the DE.

This took two climbs, and ended up with the 10, 15 and 40m SWR curves well centered in the bands, and 20m right at the bottom of the band. This isn't perfect, but it is usable. Note I did not make any adjustments to the Reflector or Director, as they are well out of reach.

Next time I set up an A3S/A743, I think I will adjust the 10 and 15m portions to the MID-band settings, and split the MID and CW settings for 20 and 40m. That's roughly where I ended up anyway. 

I'll also consider replacing a lot of those stainless steel worm clamps. After being out in the weather for 30 years, a few of them would not tighten the way I would like. 

The A3S/A743 should be ready to go after one more climb to raise the antenna and install the rotator. I also plan to tweak the support mast a bit higher to keep water from accumulating in the 20m (TK) traps, since that's likely how they failed in the first place. 



Wednesday, December 16, 2020

4U1UN (and 4U75UN)

A little more than a year ago, I was looking at the Most Wanted list in ClubLog. I noticed that the United Nations HQ entity was number 30 on the list. In all my years of ham radio, I had never heard them on the air, much less worked them. I wondered if I'd ever have the opportunity to work them at all.

Well, the 4U1UN club has been busy, and late fall 2019, they finished their installation which allows them to remotely operate a transceiver near the top of the UN towers from a room on the ground floor of the building. Since that time, they have been sporadically active. 

I don't know what the rules are for operating 4U1UN, but the station has been active at least some time every month during the past year. They have gone from an entity you'd wonder if you'd ever work, to one that can easily be worked by anyone with a bit of determination.

Over the past year, I've kept a running DX Watch query going to see when they were on the air, and worked them any time I could hear them. They've been easy to work even with compromise antennas.

They confused me in September, as I thought they had gone silent. No, they just switched callsigns. They are celebrating 75 years of the UN with the call 4U75UN. There's a special certificate for working them. They should continue with that call until December 31st.

They'd be pretty easy from the USA on 160m, but I don't believe anyone has ever operated on that band. I doubt they have an antenna, and I head the noise level in NYC is extraordinarily high.

They QSL promptly through LoTW (be patient, it may take a week or two to be uploaded). I've gone from wondering if I'd ever work them to having them confirmed on nine bands (80m-6m) and three modes: CW, Phone and Digital. 

Keep an eye peeled on the spotting networks, and perhaps you can work a new one.

Sunday, November 1, 2020

Rebuilding the A3S/A743

I've had the A3S/A743 down for several weeks now. I've gotten it mostly rebuilt, but I'm waiting on parts. More about that in a moment. 

I wrote previously about my inspection of the traps. The 20m TK traps are completely toast. But the TA (10m), TB and TC (15m) traps appeared to be fine. All the plastic end caps, however, were toast.

This particular A3S/A743 has been up for a while. I originally purchases the A3S in 1991. It spent three years in the air at the old Stone Mountain QTH, then several years in my basement in Gwinnett. Then it spend a couple of years on W1YM's tower while he was waiting for his Skyhawk to be delivered. And nineteen years at the Gwinnett QTH. All told, that's twenty-four years exposed to the elements. The A743 40m option has only been up fifteen years. 

A few years ago, I bought another A3S at a hamfest for $100. Such a deal! This unit was manufactured in 2007 and does not appear to have been outside for any length of time. The plastic end caps on the traps look practically new.

During the rebuild, I decided to use the TA, TB, and TC traps from Cushcraft #2 on the Cushcraft #1 tubing and vice versa. Cushcraft #2 isn't going up any time soon (perhaps when I move to another QTH and can build a 70 foot / 35 foot stack). I figured I would use the least weathered traps on the antenna that I'll be using. 

I used No-Al-Ox liberally when I assembled the A3S nearly twenty years ago. After nineteen years in the weather, much of the original application had evaporated, but the sections came apart easily after unclamping. The traps from Cushcraft #2 had never seen a drop of No-Al-Ox, unfortunately. So, as I intermixed the parts, I made sure I applied some to every joint. 

I ordered all new trap end caps, boom and element end caps from MFJ, along with new TK traps. Laird communications sold off Cushcraft several years ago to MFJ. I was happy that parts were still available. However, the ordering system left much to be desired. MFJ is in the middle of a web site re-design, and there's no way at present to order individual parts. Their older web site would list parts on the same page as the product, and you could click through to the parts link to order each one. Why they would switch to a new web site that doesn't have this capability is beyond me. 

A call MFJ with all the proper part numbers, I ordered everything pretty easily. Then it got weird. The gentleman on the phone didn't tell me the total of my order, he just guessed it would be $130-140, which is about what I expected. He estimated my order would ship in two weeks, and that I should see an order confirmation email and another email when the order shipped. All good, I thought.

Then I noticed my credit card was charged $169.90 almost immediately after I got off the phone. I waited a few days, but I received neither a order confirmation or shipping confirmation email.

This is not right. Indeed, this may be illegal. You're not supposed to charge someone for an order unless their goods have shipped. That's how it is supposed to work. I called and asked about it, and they said they corrected my email address and I should get a confirmation. My order hadn't shipped yet, because the TK traps needed to be manufactured, and that would take at least two weeks. Fine. But, then I didn't receive any order confirmation emails. A week after my original order, I called again, had my email address corrected again, and asked that a confirmation email be sent. This time, I received it. At that time, I was told my order would ship in ten days. 

And, sure enough, ten days later, they shipped something. I was surprised when I received a very small box -- clearly not large enough to contain the two TK traps. Opening it, I found my entire order of plastic end caps. But no traps. 

It's now been four weeks since I placed my order, and no indication they are shipping the traps that take them two weeks to manufacture. There have been at least two good weekends for putting the tribander back on the tower, but without traps, I can't finish the assembly.

Keep your fingers crossed I actually see these traps sometime soon.




Sunday, October 4, 2020

A3S/A743 On The Ground

A3S/A743 on the ground

I've known for some time now that my A3S/A743 has problems. Back in March 2019, I noticed that one of the 20m traps was arcing. Then a couple of months ago, I could see that several of the trap end caps were either missing or damaged. 

It's taken me several tower climbs to bring this antenna to the ground, but this weekend, we were finally able to successfully lower it down without incident.

My daughter Lauren acted as my ground crew and did an excellent job. I couldn't have done it without her.


Antenna mounted on tripod

Once the had the A3S/A743 on the ground, the next process was to carefully mark, measure and inspect the antenna. I didn't want the antenna lying on the ground. I had a roof tripod I'd picked up somewhere along the way, and with a short piece of mast, it allowed me to work on the antenna horizontal at ground level.

As soon as we had the antenna on the tripod, I marked all the traps. The original Cushcraft trap markings weather off rather easily. I used a sharpie to indicate the element, trap band, and an arrow pointing toward the boom. It will be important to reassemble the antenna with the traps in the correct direction.

DE traps showing disintegrating
end caps.

Next step was to mark all the element distances. This just required a quick sharpie mark at each tubing junction. 

After this, I got out a clipboard and a measuring tape, and took measurements of all element segment lengths for all three elements. I wanted to see how the antenna measurements matched up with my records. As it turns out, even after 19 years in the weather, the director and reflector elements were spot on. The driven element was a little asymmetric -- that likely happened when I added the A743 kit in 2005. 

DE support rope covered 
in lichen.

With the marking and measuring done, it was time to inspect the antenna. Overall, all of the aluminum tubing appears to be in fine shape -- nothing bent, warped or cracked. The traps were a concern. All of the trap end caps were either missing, damaged, cracked or weathered. Three of the element tips were missing, even the boom end caps bad broken. 

My daughter Lauren noticed the lichen growing on the antenna. Lichen covered a few trap end caps as well as the entire DE support rope.

I was surprised to find the bead balun in such good shape after 19 years. The feed line it surrounded seemed rather weathered, and it is my intention to replace it.

Next, I disassembled the antenna. Because I used No-Al-Ox 19 years ago, separating the sections was easy. Once a clamp was loose, they slid right off. I removed the traps and outer sections, leaving the center part of the elements intact. The outer sections I stored in my basement, and the traps went to the workbench. The boom and center part of the elements, I lashed to my back porch for now. 

With the outside work done, it was time to inspect the traps. I pulled all twenty-eight end caps off. Maybe four or five were intact, but even those are heavily weathered. I blew all traps out with compressed air, finding surprisingly little material come out, which I took as a good sign.

The two 20m (TK) traps were a concern. These traps I saw glowing back in March 2019. One of the end caps had melted. With the end caps off, I could see the outer end insulator on both traps had melted.

Only a little char on this one.
To know how bad it was, I had to disassemble the 20m traps. Disassembling these traps is a difficult proposition. The outer end of the trap cover is dented inward in four places to hold on to the end insulator. Because of this, it can only slide outward. The inner end of the trap cover has a double-z bend to make connection to the element tubing. If you undo the bend, the cover will slide off outward. But undoing the bend will likely break the aluminum. 

A lot of char on this one...

For the 20m traps, the outer insulators were toast anyway, so I didn't have any trouble sliding the trap cover inward. I just had to remove the screw at the double-z bend first. 

What I saw inside was not pretty. Both traps were damaged due to arcing and will need to be replaced. 

I also disassembled one of the 15m DE traps. Of course I broke the double-z bend in doing so. However, the inside of the trap looked clean, and, unlike the 20m trap, the coil windings were protected with resin. I didn't think it was worth disassembling any more traps and breaking more double-z bends.

I believe the 20m traps may have suffered from too much droop on the elements and collected a lot of moisture inside the trap. Once fired up with RF, it arced and toasted the traps. 

Some of the traps had corrosion evident around the hold-down screw on the trap covers. I removed the screw and put a thin layer of No-Al-Ox between the z-bend and the trap element tubing. This should limit further corrosion in this joint.





Sunday, August 2, 2020

OK, That's Not Good

Noticed today while I was mowing grass that two of the traps on the A3S/A743 -- the 15m trap on the director and the 20m trap on the driven element -- both have end caps that have come off the traps. 

This means the traps are exposed to the weather, insects and what not. 

That's not good. 

Indeed, from the ground, this antenna isn't operating correctly, either. The SWR is over 2 to 1 on 15 and 10m, and the antenna doesn't seem to be that effective on those bands, either. Only a little bit better on 20 and 40m.

The A3S has been up since 2001. I added the A743 in 2005. That's been 15 to 19 years exposed to the elements. It's not surprising this antenna needs maintenance.

I've got the gin pole on the tower, just need a couple of days at the Gwinnett QTH with a little help to get that antenna on the ground.

Saturday, December 21, 2019

Replacing the AL-80A Bandswitch

The AL-80B bandswitch, compared to the existing switch shaft.
With my wallet being $115 lighter, the AL-80B bandswitch arrived within a week. Now, it isn't the same as the original AL-80A bandswitch.

There are two key differences. First, as you can see from the picture, the shaft layout is different. In the original AL-80A bandswitch has the input network switch wafter in front of the bandswitch, whereas the AL-80B has it behind the bandswitch.

This means you can't just replace the AL-80A switch with the AL-80B switch. The best you can do is to unstack the wafers and put them on the original AL-80A switch shaft.

AL-80B switch with AL-80A wafers.
The second difference has to do with the switch wafers. Electrically, they are identical. The AL-80B switch has the 160m padder cap and the Pi-L network wafers reverse. Since we're going to re-stack the wafers anyway, this doesn't matter.

The Pi-L wafer is positioned differently. The contacts are two positions counter clockwise (as viewed from the front of the shaft) from the AL-80A. This means that a bit of re-wiring is necessary to make the connections.

Wafer-less switch.
Removing the switch wafers isn't a big deal, since I have done this earlier. The rear wafer comes off with all the coils attached, and the padding caps unscrewed, there being only one wire that needs to be unsoldered, and it slips off. The middle wafer has a similar wire to be unsoldered, and it comes off as well. The front wafer has one wire to the padder cap, and it comes off as well.

With all the wafers off, the new switch wafers are stacked on. Because the Pi-L wafer has contacts rotated two positions, they are a little harder to access between the switch and the loading capacitor.

New wafers in place.
Once all the wafters are on and screwed down, the next step is to re-solder all of the connections. I took lots of pictures before unsoldering the old wafers, so I had a pretty good idea of what goes where.

Front switch wafer anchors the coax shield, and adds the 160m padder cap. The Pi-L switch wafer was the only one that gave me trouble. Since the contacts are rotated from the original, this required a bit of extra wire to make the required connections. The rear switch wafter has five connections tot he coil assembly. It took a bit of work to unsolder. This sort of thing is best not rushed and done with great care, to avoid damaging the coils. Everything goes in the same place on this last switch wafer, which was easy once I got all the coil wires into the right positions in the narrow switch contact lugs.
The finished product. Reassembled with new switch wafers.

Sounds easy, eh? But realistically, it was nearly three hours on the workbench.

Moved it back to the operating desk and tested for full output into a dummy load on all bands. No problem on 160, 80, 40, 20, 15 and 10m.

For 17m and 12m, I proceeded more cautiously. The AL-80A is designed to operate on 12m using the 10m switch position. It works on 17m using the 20m switch position. But it has often been on 17 or 12m that I've had the most issues with arcing in the PA circuit.

For this reason, I've decided to reduce drive to about 30 watts for 17 and 12m. It's a little less output power, but also less of a chance of burning up a $115 bandswitch.

With the testing done, it was time to button up the amp. Took me about 20 minutes to find 10 of the 13 screws that hold the cabinet top on. I had removed them a year and a half before, but finally found them in a neat pile on the workbench.

The AL-80A is back up and running on all bands!










Sunday, August 25, 2019

Rebuilding the HF4B

It's been a long time since I picked up the Butternut HF4B project from a friend. I decided it would be a good fit at the Fulton County QTH. It's small enough to be supported by a mast, and will turn with a tiny rotator. I took all of the pieces to Fulton County, disassembled and cleaned everything, and took stock of what I needed.

The basic components seem to be OK. One of the 1/2" tubes is damaged with a gouge near the end, nearly ran over by a lawnmower no doubt, but will be serviceable. One of the 1 1/8" element support tubes has a crack. I've looked for a replacement locally without luck. I think for the moment I'll use a clamp to hold it together.

Two of the four doorknob capacitors have cracked. I managed to find five 75 pF caps at a hamfest a couple of years ago. I bought five in order to have a spare. These things are fragile.

All of the stainless hardware is serviceable despite being out in the weather for over 25 years. The U-bolts, however, are another story.

I don't know what genius thought it was a good idea to sell an antenna with zinc-plated U-bolts, lock washers and nuts. After 25 years of weather, they are rusted junk. Some of the legs broke off when trying to undo the nuts. Those that didn't are so rusty as to be unusable for any purpose.

I ordered replacement U-bolts from McMaster-Carr, who had exact replacements for a reasonable price. Except these are stainless steel.

With replacement hardware in hand, I started to re-assemble the antenna. The wires of the bowtie elements needed replacement. This antenna has eight of these, but only four survived to make it home with me. Of these, only one is intact. I used it to make measurements and make eight identical replacements.

I hit the a snag assembling the first element. The clamps that hold the vertical tubes aren't tight enough to keep them from rotating on the support tubes. Butternut replaced these sheet metal clamps with U-bolts in a later release, which would work better. This requires sleeving about four inches of the vertical tubes.

I guess that's what I'll have to do.

Monday, March 25, 2019

Rotating Again!

Well, it didn't take months after all. As I wrote last month, my A3S/A743 had been stationary since December. But with the beautiful spring weather here in Georgia, I managed to get to the top of the tower and finish the installation.

It's now rotating freely, as expected. It's really good to be able to use the beam as intended, and not have it fixed roughly east.

I do wonder if the A3S/A743 needs repair, however. I'm still seeing occasional SWR shifts at 100 watts on 40 and 20m. I'll need a gin pole to take the antenna down to refurbish.

Thursday, February 28, 2019

Back on the Tower Again

During my December vacation, I started a rather ambitious project on the tower. Since its installation, my A3S/A743 has been about eight inches from the very top of the mast. My intent was to put the beam at the very top of the mast, in order to give more room to stack an A50-3 under it.

It had been a while since I climbed on the tower, and any work at the very top is always nerve-wracking. As I've written before, sometimes you get up there and decide you've had enough.

Anyway, back to the December project. I conscripted my daughter Lauren to be my ground crew. I ascended the tower, removed the rotator and hung it from a couple of nylon loops off the side of the tower. Then I lowered the mast into the tower, until the A3S/A743 bracket was right at the top of the tower. The mast and antenna are somewhat heavy, weighing about 50 lbs. I relied on a pulley at the top and bottom of the tower and a haul rope to get support from my ground crew.

The tricky part of this operation was going to be moving the antenna higher on the mast. I had two options. First, I could loosen the bracket U-bolts, lift the antenna higher, then retighten. This would only take me about five hands, and I was only born with two. Second, I could loosen the bracket U-bolts, then lower the mast into the tower. While this seems easier, I had visions of the mast going too low and the antenna falling off the tower. Plus, I was afraid that we'd drop the mast and it would fall some 40-some feet into the base of the tower. And then the antenna would fall off the tower.

Plus, my daughter was having a lot of trouble getting sufficient leverage on my pull rope, which was 1/4". After being at the top of the tower a little over and hour, I decided to continue the project later.

Little did I know that it would take two months before I could get back up there!

In the intervening time, I had purchased 120 feet of 9/16" braided black poly rope. Our first order of business was to replace the existing 1/4" rope with this much more substantial lanyard. Once again with my trusty ground crew, we set out to complete the project.

With the bigger haul rope installed, I surveyed the top of the mast. I had thought that perhaps the antenna had slid down the mast in the 18 years it has been up. But a close examination of the mast showed no evidence of that. It had always been at that level.

Standing there 40-some odd feet in the air, 20 feet above the edge of my roof, I wondered if loosening the antenna would get me into a whole new world of problems. I decided at that moment I wasn't going to mount the A50-3 under the larger beam. What we needed to do was hoist the mast back and up and put the rotator back in place.

This proved to be a problem. Despite all her hauling away on the rope, Lauren was unable to raise the mast any significant distance. It was only with me grabbing the mast with two hands and pushing we were able to move it at all. I ended up locking down the mast with a couple of bolts in the tower and climbing down to solve the problem.

I had a ratcheting come-along, but hauling it up and using it on the tower was problematic. I ended up tying the come-along to a support pole, then hooking it into the haul rope via a tied loop. This would allow Lauren to use the come-along to provide lift, and I could manage things at the top of the tower.

After climbing back up, things moved a little more quickly. The come-along provided plenty of tension, but I found that I had to move the mast with my hands to get it to budge -- there's just too much friction and too much stretch in the poly rope. In a few minutes, we had the mast nearly back up into position. I had to re-position the pulley to get the last few inches to make room for the rotator.

With the mast locked down again, I hauled the rotator back into position. Thereupon I discovered two problems. First, one of the four nuts on the U-bolt that clamps the rotator to the mast was missing. In the two months on the tower, it apparently shook loose and fell off. Second, the rotator connection at the base of the rotator were loose -- one of the forked lugs had fallen off the wire and would need to be replaced.

Not having the necessary hardware at the top of the tower, I finished as much of the assembly as I could and came down the tower knowing that this project would be finished on another day. Hopefully, it won't take a couple of months to get back up there.



Wednesday, September 14, 2016

Ameritron AL-80A - Fixed!

AL-80A re-assembled, needing just 3-500Z and cover.
As I wrote previously, my AL-80A needed a repair. The plate choke was burned, with several windings melted, the protective diode and capacitor on the B- rail to ground had gone open, and I'd found that the amp would not tune on 160m -- due to some melted switch contacts.

I thought it might be a while before I could get around to doing this -- considering the last repair took about a year. However, since I had some parts on hand, I put the amplifier on the bench and got started.

1N5308 diode next to glitch
resistor on rectifier board. And
the replaced capacitor below.
First order of business was to fix the protective circuits on the B- rail. I removed the 1N4007 I had installed earlier. I tested it and found it to be completely open. Which is pretty much what I expected, given that the capacitor had opened destructively....

I replaced the capacitor with a fresh part, and installed a 1N5308 diode, as recommended by W8JI. And I mounted it on top of the board this time.

Next part to arrive was the Ameritron Plate Choke (Part Number 10-15197). It was a thing of beauty, and despite the package having a nice accordion dent in one corner, was intact.

Replacing the choke was actually pretty easy. I figured out I had to unsolder the wire to the parasitic suppressor and plate cap connector, and then the two blocking capacitors. This was much easier with the tube removed. (I put the tube inside the plate choke's packing box). I then removed the mounting screw and unsoldered the high voltage and the bypass cap.

Beautiful new choke installed.
Oh! Did I mention that you need to unplug the amplifier and make sure the plate circuit is completely discharged before sticking your hands into the amplifier? No? Gosh, that would be dumb. Of course, you do that first.

The old choke had a teflon washer under the ceramic, but it completely disintegrated when I removed the choke. I decided it wasn't required, and mounted the new choke directly to the sheet metal base.

The new choke had a slightly different geometry with respect to the lugs at the base and top. I decided to loosen the lug on the top and rotate it about 100 degrees. Otherwise, the blocking caps were not going to reach. To move the lug, I first had to unwind the top end of the winding and re-wind it to the lug. I think the choke wire ends were unsoldered for this reason.

Once in position, the lugs were easy to solder.

The final task replaces the melted switch contacts. I must say I got a lot of positive answers from the Amps email reflector (amps@contesting.com). Their diagnosis of my issues was spot on, and I got a lot of helpful advice.

Vic Rosenthal 4X6GP sent a link to an article about band-switch arcing on the Heathkit SB-1000, which essentially was a clone of the AL-80A. He suggested I should add the corona washer, which would help prevent more melted switch contacts. From what I can tell, my AL-80A is a very early model, and it did not have this modification. George Hall N2CG also sent me an email with pictures of the washer.

A huge thank you to goes to Louis Parascondolas, who not only wrote to me with suggestions on how to replace the switch contacts, but mailed me six contact elements (I needed four), plus the brass 2-56 hardware needed to secure them. Thank you, Louis!

Switch wafers disassembled. This was the hard part.
On left is the wafer where the contacts were replaced,
shown with contacts removed, and glued.
Replacing a switch contact isn't a huge deal. The first step is to remove the switch wafer. That took some doing. I deduced I could accomplish this without doing a lot of desoldering and re-wiring. The rear bandswitch wafer is basically connected to the coils and a couple of padding capacitors. One end of each coil was fastened to the capacitor studs, which simply required removing a couple of nuts. The larger coil had two small phillips screws holding it to plastic mounting blocks. The padder capacitors could also be unscrewed from their lugs. Easy right?

Not so fast! a single wire needed to be unsoldered connecting to the loading cap, and the rear switch wafer slid off with both coils attached.

The second wafer just had three connections, easily desoldered: coax and coil end, coil tap, and the cap. Once those were removed, it slid off.

The third wafer is the one we are after. I unscrewed the connection to the plate padder cap, and slid it off with the coax connection in place. That made it easier to unsolder the coax.

Once you get these wafers off, you have to handle them very gingerly! They are delicate ceramic and can easily shatter. The tricky part is to remove the old contacts. I recommend a drill press and very small drill bits to drill out the rivets holding the contacts in place. Gradually go to larger bits until you have removed all of the rivet material. Go very slowly because you don't want to break the ceramic switch wafer.

This is what I told myself, and I managed to get the contacts off with no trouble. I still had the shell of the rivet, which I carefully drilled out of the first hole. The last hole, of course, was a problem. I broke the switch wafer.

New switch contacts engaged for 160m.
I apparently said something aloud which brought my younger daughter into the basement to see if I was OK. (I was) The wafer was now in three pieces. What to do? I decided that I could glue the three pieces together, and it should hold. Superglue to the rescue! The glue took easily to the ceramic, and soon I couldn't tell where the split was.

I cleaned as much of the burnt contact debris off the two switch wafers as I could. When I was done, you could not see any discoloration of the L network (second) wafer, but there was still a little in the contact well of the 160m padder (third) wafer. The contacted would cover that up.

Adding the four contacts to the switch wafer was really easy.

Getting all the switch wafers re-assembled was the hard bit. I added the coax ground connection to the 160m padder (third) wafer, but I held off on the padder capacitor connection until the very end, so I could place the corona washer.

The L network (second) wafer was a bit problematic. I couldn't remember the orientation of the switching portion of this wafer, as there are two ways to put it on. Then I couldn't remember which wires went where. More pictures before disassembly would have been helpful. Studying the schematic made it clear which way things went.

Corona washer in place.
The bandswitch (first) wafer was easier. The tricky bit was soldering the connections to the loading capacitor.

Last bit was to install the corona washer to the padder cap. A brass washer was specified, but I didn't have one in the junk box. I made do with a steel washer and a lot of solder. I verified the continuity of the connection with an ohmmeter. Perhaps I'll redo this the next time I have to fix the amp. (which I hope may be a while)

After any fix like this, there's always the moment of truth. No sparks turning it on, and a quick test on a dummy load proved it tuned up with no surprises on 160, 80, 40, 20, 15, 10, 12, and 17m.

Ten minutes later, I had replaced all 13 cover screws and was already using the amp to chase DX on 40, 20 and 17m.

Working great again!

Monday, April 18, 2016

DXCC - Meeting the Challenge

Since I started uploading my logs to the ARRL Logbook of the World in November 2003, I've been working toward the DXCC Challenge. I've been carefully trying to work DX stations on multiple bands, hoping to get my current entity-band totals past the Challenge threshold of 1000.

Well, sometime this weekend, I received enough confirmations to get me past the 1000 mark. At the moment, I have 1003 entity-bands confirmed.

I guess I'll be submitting an application for the DXCC Challenge this year! That along with 30m DXCC.

UPDATE: I also notice that I have exactly 239 current entities confirmed for Mixed DXCC. This means I'm exactly 100 entities away from working all 339 current entities, or 91 away from the DXCC Honor Roll.


Saturday, April 2, 2016

DXCC - Excellent Service!

CP1FF QSL clearly shows 15m Phone.
I recently uploaded all my logbooks to ClubLog, and I was trying to reconcile my DXCC credits with those shown in LoTW. While doing this, I noticed something odd.

Back in 2009, I submitted a hybrid application for Phone DXCC using, 52 LoTW credits, and 10 paper QSLs. Among the paper QSLs was one for an SSB contact with CP1FF on 21 MHz.

I received credit for Bolivia for my SSB contact, so I didn't think much of it. However, in trying to reconcile with ClubLog, I noticed that the credit was apparently entered for 80m instead of 15m.

I've never worked CP1FF on 80m. Indeed, I have never worked Bolivia on 80m at all. Why did I have credit for it?

A quick email to the DXCC Admin sorted this out right away. She changed my credit from 80m to 15m, as it should be. Thank you!

Of course, this means I'm one more entity further away from 80m DXCC....

Saturday, January 9, 2016

Project From a Friend - HF4B

HF4B Parts, after sitting out in the weather
for about 25 years.
I had a friend call me the other day. She was licensed about 25 years ago as N4VMN, but her license has since lapsed. In any case, she had some antennas that had been sitting out at beside her house in Marietta for quite a few years now -- she wanted to know if I might know anyone who could make use of them.

Well, I'm always interested in antenna projects, and I could certainly use some smaller antennas, so I said, sure, I could use them.

She had a slightly bent Ringo Ranger, and an old Butternut HF4B. Ah, the Butternut HF4B. I had one in Stone Mountain, GA from late 1987 until 1991, when I replaced it with a Cushcraft A3S.

N4VMN lived in another part of the same subdivision back then. She gotten licensed, bought a rig, and put up this antenna on a roof tower -- and she did it all without consulting me. While I was a bit disappointed I couldn't have given her advice, I was still impressed that she managed to do it all herself.

My experience had been that the Cushcraft A3S worked way better than the HF4B, but the Butternut was a solid performer.

The HF4B is a light-weight, trap-less tribander that uses large bow-tie shaped elements and a clever matching network. It supports 10, 15 and 20m, also also works on 12m. I never could get mine to match well on 12m, but it worked OK on the other bands. Being only two elements, it didn't offer a lot of gain, but had solid front to back. On difficulty in dealing with this antenna was it was so three-dimensional, as the bow-tie supports go three feet above and below the elements. Overall, though, it is pretty small. It can be easily turned with a small TV-type rotator.

N4VMN's antenna had spent a couple of decades outside next to the house. I expected after all this time it might need some repairs. The U-bolts are all shot, and will need to be replaced. The bow-tie supports were all bent, but look repairable. All of the bow-tie wires were broken or missing. The matching network tube supports were all bent, but look repairable. One of the element tubes had filled with water at some point, froze, and split about five inches from the center insulator. It might be repaired with a clamp or two, but replacement is probably a better option. The two fiberglass insulators seem to be in OK shape, although they need to have some of the weathering sanded off and protected with a nice coat of flat black paint (as I did on the R7000).

OK, this is going to be a project, but it looks like what remains is serviceable. I could definitely use a small tribander at the Walton County QTH, or even as a South-America facing antenna in Gwinnett County. I'll have to work out a 20-25 foot support to mount it on, eventually.

Monday, February 16, 2015

K1N - Fabulous DXpedition

My Results from K1N
Well, it's over now. The much-anticipated K1N DXpedition to Navassa Island is now over. Lucky for me, I made it into the log multiple times, which makes me quite pleased.

Granted, it was a pretty easy shot from here in northwest Georgia to Navassa Is compared to other parts of the world. They were quite strong on just about every band, with the exception of 10 and 12m. I never heard a peep from them on 6m.

The pileups in the low bands were completely crazy in the evenings. All of my contacts 30m and below were made in either the 0900z or 1000z hour -- 4 or 5 AM local. That's one of the secrets of working DX -- be on the band when others are not! The one exception was 60m, and, honestly, the channel was so crazy I'm not entirely sure how I made it into the log.

All of these contacts were made with 100 watts and wire antennas, either the Inverted-L or the 80/40m dipole. Working DX does not require huge amplifiers and large antennas.

The team on Navassa Island did a fantastic job handing out contacts despite unruly pileups, deliberate QRM and the usual craziness. I witnessed on CW pileups that extended over 30 kHz with people continuously calling. Finding the listening frequency in the second receiver was an incredibly difficult task, and quite often I was just guessing -- but a few times I got lucky.

As I told my friend Mike, W1YM, now that I have Navassa Is on nine bands, I'm planning to volunteer to operate the next time team heads to the island. Perhaps in 10 years....

Monday, December 23, 2013

Audio Games

Recently, I was trying to explain amateur radio contesting to a non-ham friend. "You know what video games are, right?" She gave me a cold look, as if to say, of course I know what video games are. "Video games," I continued, "are games you play with your eyes and fingers. Contesting is a game you play with your ears and fingers."

In a nutshell, that's pretty much it. Described that way, however, doesn't tell you a whole lot. Video games described this way doesn't tell you much, either. The reality is that every game worth playing has strategy.

To understand radio contesting, you have to understand the nature of radio. Most contests take place in what we call the "short-wave" or HF (High Frequency) bands. There are six bands in this spectrum, all identified by their (approximate) wavelength.

160, 80 and 40 meters are basically night-time bands. Ever notice that you can't hear far-away AM broadcast stations during the day, but you can at night? That's exactly how 160m is -- open during the darkness hours only. 80m and 40m are the same way, but are open a bit longer before dusk and after dawn.

10 and 15 meters open during the daylight hours, and possibly shortly after dusk -- just the opposite of 160, 80 and 40 meters. During sunspot minima, 10 meters may not open at all, and even 15 meters can be lackadaisical. 20 meters rounds out the bunch. It's mostly a daylight band, but during sunspot maxima can be open round the clock.

The basic idea of a contest is to make as many contacts (what hams call a QSO or "Q") in a defined period of time. Each contact involves the exchange of call signs ( unique identifiers assigned to each station by their governing agency ) and one or more other pieces of information. Typically, it's pretty simple - like a signal report and a state, province, country or zone identifier, maybe a name.

A game isn't fun if you don't keep score. Most contests use a two-factor scoring method. First, you get a certain number of points per contact, depending on the contest. You can't contact the same station more than once, or at least once per band. Those duplicate contacts don't count for any points.

Next, each contest defines a set of geographic areas that count as "multipliers." These could be states, provinces, ARRL sections, ARRL DXCC entities, or zones. In some contests, the multipliers count for each band.

The final score, then, is the number of contact points times the number of multipliers. As you can see, it's important to have a large number of both contacts and multipliers (or "mults") in order to make a high score.

There are two ways to make contacts in a contest. You can call CQ -- for the old morse-code pro-sign for soliciting for contacts -- and get people to call you. This is called "running." The alternative is to tune the band and look for others calling CQ. This is called Search and Pounce, or "S & P." Generally, you can make a lot more contact points running than you can doing S & P, provided you can attract people to call you. The disadvantage of running is that you may miss some rarer mults who are also running. The best contesters use a mixture of both techniques - periods of running punctuated with S & P.

Add to this mix the need to get multipliers on multiple bands, the varying propagation during the day, night, by season of year and the 11-year sunspot cycle, plus the unpredictable nature of the sun, and you have the recipe for a big challenge.

Plus, a contest can really help build your confirmation totals in pursuit of any number of awards -- like ARRL Worked All States, ARRL DX Century Club, CQ Worked All Zones, CQ WPX as well as others.

There's something satisfying to calling CQ and running a rate of 100 contacts per hour for even a few minutes, or to tune across a band at an oddball time and be the only one to catch a rare multiplier. You can run the same contest a dozen times and never experience the same situation. It never grows old.


Monday, October 10, 2011

Awarded: 6B WAS

I discussed my pursuit of WAS, and then 5B WAS before.

Well, after a couple of miscues, including a lost QSL card, cancelled and re-issued credit cards, and a few month-long delays -- I finally received my 5B WAS award with the 160m endorsement.

Thank you so much to the hard-working folks at ARRL HQ for finally straightening this out. It's nice to meet a goal after 35+ years of hamming. Something that only 3,004 hams before me have done.

WAS on 30m, 17m, and 12m will take some doing, but, with time, it may happen. Although, right now, I'm more interested in building my DXCC totals.