Friday, September 18, 2015

The Venerable TS-430S

The Venerable TS-430S with AT-250 antenna tuner.
I realized earlier this week that my backup rig, the Kenwood TS-430S, turns 30 years old this month. Yup, I bought that rig back in September of 1985. For the next 16+ years, it would be my only HF rig.   I held on to that rig so long, by 1995, I was already calling it "venerable."

How I got to that point is an interesting story. My original Novice setup was an SB-301/SB-401 combo. In my second or third year of college, I sold my SB-401 to my brother Ben (now NJ8J). I still had the SB-301, and eventually I set it up in one of my college apartments. But I lacked a transmitter.

One summer, I attempted to rebuild my Novice transmitter using a 6GK6 and 6146 design published in the ARRL handbook. I added a lot of extras, like a built-in VFO and a KOX (key-operated-switch), with automatic T/R switching. (the VFO and KOX board were salvaged from a home-brew 40m QRP rig project that I assembled, but never could get to work) I never could get any output from that 6146 rig, and it chirped pretty badly.

Shortly after I finished college and moved into an apartment, I borrowed a friends FT-101E. The rig worked great. Because of my crummy antenna situation, I had a lot of trouble making contacts. Eventually my friend asked for his FT-101E back.

Since he bought the SB-401, my brother wasn't using a Heathkit DX-60B he had, so I borrowed it. I pulled the VFO out of the Novice transmitter, mounted it in a box with the KOX circuit board, a power supply and connectors for the DX-60B. This actually worked! I made a handful of contacts, but again the antenna situation really limited me.

In the summer of 1985, I moved to a new apartment much closer to work. It was two stories tall, and there were a number of trees about 30 feet away from the back. I took a couple of 100 foot spools of #26 wire wrap wire and strung them into the trees from my second-floor shack window, fed from the back of a crappy MFJ tuner with a balun. This formed a crude doublet.

For an operating table, I bought a door, placed it on two short two-drawer filing cabinets, and finished it with stain and polyurethane. I did a good job, because this door is still my operating table to this day in Gwinnett county.

I still needed a rig. I decided I didn't want to fool with tube-type radios any more. (That urge would return later) I wanted something that was all solid-state, had a direct-reading frequency display, supported the new WARC bands, and didn't cost terribly much.

At that time, the top contenders were the Kenwood TS-430S and the Yaesu FT-757GX. Both had a reasonable feature set, and were similarly priced around $600. I don't know what tipped me toward the Kenwood. In retrospect, based on what I know today, the FT-757GX had more features -- it does full QSK and has a built-in keyer, as well as supporting computer control via the CAT system. Computer control would be something I would pine for a few years later when I got into contesting.

Back in 1985, I wanted to get the best deal on my TS-430S, and I must have called a dozen different dealers for a price quote. The deal I found was a TS-430S for about $630, including the optional FM board. I placed the order with my credit card -- and this was perhaps the first time I would go into debt for my hobby.

I didn't do a lot of operating from that apartment, but I did enjoy the TS-430S. The crude doublet actually worked pretty well. I spent a fair amount of time on 30m, which was a relatively new back then, but I also hung out around the Novice bands on 80, 40 and 15m.

I moved to a house in Stone Mountain, GA, and the TS-430S was my main rig. My antennas progressed from a 300 long wire to a loop skywire, to a 125 foot doublet, eventually complemented by a Butternut HF4B beam on a roof tower that eventually gave way to a Cushcraft A3S. I started contesting in 1986 with CW Sweepstakes. The TS-430S paved the way for a whole lot of radio experience for me.

As a rig, the TS-430S is not a bad performer. There are two key deficiencies that were fixed by it's successor, the TS-440S: a) computer control, b) 100% duty cycle. The TS-440S adds a host of other features (100 memories, internal antenna tuner, selectable filter bandwidths, FSK, selectable AGC) Ironically, the TS-440S would be introduced at Dayton in 1986, just a few months after I bought the TS-430S.

CW performance is reasonable, depending on your expectations. There is no QSK, but the VOX operation from the key is quick and reliable. You can at least listen between words. AGC action is fast. The 500 Hz CW filter is a must-have.

SSB works well. VOX is fully adjustable, and the speech processor produces reasonable results on air. Choosing LSB or USB, though selects the slow AGC, which is annoyingly sluggish.

FM is interesting. I played around with 10m FM in the late 80s. There used to be a few guys in the Atlanta area that would hang out there back then. I think it may have faded, along with a lot of 2m FM.

Receiver performance is pretty good considering the up-conversion design and the vintage. There's certainly some front-end IMD, which you hear as a "sparkle" sound, especially on 10m when it is open during a contest. Usually hitting the attenuator knocks that out. The notch filter is pretty good, provided you are only dealing with one carrier. Of course, you have to adjust it manually. Noise blanker is one of the better ones.

Some contesters would be displeased with the manually-centered RIT. Never bothered me. IF Shift can sometimes help fight QRM -- but not in really crowded conditions.

This rig has some features I have rarely used. General Coverage Receive is one of them. Program scan has got to be the most useless of all -- since you have to manually hold the scan if you hear a signal.

I have made a handful of mods to my TS-430S. I did the 10 Hz frequency readout right away. (Why they didn't ship it from the factory this way, I'll never understand) Back when I used transverters for 2m, I enabled all-frequency transmit. Oh, and I did a simple mod that allows the YK-88C 500 Hz CW filter to be used for SSB narrow. This is useless for Phone, but makes easy work for RTTY.

Running RTTY is a mixed blessing. With the 500 Hz filter and the IF Shift adjusted, it does respectably on receive. The slow AGC is a little bit of a problem. Transmitting, though, should be limited to about 50-75 watts. Be sure to turn off the speech processor.

This rig has been with me at five different QTHs, as well as a host of Field Day operations. Although I long ago bought an MB-430 mobile mount bracket, I have never mounted it in a mobile.

Considering all the rapid changes in electronic and radio equipment in the late 70s to mid-80s, what with the transition from tubes to transistors to integrated circuits, plus the addition of new amateur bands -- it is amazing this rig still holds its own. I certainly didn't expect to be using it 30 years later.

Wednesday, September 9, 2015

BAM! - AL-80A Broken Again

Well, crap. The AL-80A is broken again. Yup. I was on 17m chasing a bit of DX, when I decided I needed more than 100 watts. I hit the A->B button, then A/B, then tuned a bit away from the DX frequency (never tune up on DX - ever), dialed in 50 watts, switched the amp to operate and hit the Tune button.

Heard something go POP! as I turned the plate tuning knob, and immediately the grid current meter pegged. Not good.

A little diagnoses -- with no RF, keying the amplifier the grid current meter reads about 100 mA. Even with about 20 watts, the grid current meter pegs. Seeing the output meter peg, too.

At the worst, I may have fried my tube. I suspect I may have blown more of the metering circuitry.

This amplifier is very picky about 17m....

Monday, August 31, 2015

Pursuit of 5BDXCC III - 80m

I wrote of this dream first two years ago. Back then, I thought it would be an easy thing, perhaps to work (and confirm) nearly 30 countries on 80m in a single winter. Boy, was I naive. I only added six confirmations on 80m the entire year.
Can this shunt-fed tower put me over the top?
The next  year, I at least had the sense to understand the difficulty of the proposition. I enumerated things I might do that year. In the end, I only did a couple of them. I did not add more radials to the Inverted-L, I did not bring the amplifier up to Floyd county, I never did finish the new K9AY controller. 

However, I was there a lot. I spent a lot of time on 80m. As a result, I now stand at 89/88 confirmations - I added a dozen over the year. That's twice as productive as the previous year. 

If I can pull it off again this year with a dozen confirmations, I should be able to meet all the requirements of 5BDXCC.

It's going to be interesting. At the moment, the Inverted L, with over 30 lbs of radials, is sitting in a box. I'm still trying to figure out if I can put it somewhere where I can lay down those radials safely. My only 80m DX antenna is the shunt-fed tower in Gwinnett county. 

Wish me luck.

Wednesday, August 12, 2015

AL-80A Repairs

AL-80A back in the operating position
Hard to believe, but it has been 10 years since I purchased the AL-80A. Archie, K4GA owned it before me, and it has served me well since that time. I added a step-start circuit a few years ago, and it's been doing well until April 2014.

I wrote earlier this year that the AL-80A had a failure that I traced down to an open 1.5 ohm 3 watt resistor on the meter board.

I finally got a replacement part from a source in China. (Well, it was cheap, but not fast) Installing the resistor was the easy part. While I had the amplifier away from the operating position, I decided I needed to do a couple of other updates.

Back in 2009, I added a glitch resistor, but I installed it on the wrong side of the B- line. It was between the capacitor bank and the rectifier, where it wasn't doing any good. I moved it into the B- line between the capacitor bank and the meter board.

Glitch resistor on the rectifier board.
My AL-80A rectifier board had a number of unused lands (likely for full-wave rectifier bridges in other amplifier designs), two of which were perfect for the glitch resistor. If you look carefully at the photo, you'll see a darker brown wire going from the capacitor bank land near the middle back to up the board. This goes to the far end of the glitch resistor.

The near end is hooked up to the brown wire that disappears off the bottom of the capacitor board, heading to the meter board. 

This made for a neat installation, and now that is is on the right side, it will actually do some good.

The other issue I addressed was the meter lighting. Because of a bad trip to Barbados long ago, the two grain of wheat bulbs were not affixed to the grid meter. One of them had been destroyed, and one other bulb on the multi-meter had burned out.

Grain of wheat bulbs like this are nearly impossible to find these days, plus I didn't want to have to fool with changing them when they burn out. So, I took a tip from the internet and replaced them with white LEDs. The LEDs were ones I had bought some time ago from (Mouser part # 593-VAOL-5LWY4 - 4000 mcd standard white / clear LED -- these are still in stock, although you can get way brighter ones (35,000 mcd!) for less money) At 5mm (T 1-3/4) they were the perfect replacements for the old bulbs. 

The Grid Current meter did not have the holes drilled for the lamps. I held my breath and did this, using a very slow drill speed and working slowly. I didn't want to mess up the meters. Since the lamps are run from the internal 12 volts supply (actually about 13.5 volts), a 1.5 kiloohm resistor was wired in series to set the current at about 9 mA.

LEDs being glued in place on the meters.
The LEDs are glued to the back of the meter faces. Superglue would have been perfect, but unfortunately, I was out. I ended up using 30 minute epoxy, but this particular stuff is so old it was more like 240 minute epoxy.

I re-used the blue leads from the defunct grain of wheat bulb to wire in the negative terminal of the LEDs, and picked out some red wire for the positive side. I mounted the LEDs so the negative and positive corresponded to the terminals on the meter. Less chance of screwing something up.

Toughest part of this exercise was wrestling the meter board back into place. After buttoning it all up, it was time for the moment of truth.
Lighted meter faces.

Et voila, it works! The LEDs are not quite as diffuse a light as the grain of wheat bulbs, but they do a respectable job of indicating that the amplifier is turned on. 

It might be nice to get some more even illumination, but I'm pretty satisfied. Perhaps I might add some reflection inside the meters next time I need to open the box -- which hopefully, won't be for a while. Maybe in another five or six years.

Saturday, July 25, 2015

Fixed the AL-80A (Sorta)

My AL-80A amplifier has been busted for a while now. I think it was back in April of 2014 that I was chasing some DX, trying to quickly tune up the amplifier and something went ZAP! inside the box.

After that, the grid meter was reading all funny, like registering about 60 milliamps even with no RF. That's not right.

I put it on the workbench, and at some point disassembled it. I had pulled the front faceplate off, then pulled the meters and meter switch board out through the meter holes. But I never got around to fixing it. It sat like that, taking up much space on the workbench for months. Until today.

I had determined that the 3-500Z tube was likely OK. No indication of shorts or other damage. I figured the problem must be on the meter switch board -- one of the components there must have gotten damaged. Sure enough, a little probing around found that the 1.5 ohm 3w 1% resistor in the grid current network was showing as completely open.

I also figured out that the 10 ohm 20w "glitch" resistor I put into my amp was wired in incorrectly. The resistor needs to go in the B- circuit on the same side as the capacitor bank. I had placed it before, were it wasn't doing any good.

It's quite possible a glitch took out the 1.5 ohm 3w 1% resistor. This is not a typical value that I have lying around in the junk box. However, I did have a 1.5 ohm 1w 10% resistor. That would do at least for a proof of concept fix.

Wired the resistor in, put the switch board, meters back in place and put the front panel and covers back on.

Moved it over to the operating position, and behold, it amplifies! Well mostly. I got it to work on 80-10m, but I wasn't getting much of any output on 160m. Not sure what's wrong there. That fix will have to wait a bit.

However, I don't have any antennas for 160m that can take more than 100 watts anyway. Seems like the AL-80A should be good to use for a while, at least until I can get the proper resistor and troubleshoot 160m.

Wednesday, June 24, 2015

Farewell to the Micro-Shack

Micro-Shack desk in all of its glory, just before I started packing
Impermanence is the only absolute in life. Once you get used to something, it's bound to change. And so it is with the Micro-Shack. It took a couple of months to prepare this space in 2011. Now the time has come to leave.

My wife has been assigned to a new church, so we leave Floyd County and go half-way across the state to the new church in Walton county. The good news is that the new church is just a few miles from my Gwinnett County QTH -- so I'll be able to spend more time there.

For now, though, I wanted to reminisce about this tiny little room where I spent many hours enjoying my hobby. It's hard to get a picture of the place -- camera angles are difficult in such a tiny room. The view above shows a clutter of equipment on the shelves, as well as other electronic debris at the periphery of the very tiny desk. To the right is the storage room door that swings outward (because there's no room to swing inward), to the left a window, and behind me, water heaters, electrical breaker boxes, and a miscellaneous pile of tools on a cheap plastic shelf unit.

In other words, it's a cluttered but well-loved and well-used space.

The operating desk is just 29 inches off the floor. I found this to be the perfect height. At the Gwinnett County shack, the operating desk is a 30-inch door sitting on top of a couple of filing cabinets. It's too high (about 31") and makes for uncomfortable operating. I'm seriously thinking about building support legs for the door and moving the filing cabinets elsewhere.

Micro-Shack just after construction, before
I brought in a bunch of stuff. Note the
nice stack of shelves. Plenty of room for
just about anything. The desk and shelves
will stay with the parsonage.
That desk has seen a variety of equipment. Originally, I had the Kenwood TS-430S there, as well as my "Novice" transmitter and receiver. As I spent more time there, I swapped the Kenwood for the Elecraft K2/100 in Gwinnett. And two and a half years ago, my wife surprised me with the Elecraft K3/100, which I assembled on that very desk.

I build several projects on that desk - several antenna traps, the K1EL K12 keyer, rebuilt the Mini-MOS keyer, as well as a couple of other projects I have not written up yet.

The antenna setup out here in Floyd County has been extremely modest: R7000, 80/40m Trap Dipole160/80/40m Trap Inverted-L, and a 6m Dipole.

To be honest, the R7000, despite the rebuild and the ground-mounted radial wires, has pretty much been a waste of time. This antenna never did perform well at the Gwinnett QTH, and while it is better than no antenna, it couldn't hold a candle to the wire antennas in the trees. I don't plan to put it back up, I'll probably sell it off.

The 80/40m Trap Dipole, despite being at a modest height of roughly 10m has done extremely well, especially on 40m. On 80m, I did have some trouble with a weird fundamental overload of the Acer laptop keyboard -- transmitting on 80m would cause the Acer not to accept keystrokes for a short time afterwards.

The 160/80/40m antenna has been the sweetest deal out here in Floyd County. With 1500 feet of radials, it's reasonably efficient, and has worked well even as a random vertical on the other bands. I made my first 6m contacts on this antenna.

I haven't written about the 6m dipole antenna, because there's not much to talk about. It's just a simple  dipole made with junk wire hanging in the trees at about 3m high. When 6m is open, it works!

In this tiny room, I've done a ton of operating. Contests - CQWW CW (3), ARRL 10m (3), RTTY Round Up (4), NAQP CW (3), NAQP Phone (4), NAQP RTTY (3), WPX Phone (2), Georgia QSO Party (3), ARRL Field Day (2), IARU (2), CQWW RTTY (3), Sweepstakes Phone (2), ARRL 160m, Stew Perry (3), VHF Sweeps (2), ARRL DX CW (3), ARRL DX Phone, WPX CW, VHF QSO Party, CQWW Phone (2), Sweepstakes CW, ARRL 160m (2), CQ 160m CW, CQ 160m Phone. Some of them were just a few hours on a Sunday afternoon, perhaps a handful of contacts but there were several I set a new personal best score: George QSO Party, ARRL 160m, SS CW, Stew Perry.

Estimating from my logs, I have made over twelve thousand QSOs from this quiet little room.

Being more than 25 miles from Gwinnett County, I had to start over for WAS. During my brief three and a half years of operating, in Logbook of the World, I have confirmations for WAS several ways:
  • Mixed
  • CW
  • Phone
  • Digital
  • 40m
  • 30m
  • 20m
  • Triple-Play
As well as being very close on a few others:
  • 160m - 49 (AK)
  • 80m - 49 (UT)
  • 17m - 47 (AL, KY, SC)
  • 15m - 46 (DE, MS, SC, WV)
  • 5-band - 230 out of 250
A lot of that came from 10 months of very purposeful pursuit of the W1AW-portable operations in 2014, especially on the WARC bands. But most of it was operating a bunch of contests.

Yes, I have a lot of fond memories of this place. Like pursuing the K1N Expedition. It was so much fun busting pileups with just a wire antennas, or getting up at 4 AM to outsmart the competition.

The Micro-Shack wasn't always the most inviting place. In the wintertime, it could be quite cold. The digital thermometer would sometimes read about 45 degrees F on the coldest days. However, a small space heater would warm things up in a half-hour or so. Summertime was much tougher. When it is hot in Georgia, it is hot. I could open the door and run a floor fan to cool things down a bit -- but in the height of summer, it would just blow hot air around. I don't know how I operated contests such as Field Day or IARU in the heat of the summer.

The Micro-Shack wasn't convenient, either. Feel the call of nature? Well, you have to go out of the storage room and walk to the house. More than once I was outside operating late at night and my family would lock the door. Perhaps they were trying to tell me something. I told my wife the next place should definitely have a shack where you don't have to walk out of doors to get to the operating position.

Small, cluttered, inconvenient, often uncomfortable. That well describes the Micro-Shack. However, I will remember it quite fondly. It allowed me to stay connected to my hobby despite being a hundred miles away from my main QTH.

Farewell, Micro-Shack. You may be gone, but you will not be forgotten.

Friday, June 12, 2015

Things I've Learned about Antennas - Horizontal Antennas

I've been fooling around with radio for more than 40 years. Finished my first receiver January 1971, so I guess it's closer to 44 years. In those early years, I didn't know anything about antennas. My initial antennas were nothing more than magnet wire strung up around my attic bedroom. They worked - Badly.

Over the years, I've learned a few bits of wisdom about antennas. This article is about:
  • Horizontal Antennas
Be they dipoles, center-fed Zepps, yagis, quads, Vee beams or rhombics -- horizontal antennas share one key characteristic -- their most important dimension is height above ground in wavelengths.

The height determines the radiation pattern, impedance and much of the loss. I remember a few years ago on the QRP mailing lists there was a hot debate about one of W4RNL's designs -- the "88 foot" dipole. When LB modeled this antenna -- meant to be a secondary or spare antenna when your beam failed in the middle of a contest -- he did so at 100 feet and also at 70 feet. 

This design was supposed to give reasonable performance on 80, 40 and 20m. 88 feet worked out to be about right. Long enough not to have too crazy impedance on 80m, and short enough to not have a lot of deep nulls on 20m. At 100 feet, I bet it is a pretty good performer. At 70 feet, it wasn't a slouch, either. The odd-ball impedance would make for some loss in the feed line, but for a spare antenna, that wasn't a huge concern.

From the discussions, you'd like that 88 feet was somehow a magic number that made everything work better. Heck, if you have the room make it a full-size 80m dipole then add a couple of traps, for pete's sake. And do you think those QRP stations put up that 88 feet of wire at 100 or even 70 feet? Heck no, they were down at more practical heights of 20-35 feet. 35 feet might be passible for 20m, since it is 1/2 wavelength up. But it is only 1/4 wavelength for 40m, and 1/8 wavelength for 80m. 

Here's the deal: the pattern of a dipole is hugely affected by the height above ground. About 1/2 wavelength, it just starts to have a bidirectional pattern, and only that at pretty high angles. Lower than 1/2 wavelength, it's basically got an ice-cream-cone shaped pattern going straight up. This pattern is rarely desirable.

How high is enough? At some point above about 2 wavelengths, the dipole pattern looks a lot more like free space. For beams, at these heights, you can start to get nulls in your pattern at useful angles, so you have to be careful. Somewhere between 1/2 and 2 wavelengths is generaly the "sweet" spot for horizontal antennas. For specific applications, your best bet is to model the antenna at the desired height and watch for undesirable nulls.

Given that most hams don't have supports for antennas above 50-70 feet, it's likely that any antenna below 20m is too low. Get those antennas as high as you can.