Monday, June 17, 2024

RealVNC Changes Terms, without Notice.

Just over three years ago, I figured out how to Remotely operate FT8 using a product called RealVNC. 

RealVNC had a Home plan that allowed up to 3 users and up to 5 devices for non-commercial use. Perfect for remotely controller computers in a ham radio shack.

Today, without any notice, RealVNC disabled my Home plan, and I had to choose between paying each month a plans, or adopting their Lite plan, which allows 1 user and up to 3 devices for non-commercial use.

That's fine. They allow me to use their secure remote access software without fees. I can understand they might want to change the terms.

The Lite plan fits my usage. I've only ever had two devices active anyway, and it's just me as the user. 

But, without notice - that is just damned inconvenient. Since I switched plans, I need to visit each device and re-configure them to be part of the new plan. Which means I can't remote into those computers until that is completed. 

And, of course, since I'm remote, I'm not there.

Quite inconvenient.



Saturday, June 1, 2024

FT8 is supposed to make DXing easy, why is it so hard?

FT8 has been a revolution. The technology has made DXing really easy. Or has it? I continue to be amazed at how much difficulty people have working DXpeditions on FT8. 

Last year, there were DXpeditions to Bouvet (3Y0J), Crozet (FT8WW) and Sable Islands (CY0S). The most recent DXpedition to Glorioso Islands (FT4GL) has brought it all back to me.

Let's start off with a few observations on people trying to work these DXpeditions:

  • Wrong Cycle - It's amazing the number of folks trying to work DX that are calling on the wrong cycle. FT8 has even and odd cycles. Even cycles start at 00 or 30 seconds, and odd cycles start on 15 and 45 seconds. You always call on the cycle the DX station is NOT transmitting. Indeed, if you double-click on a decode of the DX station, WSJT-X will set up the correct cycle. So how are people getting it wrong?
  • Endless Calling - I've noticed some stations keep calling the DX after the DX station has QSYed or QRTed. A little bit of hopeful calling isn't unusual on Phone or CW, or even RTTY. But stations continue to call much later -- like an hour later, and they are still calling.
  • Calling without Response - Some stations don't respond when the DX station calls them. They keep calling instead of advancing to the next step. This can get really bad. During the FT8WW expedition, I saw FT8WW keep responding to the same station for more than 10 minutes. Each response had a different signal report. This made it clear that FT8WW was heading this caller quite well, but the caller wasn't hearing FT8WW at all. Instead, that station took up a valuable response slot for 10 minutes -- denying perhaps 20-40 stations from working FT8WW.
  • Confusing Fox/Hound (FH) and MSHV - Most DXpeditions using FT8 use either FH or MSHV in order to maximize the number of contacts they can make. It is easy to get confused with these two modes. They appear similar. Both allow for the DX station to transmit multiple FT8 carriers at the same time. FH imposes additional behavior to both the Fox and Hound ends of the contact. In particular, there are audio-frequency dependencies that FH enforces. But, it is perfectly possible to work a Fox station even if you are not in Hound mode. MSHV requires no special modes. And yet someone accused people of DQRM, calling FT4GL below 1000 Hz, when the DX was using MSHV, not FH.
What causes all these odd observations? I believe they all resolve to a single cause -- people are calling DX they cannot hear. That's right, people are calling DX stations they aren't decoding at all.

This is fundamentally wrong. I wrote about this years ago on how to bust a pileup. You cannot work DX if you cannot hear them. If you aren't decoding the DX station, stop calling. Yeah, that's hard, but your calls won't net you a contact, and you may be actively depriving someone who can hear the DX from making one. 

I think FT8 has made some people lazy. They hear some DX station is active on some frequency, probably through a spotting network. So they switch to that frequency, set their watchdog timers to an hour or more, and enable their transmitter. Then they go off and drink a few cool 807s while their computer works the DX for them.

Farfetched? No, it explains all the observations above.

Be a good FT8 operator -- don't call DX when you cannot decode them. Wait until you can decode them reliably, just about every cycle -- then start calling.


Monday, May 27, 2024

The Great LoTW Outage

May 16th, there was an issue with Logbook of The World (LoTW). I could not load the main page at all -- receiving an error indicating the server wasn't responding.

That's pretty normal stuff, actually. There are dozens of problems that can result in this kind of error, so I wasn't surprised. I figured the ARRL staff would address it quickly. But, after much of the day, I was still getting the error. 

So, I sent a message to lotw-help@arrl.org, informing them that the web site wasn't responding, kindly asking when they expected it to be back up. I mentioned I was surprised there was no notice of the outage on the ARRL.org web site.

Later that day, the ARRL put up a notice that there was a service disruption involving access to the network, and that it affected LoTW and the ARRL Learning Center. They even updated it the next day, addressing concerns users had over information privacy.

But then, nothing happened. Not until May 22nd, when they updated the notice without really adding any information. 

Now, part of this delay may be due to the fact that much of the ARRL staff were all out at the Xenia Hamvention. But, that was a week ago.

What gives? Sure, networking problems. Honestly, though, as a computer professional, networking problems generally don't take more than a week to solve. I'm beginning to suspect there's something more than the ARRL hasn't told us, but I can't be sure.

I'm really missing access to LoTW. In the last 20 years, it has really become central in my enjoyment of the hobby. I do hope I'm wrong, and that ARRL manages to fix this problem soon.

Tuesday, May 21, 2024

Fixing up the Cushcraft A50-3S

A50-3S standing tall and
straight next to the house.
Last year, I moved the A50-3S out of the yard and up next to the house. I used a 19 foot mast made of two pieces of EMT. While putting it up the reflector bumped against the roof and turned askew about 15 degrees. 

Never the less, it worked well. I worked a few Europeans and several South and Central American using this antenna.

Still, it needed a bit of work. A one-piece mast would be better, and I could straighten out the reflector when I swapped masts. A bead balun at the feed point wouldn't hurt either. 

So, I researched these. You would not believe what a 20 foot piece of 1 1/2" 0.058 wall aluminum tubing goes for these days. A few years ago, I purchased a 12 foot piece of 2" diameter 1/4" wall 6061-T6 tubing for my gin pole. It was about $150, which seems right for such a substantial piece of metal. 

But 20 feet of the thinner mast? They quoted me $500! If I went with the 1/4" wall, well that was manufactured with a different process -- extruded instead of rolled, so it would be $250. Ridiculous. There had to be another solution. 

I did have 20 feet of mast in two 10 foot pieces. This was from an earlier experiment. I had an old Butternut  HF4B that I had rebuilt, and was hoping to erect in Fulton County. I bought two pieces of Rigid Metal Conduit (RMC) for this purpose. 

EMT and RMC are easily found at your local Home Depot. But it isn't exactly what you would call structural. EMT is design to bend. Easily. I have had some success using it as masting for very small, light antennas. The two pieces I used on the A50-3S lasted for over eight years, plus the several years holding up a 19 element 2m boomer Yagi. RMC is more substantial, and comes with threaded couplings to connect them together. 

Two pieces of 10 foot RMC was $30 a pop, so this wasn't a cheap experiment. Even with the coupling tightened all the way down, the 20 feet of mast had a substantial wobble in the top section. I tried inserting a solid piece of HDPE. That helped, but not enough to hold up the HF4B. 

It occurred to me that this might work with the A50-3S, even with the wobble. The A50-3S is held upright by a wall bracket at the eve of the house, well above the wobbly union. I just needed the vertical support, and not so much lateral rigidity. Besides, I already had $60 invested.

First order of business was to find the doggone things. I put them away three parsonage moves ago, and had hidden them well. They were hiding in my basement. After that, I had to locate the piece of HDPE, which I found in another box. 

It all came together this week. My youngest daughter Lauren helped me to lower the existing A50-3S and mast to the ground. Off came the antenna and the feed line, and the old mast was disassembled and put away. Then I coupled the RMC together with the HDPE stiffener and taped the coupling joints against any water intrusion. With the A50-3S mounted on the new mast, the reflector was aligned with the rest of the elements. 

For a balun, I used five snap-on ferrite beads. I measured these at about 100 ohms resistive at 50 MHz. Five conveniently fit on the 9913 coax from the driven element to the mast, so that is what I used. 

A50-3S facing South East.
Swinging the new mast up into place without bashing the antenna against the house took some patience. The RMC mast is much heavier than the two pieces of EMT. Once vertical, I positioned the mast in the eve bracket and loosely connected the u-bolt clamp. Both my daughter and I lifted the assembly to the top of the railing. From there, I tightened the bracket to eliminate play, but loose enough to allow the antenna to rotate. I used a couple of extra 1/4" nuts as jam nuts so the bracket could not tighten or loosen. 

The antenna is easily Armstrong rotated from the base. Eventually, I'll mount a rotator on the top of the railing and retire my arms.

A quick SWR check showed a 1.2:1 SWR at 50.313 MHz. The antenna is pretty broad. Minimum SWR is around 50.8 MHz at 1.07:1. I suppose I could mess with the matching network to get a better match on the FT8 frequency, but the whole bottom 2 MHz of 6m is less than 1.5:1. 

The antenna is 28 feet (8.5m) off the ground with clear shots from the North clockwise to the South West. Points to the West and North West have to pass through the house roof.

I hope Es season hasn't passed me over yet. 

Wednesday, February 14, 2024

How 1984 wasn't like "1984."

In 1984, I was working at Hayes Microcomputer Products. They were the premiere modem manufacturer for small computers, back in the days when modems over telephone lines were a primary means of computer to computer and user to computer communications. 

In my job, I created communications software to talk to the modems. The software dialed the modem, established connection, provided terminal emulation (my specialty), allowed for the capture of the data stream to files, printing, file transfer with the remote computer (using protocols like XMODEM and YMODEM), and other features. 

These were the early days of personal computing. IBM introduced the PC in 1981, and it had rapidly evolved into a defacto standard computer, shoving out various CP/M designs from the previous decade. Personal computers were so new, people were trying to figure out what to do with them. Word processing, spreadsheets and other office applications had just been introduced. 

Hayes was trying to stay at the forefront. We had a laboratory filled with pretty much one of every personal computer, and when new ones came out, we would buy one. In late 1983, we got an Apple Lisa. It was a very different kind of computing experience. It was a curiosity to us, and as there was no programming environment available, we didn't see how we could build software to talk to a modem. Plus, at the price point, there were few buyers.

The Macintosh

Though the Macintosh was introduced in January of 1984, I didn't get hands on one until the late spring of 1984. Yes, we brought one into the lab, and it immediately garnered a lot of attention. 

While there were similarities to the Apple Lisa, the small screen with square pixels just seemed sharper and more distinct. The whole interface was friendly and approachable. We messed with MacWrite, MacPaint, and MacDraw. We printed on an ImageWriter, making appreciably decent images unlike anything we could do on another type of computer. There were several of us hooked and enthusiastic.

It's hard to describe those days. At this point, everyone has had decades to become familiar with computers that use a graphical user interface and a mouse or other pointing device to interact. Back then, it was a revelation. It was much more approachable than the command-line interfaces of the day. 

As I described it to someone in the early 90s -- other computer interfaces required one to reach toward the computer. You had to learn the special language and commands of that computer. The Macintosh was the first computer that reached back toward you -- the user.

The Machine

The Macintosh was based on a 16-bit Motorola MC68000 processor, running at 8 MHz. This was more than competitive with the Intel-based IBM clones circulating at the time. This processor was a great choices by Apple. It had many registers and powerful instructions for manipulating the bit-mapped screen.

Biggest constraint was memory. The 128 KB in the Macintosh was shared with 24 KB used for the screen, several more KB for operating system usage, leaving about 90 KB to run your program. Most of the critical operating system routines were in the Macintosh ROMs, which saved space. Building a program of any sophistication was difficult -- It was very tight to work with.

The single 400 KB floppy disk drive was also a limitation. Trying to save a file to another diskette could produce an endless amount of swapping. It was the lack of addition storage that kept me from buying a Mac until the Mac SE/20 was introduced in 1987. 

Next Steps

By summer, Hayes hired some consultants to look into the feasibility of developing communications software for the Macintosh. In just a few weeks, they had some rudimentary software going and concluded that it was quite feasible. 

We were soon green lighted to create a product for the Macintosh.

Wednesday, January 31, 2024

Forty Years of Personal Computing - Gimix 256 KB Static RAM

256 KB Gimix Static RAM board, sans battery.
In 1991, my employer moved to a new building. Before the move, we cleaned out storage closets containing old equipment. Much of this was obsolete gear. Things like pairs of "twiggy" disk drives removed from early Apple Lisa systems upgraded to 3 1/2" disks in 1985.

In one closet, we discovered something unusual. It was a complete Gimix III "Ghost" system. This was a  2 MHz 6809 system sporting a fifteen-slot SS-50 motherboard and eight SS-30 slots and floppy disks: a top-of-the-line 6809 system from the early 1980s. 

By 1991, the company had no use for this equipment. I had the impulse to take the entire system home, but I didn't have room. My wife and I were living in a small house and the garage was already packed. She would not have been happy if I brought home a bunch of equipment. 

Instead, I salvaged exactly one board -- a Gimix 256K CMOS Static RAM board. It sported 256 KB of memory, with several options, including battery backup. The rest was scrapped by an electronics recycler. 

Obtaining the board, I tried it out in my system. I was able to map in 4 KB blocks of memory and test them. They all worked. I might use the additional memory as part of a virtual disk drive. 

In 1994, I moved, and the entire system was stored away for over 25 years. Looking at it recently, I found it needed repair. Over the years, the backup battery failed and leaked electrolyte on the board and motherboard. Several Molex connectors are damaged, and need to be replaced. Some of the components show signs of corrosion from the battery electrolyte. 

I removed the failed battery. I do hope the rest of the board still works once the repairs are complete. Perhaps I'll fix it in my retirement.