My home digi in operation.
For a long time I thought that APRS was pretty much a solution to a nonexistent problem. It provides position tracking, but how many times can you follow your buddies around on a map before that gets boring? It uses a 1200 baud packet radio protocol, but most packet has been dead for years. The only exceptions are a few DX cluster nodes and some emcomm stuff. And even at that, 1200 baud is slow when most any gear can run 9600 now. So, what’s the attraction?
My thoughts changed after tracking a high altitude balloon. APRS really proved itself invaluable in this endeavor. We were able to not only copy direct packets from the balloon, but also see the beacon packets on aprs.fi using a smart phone when we were out of range. This made recovering the payload much easier–of critical importance when there’s the potential for a high altitude to travel outside of state lines and beyond.
At some point the location beacons stop getting reported to the APRS-IS network if it gets out of range of a digipeater. The last two times it was when the balloon was still 2-3000 feet up. This prompted me to examine how many digipeaters were in my local area. I live directly between two fairly large cities. Indianapolis and Lafayette both have wide area digipeaters but there aren’t any local digi’s in my area. Just one I-gate in Lebanon. I thought it might be nice to set one up. This should help provide coverage for local passing motorists and may be of help to the local ARES team in the future. Just last fall we had a destructive tornado come through my county only 10 miles away!
I’ve done a lot of reading on different ways to setup digi’s and I decided to purchase an older Kenwood TM-D700. This dual band data radio will operate APRS on one VFO and also VHF or UHF FM phone on the other VFO simultaneously. This is different than many dual banders that will operate phone on both bands, but not data and phone at the same time. The added benefit is that I now have a handy radio in the house for repeater/simplex operation. It was easy to setup the APRS features and get the packets beaconing. Then I enabled it to digipeat local WIDE1-1 packets and saved this config to one of the Programmable Memories. Phase two involved taking the digi to the next level. I downloaded
The guts of the system are housed in this box under the table.
aprsisce/32 on my spare laptop. I had to make a couple changes to the xml file and then it would operate as a digi. Then I changed the 700 to run as a KISS TNC and connected it to the laptop. This proved simple once I found correct straight through F/F serial cable. The 700 still has an old school DB9 male serial port so I didn’t have to construct a special serial cable with a mini DIN connector like the newer TM-D710 requires. After making all these changes I saved the config to another Programmable Memory channel. Now my digi can operate stand alone or with the laptop. Using the laptop is nice since it shows all the activity in the area and also handles APRS messaging.
I have a feeling this is going to be a long blog post. But hey, sometimes I have a lot to say. Occasionally, it’s even interesting. If you like older Kenwoods or just playing around with different rigs, then this will be for you. It’s not really a product review, just some general observations.
Over the weekend I hooked up a nice, old Kenwood TS-450SAT. This is one of the radios I got from Mark Quebe N9EKG over the summer. Some readers of this blog will remember my previous post on this adventure. Sure was glad to have Dad and my sidekick Nick N9SJA there for the long day of work. Initially, I’d hooked the radio up just to try it out and didn’t have spectacular results. I could hardly make it work at all. With disappointment I’d packed it away for another day. Having nothing better to do, I hooked it all back up again. I think the cabin fever is setting in. What I found out is that it seems to receive quite well, but has very little AF output. This is likely something easily fixed. Even better, it was now showing full power output into the dummy load. I don’t remember it working at all last time so maybe it’s had some group therapy sessions in the shack with the other gear I’ve banished to the shelves. Either that or reading the operator’s manual has paid off. I don’t know which?
I attached an MC-60 mic and hooked it up to the hexbeam for some real testing. This proved to be successful as I made several contacts on 17m, including DX. For a smaller radio it has a good, solid feel to it. Kenwood built some quality into these back in the day. In spite or converting to a Flex-5000A as my main shack radio, I still love to spin the dial and push buttons. But what to do about rig control? I’ve gotten used to having all my gear interfaced to the computer with the Flex. I had to keep reminding myself to manually input band, freq, mode, etc into the HRD logbook. Then I remembered this USB rig interface kit I built years ago for an original Icom IC-756. It was designed by N0XAS HamGadgets. Sadly, it’s no longer produced, but it worked quite well on the 756 and also a Yaesu Ft-736R. After I dug it out I found that it even had the correct 6-pin DIN plug on it for the TS-450, and it was wired correctly! When you’re hot, you’re hot. After a little bit if research I found that Kenwood used inverted TTL for their serial rig control. I can’t even guess why they would do that other than to be different. This normally requires buying their interface box or a homebrew lashup with opto-isolators and such to deal with the inverted logic. Fortunately, the rig interface had a utility program on the software disk called MProg. It allows you to change the settings and configuration for the FTDI chip and then flash them to it. It worked quite well and I’m pleased to report that the radio is now communicating happily with the HRD suite.
Other than having to run the AF gain all the way up I’m pretty pleased with this radio’s performance. The antenna tuner seems to be jammed up so I don’t use it. Maybe when I dig into the low audio issue I can check out the tuner, too. As I’ve researched it on the web there are very few known issues requiring mods. That says a lot about the radio’s design. It’s not fair to compare it with the Flex but it does perform solid. I could improve it a little by adding better filters and maybe a Heil mic. International Radio has an excellent assortment of them available. Unfortunately, I could spend more than the radio’s worth on filters! It’s still going to be an early ’90s compact HF transceiver, though. I don’t want to try and make it more than what it is. I think I’ll just enjoy it for now…and then on the the next project!
New year, new projects. Trying to kick off 2014 in grand style. I’ve been so busy working on ham radio projects I’ve hardly even gotten on the air. My online logbook looks pittiful! Projects are really enjoyable for me…and often are very good learning experiences. But I do miss making radio contacts. One of my recent projects involves setting up an APRS digipeater. Not a wide area one like in big cities, but something local that will help get packets from mobile or low power stations out to the bigger stations and onto the world wide networks. This interest all started back in November when my buddy Nick N9SJA and I went chasing a high altitude balloon that had APRS tracking. You can read about that adventure in my previous post.
I’m happy to say that the project is successful and fully operational. However it’s potential is not yet fully realized. I feel like I’ve just begun and have so much to learn about best practices and proper setups for a local digipeater station. My choice of radio is a Kenwood TM-D700. This radio is no longer in production, having been replaced by the TM-D710, but it’s still a good radio and available at a discount used. It’s mounted in my family room and connected to a dual band J-pole antenna in the attic. The antenna is one of those homebrew arrangements constructed from a piece of 450 ohm ladderline. The nice thing about the Kenwood is that it has built in APRS capabilities that can operate on one band of the radio while letting the other band function for normal voice duty on 2m/70cm, simultaneously. Right now this is a very simple arrangement.
The D700 has a serial port on the front of the radio that will allow it to interface with a computer. This will allow you to get a visual on what the radio is hearing. One of the programs I’ve used for this is called APRSISCE/32. It can operate as a monitor only or can actually control the radio. After getting a passcode, it’ll allow you to beacon packets from the radio and also directly to the APRSIS network if connected to the internet. With some modification to the XML file it will also act as a digipeater. So now I have multiple options on how I wish to operate the station. An added bonus is now I can monitor local simplex and repeaters without having to go out to the shack.
So where do I go from here? I think I’ll mount it all in a box and do a little cable management so it looks better in the main room of the house. I also think it would benefit from having a backup power supply in case of power outages. This happened just last fall when a tornado ripped through my part of the county. It’s my hope that the local ARES/Skywarn volunteers might be able to make use of my digipeater when needed. When the weather gets up somewhere above freezing I plan to construct a new and improved antenna and locate it outside for better coverage. This attic antenna is deaf compared to the Diamond X500 I have connected to the dual bander in the shack. Crossband repeat might also be handy as I have a couple dual band HTs that could be pressed into service. A final option is to setup different operating modes using the Kenwood Programmable Memory function for each scenario. This allows for five completely different setups that can be programmed into preset buttons on the radio control head. I’ve rambled on long enough. Stay tuned for another upcoming project blog coming soon. After that I may get around to making some contacts!
I’m still sorting through the colossal stack of ham stuff I collected from Mark N9EKG. One of the more interesting items is an Amp Supply LK-500NT. Here’s a pic of the amp in my cluttered shack not long after I brought it home.
This amplifier uses a pair of Eimec 3-500Z tubes to operate on 160-10M. It differs from most traditional amps in that it’s designed to be no-tune. There are no Plate Tune and Loading knobs. All you have to do is select the correct band for operation and go. There is a fine tuning knob that may be used for making minor tweaks but it’s not always needed. Inside there are banks of air variable caps for each band that are factory adjusted as presets. Another nice feature is that it’s capable of QSK keying for those high speed CW ops. I’m guessing it must’ve been fairly expensive back in the early 1980’s when it came out.
The Amp Supply was pretty clean outside and in, but the high voltage power supply was a little weak. The High Voltage meter was reading about 1000V low. Some of the components definitely looked suspect.
To remedy this, I purchased a rebuild kit from Harbach Electronics. I have to say that I’m very impressed with the quality of this kit. The circuit board and components are top notch. I found the instructions pretty easy to follow. I didn’t have any issues building or testing it.
The size of the new components were much smaller when compared to the originals. This made it a lot easier to fit it back into the chassis after landing all the wires in their appropriate locations.
Now my High Voltage meter is reading 2800V while idling. I’ve been testing it into the dummy load and seeing around 1000W. The engineers must have been constantly changing the plans because I’ve found multiple different versions of the manual on the web. I’m currently checking to verify what the max currents should be for the Plate and Grid Meters. Don’t what to tear it up. I’m making some final tweaks and it’ll be ready to button up and put into service. If a ham was really motivated, I think this amp could be modified to operate as a traditional amp. With the stock tubes and HV power supply It should be capable of legal limit. But for now it makes a great instant-on no tune amp providing a solid 10db boost when conditions require it.
Now that it’s February and well into the new year I might as well get around to making some resolutions. Not really resolutions so much as an attempt to set targets for a variety of projects I attempt each hear. 2013 is no different. I only have the cash to fund some of them but you just have to do your best.
One of the things I’ve been busy with lately is the WD9BSA Memorial Scout Radio Station. It’s located at Camp Belzer in Indianapolis. I just recently became active with the group, but the other dedicated members have been working on it for over two years. Tabb, W9TTW, has been helping me with this, and together, we’re launching a social media blitz to try to get the word out about it. We’re also the only ones who know much about digimodes so we’ve made it our mission to get those up and running in the station as well.
Here at my home shack I’ve been busy updating the computer to the latest and greatest new software for the Flex5k. This has been surprisingly painless, and each new upgrade yields new features or better performance. Going along with this theme is an upgrade to Ham Radio Deluxe Ver. 6. I paid for the subscription to the new version when it becomes available. I have it downloaded but not yet installed. It’s still a Beta, but nearly ready for release. I’m looking forward to taking it for a test drive.
For projects I’m planning a tape measure beam. One of the events we’d like to plan for the WD9BSA station is fox hunt. It would be a good outdoor activity for the boys that incorporates radio and physical activity. There are a lot of plans for these and parts are cheap.
One last item is to recreate a solid state linear amp from an article in the Oct. 2012 QST. It only uses one transistor in the PA and is good for up to 1kW. The one in the article was for 2m EME use but the transistor is very broad banded and there’s no reason it can’t work on HF. With proper low pass filtering on the output, I think it would make a great no-tune amp for the shack.
FreeDV is another item I might actually get going fairly quickly. Since it’s really just software it shouldn’t require too much in the way of construction and building. I found out about it from a post on the Flex Radio Reflector while back. Then I saw further discussion about it on Episode 47 of Ham Radio Now. It was the topic of one of the talks from the TAPR/ARRL DCC conference. Nick, N9SJA, beat me to the punch on getting it up and running. We hope to experiment with it some here locally, maybe on 6m SSB. You can see his impressions of the software so are at his webpage here.
That’s all for now, folks. This should be enough to keep me busy for years to come! It also breaks a two month streak without a post. All the best!
Lots of stuff in this post. Really should be three posts but everything is pretty much intertwined. I guess this is what happens when you wait too long between posts…too much stuff! Consider yourself forewarned.
I’ve been contemplating an antenna project for quite some time. I recently attached a fiberglass cross bar on my tower with pulleys and rope in hopes of raising something interesting. I’ve actually had it since I put the tower up but just never got around to attaching it. The idea was that I could easily raise and lower a project antenna because of the pulleys. I still have a lot of interesting ideas but with winter upon us it was time to act. I decided to buy a Carolina Windom 80 from Radio Works. I guess it’s really just a hybrid off-center fed dipole that’s supposed to work all bands with a tuner. It has some kinda special matching balun and line isolator to allow part of the feedline to radiate while also keeping RF out of the shack. It was supposed to go in the top of the oak tree at about 65′ but there were too many uncooperative branches. For now it’s pretty happy at about 38′ from the tower cross bar. Thanks a lot to Tabb and Nick. Time will tell how this works.
I’ve had the FT-897D complete radio station in a go box since the trip to Dayton this year. There’s a post about it somewhere down in the previous blogs. Until now it’s been sitting in my shack playing second fiddle to the Flex 5k. Now it resides in my family room with the server and old desktop computer to keep it company. It’s actually a nice fit in this location. I’ve had a radio in here before but due to little children it had to get relocated for its own protection. The boys are older now and somewhat interested in the thing. For now it’s something of a fascination for them. This may be just the right time to introduce them to the magic of ham radio. Since I have a new antenna and plenty of feedline why not hook it up to the go box radio in the house?
This is where the linux stuff comes into play. Now that I have the nice, new antenna connected to a suitable radio station I need a way to log and also run digimodes. I could just use my old paper log but this is the 21st century, right? I carry a radio all day at work so it’s nice to work digimodes and not have to talk…or even listen since all there is to hear is tones. They’re pretty efficient and seem to overcome the local noise I get due to having power lines around three sides of my house. Several years ago I converted my old Gateway desktop to a linux box. It’s currently running the latest version of Ubuntu. I was going to need some linux-friendly software for logging and digimodes. I was able to install a logging program called CQRLog (CQRL) that reads the band, mode, frequency, etc from the radio and also completes logging fields using QRZ.com lookups once the callsign has been entered. It’s nowhere on the scale of Ham Radio Deluxe (HRD) but about as good as it gets for linux. For digimodes I installed Fldigi. Something neat I found is that it works with CQRL similar to how Digital Master 780 works with HRD. All I have to do to go from operating SSB or CW to digimodes is select Remote Mode in CQRL and it automatically opens up Fldigi. CQRL goes into an offline mode and accepts all logging fields and radio parameters directly from Fldigi. I’m pretty impressed! As usual with linux the install was a little quirky. I could get the programs from Ubuntu’s software repo’s but they weren’t the most current. I ended up having to do some manual installs. Also had to open a terminal window and work with the command line. Still not bad for free stuff that actually works. I usually end up learning something in the process, too.
So this takes up us back to the beginning…how’s it work? The 10M band was open all weekend. Since this antenna isn’t really resonant there I figured it would be a good test. Well, the LDG AT-897 Plus tuned it right up. Was able to work Brazil and also a strong station in California that was part of a 10-10 special event station. Switched to 20M and worked a strong station in Michigan on psk-31. He helped me get the transmit level set on the SignaLink USB so it wasn’t overdriving the waterfall display. Well, there’s three QSO’s on two bands. It’s a good start. Jared seems to be interested in what I’m doing. He even made his own lego radio to set next to mine. All is well in the world for now….
I think this is maybe like part 3 of the ongoing saga of Hamvention power supplies. When I got my first power supply working it was just running unloaded on the bench. Basically just checking the the voltage stability and making sure nothing blew up. In the past I’ve seen some supplies work fine this way but fail under a load. Sometimes there’s considerable voltage drop, or some type of failure in the the regulation of a set voltage. I have one supply that seems to eat LM 723 chips.
I still have a couple small components to solder in but right now I’m waiting on the mail to deliver them. In the meantime I thought it may be useful to put a static load on the supply. This should allow me to verify it’s regulation and hopefully stress it enough that any problem might come to light. I’d rather find an issue now that after I go to the trouble to set it up as my whole shack power supply. I found some 75 W 12 V lamps at the hardware store. I think they’re intended for low voltage track lighting or some such. I wired up some connectors for the bulbs and hooked the whole mess up to the supply. The first one worked fine so I connected the second. Finally, the third was in line. It ran this way on several occasions so I think this supply will be a winner. The test isn’t a true simulation of what would occur during typical SSB or CW intermittent operation but at least I know the supply can hold up to the current demands for a specified amount of time.
After I set up this whole test stand contraption I was bored. Nothing to do but watch the lights and make sure nothing caught fire. Those bulbs put out some crazy amounts of heat. I didn’t dare leave it unattended. So, I decided to make a little video for youtube. I’ve had it on my channel now for a few weeks. Hope everyone enjoys it! This is basically a trial run for the next supply. It needs a little more work so I hope to get all the bugs out with this one.