Digipeater

Speaking of packet radio...

I'm a huge fan of the radio email system called Winlink. If you are something of a 'prepper' or just want to make sure you can get messages out to your loved ones in case of an emergency this application is a must have. In fact, being able to use Winlink is, by itself, justification for getting your Amateur Radio ticket (Technician or General) and buying whatever equipment is necessary to be able to hit a Winlink node. It's that good.

I mostly use HF radio to hit various Winlink nodes around the country. We have two Winlink nodes in my county just south of Atlanta (run by local ARES coordinators), but because they are VHF nodes they are line-of-sight only and hard to hit. In fact, it was easier for me to hit Winlink nodes in Ohio or Indiana via HF than it was to hit these two VHF nodes just 10 miles south of me!

So our local ARES group decided to install a digipeater on a public service tower in the north-central part of the county to see if that improved the overall ability to hit the Winlink nodes. That forced me to resurrect my (very) rusty telnet skills and re-program a donated TNC. After a few tries and some help from other Winlink sysops, success!

The digipeater, in all its glory, just waiting for someone to connect

The antenna for the digipeater sits at the 250' level on the tower and has clear radio line-of-sight to the two Winlink nodes. We're getting reports that the digipeater can be accessed from as far away as mid-town Atlanta all the way down to Thomaston, GA in the central part of the state. Before installing this digipeater I couldn't hit either of the Winlink nodes with a 50 watt mobile radio hooked to an antenna at 40'. Now I can now sit inside my house with a 5 watt handheld radio and TNC and hit either Winlink node with 100% reliability by routing through the digipeater.

Winlink packet interface screen shot. Note the routing 'Via KK4GQ-15' - this is the digipeater ID

Our spring storm/tornado season traditionally starts ramping up in mid-April, so getting this digipeater on-line was critical. We'll see just how much it comes in to play when the bad weather rolls in.

Aaah, the dulcet tones of two packet stations chatting with each other. In this case passing Winlink email traffic via the digipeater

Being able to hit these VHF nodes does not mean I'll abandon using HF for the same purpose. It just gives local Winlink users more options and ensures there's redundancy and depth to a critical piece of communications infrastructure.

So you see, packet radio really isn't dead.

W8BYH out

Packet Radio Is... Dead?

Google the term 'packet radio' and what returns are links to discussion after discussion on various ham radio forums focusing on the death of packet radio. Either packet radio is dead or it's dying, or its been dead for decades and why are you bringing this up again? Folks blame the internet, or cheap cell phones, or the slow communications speeds allowed under the Amateur Radio rules, or the antiquated gear, or global warming, or whatever.

There's truth in much of that. Cheap worldwide communications modes via the internet and inexpensive cell phone plans certainly have taken a bite out of the popularity of packet radio, but I think that's over-stated. For hams it was never about communications speed or the ability to instantaneously update your Facebook status so friends on the other side of the globe know which new puppy video you 'liked' this morning. It was about the technical challenge and building robust communications backbones. Packet radio is a digital point-to-point communications protocol, and if you buy the 'internet killed packet radio' line how do you explain the exploding popularity of low speed digital modes on HF?

But first, what is packet radio? The concept is simple; packet radio is the process of bundling digital data (ones and zeros) in to 'packets' of data and sending them out over the airwaves. The make-up of the data packet is controlled by the digital protocol used, and the protocol may add additional information to the packet as it is sent. For example, the standard UHF/VHF packet protocol, AX.25, adds the originating station's callsign, any digipeater routing information and the receiving station's callsign to the information packet as it is sent. This gives any digital repeater (digipeater) the information it needs to move the packet on to its intended recipient station. Some protocols, like D-STAR (discussed below) embed forward error correction blocks to the packet stream to ensure the data is not corrupted in transit. Generating packets is normally done using a terminal node controller, or TNC, connected to a radio which is in turn connected to a computer running one of a number of packet radio applications. A TNC is simply a radio modem that takes an audio signal generated by the packet radio software, and converts it to a digital signal and sends it out over the air. The TNC generates the 'packets' based on the packet protocol used.

The digital communication protocol traditionally used for packet radio - AX.25 - is an old standard that lacks error correction. A new standard with forward error correction was introduced by TAPR about a decade ago (FX.25), but adopting that would mean wholesale abandonment of existing packet gear, and hams are notoriously cheap and will cling to whatever works for as long as possible. So the old AX.25 standard soldiers on, but it is soldering on a shrinking battlefield where fewer and fewer Amateurs are getting involved with VHF or UHF packet.

When I stepped away from Amateur Radio almost a decade ago packet radio was already dying. I used to run a packet station (a VHF radio slaved to an external TNC) and played around with packet bulletin board systems (BBS) and the new-ish Automatic Packet Reporting System (APRS). Playing on the packet systems was fun - hopping through digipeaters to get to the station or BBS you wanted check in with. There were digipeater networks that spanned the southeast, and as long as you could get to a local digipeater on a tall enough tower you could in theory 'talk' from Atlanta south into Florida or north into Kentucky. The AX.25 standard, at 1200 baud, was fast enough to support real-time keyboard-to-keyboard chats or, if you checked in to a BBS somewhere, to send or retrieve short messages.

When I stepped back in to Amateur Radio a little over a year ago I was saddened but not surprised to see that packet radio as I knew it was dead. Tune around to the old packet radio frequencies on 2 meters and all you'll hear is dead air. What happened? Well, as I said earlier, the internet, expanding wi-fi services, inexpensive cell phones and rate plans, web-based global email services like GMail, and social media sites like Facebook are partly to blame. Then there's the overall decline in interest in Amateur Radio. In the Atlanta metro area the local voice repeaters sit unused for much of the day, and even the flagship repeaters like W4DOC in downtown Atlanta are silent most of the time.

Some of the blame also goes to new digital modes on HF and UHF/VHF. Hams are like crows - they are attracted to shiny objects, and HF digital modes are big, shiny objects. What helps is that if  you have the gear needed to work one digital mode, an HF radio, a sound card interface and a computer, you have the gear needed to work them all.

A decade ago, on HF, you had RTTY and the new-ish PSK-31. There were other digital HF modes out there but these two were the dominant ones. RTTY was an old standard, predating WWII, but it worked and was great for keyboard-to-keyboard chats. PSK-31 was hot, hot, hot - everyone was getting in to PSK-31. It is a very robust comms mode, used little transmit power, wasn't a bandwidth hog and permitted either traditional keyboard-to-keyboard chats or communications via macros. I believe it was the success of PSK-31 that spurred the development of other digital modes, particularly weak signal modes like JT65 and JT8. For many hams, working HF digital became the all-consuming passion and they turned away from UHF/VHF packet with it's clunky telnet interface and heavy dependency on point-to-point infrastructure.

But things had changed on the UFH/VHF bands too. When I stepped away from Amateur Radio we were just beginning to hear of a new digital standard under development by the Japanese Amateur Radio League called D-STAR. The Japanese amateurs saw the need for a narrow-band digital FM protocol that could carry voice and data. D-STAR is an open protocol with a heavy dependence on the internet. While direct radio-to-radio or local repeater chats via the D-STAR protocol are possible, D-STAR is mainly used in the 'reflector' mode here in the US - a local D-STAR node (or repeater) is connected to one of several internet-based reflectors so that all stations linked to that reflector, regardless of location, can pass traffic. This means that an Amateur Radio operator in Atlanta talking on D-STAR on a local node tuned to reflector 30C can talk to another ham radio operator in Sydney, Australia who's local node is also tuned to reflector 30C (and I've done this). But D-STAR is mainly a digital voice mode, not a data mode. Data can be sent over D-STAR, but most of it is throttled to 1200 baud by hardware restrictions. D-STAR can support APRS-like functionality and be used in packet chat and BBS-like modes using a program called D-RATS, but D-STAR as a digital packet tool seems to have been slow to catch on. The reason? Most likely the near wholesale adoption of Winlink.

Winlink deserves its own separate discussion and I'll cover it more fully in a later post, but essentially Winlink is world-wide email over radio. The system was developed in the 1980's mainly to support sailors, missionaries and other individuals and groups who didn't have access to traditional email services. It is extremely flexible and can use a wide variety of protocols (including AX.25) to 'get the message out'.

Winlink has been adopted wholesale by emergency response services across the US, including Amateur Radio emergency groups like ARES. One of the most common protocols used for sending Winlink emails or messages is (from what I can see) the AX.25 protocol riding on the 2 meter HF band. This means you need a packet TNC to run Winlink on VHF, and I suspect Winlink drives the majority of TNC sales these days.

So packet radio really isn't dead. Old applications for packet, such as BBS systems, have died off, but new ones like Winlink have come on line. No, packet's not dead - it's just carrying on in other ways and in other formats.


W8BYH out

Cross-Band Repeat

The more I use it, the more I like it.

Several months ago I bought an Icom ID-5100, both for its D-STAR capabilities but also for its cross-band repeat feature. I had never run a cross band repeater before (UHF in, simultaneous VHF out) but found myself bumping up against several scenarios where it looked like it might be a useful tool.

The basic concept behind cross-band repeat. A signal on one band (UHF or VHF) comes in
and is simultaneously re-transmitted on the opposite band

The first was a charity bike ride event where I was the only communicator at a large but isolated rest stop at the turn-around point on the ride route. I needed to roam around the rest area, checking on bike riders and coordinating with ride officials, but the repeater we were working through was too far away to hit reliably with a 5 watt HT. In this situation I ran a 50 watt VHF transceiver connected to a tripod mounted j-pole antenna and was able to hit the distant repeater with no problem, but this setup tied me to the fixed radio setup. In this case a cross-band repeater would have allowed me to roam the rest stop at will with just a low powered HT set to a UHF simplex frequency, hit the on-site cross-band repeater with ease and get my signal out on VHF at 50 watts.

The second scenario involves my local neighborhood. I live in a fairly hilly subdivision and when I walk my dogs there are several 'dead spots' on my waking route where I can not reliably hit our local 2-meter repeater with a 5 watt HT. By running a cross-band repeater at my QTH I can reliably hit the local repeater with only 1/2 watt on UHF using my HT.

The last scenario is similar to the first, but involved needing to run a simplex VHF net in support of a recent charity 5k trail run. The course covers a small area and the trails fold back on each other, but the terrain is rough and in many spots blocks signals from getting to the local repeaters. We decided to run this event using a simplex frequency, but because of the terrain masking challenges I needed to increase the odds that the communicators at the checkpoints could reach net control with 100% reliability. I also needed to be able to roam the race operations area to coordinate issues. This was the perfect scenario for a cross-band repeater setup. At a high point near the race operations site I set up a mast-mounted j-pole antenna and ran the coax into my truck to the ID-5100 set up to cross-band repeat the VHF simplex frequency we were using.

Icom ID-5100 set up as a cross-band repeater. The radio is sitting in the
back seat of my truck, powered by a 33 amp hour golf cart battery

A j-pole antenna (an Arrow open stub j-pole) provided the elevation needed
to ensure communicators with simple HTs could reach net control. The cross-band
repeater setup re-transmitted their signal on a simplex UHF frequency that the net
control HTs were set to, allowing us to freely roam the race operations site while still
maintaining contact with all communicators

This set-up worked great. In fact, better than I expected. The ID-5100 is a no-brainer when it comes to running a cross band repeater setup. Icom did a great job of incorporating the feature in the firmware, and the touch screen interface makes it easy to select the mode with just a few finger pokes. My overall repeater setup is fairly simple, but it can be done even cheaper and simpler, yet still be just as effective. The ID-5100 is one of the more expensive dual-band mobiles, but all of the 'big three' amateur radio manufacturers offer less expensive mobile rigs with cross-band repeat capability. For almost $200 less than what I paid for the ID-5100 you can pick up the very highly regarded Kenwood TM-V71A, connect it to an inexpensive twin-lead j-pole antenna and achieve the same results. All you need on the HT side is an inexpensive UHF transceiver - even a $40 Baofeng dual band radio will work nicely.

As I use cross-band repeat more and more, more and more use cases pop up. For example, fishing with fellow ham radio operators on remote streams in north Georgia, well out of range of cell towers and local ham radio repeaters. By setting up a cross-band repeater in my truck (with a roof mounted antenna) we can work the stream in opposite directions from the truck but still maintain reliable communications.

I love it. Things like this bring out the geek in me and keep me off the streets at night 😄

W8BYH out

An Update To The Yaesu FT-817?

The Amateur radio world went into a bit of a high hover this week over the discovery that Yaesu has submitted a new transceiver design to the FCC for testing and type acceptance. Of course Yaesu is mum on the subject, but the FCC filing gives us a few interesting tidbits.

According to the filing the radio has been designated the FT-818 (gee, no give-away there!) and the submitted test unit has the following basic functionality:

• Superheterodyne design. Sorry, this is no software defined radio 😒
• HF/VHF/UHF operations
• Wide band receive
• Battery power source (although I think most are mis-interpreting this entry. It does not mean the radio will have an internal battery pack, it just means it's designed to operate off of standard 13.8 v DC vehicle power. In other words, a mobile radio)
• BNC antenna connection. This is interesting since there's no SO-239 connector listed. This indicates a low power design and it could also indicate a smaller form factor than the current FT-817 design (SO-239 connectors can eat up a lot of 'real estate' on small radio designs)

There's a lot of wishful thinking going on regarding this announcement, mainly because of what isn't stated. What's the form factor? Will it have an internal battery setup? What's the power output? Will it have an internal antenna tuner? What does the display look like?

The confidentiality request Yaesu has submitted to the FCC, restricting the release of manuals and photos, is set to expire just before the Auguts 2018 JARL Ham Fair in Tokyo, so we'll likely see a product introduction at that show. Until then, on with the speculation!

W8BYH out

Hey Lenny, Pass Me My Shiv

What does one do for entertainment while in prison? (Please, no jokes about dropping the soap.) Well apparently, if you are a good little felon, you get to listen to the radio. Not just any radio, but a radio that can't also be used to hide contraband. That's why radios with clear cases are all that the well behaved prisoner is allowed to have. There was (and may still be) a small but thriving market for clear cased radios (and TV's DVD players, clock radios, etc...).

Perhaps the most famous of the prison radio series is the Sony SRF-39FP. The 'FP' in the name stands for Federal Prison - one heck of a marketing gimmick, and it worked! These little radios were hard to find 'on the outside' when they were being manufactured. Sony didn't sell the clear version to the law abiding - you had to be behind bars to be able to buy one (through a prison commissary system). The radio also had a reputation as a great little receiver that sipped battery power. The fact that they only used one AA cell was a big plus too; batteries tend to be expensive when your pay is just a few cents a day. The little Sony quickly gained minor cult status among radio collectors. One wants what one can't have, at least not without breaking the law. Occasionally small lots of these radios would make their way to eBay or other auction sites. Some were new, but others were in used condition, often with prisoner numbers etched on them and a patina that could only come from constant use. Collectors and enthusiasts who got a hold of these little radios reported they were excellent performers, particularly on FM.

You can still find these radios new in the box, but at an astounding 300% over the original price

One bored collector actually tested the run time of his SRF-39FP and found out it would operate for over 163 hours straight - on a single battery!

Last week a small lot of these radios came up for sale on eBay at a very reasonable Buy It Now price. They were used, but working. They came out of the Tennessee prison system and I'm not sure if they were personal property left behind or the prison issued them to the prisoners. Regardless, these were the first reasonably priced SRF-39FP radios I'd seen on eBay in a quite a while.

So of course I jumped. When it arrived it was clear this radio had been 'well loved'; in fact, it looks like part of the front face of the radio was sand papered to remove some sort of marking. Perhaps a secret prison code carved into the plastic by a desperate inmate using his home made shiv. OK, too many James Cagney movies. But the seller said it worked. And work it does! I popped in a fresh AA battery and plugged in some ear buds and was very pleasantly surprised. Sensitivity is excellent - this little radio is a hot performer on FM, and stereo FM stations sound great. Selectivity is good, but the small tuning dial means you'll be doing a bit of tweaking to lock on to the station you want to hear. AM performance is not as good, but it still pulls in local stations with authority. All-in-all a remarkably good little performer, and I can see why they were popular with prisoners.

Everything the successful prisoner needs in life - his Sony SRF-39 radio and a couple of files

Sony took the SRF-39 series radios out of production several years ago. I'm not sure why. It could have been declining sales, rising production costs, parts shortages or any number of factors. What is clear (pun intended) is that Sony decided to leave the niche prison market all together - as far as I can tell Sony no longer makes any clear-cased radios or other electronic devices. That market seems to have been taken over by Taiwan-based Sangean, which now offers a wide array of 'prison ready' electronics.

So next time you are banging your tin cup on the table in the prison dining hall, demanding better food, make sure you have your SRF-39FP along so you can keep up with world events while the bulls are giving you a beat-down. OK, OK, I promise to stop watching Jimmy Cagney movies.


W8BYH out

Things That Just Work

Time for a list of things that 'just work' - ham radio gizmos I use and can personally recommend. If it's not on the list either I haven't played with it or I have and it isn't worthy of being on the list.

This list is permanent under the 'Pages' section of the blog. It'll change over time as I get to play with various items and find them worthy.

W8BYH out

Yaesu FT-817ND

Time for a little fun (pun intended).

Is the diminutive little Yaesu FT-817ND still a valid radio with today's lousy band conditions?

My FT-817ND standing on the shoulders of a giant - the AN/PRC-77.
The FT-817 does everything the PRC-77 does, and more. Much more.

The Yaesu FT-817 is by no means a new radio. It's been in production since 2001 and its last update was in 2004 when the ND model was released. The FT-817 has been in production so long, and is so popular, that entire industries have sprung up to support it. Introduced near the peak of the last solar cycle when propagation was good, the FT-817 was designed as a low power HF rig. It's maximum output is only 5 watts (out of the box most Amateur radio HF rigs put out 100 watts). The little radio was designed to appeal to a specific market niche - Amateur radio operators who enjoy the challenge of making contacts using very little power. In Amateur radio its known as QRP, radio abbreviation for low power operations. Using low power to talk hundreds or thousands of miles is a fascinating challenge, and when there's good radio wave propagation it is actually quite doable. Radio contacts across continents or oceans on just 5 watts is actually fairly easy during high solar activity periods, when propagation is at its peak.

My FT-817 wearing the excellent protective bracket set made by Portable Zero

Because the FT-817 only puts out 5 watts the designers didn't have to worry about building in a large RF output stage. This allowed them to keep the overall size of the radio very small. It also allowed them to incorporate an internal battery system to power the radio for a limited amount of time without an external power source. With a proper antenna like one of the MJF single band whip antennas you can actually walk around and talk on the HF bands.

The FT-817 is little more than twice the size of a modern handheld radio

But Yaesu's designers didn't stop there. They figured, why not throw the VHF and UHF ham bands into the mix? By the time they were done the FT-817 was a true multi-mode radio, able to work the Amateur radio UHF, VHF, and 6 meter through 160 meter bands using FM, AM, USB, CW and digital modes. A later update added the new 60 meter band allocation. It was an extraordinary design feat - a portable, extremely capable and affordable all-mode radio. When introduced it took the Amateur radio world by storm and Yaesu was selling these little radios by the truck load. I'm sure Yaesu figured the gravy train would last only as long as the solar cycle was near its peak and propagation was good. But something interesting happened - the little Yaesu held its appeal as the solar cycle tanked and it became harder and harder to get anyone's attention on the HF bands with just 5 watts of transmit power.

The FT-817 is a little over twice the size of the Kenwood TM-D74 handheld but adds HF and 6 meters

Like a number of FT-817 owners I've made the switch to rechargeable lithium-ion AA batteries.
They are easy to replace but you have to be vary careful about polarity when inserting new ones

I think the FT-817's long long term appeal stems from it's incredible versatility. There are plenty of multi-mode radios out there. Heck, even Yaesu makes an up-sized and more powerful version of the 817, known as the FT-857. The 857 actually pre-dates the 817 and is itself a crackerjack radio, but it is significantly larger and heavier than the 817 and doesn't have an internal battery. You can grab an FT-817, sling it over your shoulder (Yaesu even provides the shoulder strap), and be walking and talking while your buddies are still struggling to get their radios, power sources and antennas set up. A lot of Amateurs are willing to overlook the low power output and focus on the extreme versatility of this little jewel. This has kept the FT-817 a strong seller, and reports are Yaesu still sells them by the truck load.

Foot mobile? No problem! With internal batteries and a shoulder strap the
FT-817 works quite well on UHF, VHF and 6 meters. With the right whip antenna
and a counterpoise you can even do HF while out walking around

So the solar cycle is in the pits. Even guys running 1kw amplifiers have trouble talking across town on the HF bands. Is the FT-817 with its measly 5 watt output still worth owning?

Yes! Amateur radio operators too often fixate on 'long haul' communications - "If I can't talk from Denver to Dusseldorf why bother?"  If that is your outlook then ham radio at times like these is a very frustrating exercise. But if your goal is to communicate and experiment to get around challenges then the FT-817 is a perfect tool. The low power output forces you to focus on efficiency and flexibility. Supporting a tactical communications scenario such as local disaster relief? The FT-817 connected to a tuned NVIS antenna will work just as well as the same antenna hooked up to a 100 watt rig, regardless of the band conditions. Need to talk simplex or through repeaters on UHF or VHF? No problem. Hook a VHF/UHF antenna up to the front connector, and the NVIS antenna up to the rear connector and switch effortlessly between the two. The internal battery in the 817 can provide immediate coverage and flexibility while you bring other, more powerful communications systems on line. This was a paradigm we followed all the time in the Army. The advanced or scouting party arrives on scene with just a low power vehicle mounted radio and runs as net control as the main party closes on the site and gets their more powerful radios and antenna systems set up.

Need to run UHF/VHF/HF off of one radio? The FT-817 can do it. By default the UHF/VHF signals are routed through
the front BNC connector and all HF signals are routed through the rear SO-239 connector.
LDG makes a a small battery powered tuner specifically for the 817 that does a great job matching antennas

FT-817 'kit' in a small waterproof Pelican case. The radio, tuner, microphone, whip antennas,
accessories and an external LiFePo battery all fit neatly, making an excellent emergency communications kit

If we are talking about running digital modes the picture improves. By their nature most digital modes require very little output power to be effective. This means in scenarios where HF voice doesn't work - you can't hear anybody and nobody can hear you - you are still likely to make a digital connection. With a sound card interface like a SignaLink you will be able to effectively communicate via the FT-817 even under the worst of band conditions.

An external sound card interface like the Tigertronics SignaLink
lets the analog FT-817 work digital modes like PSK-31

I hinted earlier that the FT-817 is getting 'long in the tooth'; it's an old (though not antiquated) design, and as long as it continues to sell and Yaesu can get components I think it'll stay in production. But it would be nice if the little radio got a refresh. Move it into the digital signal processing realm (like the recently released Yaesu FT-891), add a sound card interface for digital modes, incorporate better power/battery management functions, bump the power output up to 10 watts to help us get through this awful solar cycle, and build it so it gets an IP54 rating. Oh, and for God's sake drop the old multi-pin CAT interface and build in a real USB port to control everything

Other than that the radio's fine. Get one.

W8BYH out