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

Antenna Work

Yesterday my local Amateur radio club, KK4GQ, did some extensive repair and replacement work on our antennas on our flagship tower in Fayetteville, Georgia. The club or its members own an extensive network of 2 meter and 70 centimeter-band Amateur radio repeaters around the south metro Atlanta area, and we support a wide variety of public events and emergency response activities with this network, including supporting the National Weather Service office in Peachtree City, GA. So it's important to keep this radio infrastructure as healthy as possible.

About 10 years ago we got permission to put several repeaters on a public service tower in Fayetteville. We even got permission to take our antennas all the way to the top of the tower, to the 300 foot level. While this affords outstanding signal coverage, being the top guy on the totem pole also means you are the prime target for whatever Mother Nature throws at the tower. Over the years our antennas developed problems related to wind, rain and (we suspect) lightning damage. After almost a decade we decided it was time to put some money and effort into rehabbing the antennas and replacing what couldn't be fixed.

So we found a climbing crew that gave us a price break, bought a new Andrew DB420 antenna for the 70 cm repeater, gathered at the base of the tower, and got to work.

Five hours later we had the new antenna in place and the climbing crew performed maintenance on the still serviceable antennas on the tower. They straightened up the tower stand-off brackets, re-secured the mounts for many of the antennas, checked cable connections and wiring harness condition and generally got things back in good operating order.

Our primary 2 meter and 70 cm antennas are back up at the 300' level and we're getting great signal reports from around the metro Atlanta area. Hopefully we're good for another decade!

Tower crew at the 300' level taking down
the damaged 70 cm antenna

Andrew DB420 antenna being prepped

DB420 close-up

DB420 being hoisted to the 300' level

At the very top (300'), 70 cm (444.600 mHz) antenna on
the left, 2 meter (145.210 mHz) on the right.
Perfect targets for Mother Nature, but we made
sure everything was well bonded 

Tower crew working to straighten & tighten down the
stand-offs and re-tighten some of the antenna mounts.
The two antennas on this stand-off are part of the remote base
 system that supports the National Weather Service

W8BYH out

Amateur Radio Repeaters in Georgia

When I'm not playing radio I'm making maps for a living (yes Virginia, you can make a living making maps). Most of the maps are very esoteric and tightly tied to the needs of people who do things like inventory utilities or inspect retail operations. But every so often I get to indulge myself and put together a map that is fun to work on, presents a challenge and provides what I hope is real value to folks who share my interests.

Earlier this year, as the spring storm season approached, I put together a web map that depicted all the Amateur Radio repeaters in the State of Georgia. The map is built using a system called ArcGIS Online, a service provided by ESRI, and is hosted in ESRI's cloud environment.

Compiling this map presented some interesting challenges, the biggest being the collection and aggregation of location information for the repeaters. At first I thought it would be an easy task to just go to the FCC's radio license database (ULS), do a search on Amateur service repeaters in Georgia, download the data, geocode it and publish it. Simple, straightforward, easy. Hah! Silly me. The FCC either doesn't have, or doesn't make public, Amateur radio repeater information.

To throw together the repeater information I went out to multiple on-line sources that held the bits and pieces I was looking for - regular repeater data from this source, digital repeater data from that source, and some 'insider knowledge' of the actual locations of repeaters near me. It was an inexact, tedious and error prone process, but I wanted to get it done so I had something to use and share with the local Amateur radio community. The map was completed and published, but I knew there were a lot of problems with the repeater data.

Amateur Radio Repeaters in Georgia

Fast forward to a few weeks ago and I figured it was time to try to update the repeater listings in the  map and present complete and authoritative information on each repeater. With accurate repeater locations you can do lots of interesting things like line-of-sight analysis, terrain masking studies, RF coverage polygons, and more. This has the potential to help visualize the repeater infrastructure in Georgia in entirely new ways.

After some emails and phone calls I found out that the actual repeater locations (and all other information about the repeaters) are held by the  Southeastern Repeater Association (SERA). SERA is the recognized repeater coordination group for the southeastern US. The term 'coordination' refers to the process of having a regional coordinating organization like SERA assign a frequency pair (input/output) and PL tone to your repeater. If a repeater is coordinated then it assures that the repeater will not cause interference with other repeaters in the region (and vice-versa) and that the FCC will resolve any interference issues between a coordinated and uncoordinated repeater in favor of the coordinated repeater. Repeater coordination in places like the Atlanta metro area is absolutely essential to keep the repeaters from stepping all over each other. In fact, I've been told that there are so many Amateur radio repeaters in the Atlanta area that there are no more 2 meter frequency pairs available above a line that runs from Columbus to Macon. That's a LOT of repeaters! If you live in the Atlanta area or are visiting you can be assured of finding at least one (and usually several) repeaters that you can hit with just a handheld radio. The fact that these repeaters are not stepping all over each other and causing interference is due to the hard efforts of SERA.

SERA considers the locations of its coordinated repeaters to be proprietary information. Part of the issue is security - a lot of repeater owners are uncomfortable with the idea of their repeater/tower locations being made public. The other issue is that SERA makes a small profit by selling repeater guides and journals that contain this proprietary information. Since SERA is a non-profit organization they see this as a way to help cover their operating costs. I can understand and respect that.

So this has me facing my original challenge - how to collect accurate repeater data? I still have the old method to fall back on - scrape the data out of a number of different sites on the web that hold the data and do not put any restrictions on its use. However, I'd also like to take this opportunity to invite individual repeater owners/trustees to review their repeater data in this web map and provide me any necessary updates or corrections. I'll respect your wishes and show only the data you want displayed.

If you are a repeater owner or trustee and would like to help keep this data up-to-date please contact me at w8byh@arrl.net.

Thanks!

W8BYH

Early History of the PRC-25 and -77

Very few things in this world are a wholly original idea. So it is with the AN/PRC-77. The PRC-77 is actually a product improved AN/PRC-25, a radio that was revolutionary it its design.

The PRC-25 was introduced in the early 1960's and was the right radio at the right time. In 1965 General Creighton Abrams called the PRC-25 "The most important tactical item in Vietnam today". More important than the M-16 rifle, more important than the UH-1 'Huey' helicopter. In fact, it was the light weight, rugged design, ease of use and wide fielding of the PRC-25 that allowed the US Army to successfully implement the new tactic of vertical envelopment by helicopter. Vertical envelopment requires close communication between ground and aviation elements, and the PRC-25 filled this role perfectly.

The early history of both the PRC-25 and PRC-77 is not well known. The PRC-25 and -77 series radios were the most widely produced military communications systems ever fielded (estimates are that over a half million units were eventually produced in the US alone) and the PRC-77 is still in use with militaries around the world. They are also immensely popular with collectors. But the history of these radios, particularly the developmental history, is a bit foggy.

Back in 1999, Mr. Dennis Starks, a military radio collector and former editor of the Military Collector Group Post, put together an article that was, and remains, the the most comprehensive history of the PRC-25 & -77 series radios. The article, titled 'PRC-25, Forgotten Legend', was published on-line and is still referenced as a link from a number of collector and military history websites. Sadly, the hosting site Mr. Starks used was closed down several years ago and since then his article existed only as partial extracts on various discussion forums.

In December 2017 I was able to contact Mr. Starks and obtain an original copy of his article. With his permission I edited the article and re-created it as a PDF document. The article is a great read, with lots of important information on the early design and fielding of the PRC-25 and -77 radios. It is an important historical and collector's resource and it deserves a wider audience. Towards that end I have added a link to 'PRC-25, Forgotten Legend' (as a PDF) in the 'Links' section of this blog.

PRC-25, Forgotten Legend by Dennis Starks

Enjoy!

W8BYH out

Snow!

In case you hadn't heard, the Atlanta area got a rare treat this weekend - snow! The VX-6 begged to go out and play.

It had a tough time making snow angels, though.

These radios are tough little buggers!

W8BYH out