Mobile Weather Balloon Chasing Rig

A few locals (mostly part of the SecKC crew) have been chasing weather balloons for the past few months. It's an interesting way to get out of the house and go do something. We are also trying to reverse engineer the guts of these weather balloon payloads, but that's a story for another post.

Weather Balloons and Radiosondes

In the US, a number of National Weather Service offices (I'm guessing about a third to half of them) deploy weather balloons every day at about 0:00 and 12:00 UTC, give or take an hour either way. They often launch at about 45 minutes ahead of time, but they can be delayed by severe weather. That's over 700 weather balloons per year from each of the dozens of stations that launch them!

The weather balloons carry something called a radiosonde into the stratosphere. This package contains a battery, radio transmitter, GPS, and weather sensors. The radio transmissions include position information, humidity, temperature and other metrics, once per second. Position information is used to determine wind speed and elevation to correlate with the other metrics. This data is shared internationally and is used for local forecasts and models, and worldwide climate trends. 

Close up of the bottom panel of a 400 MHz Lockheed-Martin Sippican LMS-6 Radiosonde.

The air gets thinner and the pressure lowers as the balloon climbs past 100,000 feet, and it eventually bursts. The package, weighing less than a pound, falls back to the ground under a small parachute so that it doesn't hurt anyone or anything when it lands. 

Here's a video I shot through a telescope, of a weather balloon bursting at about 130,000 feet. You can faintly see the radiosonde swinging beneath the balloon. When it bursts, the parachute expands as the package falls.

 

A recovered weather balloon, after untangling all of the rope.

The National Weather Service does not recover these devices from the field. Some of them have a mailing bag and shipping label attached so that folks who find them can return them to be refurbished. The radiosondes that we've been finding have no instructions aside from "dispose safely". That is to say, once they have fulfilled their mission and landed, these radiosondes are very much "finders keepers" and are no longer government property. They can land more than a hundred miles away from the launch site, depending on jet streams and wind conditions closer to the surface.

Tracking

To facilitate the tracking of these devices, a number of software tools have been created to make use of software-defined radio receivers (such as the RTL-SDR or HackRF One) or simple audio-decoding from a computer sound card. My favorite tools are radiosonde_auto_rx and chasemapper, both part of Project Horus, an amateur radio high-altitude-ballooning project in Australia. The tools to monitor amateur balloons happens to work just fine for tracking weather balloons, and folks have added code to help decode the payload data for weather balloons. 

radiosonde_auto_rx scans a small range of frequencies you define, looking for a signal that's likely to be a radiosonde. It then tunes to that frequency and tries to decode the location data. Once it's locked on, it continuously tracks the location of the balloon. It can also upload balloon location data to websites like sondehub (radiosonde tracking) and habhub (high-altitude balloon tracking), so folks can share data about these balloons' trajectories with a world-wide audience.

Screen shot from sondehub.org showing multiple weather balloons in flight, and locations of auto_rx sites:

Chasemapper acquires the balloon location data from radiosonde_auto_rx, and your location from local GPS data, then draws a map of your location and the payload's location, in a browser session. This is a nice visual aid when you're planning on recovering a radiosonde. Here's a screen shot showing my vehicle's track and a radiosonde payload location on a recent balloon chase. The payload location doesn't have a track following it because I rebooted my setup to move it to my car. The movement was from me hiking toward my car while unplugging the battery.

Building the mobile tracker

I decided I'd like to build a semi-mobile balloon tracker that I could leave running at home most of the time, but also quickly toss into my car or even carry with me if a radiosonde was going to be landing nearby, to help me recover it from some corn field or woods or an 8-foot tall patch of thistles and prairie grass out in the middle of nowhere. These things never seem to land anywhere convenient, like in the ditch of a dirt road. 

I decided to make do with stuff I already had laying around. You may recognize some pieces from previous articles. The below links are Amazon affiliate links to the parts I used if you wish to reproduce my exact setup, and purchasing from these links supports this site).

• Raspberry Pi 3 with an AdaFruit 3.5" TFT
• RTL-SDR v3 receiver kit or NooElec NESDR Nano Three kit (you only need one SDR, both of these models work in this setup)
• Inseego MiFi 8800L WiFi Hot-Spot
• Rii wireless mini keyboard/trackpad
• 26800mAh USB battery pack

The MiFi 8800L not only offers 4G wireless connectivity so radiosonde_auto_rx can upload location data and chasemapper can download map data, but it also has a GPSd server integrated so other devices (like the Raspberry Pi) can use the GPS location of the hotspot. You must log in to the MiFi admin page to activate the GPS Service. By default, it runs on port 11010, and it's recommended to leave that default set.

Actually getting chasemapper to use that GPS data turned out to be more trouble than I had bargained for. You may be better-off connecting a USB GPS to your Raspberry Pi. I'll cover how I managed to cobble everything together as I go through this post. 

The first order of business was installing the latest RasPiOS to a fresh 16GB SD Card. There is more than enough documentation on raspberrypi.org to get you started. The Rii keyboard works both with a nano-receiver or via Bluetooth. Pick your poison. I chose to use the nano-receiver because bluetooth seems to not like to auto-reconnect on reboot some of the time. Feel free to use whatever kind-of-portable human-interface device you like.

Next, I had to get the display working. 

I had really good luck with the fbcp-ili3941 driver on this Raspberry Pi with Kali Linux, and the instructions I wrote about setting up fbcp worked fine on the latest RasPiOS. You can follow most of the instructions in that article to get the AdaFruit TFT working, just keep in mind the touch screen won't work with the fbcp driver. The digitizer on my display actually broke a few years ago, so I don't miss it.

For my setup, I uncommented the following lines in config.h. Note that these lines need the # at the beginning of the line. I removed the // from these two lines to uncomment them:

#define DISPLAY_ROTATE_180_DEGREES

#define DISPLAY_BREAK_ASPECT_RATIO_WHEN_SCALING

I used the following options to build fbcp:

cmake -DADAFRUIT_HX8357D_PITFT=ON -DSPI_BUS_CLOCK_DIVISOR=30 ..

As per the Kali instructions, I put the call to /usr/local/bin/fbcp near the top of /etc/rc.local so that it runs on boot.

I set my display up to run in 480p mode since the display is so tiny. The entirety of my /boot/config.txt file is:

hdmi_force_hotplug=1

dtparam=audio=on

hdmi_group=1 

hdmi_mode=3 

dtoverlay=pwm,pin=18,func=2

Reboot and make sure the TFT display works.

Now for Radiosonde_auto_rx. The setup instructions mostly work. You'll need to install a bunch of dependencies. They recommend installing rtl-sdr from source. I just added it via apt, and it supported the bias-tee option. Make sure you install the udev rules and module blacklist options per the instructions. 

Keep following the instructions. Maybe, if you're lucky it'll just work. For me, though, I had to do some hacky garbage to get it to compile. If build.sh fails, you can try these tricks: 

I had to tell the compiler use the c11 standard for compiling fsk_demod by adding “-std=c11” to line 50 of auto_rx/build.sh, which now looks like this:

gcc -std=c11 fsk_demod.c fsk.c modem_stats.c kiss_fftr.c kiss_fft.c -lm -o fsk_demod

I had to tell the compiler to use the built-in alloca() for some reason, and the real baffler was having to define the meaning of freaking Pi, twice.

In utils/fsk.c, I added these lines to the "includes" block near the top:

#define alloca(x)  __builtin_alloca(x)

#ifndef M_PI

    #define M_PI 3.14159265358979323846

#endif

And I added the following to utils/modem_stats.c, also near the top. 

#ifndef M_PI

    #define M_PI 3.14159265358979323846

#endif

With all that out of the way, the instructions for setting up Radiosonde_auto_rx work just fine. Make sure to edit station.cfg. You probably want to specify a name, callsign or handle for uploading to HabHub (and enable uploads), and you should specify your latitude and longitude. You could, in theory, also use gpsd for radiosonde_auto_rx as well. I didn't set up auto_rx to use gpsd, so even when I'm mobile, the reports appear to come from the hard-coded location in auto_rx. I'm fine with that.

It seems that the National Weather Service relies mostly on radiosondes made by Lockheed Martin Sippican. The LMS-6 Radiosonde comes in two "flavors", one operating between 400 and 406 MHz and the other one operating around 1680 MHz. The Vaisala RS41 is a newer radiosonde model used at some locations, and it also operates around 400 MHz. You should ensure the proper frequency range for your location is enabled. The 1680  MHz radiosondes also work best with a circular-polarized antenna, similar to those you might use for certain FPV drone video.

Setting up Chasemapper

The instructions for Chasemapper mostly work out of the box, with the exception of GPSd in my case. The version of GPSd on the MiFi 8800L doesn't support JSON output which Chasemapper requires, so I ended up running a modern version of  GPSd on RasPiOS, pointing it at the GPSd on the hot-spot. Details on that toward the end of the article. I also had some trouble running GPSd on the default port of 2947, so of course I ran it on port 1337. 

For horusmapper.cfg, I changed only the following lines:

car_source_type = gpsd 

gpsd_port = 1337

habitat_call = [my amateur radio callsign]

Tying it all together

I didn't set up systemd services for anything, but you may want to follow the instructions in the git repositories to enable systemd services if you plan on building a dedicated tracker. I run gpsd, auto_rx and chasemapper on-demand with a simple shell script that I call "loon.sh":

#!/bin/sh

gpsd -S 1337 gpsd://192.168.1.1:11010

cd ~/radiosonde_auto_rx/auto_rx

python auto_rx.py&

cd ~/chasemapper/

python horusmapper.py&

Everything runs in the background, and the terminal will fill up with logs about both chasemapper and auto_rx status. You can fire up your Raspberry Pi's web browser and hit localhost:5001 for ChaseMapper, and localhost:5000 for the auto_rx status page. 

GMRS and You

With the availability of handheld radios that are more powerful than cheap walkie-talkies, even more powerful radios for your home and vehicles, antenna masts and a small network of repeaters, GMRS allows your family some of the benefits of amateur radio, at a marginal cost, and without every member having to pass an exam. With a decent home and mobile GMRS radio set-up, your family could likely stay in touch even if you stray several miles from home for work or errands.

With the potential of a wide-spread infrastructure outage in an emergency, and increased tracking of location data via smart phones, payment card transactions and the like, adding GMRS to your family's communications strategy can make a lot of sense.

FRS vs GMRS

General Mobile Radio Service (GMRS) is a UHF Land Mobile Personal Radio Service, not much unlike Citizens Band (CB) or Family Radio Service (FRS). In fact, 14 frequencies used by GMRS are shared with FRS.

Up until the rules changed in 2017, one had to obtain a GMRS license to use channels 15-22 on FRS/GMRS handheld radios that look a lot like the one on the left in the title photo above. That radio is actually a 5 watt Midland GXT-1000 GMRS radio, but with a few caveats, it can be used for FRS as well.

Recent changes were made to allow up to 2 watts on channels 1-7 and 15-22 as part of FRS without obtaining a license. Channels 8-14 are still reserved solely for FRS use in the US, with a maximum of 500mW output. A number of FRS radios are available that run close to 2W on legal channels, but today I'll be focusing on GMRS specifically. The primary differences between FRS and GMRS are:

• GMRS handheld radios are allowed to transmit up to 5W
• GMRS mobile and base-station radios are allowed up to 50W
• Removable antennae are allowed
• Repeaters can be used on GMRS
• An FCC license is required for GMRS, but there is no exam.
• Businesses can legally use FRS for operations, but business use of GMRS is mostly disallowed.
  

The Rules

A short, multi-page primer on GMRS is provided by the FCC.

The full rules for operating on GMRS are in FCC Part 95 subpart E.

The short, short version of the rules that should cover most of the highlights:

• No "public broadcast" messages, advertising or music
• No profanity
• Only communicate with other GMRS or FRS users. Communication with amateur radio stations is not allowed.
  
• No "Jamming" or continuous transmissions
• Don't use GMRS to assist in any criminal activity
• You must identify your call sign (e.g. WRBX000) in English or morse code
• At the end of a single transmission that you do not expect a reply to
• At the end of a conversation
  
• At least once every 15 minutes while communicating
• You can authorize any family members to use your license with your permission.
• Your parents, children, grandparents, nieces, siblings and uncles can legally operate on GMRS under one single license, if you give them permission and ensure they know the rules.
• If they break the GMRS rules under your license, your license is likely in jeopardy. You are ultimately responsible for the actions of those using your license.

While GMRS is provided as a convenient way for family members to stay in touch, an authorized GMRS user is allowed to talk to others outside of their family. They do not need to be physically close enough to you to communicate with you as the license holder as long as they obey the rules.

Licensing

Most adult United States citizens are eligible to apply for a GMRS license. As of 2020, the license fee is $85, and it is valid for 10 years from the date of issue.

One can apply for a GMRS license online through the Universal Licensing System, or by mail. Either way, you must fill out FCC Form 605. Filing online requires you to register for an FCC Registration Numer (FRN) if you do not already have one. Amateur radio operators may use their existing FRN, for example.

Once logged in to ULS, click "Apply for a new license" and choose "ZA - General Mobile Radio Service" from the very bottom of the drop-down list.

Upon completion of FCC Form 605 for GMRS, you will be required to make an online payment. Your license will usually show up within a few hours or on the next business day. You will also likely receive an email about your license grant.

Hardware

YOU MUST NOT USE AMATEUR RADIO EQUIPMENT* ON GMRS.

Transceivers specifically designed for amateur radio are not allowed on GMRS. Some hams use commercial radios that have been tuned to work on amateur radio frequencies, and there's a bit of a grey area there.

Until recently, hardware specifically designed to take full advantage of GMRS was pretty rare. Radios must be type-certified under FCC Part 95 to operate on GMRS and strict standards must be met with regard to channel deviation, frequency stability at a wide variety of temperatures, and spurious emissions. It just so happens that commercial land mobile UHF Radios type-certified under FCC Part 90 meet or exceed the specifications for GMRS, so long as they do not exceed 50 watts of output power. As such, many GMRS users will re-program commercial UHF radios to operate on GMRS frequencies. The FCC hasn't ever given a straight answer about if this is allowed, but most repeater operators are okay with it. The Motorola Radius in the above photo is one of these, but a variety of 15-45 watt mobile radios and 2-5 watt handhelds from the commercial lines of Motorola, Kenwood, Bendix/King and others can often be found inexpensively on the used market. Just make sure you, or the seller, can program them properly.

BTech (purveyors of the ubiquitous, cheap "Baofeng" ham radios) markets two GMRS-specific radios: the GMRS-v1 handheld and the GMRS-50X1 mobile radio. These two have been type-certified for GMRS, have the ability to use GMRS repeaters, and are legal. The GMRS-V1 is, in fact, the only GMRS-specific handheld radio I was able to find that has repeater capability.

Midland, Cobra, and Uniden have also been making a variety of type-certified GMRS radios. Most of the handheld units, like the Midland GXT-1000 I have, do not have the capability to use GMRS repeaters, but the Midland Mobile and Micro-Mobile radios, designed to be installed inside vehicles, do have repeater capability.

Most GMRS radios are interoperable with FRS radios. The GMRS-specific radios mentioned above may have more than 22 channels, but channels 1-22 are almost guaranteed to work between any GMRS and FRS radio. If your family does a lot of outdoor activity, you may find that inexpensive FRS radios work fine for kids, and your GMRS radios will let you communicate with them.

Many old-school GMRS users refer to frequencies -- and especially repeaters, by the kilohertz part of the frequency only. I suspect this persists in part because GMRS users are begrudgingly sharing practically all of their frequencies with FRS users and dislike the concept of channel numbers. At any rate, "700" refers to either 462.700 MHz, or a repeater that uses 467.700 MHz on the input and 462.700 MHz on the output.

You can see actual frequencies in this chart on Wikipedia:

https://en.wikipedia.org/wiki/General_Mobile_Radio_Service#Frequency_Table

Repeaters

Like amateur radio, GMRS operators can run repeater systems. These repeater systems listen 5MHz higher than the base frequency, and re-transmit the signal on the base frequency so that all radios listening can hear the message. Not all regions have GMRS repeaters, but here in the Kansas City area, there are several to choose from. Unlike amateur radio repeaters, most of them require permission from the repeater operator before you use them.

MyGMRS.com is probably the closest thing there is to a directory of all GMRS repeaters in the United States. You can browse the repeater listings without signing up for an account, but many repeater details (such as the CTCSS or DCS codes to use them) are hidden until you log in. Some of these details are completely unlisted, instead requiring you to ask the repeater owner for permission. You can only create a MyGMRS account once your GMRS license has been active for a day or two and the website has imported your license from the FCC.

You can also buy or build your own GMRS repeater, and it probably comes as no surprise that commercial repeater hardware is also quite common. Repeater building is a complex topic I won't cover here, but the cost is usually pretty significant.

Yaesu FTM-400XDR - Undocumented Cross-Band Repeater Mode

I was in the market for a new dual-band amateur radio. I'm a bit of a Yaesu fan, and I was torn between trying to find a used workhorse like the  FT-8900R, or trying something a bit more modern, like the FTM-400XDR. The one thing I really wanted the '8900R for was its cross-band repeater. That was the only thing missing from the new '400XDR.

Cross-band repeater mode will listen on two different bands (usually 70cm and 2m) and repeat what's being "heard" on one of the bands, transmitting it on the other. You can use this for a variety of purposes, but it's most commonly used to boost the range of a small handheld radio when you can't feasibly take a high-powered radio with you -- such as into an office building, down in your basement storm shelter, or keeping in touch with a group of spread-out friends while in an area without good repeater coverage.

Lo and behold, the FTM-400XDR does have a cross-band repeater built-in. It's just not documented officially. It's actually pretty easy to set it up.

Start by configuring your radio's tuners the way you want them to work together. Check that the frequencies, repeater offsets, squelch are all correct, and disable APRS if you had it enabled.

In this case, I configured the top tuner to communicate with a local repeater, on medium power. It might be kind of hard to see, but there are indicators "-" and  "T-TRX" in the header of the top tuner that indicate a negative repeater offset, and "Tone Squelch on Transmit and Receive" which are common radio configurations for repeater use. You could instead set the upper tuner to a simplex frequency if you want to run it as a stand-alone temporary repeater.

The bottom tuner has to be on the other band. Since the repeater I wanted to talk through is on the 2m band, I selected a simplex frequency from within the 70cm band.  Since I plan on staying pretty close to my radio for this test, I set the power level on the bottom tuner to low power, and made sure there was no auto-repeater-shift offset. You'll notice there are no indicators in the header of the lower tuner. You would not want to accidentally link two other repeaters together. Don't cross the streams.



Power the radio off. Next, hold the SETUP, F and GM buttons under the power button at the same time. Keep holding them while you power the radio on.



When it powers up, you will see an "X-Repeater" indicator in the middle of the screen.

If you're setting up a stand-alone repeater, all users will have to configure their dual-band handheld radios for "split" operation. This varies by make and model, but you'll want them to transmit on the same frequency as the bottom tuner, and receive on the same frequency as the top tuner of the '400XDR. Anything transmitted by members of your party on the lower tuner's frequency will be repeated out to everyone else listening on the upper tuner's frequency.

To use the cross-band repeater with another repeater like I did, you'll want  to set your handheld radio to use the simplex frequency, without a repeater shift, that's displayed on the bottom tuner. The cross-band will relay bi-directionally, so whatever you transmit will be sent to the repeater configured on the upper tuner, and whatever the repeater transmits will be sent back to your handheld via the simplex frequency on the lower tuner.




To disable cross-band repeater mode, power the radio off, then use the same 3-finger-salute while powering it back on.

Caveats:

• When the repeater isn't being actively used, you're still responsible for ensuring it is functioning properly. Your cross-band repeater has no way to identify itself. (e.g. CW ID) and lacks the sophistication of a real repeater.
• You or someone you trust should be close enough to your cross-band repeater to shut it off quickly should it malfunction or otherwise transmit undesired activity (such as static, intentional interference, radio pirates).
• Turn the radio off or disable cross-band repeater mode if you are not actively using it or are unable to monitor it.
• Use the minimum power level possible for the communications required. This is just best-practice, but also, if you end up cross-band repeating a long-running discussion, you may overheat your radio and/or drain your car battery. Mobile radios like this are designed for a relatively low duty cycle -- transmitting only for a few minutes at a time, then given a chance to cool down while others talk. Low power (5 Watts) is probably safe for extended, continuous bidirectional operation.
• The FTM-400XDR is capable of operating on Yaesu System Fusion (C4FM) digital modes, but under cross-band repeater mode, it will only operate in analog FM mode. You cannot cross-band repeat to a digital repeater from an analog handheld radio.
• I do wonder if another Fusion radio could communicate through a cross-band repeater to a Fusion Repeater and vice/versa... I don't have a second Fusion radio to test this with.

Recent Baofeng vs. Classic Yaesu

My first real ham radios were a pair of outdated Yaesu handhelds -- The VX-7R, and the VX-2. Both of them entered production more than a decade ago, and while I believe Yaesu still makes the VX-7R, the VX-8 series de-throned it as Yaesu's Flagship Handheld radio in 2008. The VX-2 was replaced by the VX-3 in 2007.

When I got my license a few years ago, inexpensive handheld radios were just starting to become popular. I've had more than a year to put two polar-opposites head-to-head against each other.

I won't dwell much on my VX-2 or the newer VX-3. These diminutive Yaesu handhelds pack a lot of features into a small package, but with a maximum of 1.5 watts when running on battery power, they aren't very practical for most hams. It's a good, compact radio if you only want to monitor or scan ham and business band channels.  Much of what I write below will hold true for the VX-2 and VX-3 compared to the similarly-sized, low-power Baofeng UV-3R radios.

To provide some context, I've been using the Baofeng almost daily since early March of 2013. The stock battery in my Yaesu had become almost unusable, and the cheap ($20) replacement battery failed within 9 months. A new "official" Yaesu battery for the VX-7R costs between 70 and 100 dollars depending where you look. I opted to spend half of that on a new, cheap Baofeng UV-5R. After more than a year of using it, I figure I'm qualified to make a comparison.

On with the show.

Left: Baofeng UV-5RA (Circa 2012)
Right: Yaesu VX-7R (Circa 2007)

Let's start with the Baofeng, because this radio, and ones like it available under brand names such as Wouxun and TYT, have become quite popular among new ham radio operators mostly due to their low prices, ranging anywhere from $30 to $160. Many of these radios were designed to be programmed for Business Band (FCC Part 90) use, and some even bear type certification for this use. They are clearly competing with Motorola and Kenwood in the business radio arena. Others, like my UV-5RA, bear no type certification and can only be legally used for ham radio frequencies.

The Good:

• These radios will get you on the air for 2m and 70cm repeaters, which is many peoples' first step to becoming an active ham radio operator.
• On simplex freqencies, they make excellent walkie-talkies (assuming everyone's licensed, of course) and will provide much better range than a pair of FRS or hand-held CB radios. Highly recommended for camping, bike trips, road convoys, the bug-out-bag, etc.
• This radio can receive broadcast FM, and can receive and transmit in the 136-174 MHz and 400-480MHz bands including weather radio.
• Relatively inexpensive
• Long battery life, even for long-winded ragchews or an active day helping with a public service event (marathons, bike races, storm spotting)
• The backlight is very bright and the display is fairly easy to read in all lighting conditions.

The Bad:

• Although it displays two frequencies at once, it cannot actually use both at the same time. "Dual Watch" tries to emulate simultaneous use of both tuners.
• Dual Watch functionality can be problematic and lead to you inadvertently transmitting on the "wrong" tuner if you're not careful. 
• Scanning is very slow: in 5kHz steps, it takes exactly one minute to scan 1MHz. 
• Poor interference rejection either due to or causing RF squelch to be over-sensitive
• When using CTCSS tone for squelch, the speaker still un-mutes when no CTCSS carrier is present on occasion

The Ugly:

• The backlight is very bright and cannot be turned down, only off. You can change the color between a reddish-orange, purple and blue. At night, the display seems far too bright to me.
• The construction is cheap.
• Ambiguous menu abbreviations are difficult to navigate without a manual.
• Complaints of parts failures are common.

In short, this makes a good back-up radio, or one to lend to a new ham for a few weeks while they save up for a rig, but it leaves plenty to be desired. I'm not sure I'd recommend that a new ham goes out and buys one as their only radio.

The Yaesu, by comparison, has quite a bit more going for it, at the expense of... well... money.

The Good:

• VERY fast scanning: 1MHz at 5hKz increments in 10 seconds. 
• Dual VFO functionality can receive from two channels at the same time. 
• Can receive almost every frequency between 500kHz and 1GHz, with a few gaps in coverage for legacy mobile phone frequencies that the FCC forbids reception of. This includes weather radio, AM/FM broadcast radio, CB, shortwave and most analog two-way radio transmissions.
• Quad-band transmitter that's capable of operating at full power on 2m and 70cm as well as limited power on 1.25m (220 MHz) and 6m (50MHz). 
• Alloy case is an excellent heatsink and construction is very solid
• Water-resistant to 10 feet, which makes it my go-to radio for storm spotting if I need to be outside my home or my car.
• "Smart scan" loads in-use ham frequencies into memory for you automatically (requires a few hours of scanning)
• "Frequency counter" mode, which isn't really a frequency counter, but is good for finding the frequency being used by almost any nearby RF transmitter
• "Spectrum analyzer" mode that I've found comes in handy for rough calibration of transmitters, identifying spurious emissions and visualizing how wideband certain transmissions are (hint: my 900 MHz wireless headphones use almost 100KHz of bandwidth!) 
• Severe weather alert mode
• Superior interference rejection
• Can be hacked in interesting ways with software. Don't get yourself into trouble.
• Menu options are pretty self-explanatory.

The Bad:

• Cost! The radio, brand new, retails for $350 or more, making it literally 7 times more expensive than the average Baofeng on Amazon. Used, expect to pay $250 for one in good condition.
• Most official parts and accessories from Yaesu are also expensive, especially batteries.
• Overwhelming number of menu options might daunt some users.

 The Ugly:

• The alloy case is prone to superficial cracks and blemishes.
• The display has very flexible options for large numbers, but seems difficult to read with default settings. 
• The backlight is adjustable, but its highest setting isn't very bright.

Programming either of these radios is a task best left to the software, which may cost money, and requires a programming cable, which definitely costs money. Programming either of them from the keypad can be a chore, but that's how I opted to set mine up. Overall, the Yaesu's menus make programming channels in with meaningful labels a lot easier than the Baofeng.

There are quite a few websites dedicated to hacking and using the cheaper radios. The one I stumbled across most often was http://www.miklor.com. Without the programming guide there, I would have never figured out how to get the local repeaters plugged into my Baofeng.

This week, the Baofeng experiment ended, as I finally caved in and bought a new battery for the VX-7R. The moral of the story is that you really do get what you pay for a lot of the time, and the more expensive handheld radios can pay off in the long run. The Baofeng will still be my backup radio. It's proven to be reliable, and when you just need to get on the air, that's what counts.

Baofeng Antenna Hacking

The infamous Baofeng. Specifically, I have the UV-5RA model. This is a lot of new hams' first handheld radio, and perhaps first radio period. I picked this one up because it was half the price of paying for a new battery to get my Yaesu VX-7R back on the air, and I had to get a reliable handheld radio quickly. I've had this one for about a year. I'm not sure I'd recommend it as a first radio unless you're really on a budget, but for what it is, I've been pretty happy with it. Lack of features compared to my Yaesu radios aside, my only complaints are that it poor intermod rejection, and the receive CTCSS squelch frequently fails to keep RF noise from coming through the speaker when there's not a real carrier there.

One thing that a lot of people complain about is the OEM antenna, but people complain about stock antennae on all handhelds. I stay pretty close to the repeaters I use frequently, so mine hadn't given me any problems until recently. A few weeks ago, I noticed that I had trouble picking up a repeater that's REALLY close during the weekly storm spotter net. Checking into these discussions weekly, even in the off-season, is one way to check that your equipment works. Mine wasn't. After testing everything else, the OEM antenna turned out to be the culprit. I cut it open to see what's inside. In my case, the wire going from the center SMA pin to the antenna coil had broken loose. You can see the antenna guts below.

I have a lot of antennae with male SMA connectors for my Yaesu handheld radios. A lot of these inexpensive Chinese radios (Baofeng included) use a female SMA antenna for whatever reason. Instead of coughing up $20-$40 at the local candy store for a new antenna that works with my Baofeng, I picked up an SMA coupler similar to one you can find at Radio Shack. It has flats on the sides, so I used a pair of needle nose pliers to screw it tightly into the Baofeng. You don't want to strip the coupler or the radio's connector, but it should be pretty snug there, so that it'll stay in the radio when you unscrew antennae from it. I had this Comet SMA-24 laying around, and chose to use it on the Baofeng. It comes with a rubber spacer, which comes in handy for this install. The new antenna fits on nicely with the addition of the spacer. Without it, a little section of the coupler shows through. The end result is that all my other HT antennae now work perfectly on this radio.

Westlake Hardware: My hackerspace?

 

It started as a simple trip to the hardware store. My mission was to find some 3/8" threadrod at 24 threads per inch. I was going to chop it with my dremel to a length of 6 and 9/32 inches long and use it as a 1/4 wavelength antenna in a mount similar to the one shown above. What I found were many kinds of threadrod, but nothing that would screw into either of my antenna bases.

I opted for a piece of 3/8" smooth rod without threads, figuring I could just wander over to the hardware store's selection of threading dies and pick up the one I  needed to cut a dozen or so threads into the rod. There, I found many dies, but not the 3/8" x 24 I needed for the project. There was a spot for the die I needed, but it was empty.

I finally cornered a sales associate, who looked up the part number, said they had one in stock, and even scoured the shelves looking to see if someone had placed it in the wrong spot.  What happened next took me by surprise. The associate went around to the back shop, pulled a full set of dies out of the tool chest, found the one I needed, and brought me around to the vise and tossed me some cutting oil and gloves so I could tap threads onto the rod myself. While I was working away, curiosity got the best of him. "What are you building?" he asked.  I explained that I was building a very cheap antenna, and explained that I was going to take it home and cut it to length so that it resonated at about 448 MHz. That's about the time he took me over to the chop saw with a cutoff wheel and a bench grinder. He found a couple pair of goggles and we got to work.

So there you have it. I walked in, spent a few bucks on a steel rod, got about 20 minutes of free shop time and left with a finished product. Westlake, you're like having a hackerspace a mile from home!

Why Ham?

Amateur radio is called "ham radio" by many. Ham isn't an acronym, but the origin of the sobriquet is a topic of debate. The most plausible explanation I heard is that professional telegraph operators considered amateur radio operators to be inferior, ham-fisted tinkerers. In this case, "ham" is actually a derogatory remark. Despite the fact, it's been adopted by the community now and is synonymous with "amateur radio." Amateur doesn't mean neophyte, however. It is the antonym of "professional radio," in that amateur stations are not commercial, and hams cannot recieve compensation for operating their equipment.


(The ham shack at MST's Amateur Radio Club, W0EEE)

Several co-workers and friends flaunted their amateur radio gear and goaded me into joining their ranks last year. Many hackers carry a ham license, or are getting interested in the hobby. Still, some people occasionally ask me "what's the point? We have smartphones and the Internet now." It's true. The telephone as we know it has indeed enjoyed evolution at a breakneck pace. My co-worker's Nexus LTE sucked 20 megabits per second out of thin air the day he got it. I don't even get that kind of pipe to my home. Still, to me, there's always been something about amateur radio that can't quite be compared with the Internet or mobile phones. I'll explain just a few of those things, from my own novice perspective.

In 1987, I saw an amateur radio demonstration that was given to my scout troop in the middle of Nebraska. With a brick-like walkie-talkie weighing more than a pound and about the size of two Wiimotes side by side (not counting the big rubber antenna on top of it), the presenter was able to communicate with others several counties away, and even place telephone calls. He said that with a bigger antenna and more powerful radio at home, he could talk to people all over the world, all without relying on telephones or even the power grid, because much his radio equipment could be powered by car batteries.

This blew my 8-year-old mind. It was nothing like my little walkie talkies at home. I wanted to be a ham, and even put in some work toward it, but I simply wasn't ready. The urge hit me in waves on occasion. In high school, I experimented with CB. In college, I took some interest in those FRS walkie-talkies that are now ubiquitous in every department store. A few classmates were amateur radio operators, and I got the itch again, but never really got the motivation to get licensed. It would go on like this for many years. For me, it took a friend in California selling me some of his used radios for cheap. At that point, I had the equipment in my hot little hands, but I didn't have a license to use them for anything other than listening. That lit a fire under me.

Aside from their size (owing to advances in surface-mount electronics and battery performance), the most basic hand-held ham radios haven't changed a whole lot in the last 20 years. For reference, my smallest radio is about the size of a closed Motorola StarTAC, but packs nearly as powerful a transmitter as the giant brick radio that had me awestruck more than 20 years ago. Most hand-helds work on the FM Voice part of the VHF band (~144 MHz) or the UHF band (~440 MHz), or both. Some operate on other bands as well. Transmit power from 300mW to 5W is common. Although these smaller radios are most often used to contact a high-power repeater, they can also be used directly between licensed amateurs over shorter distances with some rules and restrictions noted. They have more power and better antennae than FRS radios, and can be connected to an externally-mounted antenna if desired. They're great for highway convoys and outdoor activities. Many hand-held transceivers are capable of tuning in a very wide range of frequencies, so they can be used somewhat like analog non-trunking scanners and frequency counters for finding and listening to public safety, railroad, airport or rent-a-cop chatter. More on that in a separate article.

Repeaters are usually mounted on radio towers, tall buildings or up in mountains. They recieve on one frequency (an input frequency), then transmit what's received in real-time on the output frequency, allowing one-to-many conversations over a relatively large region within a 20-50 mile radius. Radios designed to be used with repeaters are able to automatically switch to a repeater's input frequency when transmitting. Repeaters are often linked together via high-power point-to-point radio links, telephone lines or digitally over the Internet. Some repeaters are actually built into satellites in space, covering extremely wide areas, but those can be a challenge to use as they traverse the sky. Many repeaters have redundant power, via battery and generator backup. And yes, a lot of this stuff is very similar to what existed 30 or more years ago, save for the Internet-connected repeaters.

Hams are often called upon to help where efficient communications are desired. You're likely to find amateur radio operators volunteering behind the scenes helping marathon or charity bicycle ride officials locate event participants in need of assistance, providing the National Weather Service with critical storm data from the ground, or establishing point-to-point radio links with nearby hospitals and participating in relief efforts in communities whose infrastructure has been crippled by floods, tornadoes, hurricanes or earthquakes. All of this is made possible because hams know how to communicate efficiently in groups, and their equipment isn't completely disabled by disruptions of complex infrastructure (although, as noted, infrastructure such as the power grid and telecom is often used when available.)

Many people think of morse code when they think of ham radio. Morse code is still in use, but you no longer need to know it to get licensed by the FCC. Morse code is essentially a human-comprehensible binary mode of communication. There are several other digital modes available, allowing you to blend technologies, and some common modes rely on AX.25 packet data. You can run a packet radio BBS over the air if you like, or transmit your GPS coordinates while hiking through the woods or helping disaster relief efforts. Some of these digital modes are extremely efficient, use very little bandwidth, and can be easily received from long distances, even if they aren't transmitted with much power. Conversely, hams can also enjoy many parts of the amateur bands, including parts of the 2.4 GHz spectrum (with some overlap on WiFi channels) with up to 1500 watts.

Although some hams might seem like retro-grouches with their morse code conversations, technology doesn't stand still with amateur radio! There's a very hearty "do it yourself" spirit here. Many participants might very well be considered radio hackers. They build their own transmitters, recievers and repeaters, and most of them are -- by nature -- gifted problem solvers.

Check out this video from ARRL for some more info.



What's it take to get licensed? There are three classes of amateur radio licenses in the US. In order from lowest to highest, they are Technician, General and Extra class. The exams are multiple-choice quizzes, each coming from a pool of several hundred possible questions. The Technician and General exams have 35 questions each, while the Extra exam is 50 more challenging questions covering material that's ostensibly arcane. The test to get each license requires progressively more depth of knowledge in safety (RF exposure, antenna towers, grounding), electronics, FCC rules, transciever and antenna designs and other information that proves the licensee understands the craft well enough to safely operate their own station. Each higher license class grants access to transmit on more frequencies, usually in the lower frequency bands that are more useful for reliable long-distance communication.

Since the question pools and study materials for licensing are publicly available, I studied the Technician material on my own for a few weeks before acing the technician exam. Most major metro areas have groups that give frequent classes, and all metro areas have volunteer examiners who will administer the test to those who have studied on their own.

I may upgrade to the General class license this year, but I'm honestly a lot more interested in the merge of digital technology with amateur radio. The Technician class license allows me to operate digital and "sideband" voice on the 10 meter band, but there's a lot of digital stuff in the higher frequencies that Technicians are allowed to use.

If you are interested in learning more about amateur radio but can't seem to find anything in your area, post away in the comments and I'll see if I can help you out.

Personal Radio Serice

The United States has 4 sets of frequencies under the category of "Personal Radio Services" which any one can use with certain restrictions on power output, antenna height and location. There are three others (MICS, WMTS and GMRS) under this category however they require that you are either a medical care facility or have special permissions or certification to use.

No FCC License Required Frequency Bands:

• CB (26 & 27 Mhz) HF 4W AM Carrier, 12 W PEP Single Side Band
• MURS (151 & 154 Mhz) VHF FM 2 W
  
• LPRS ( 216-217 MHz) UHF FM 100mW
  
• FRS(462-467 Mhz) UHF FM 500 mW

FCC Restricted Frequencies:

• MICS - Health Care Services - (402-205 Mhz) FM UHF
  
• WMTS - Health Care Services - (1429 to 1432 MHz)-(1395 to 1400 MHz)-(1429 to 1432 MHz) - FM UHF
  
• GMRS (462-467) - Certification required - FM -UHF 5W+

I found this to be very interesting because of my involvement with amateur radio.
I also found that CB radio used to be the old 11 meter HF amateur radio band. The nice thing about HF radio is that its range is greater than line of sight due to atmospheric bounce. The FCC limits the power on most of these frequencies because in order to amplify a signal they have to take great care in not creating interference on other frequencies.

GMRS radios are readily available but require a license to use. The GMRS radio license allows for the use of repeaters and higher output. FRS and GMRS share several frequencies, the difference is that GMRS radios are allowed to broadcast at 5W instead of just 500mW.

You can find FRS/GMRS radios just about any where for under 20$, MURS radios range from
50$ to 100$, CB's range between 40$ to 100$, I couldn't find anyone selling LPRS.

Links:
CSG, Computer Support Group, Inc. and CSGNetwork.Com , "Glossary" (Accessed Dec 2009)
http://www.csgnetwork.com/

http://www.csgnetwork.com/gmrsfreqtable.html
http://www.csgnetwork.com/frsfreqtable.html
http://www.csgnetwork.com/mursfreqtable.html
http://www.csgnetwork.com/cbradiofreq.html
http://www.csgnetwork.com/lprsfreqtable.html
http://www.csgnetwork.com/micsfreqtable.html

Federal Communications Commission. " Personal Radio Services" (Accessed Dec 2009)
http://wireless.fcc.gov/services/index.htm?job=service_home&id=personal_radio

See also:
HAM it up!
http://www.h-i-r.net/2009/04/ham-it-up.html
Introduction to Proximity Cards
http://www.h-i-r.net/2008/09/introduction-to-proximity-cards.html

HAM IT UP

HIR INFORMATION REPORT

Introduction to Amateur Radio by Asmodian X.

This article is intended as an informational introduction on the capabilities of
amateur radio.

Disclaimer :To broadcast using amateur radio frequencies it will require at least a FCC No-Code Technician License.

===================================
Topics:
1 . Getting your license
2 . Common HAM radio Activities
3 . Informative resources on Amateur radio
===================================

1. Getting your license

Amateur licenses are inexpensive to get and they require only a basic understanding of radio waves, Allotted FCC Frequencies for amateur use, basic electronic theory and FCC rules and regulations in regards to Ham radio.

The best way to find out about official testing for a Technician License will be through either a local radio club, a local or regional ham radio equipment store or... the Internet.

The test is fairly simple, under 50 questions and it covers mostly opperating procedures, FCC regulations, basic electronics and basic radio theory. They throw in some minutia questions covering basic electronics, radio theory and ham spectrum information just to make things interesting.

Once you have passed the test, they will send your details to the FCC who will then log your information into their national database and assign you a sequential amateur call sign. You can even create a semi-custom call sign for an additional fee.
Once you are logged into the national database you may then transmit on the amateur radio frequencies.

Gotchas:
1. You may not use codes or encrypted transmissions.
2. Only licensed radio operators may use the ham radio bands. There are specific regarding what may be transmitted and by/from and to.
3. Every radio transmission you make must have your call sign associated with it.
4. If you can't say that on television, you cant say that on the radio. (no cursing)
5. If you get caught breaking the rules, you could loose your license, go to jail and or get fined.
6. Certain frequencies are restricted to certain types of communication, for instance certain bands are limited to Morse code only, while others you can use, voice, packet radio or TV.

2 . Common HAM radio Activities
Amateur radio operators exist to innovate and expand the field of radio electronics, promote international communication and good will and provide emergency communications when needed.

There are regional, national and international radio organizations who provide resources for management of the radio spectrum and emergency communication services. A common activity to the emergency communications mission is creating an emergency "jump pack" which contains all of the necessities to create a mobile communications system. Many people have modified their vehicles to be able to serve this purpose. Others have mobile towers and camping gear to create a command center of sorts when the need arrives. Common activities amongst these groups are training exercises where radio transmissions sources are traced to their source. This is called a fox hunt.

Other activities HAM operators do is to access gateway or relay resources. A gateway could be a packet radio node which could connect a ham operator to the Internet (albeit very slowly (9.6 kbps max). There are also telephone relays which allow a HAM operator to connect to the phone network to make an out going call.

A common activity of some HAMs is to use an Internet gateway to send GPS information automatically to a tracking website, like bright kite.

You may also transmit video over radio.

The ionosphere is a wonderful thing, radio can bounce off of the ionosphere and reach whole other continents. There are no restrictions on who you can talk to, provided both governments are not at a state of war or some other political barrier exists.

Now here is the tricky part, A HAM operator must allow the FCC to inspect their radio upon request. SO if one were to modify the radio to transmit or receive on channels which the operator is not licensed for they can do bad things to you. However in an emergency transmitting on a restricted (emergency services frequencies for instance) is a forgivable offense. So it seems that there is a kind of unofficial grey area in regards to radio modification, a kind of "if you do this there had better be a darn good reason" kind of thing.

3 . Informative resources on Amateur radio

• FCC - Amateur Radio Services - http://wireless.fcc.gov/services/index.htm?job=service_home&id=amateur
  
• ARRL - National membership association for Amateur Radio operators. - http://www.arrl.org/
• ARES - Amateur Radio Disaster Services - http://www.ares.org/
• RACES - Radio Amateur Civil Emergency Service - http://www.usraces.org/