June 16, 2006
Sitting back seat felt weird tonight
I'm not used to sitting back seat in a small plane. Tonight I did sit backseat, during someone else's instrument training (missed approaches, VOR/RNAV/GPS approaches, etc.) and found I learned an incredible amount about instrument flying that is sometimes hard to absorb when you are in the hot seat (as I usually am).
I took the opportunity in the back seat to watch the plane's altimeter over the PIC's shoulder as I correllated it with altitude readings I was taking with the SU-1 barometer modification on my Yaesu VX-5R handheld HT. At 4000 and 5000 feet altitudes in the San Francisco Bay area, over 2 hours of flying with reported surface barometric pressures of between 29.94 and 29.98 inches of mercury, without calibration, I was getting agreement ranging from 0 to 200 feet. It'll be interesting to see how much better the agreement is after I RTFM and do a pre-flight calibration.
December 23, 2005
Gene Whitt's aviation essays
My pilot friend David recommended this colossal collection of aviation-related essays by Gene Whitt.
August 31, 2004
Quote of the Day
If you only encrypt important things, even without decrypting the message the simple fact it's encrypted means its important. This is information that you have given freely to whomever it is that is watching: "Pay Attention, This One Is Important."
I cannot stop the buggers from knowing everything about me if they decide I'm a target. But I can throw chaff. Encrypt everything.
As PGP's developer Phil Zimmerman said, "PGP is for small secrets."
Curt Howland
July 08, 2004
June 25, 2004
Interesting Army report on soldier experiences with weapons and gear
A couple of weeks ago, my friend Steve Pegram passed along a detailed and fascinating online version of a military report generated last summer, "SOLDIER WEAPONS ASSESSMENT TEAM REPORT 6-03". Much of the report is rather dry, given the nature of such a document, but scattered throughout are a great many little observational gems such as this:
...soldiers rank reliability and durability as key weapon characteristics and are not willing to trade them for anything – to include weight. Similarly, soldiers do not consider the weapon as part of their load, but rather as an enabler. They are willing to carry the weight if the weapon or device increases his lethality. This is best illustrated by soldiers purchasing their own magnified optics and the strong desire to carry an additional sidearm or shotgun for defensive and offensive purposes. Lethality is more important to the soldier than any other consideration or factor.
Here's empirical verification of the usefulness of white lights in combat, a point which I've had driven home by anecdotes from trainers at every school I've attended:
Several soldiers were observed with flashlights taped to their weapons and some using the Weapon Flashlight Mount. But all soldiers described using the tactical light for temporary target incapacitation.
There's quite a bit of coverage on the phenomenon of soldiers ordering personal gear from the AOR (area of operations) since "...there are a wide variety of commercial solutions on the market and soldiers would like the Army to provide them with equipment as good as what’s available to any terrorist with a credit card."
June 14, 2004
Quote of the Day
Abolishing the FCC does not mean airwave anarchy. What it means is returning to bottom-up law rather than the top-down process that has characterized telecommunications for the last 80 years...
...If the FCC had been in charge of overseeing the Internet, we'd likely be waiting for the Mosaic Web browser to receive preliminary approval from the Wireline Competition Bureau.
Declan McCullagh (cited by Anton)
May 31, 2004
Imagine PBS and NPR with police powers
I remember the odious BBC television licensing fee from my days in London long ago, but had thought the fee had been repealed. Not so, reports UK-resident Australian Monica White:
For those of you who don’t live in the UK, you may be interested in the phenomenon that is the TV License – I was truly surprised by it a year ago. Essentially, if you have a TV or receiving equipment, you are obliged to pay the government £121 per year to view the BBC channels.
Don’t watch the BBC? I’m afraid that TV Licensing doesn’t believe you. EVERYONE who owns an operational set must watch the BBC. They're compelled to. There’s something in the water.
TV Licensing ‘Enquiry Officers’ also seem to get a hoot out of slapping £1000 fines onto anyone within spitting distance.
Folks, imagine this scenario in America: PBS or NPR radio direction finding vans canvassing your neighborhood, coming to your door, backed up by police powers. Think about it.
January 01, 2004
The Valentine One radar & laser detector: don't drive through bandit country without it
This was snapped a few days ago on the way up through northern California on the way to Oregon. In the background is the beautiful, 14,162 foot, potentially deadly volcano people around here call "Mt. Shasta". I have some of these shots from the way out to Oregon, and some taken under snowy conditions on the way back to California, taken yesterday on New Year's Eve... maybe I'll post them sometime, entitled "Thirty-Six Views of Mt. Shasta" under the artist name "The Cowboy Hokusai". Or maybe not.
In the lower right hand corner, in the foreground, is my trusty Valentine One radar and laser detector. Excepting a year I spent in Japan, I've used this thing in three different vehicles - and numerous rental cars - for five years, and am incredibly happy with it. I spent about $450 for it and its accessories, but I'm sure I've saved several times that price in speeding tickets I didn't receive.
December 23, 2003
SciScoop: Exploring Tomorrow
It's great to get feedback on one's blog postings, especially when it results in the personal discovery of a great resource. Blog commenter Ricky James runs the compendious and incredibly interesting SciScoop: Exploring Tomorrow, which I strongly recommend telling all your friends about. So much to explore!
May 17, 2003
AR15.COM Forums thread: USMC after-action gear assessment
Thanks to my friend Steve Pegram for passing along this incredibly interesting thread on the AR15.com Forums: "USMC after-action gear assessment". Pay particular attention to the reports on the adequacy of 5.56mm vs 7.62mm carbine/rifle ammunition, and the spectacular satisfaction of operators with their M16 & (especially) M4 carbines.
Especially interesting is a point I've known all along: a lot of issue military gear quickly gets replaced with individually selected commercial "sporting goods" equivalents, e.g. Panoptx goggles replacing the awful issue crap.
Another interesting point: the M9 pistol still sucks. It should be replaced with the Glock or whatever the individual soldier wishes to otherwise carry.
April 11, 2003
Quote of the day
You can't have your cake and eat it too; either the Net is a business and you pay for routable IP space, or it's a communist free love fuck fest, and it's your god-given right to have portable routable IP space.
Jeremy Porter
April 04, 2003
Blazing technological idiocy from the American Bar Association
Daniel J. Boone reports on another reason why, as a lawyer, he isn't a member of the ABA: this pile of festering compost, a recommendation to regulate what they call "pirate" WiFi.
February 04, 2003
Slick (and free) GPS map display software
Forwarded with permission by Steve Pegram on behalf of a friend of his, who has asked to remain anonymous. - ed
"Go here and download USAPhotoMaps.
It is free and is one of the absolutely slickest little GPS map display programs I have come across. It does NOT have a lot of features (like route planning or any of those fancy functions) but it will give you a taste of what is possible and you will see what satellite imagery maps look like and you can also display USGS topo maps of your chosen area. What it does is download aerial photos (satellite imagery) and USGS topo maps from Terraserver and creates a scrollable, zoomable, GPS enabled moving map with your position located by a dot in the center of the screen.
Find out what your GPS coordinates are and load them into the set-up screen. On command, (if you are connected to the internet) the screen will automatically download and fill up with your choice of A) 1-meter satellite imagery or B) USGS topo map imagery centered on the coordinates you entered. Once downloaded, you can instantly swap out the overlayed satellite imagery with the topo map.
You do NOT need a GPS receiver to make this work. Also, even on a dial-up internet access, the process is not too painful if you are not too greedy and try to slurp up too big of an area. You can shut off the download anytime you like just by clicking on STOP DOWNLOADING.
Again, this is one of the slickest, cutest and easiest to use GPS moving map display software programs I have yet come across and best of all it is FREE.
It has very few features, but what it has, it does WELL and is SUPER EASY to use. If you know the GPS coordinates at the center of the area you want to look at and enter them, it automatically accesses TerraServer and downloads the satellite imagery you want.
TerraServer imagery offers just barely good enough resolution to see a vehicle on the interstate or a car parked in your driveway. Its resolution falls far short of being able to follow a path in the woods, but in sparsely vegetated areas you can pick out an individual tree. My property is heavily wooded and I can see my house and driveway clearly in the imagery as well as a large drainage ditch along one side of my property. Best of all, you can also download the USGS topo map of the same area.
You DO need a GPS receiver if you are going to locate yourself on the screen and have the maps scroll around as you drive along.
If you do have a GPS receiver with a data output connection on it, you can plug it into your laptop and USAPhotoMaps will automatically put a little colored do on the screen where you are. As you drive around, the software keeps putting little dots down every 10 meters or so and leaves a track record as you move along.
You can get your GPS latitudes and longitudes from the TerraServer address given at the top of the start-up screen or get them from your GPS receiver.
At the start-up screen, just make up and enter a name for the map area you are going to start with and enter the lat and long. You can leave the UTM Northing, Easting and zone blanks empty for this purpose.
I bought a 12-volt power supply for my laptop so I can use it for extended periods in my vehicle when I am driving around in back country roads or trails. Ahead of time, I download both the satellite imagery and the topo maps of the entire general area where I will be prowling around and store it all on the harddrive. USAPhotoMaps makes this super easy to do.
I have several GPS receivers and they all work well, but for certain applications, the 14 inch super-high resolution screen on my laptop makes all the difference in the world. Like most laptops, the major drawback is that it is hard to see in bright daylight. I rigged up a sun-screen-hood for it out of cardboard and duct-tape which helps a lot.
Just recently, a couple of laptops have come out which have the new style REFLECTIVE color screens. Very nice in bright sunlight! In fact, the brighter it is the better these screens show up. Unfortunately, these new reflective display screens on laptops are pretty expensive and not available in the larger screen sizes yet. Twelve inches is the biggest (that I know of) at the moment. Next year, maybe.... Until then I will just have to make do with the 15 inch hard-to-see-in-the-sunlight screen on my Dell Inspiron laptop."
January 20, 2003
"Doing Freedom": wish I'd seen this site earlier
Daniel J. Boone writes about a site I wish I'd paid attention to earlier: Doing Freedom. Talk about some controversial articles: take "Improvised Claymores" as a good example!
December 06, 2002
Tactical Radio Communications, installment 7
Penetration and blocking of radio waves
Radio waves are attenuated by almost all objects they pass through, e.g. air, people, trees, buildings and the ground. Dense objects such as earth or metals block radio waves very well. Only a few feet of either can make radio communications impossible. However, radio waves also bounce off objects, and this effect can be used to allow communications around corners and inside otherwise impenetrable objects such as steel buildings. Higher frequencies tend to bounce and penetrate more, thus UHF radios are the most suited for work inside buildings and cities. There is a practical limit to this however, and beyond 400-500 MHz the penetration of radio waves starts to fall off again.
Sensitivity
Good receiver sensitivity is an excellent way to make up for low transmit power. Increasing transmitter power takes more energy, and thus translates into shorter battery life on portable radios. Increasing receiver sensitivity usually does not require more power, so this is a desirable characteristic. Most modern radios have excellent sensitivity. Sensitivity is usually measured in microvolts, also abbreviated as uV. The lower the number, the better the sensitivity. A good radio will have a sensitivity of 0.2uV or lower. Up to 0.4uV is acceptable for UHF radios.
December 05, 2002
Tactical Radio Communications, installment 6
Polarization
Radio waves have an orientation, usually vertical or horizontal. Note how external TV antennas have all their elements lined up in a flat fashion (horizontal polarization), while CB and two-way radio antennas point straight up (vertical polarization). Having the polarization different between antennas can cause significant signal loss, thus it is important to always mount antennas in the same direction (vertical for most two-way radio applications).
Antenna height
At higher frequencies (30MHz and above), the height an antenna is above the ground has a direct affect on how well it performs. High frequency radio waves are blocked by the ground and tend to travel about the same as one’s line of sight. This is the usually the main limitation on the distance one can communicate. The higher one is, the farther they can see, and the exact same principle applies to radio waves. A 1-watt portable may only work for 2-3 miles at ground level. If you put that radio on a 5,000-foot mountaintop, the range can be increased to 10-20 miles or further. A good rule of thumb is if your radio contact drops off, try moving to higher ground.
December 04, 2002
Geocaching: Global GPS Cache Hunting
My thanks to friend Steve Pegram for pointing me to the Geocaching website. It looks like great fun, and an excellent way to learn and hone GPS land navigation skills. I might jump into the game myself sometime soon...
Tactical Radio Communications, installment 5
Gain
In radio terms, gain means multiplication. Gain is used with respect to amplifiers and antennas. Amplifiers obviously have signal gain, as that is their purpose. Antennas can also have gain. They accomplish this by focusing the energy supplied to them into a beam. Antenna gain works in both directions, transmit and receive. Gain is specified in dB units. dB units are a logarithmic measure, which means that the gain increases at an ever-faster rate for a constant change in numbers. Some simple rules to follow if you don’t understand what logarithmic means are as follows:
0dB = 0% change
1dB = 10% change
3dB = 70% change
6dB = 200% (or 2 times)
10dB = 300% (or 3 times)
20dB = 1000% (or 10 times)
40dB = 10,000% (or 100 times)
An antenna with 6dB gain will transmit 2 times the energy as a no-gain antenna. Thus a 5-watt radio connected to a 6-dB gain antenna will transmit a signal with the effective strength of 10 watts. Since antenna gain works in both directions, any received signals will also appear to be twice as strong.
December 03, 2002
Tactical Radio Communications, installment 4
Power
Transmitter power output is the amount of energy that is sent to the antenna. Power is measured in Watts, just like electrical appliances. However the antenna can affect how much of this power actually gets sent into the air. Some antennas absorb or reflect large amounts of power (up to 90% in some cases) back to the transmitter. Such poorly performing antennas are usually seen at lower frequencies when size of the antenna is more important than efficiency.
More power translates into longer communications distance. As a rule of thumb, signal strength decreases as a square of the distance from the transmitter. What this means in practical terms, is that if you can talk for 1 mile with 1 watt of power, to stretch that to 2 miles you will need (2 squared) 4 watts. To talk 3 miles (3 times the distance) you will need 3 squared or 9 watts.
Most portable radios transmit 0.1 watts (or 100 milliwatts) on low power and 1 to 5 watts on high power. Mobile radios typically transmit from 10 to 100 watts. Base station radios or radios with external amplifiers can transmit up to 1000 watts or more.
November 27, 2002
Garmin Rino 120 GPS Unit and 2-Way Radio
"Made for the ultimate outdoor enthusiast, Garmin's Rino 120 features the latest GPS technology, both FRS and GMRS 2-way radio frequencies, patented technology, a built-in basemap of North and South America, 8 MB of memory and much more."
I've been seeing the Garmin Rino 120 GPS Unit and 2-Way Radio advertised in some of the outdoors magazines I read, and am pretty impressed.
I've not gotten my hands on one, but the screenshots and list of features are mouth-watering, e.g.
- Voice scrambler for secure communications
- Vibration mode for "silent" calls to other Rino users
- Patented Peer-to-Peer Positioning lets you send your exact location to another Rino user within a 2-mile range
- Clear reception with a range of up to 2 miles using FRS, 5 miles with GMRS
- Each channel has 38 sub-audible squelch codes for semi-private conversations
I've not read the specs on the actual implementation of the claimed security features, but they're certainly worth investigating. If any readers have tried a Rino, please feel free to add your comments.
Oh, and do check out the Tactical Radio Communications series we've begun to syndicate on this website.
November 25, 2002
Tactical Radio Communications, installment 3
Mode
There are two main methods of sending information (in this case your voice) over radio waves. Amplitude modulation (AM) and frequency modulation (FM). AM is the older of the two methods, and transmits a voice by varying the power output of the transmitter in proportion to the loudness of the audio. Dead silence means the transmitter produces no power. As the audio becomes louder the power output of the transmitter increases. The transmitter and receiver can be fairly simple in design. AM has one major drawback: any interference on the same frequency is simply mixed into the desired signal. This makes AM very susceptible to lightning, atmospheric noise and any other transmitters in the area. Another drawback of AM transmitters is that they require special ‘linear’ amplifiers, which are not very power efficient.
FM varies the frequency of the signal in proportion to the audio. Thus, dead silence produces a constant steady signal with no frequency shift. As the signal of the audio increases the frequency changes more. Most two-way radios shift their signal up to +/- 5kHz. FM has one large advantage over AM. If two or more signals are present on the same frequency, the stronger signal will be the only one heard. This is called ‘FM capture effect’. Thus FM radios produce higher quality signals and have very good immunity to interference.
A third type of modulation method is used in modern radios, called phase modulation. This changes the phase of the signal in relation to the audio input. The effect of phase modulation is to produce a signal that has the characteristics of both AM and FM. The primary practical advantage of phase modulation radios is that they can be used to talk to both AM and FM radios.
There are other modes of transmission, but most are not used in portable equipment so they will not be addressed here.
November 21, 2002
Tactical Radio Communications, installment 2
Frequency
Radio waves behave differently at different frequencies. The radio spectrum is broken into bands, usually by segments that have similar behavior, and sometimes by type of service (such as Short Wave, AM, FM and TV). The lowest range commonly used is the AM Broadcast band (0.5-1.3MHz). Next is HF (1 to 30 MHz), this band includes short wave radio. VHF-Low (30-50MHz), FM (88-108MHz), VHF (109-172), UHF (400-512MHz), Cellular and Paging (800-950MHz). Frequencies above 1000MHz (1GHz) are called microwave as the behavior of radio waves above this region changes significantly.
You will notice there are several large gaps between the bands listed. The military or TV stations use frequencies in these gaps. Some general characteristics that change with frequency are as follows. Distance traveled: the lower the frequency, the farther a radio wave will travel. Penetration of structures (due to bouncing and scattering) gets better as the frequency goes up. Antenna size becomes smaller as frequency increases. Another characteristic affected by frequency is node size. Nodes are areas where the signal dramatically changes strength over a very short distance. This is caused by two different reflections of the same signal meeting at the same place and canceling each other. You can see this by moving a portable FM radio tuned to a weak signal. You will notice that the signal comes and goes every few feet. What you are seeing are nodes.
Below is a list that describes some basic characteristics of the bands most used for two-way communication.
AM Broadcast and HF Bands
Range can be from hundreds of miles to worldwide. Radios are large and antennas can be over 100’ in length. Portable antennas are usually not practical although there are some exceptions. From 25 MHz and up portable equipment is available, but bulky. Reception in different parts of the band change dramatically with the time of the day. Signals can be reflected from the atmosphere, thus allowing the signal to bounce over very long distances. Penetration of structures is very poor, external antennas are usually required.
VHF-Low
Range can be from 10 to over 100 miles. Antennas are large, but can be small enough for mobiles (3’-5’ long) and large portables (1’ – 1.5’ long). Radios are large, but some portable equipment is available, most commonly CB, amateur and military radios. Nighttime conditions can cause the wave to randomly skip over large areas covering hundreds of miles. Penetration of structures is often poor. Nodes are many feet apart.
VHF
Perhaps one of the most useful bands. Range is between ½ to 20 miles depending upon terrain and power used. Reasonable penetration of structures. Nodes are only a few feet apart and weak. A wide variety of antennas and radios are available, including mobile and small portable equipment. Antenna size can be as small as 4” for a portable.
200MHz
This band is used mostly by the military and specialized commercial services. A small segment is allocated to ham radio, thus making some equipment available. Has the range of VHF with almost the penetration of UHF. Not covered by many scanners. Antenna and radio sizes can be small.
UHF
Another very common band for two-way communication. Range is 1/8 to 5 miles depending up terrain and power used. Antenna size can be as short as 1.5 inches for portable radios. Good selection of equipment is available in the Ham and commercial market. Excellent penetration of structures and built-up areas. Nodes are only a few inches apart and tend to be strong, rapidly changing from barely audible to full strength when moving and listening to weak signals.
800-950MHz
Used mainly for telephone-like services, public safety trunked systems and paging. There is also the 900 MHz ISM band for non-licensed radios such as cordless phones. Range is very short, less than 1 mile unless special antennas mounted in high locations and high power is used. Limited equipment is available, mostly used cellular or data transceivers, some commercial gear as well as spread spectrum devices. Antennas can be very small, sometimes built into the device. Nodes are 1” or less apart.
1GHz and up
Newer cellular phones, wireless data, satellite and numerous other services. Not suitable for most uses due to the very short ranges. There are portable radios available for amateur radio use on 1.2 GHz.
November 19, 2002
Tactical Radio Communications, installment 1
A few days ago, I mentioned that I'd be running a serialized version of the forthcoming book "Tactical Radio Communications" by my engineer friend Eric Cartman. Below is the first installment. Readers' feedback, as we post these, would be most welcome. - Editor
Introduction
"Radios can be a very effective tactical or strategic tool. One can coordinate and deploy groups of people, perform surveillance, summon help and keep in touch with others over long distances when other forms of communications are unavailable. However, if used unwisely, a radio can be a security breach, a tactical disaster waiting to happen and even a beacon the enemy uses to discover your location.
Currently available radio equipment runs the gamut of size, power output, frequency, features and cost. Everything from a 50 dollar hand held radio from Radio Shack to a 5000 dollar all band all mode transceiver with 1000 Watts of power can be yours. The introduction of unlicensed FRS (Family Service Radio) has led to an explosion of cheap hand held radios sold in any sporting goods store or catalog. Although these radios at first appear to be a great step forward from the old CB radio, there are several reasons you should avoid them.
To make a reasonable decision on what equipment to buy, you need to understand the basics of how radios and radio waves work. We won’t cover the theory of how radio works in great detail, as this is not really relevant to buying and using a radio. Rather we will cover the behavior of radios and radio waves as they relate to the real world of the radio user.
Many of the ideas and suggestions in this book are based on thousands of hours of field use, trial and error and some hard bought experience by numerous people. There is a lot of stuff out there, some even sold to the military and police departments that simply doesn’t work. Any equipment you buy needs to be set up and used before you ever depend upon it. Imagine the embarrassment when your earphone comes unplugged and the speaker on your radio lets out a nice loud burst of static while the guy with that 7.62mm automatic rifle is standing 10 feet from the bush you are hiding in. Hope you brought your level IV body armor along… Or imagine being stuck out in the desert with a broken transaxle only to find that your antenna came loose and burned out the transmit amplifier in your radio. You can carry 10 gallons of water 100 miles, can’t you?
Finally, when you are buying radios, radio products or researching information, you will inevitably come across nosey people that want to know why. The simplest response is to tell them you are a Ham radio operator or are studying to become one. You can become a licensed ham for under $20 and a few hours study time with a book. The new “No Code” Technician class license is fairly simple to obtain. Nothing more is required than taking a short multiple-choice test and filling out two forms. Many local radio clubs give the tests, no questions asked, though an ID is required as well as a SSN. All the test questions are published and freely available, so you can even pass by simply memorizing all the questions. There are even on-line practice tests on the Internet. Just remember that your license will be mailed to you, so be sure to provide an address where you will actually receive it.
With the license in hand you can buy radios from most places without drawing any attention. Actually, almost no one will ever ask to see your physical license, but many places want to at least know your assigned call sign. You can make one up, though be aware that the call sign databases are available both on-line and in CDROM form for easy crosschecking. If you feel the need to fib on this one, find a legitimate call sign that has expired or is not listed. If asked by anyone you can say that you just received your new license and that it must not be in the database yet.
An added plus to having a license is you gain the ability to legally carry a scanner in your car in some states that prohibit it. It will also shut up officer Snotnose, as he peers into your car and asks why you have all that radio equipment."
November 17, 2002
Watch this space: Tactical Radio Communications chapter 1 to debut here
An engineer friend of mine who's working on a book on tactical radio communications has offered to run large parts of it here on Survival Arts. There's so much material, I'll be breaking it up on a near-daily basis over the course of several weeks.
Radios can be a very effective tactical or strategic tool. One can coordinate and deploy groups of people, perform surveillance, summon help and keep in touch with others over long distances when other forms of communications are unavailable. However, if used unwisely, a radio can be a security breach, a tactical disaster waiting to happen and even a beacon the enemy uses to discover your location.
Stay tuned.
