Weather and Radio Communications.
This page has received hits since May 1 1999
Looking for weather related photos? They're in the links below
Callery 2 - the week of
storms in Victoria, December 6 - 13 2004. Sunset and chase photos.
One of my non amateur areas of interest is the weather, which was brought to the fore a couple of years ago through a friend who's a member of the Australian Severe Weather Association (ASWA). He put me in touch with the Australian Weather mailing list, and the #Weather IRC channel. It was while participating in discussions on both media that I became aware of some areas where radio amateurs and weather enthusiasts, especially storm spotters and chasers can work together.
Radio communications has a lot of uses for the storm chaser/weather enthusiast. Radio's uses range from car-car communications during a chase to long range communications with other weather watches with Internet access, who can provide up to the minute information in many ways.
This page will focus mainly on the radio communications options available to Australian storm chasers, from the most basic and economical through to the most sophisticated. Each radio system will be covered, along with the potential uses.
27 MHz CB
27 MHz CB is a low cost radio system which is designed for short range communications. There are very few restrictions on how CB is used - it can be used for both commercial and private purposes. 27 MHz CB comes in two types - AM and SSB. AM is the entry level system which uses the same mode of transmission as AM broadcast stations. AM CBs are the most economical form of radio communications of use to the chaser, with a range of 5 to 15km, depending on terrain and antennas used.
SSB uses a more efficient form of transmission, which gives it up to twice the range of AM. However, this extra performance means more expensive radios.
27 MHz CB also has one other useful side effect. The band is somewhat prone to static, which makes it an excellent way to detect nearby lightning activity which might be too far away to be visible.
The main use for 27 MHz CB, however, is for car to car communications. CB is useful for co-ordinating chases and keeping in touch with other vehicles involved in the chase. On the highway, AM CB is also useful for getting road reports off other travellers (mostly truck drivers). Because of the low entry cost ($100 or less), every chaser should consider installing a 27 MHz AM CB radio in their car.
I'd recommend having at least a 27 MHz AM CB in the car for chases. As for an antenna, I prefer a 1.5m helical whip or longer. Anything shorter can limit range. Longer antennas may be unwieldy, especially in urban areas.
UHF CB is a similar service to 27 MHz and operates under the same rules. However, UHF operates in the 477 MHz band and uses FM instead of AM or SSB. The use of FM gives UHF CB audio quality which rivals a telephone, and unlike AM, the audio level at the speaker remains constant, regardless of how strong the signal being received is. UHF is also strongly affected by terrain. Hills, trees and buildings all limit range, but being on a mountain considerably extends range (sometimes to over 100 km). Because of this, a network of repeater stations has been established on mountains and other high places around Australia.
Normal UHF range (without repeaters, otherwise called "simplex") varies from 5km to about 25-30km (highly terrain dependent). Using a repeater can increase range up to 150km, depending on where the stations are, relative to the repeater. In the cities, the repeaters tend to be frequented by the brain dead morons. In the bush, it's a different story, as the locals tend to use UHF CB as a business and community resource, and the repeaters are very well run. It may even be possible to get assistance from the public in spotting storm phenomena, by asking for reports on the repeater, or for information off the Internet.
UHF CB can perform a lot of the same functions as 27
though it's somewhat more expensive for a full mobile setup (over $200
for a reasonable mobile
radio). UHF comes into its own in the bush, where local repeaters
greatly increase range and bring chasers into contact with people over
radius. If your budget will accommodate it and you chase a lot in
areas, UHF CB is well worth the investment. Similarly, chasers
enthusiasts who live in rural areas can assist people who chase in
their area by
installing a UHF CB base station.
Since early 2003, low cost UHF handhelds have come
onto the market, which make UHF a very economical choice for short
range car-car communications. These low powered UHF CBs are
capable of 1km car-car range and can cost as little as $30-$40 each and
require no installation (great for lending to someone with no radio in
the car). These units are also compatible with the more elaborate
UHF stations described above. Of course, range depends on power
and antennas, so a full power mobile station is needed if you want to
cover more than a couple of km.
4WD HF Radio
There are a couple of HF (high frequency) radio networks in Australia, the most well known being the VKS-737 network. These networks are designed for communication between recreational vehicles in remote areas and designated base stations, for safety and message handling purposes. Being in the lower HF bands (between 2 and 10 MHz, these services have long range, sometimes exceeding 1000km. While useful for long haul communications, the biggest limitation is that base stations (other than the designated base stations) are not permitted, which makes hard to use this system for logistical support.
The 4WD networks are a must for safety for people venturing into very remote areas. Their usefulness for other chasing activities is as yet uncertain as I haven't had a chance to look closely at how these networks operate and how the legal limitations affect their use for chasing.
Amateur (ham) radio is a service designed for radio experimentation and self training. A secondary role is public service communications (e.g. disaster relief). Because of the self training/experimental nature of this service, and the extra privileges given to amateurs, it is necessary to pass written exams in radio theory and amateur regulations at a minimum to obtain an amateur licence. Note that Morse Code is no longer required for any class of amateur radio licence in Australia.
Due to changes in national and international regulations, licencing conditions for the amateur service are likely to change significant around the end of this year. Possible changes include:
Surprisingly, amateur radio has a lot of uses for people interested in weather. While that connection is well known in the USA (the Americans are very good at promoting the public service side of our hobby), one hears very little about amateurs helping the public in Australia.
For those who are coming from the weather side of things, you may not know a lot about amateur radio - it's probably something that you may associate with middle aged men sitting up all night in front of a box of glowing valves talking to people in all sorts of incomprehensible jargon! :-) However, the modern amateur can be involved with some quite sophisticated and up to date technology.
Aspects of Amateur Radio and Weather Related Uses.
In my opinion, amateur radio has a lot to offer those involved in tracking and monitoring severe weather events such as thunderstorms, cyclones and tornadoes (and yes, we do get tornadoes in Australia, much more frequently than most people realise). This table below shows a list of modes of transmission available to the modern radio amateur and some possible uses for weather watchers.
|Mode||Description||Equipment required||Possible Uses|
|VHF/UHF FM voice||Voice communication - Similar to UHF CB with both "simplex" and repeater operation available. Offers excellent audio clarity. Up to 150km range possible if repeaters are used - Linked repeaters can extend range even more.||VHF or UHF mobile transceiver and appropriate antennas.||Car to car or short-medium range car to base comms. Similar to UHF CB, but higher power permitted and repeaters clear of idiots.|
|HF SSB voice||Voice communication - Similar to Royal Flying Doctor Service communications. Operational range up to nationwide, depending on the frequency used.||HF SSB transceiver and appropriate antennas.||Long haul mobile - base comms or comms between widely spaced observing base stations.|
|Slow Scan Television (SSTV)||Technique for sending still pictures over a voice grade radio channel. Can use VHF/UHF or HF. Range depends on frequency used (see above descriptions of voice modes)||Transceivers, antennas and computer to send/receive pictures. Webcam or video camera/capture card to send "live" snapshots. Suitable software can be downloaded off the Internet.||Instant relaying of photographs from storm spotters/chasers. provision of weather radar data to chasers in near real time.|
|Fast Scan Television (ATV)||Transmission of moving pictures. Similar to broadcast television.||ATV transmitter/receiver. Transmitters need to be home built. Conventional TV can often be used as a receiver, though an old satellite receiver is needed for receiving some forms of ATV.||Long range "cordless webcam" - live video can be beamed several km or more from a good observing site to a webcam server by an amateur.|
|APRS (Automatic Position Reporting System)||Position indication system. Similar in concept to systems used to track stolen vehicles or taxi GPS position reporting system. Uses Global Positioning System (GPS) and packet radio to broadcast the position of stations and other objects. Position data can be displayed on a map by receiving stations. Also offers "SMS" like messaging service.||Transceiver/antenna,
GPS with serial data output (for mobile stations), TNC (packet
"terminal node controller"). Computer and APRS software for stations
wishing to use mapping facilities.
Fixed stations wishing to monitor only can instead receive position data over the Internet - avoiding the need for radio equipment.
|Tracking storms and chasers. General coordination and planning of chases.|
Radio Linking Project), EchoLink and other Voice over IP systems
||Uses the Internet to link VHF and UHF radio sites together (usually repeaters). Enables VHF or UHF global coverage, as long as both ends are within range of a "node".||VHF or UHF transceiver/antenna and DTMF ("Touchtone") tone encoder for controlling links.||Medium - long
haul communications, especially with mobile stations. Wide area
"nets" covering geographically dispersed areas. The VoIP
Skywarn/Hurricane net is an extreme example which spans the globe at
There are two ways around the licence issue for weather people. Firstly, you can recruit already licenced amateurs and invite them to operate their station in your car. Some possible recruitment strategies are to speak about your activities at radio clubs and the like, or send invitations to radio clubs and amateur news services for amateurs to attend meetings of ASWA and other relevant organisations. If you do decide to speak at radio clubs, don't be surprised if you get a lot of interest. I have discovered a number of closet storm chasers among the ranks of radio amateurs! :-) Only the person actually in charge of the radio transmitters needs the licence. Alternatively, you may decide all this sounds like fun, and you want to study for your own licence. In that case, good luck, and look forward to working you on the air one day! :)
Note that APRS is an interesting exception. It is possible to extract useful data from the APRS network with receiving equipment only. This requires no licence, as you're not transmitting.
On the Road!
I have already made use of radio during chases. During a local chase in June 2002, I was able to maintain contact with a chaser in Darwin via IRLP. Such communication capability opens the way to feed more timely information to chasers.
In January 2003, I received a phone call from a
chasers in NSW who were looking for information on storms in their
While the phone proved useful, radio would have allowed more
longer operating times.
2003 and 2004 saw a couple of chases with "ground support" up to 200 km away on VHF FM.
USA and beyond.
In the USA and Canada, amateurs and the National Weather Service work together to track severe weather. Amateurs and their radio systems are an integral part of the US and Canadian severe weather spotting/reporting network.
The IRLP and EchoLink networks host a weekly Skywarn
net at 0000z (UTC) on Sunday mornings. During the net,
and severe weather summaries from each area are presented, and a often
discussion about a specific topic. No prizes for guessing who the
Australian contributor is. :-) If live audio becomes available on
Internet, a URL will be provided in future. It's also interesting
that I have actually run the Skywarn net out of here in Melbourne,
a number of occasions, while all the other participants were in North
In 2004, I was active as overnight net control for
the duration of the Florida hurricane events (TS Bonnie, Hurricane
Charley, Hurricane Frances, TS Gaston, TS Hermine, Hurricane Ivan and
Hurricane Jeanne). Time zone differences made this an effective
means of obtaining round the clock coverage.
The following URLs are provided for your further study.
Other radio related sites:
Australian Amateur Radio FAQ.
VoIP Skywarn/Hurricane Net - International severe weather reporting and information net on the IRLP and EchoLink networks.
Study for your licence online!.
VK2CA's Australian Amateur Radio site - Very comprehensive site, with lots of information, too much to mention here.
Wireless Institute of Australia - the national representative body.
Looking for the closest Amateur repeater? VK voice repeaters listed here (courtesy WIA).
Or perhaps a CB repeater? Here's a UHF CB repeater list (courtesy VK2CA).
APC News - a weekly online Amateur Radio news bulletin from the Moorabbin and District Radio Club.
QNEWS - The weekly news from the WIA Queensland Division (includes Real Audio broadcasts!).
VK3RHF - Melbourne's 10 metre repeater.
Melbourne Packet Radio Group.
Mini Kits - Build your own VHF/UHF/Microwave gear.
QRZ.COM International callsign server and lots of useful data.
Put your SoundBlaster to use on the air with these programs!
An excellent UK based site by Jeremy, G4NJH.
Or if you want to know more about the weather...
Australian Severe Weather Association
Australian Severe Weather
Melbourne Storm Chasers
Australian Bureau of Meteorology
US National Weather Service
Unofficial Hurricane and Weather Site - US based site with lots of weather related links.