Fernwood Autonomous Radio 99.1 FM is made possible by three things: the AAREFF Transmission Systems 12W Variable Power FM Transmitter, a tuned dipole antenna produced by the same manufacturer and listeners like you. Without these components (by any make or manufacturer, DIY or other) it would not be possible to create the terrestrial based broadcast that you receive every Thursday from our home in Fernwood, BC. My first attempt at creating a dipole antenna did not go as well as initially hoped but thankfully Marian van der Zon (founder of Temporary Autonomous Radio and co-author of Islands of Resistance) provided us with both transmitter and antenna.
The first piece of equipment needed to make this possible is indeed a thing of beauty. The AAREFF transmitter receives a stereo input from any audio source via RCA conection and has it’s initial 1 watt signal amplified by another 12 wattsi. On average this creates about 14.5 kilometres of broadcast coverage, provided the antenna is of sufficient height. Inside the transmitter is a series of dip switches that control the wattage of the device as well as the tuning of the frequency – in our case 99.1 FM.
I set out to construct my own antenna but this proved to be ill-fated. The antiestablishment website irational.org has a great section on community radio including guidelines, procedures and technical information they recommended to start your own pirate radio station. They also issue a warning for anyone setting out to do so to check the licensing requirements in order to operate a broadcast radio signal in your country and the associated penalties if breaking the law – in my case a maximum $5000 fine and the possibility of jail timeii.
Irational.org has a set of clear and easy to follow instructions on how to create your own vertically polarized omnidirectional aerial. I won’t go into too much detail as their DIY howto is much more thorough than my own and would be redundant to regurgitate but I will cover some of the basics.
First off, the polarization makes a difference in which sort of radio recievers will be picking up your signal so it is fundamental to keep your audience in mind. Most home stereos have horizontally polarized receivers where as the average car antenna is vertically tunediii. This isn’t a deal breaker as far as audience goes as most FM signals will bounce around on the way to a receiver.
To create an omnidirectional antenna the aerial needs to be balance. To create a balanced feed a Balun (Balance to Unbalance) transformer is required and can be made simply from a piece of coaxial cableiv. If you create an unbalanced antenna the feed (cable from transmitter to antenna) will emanate the signal weakly.
From an optimists perspective it should be possible to create an antenna in around two hours. It took me roughly three to complete the antenna. The materials for this are cheap and easy to come by and the experienced dumpster diver should be able to attain them from construction sites, waste bins, etc. Essentially two lengths of cable are inserted into a piece of PVC piping and then housed in another to ensure protection from the elementsv. A balun is created using a segment of coaxial cable and then from there a feed is sent to the transmitter. I was able to procure most of the necessary hardware for around twenty dollars at a hardware store and the rest was found in my basement presumably left by the previous tenants.
To find out the total length of your dipole do the following:
The reference length of the aerial for 98MHz is 2.205m (86.8 inches for Americans and other backwoods dwellers). You will need to scale this figure for your transmit frequency. If, for example, your transmit frequency is 88MHz, take 2.205, divide it by 88 and then multiply by the reference 98 to give 2.456m (96.68 inches). If your transmit frequency is 108MHz, divide 2.205 by 108, and multiply by reference 98 to give 2.000m (78.77 inches). This dimension is your overall-length.vi
In my case, 99.1 FM requires an antenna with the total length of 2.401 metres. This is an arbitrary number in itself but the fact that the physical length of some copper cable inside a pipe could radically change the tuning and function of an antenna in producing waves invisible to my eye was astounding. In their mission statement irational.org intends to “demystify the art of broadcast electronicsvii” but I found myself in awe of the sublime simplicity of it all.
After this step it went sharply downhill. The gauge of the wire I purchased was far to thin (Marian was surprised I used cable instead of metal rods) and the broadcast quality was poor at best. I used a television co-axial cable and not a proper broadcast RF socketviii. I wasted twenty bucks at a time of no income (Canada Student Loans is a bureaucratic nightmare of Orwellian proportions) and I was left deflated from the experience. After weeks of delays and talking up Fernwood Autonomous Radio I could broadcast no more than three blocks. Thankfully this all changed. Marian’s readymade and pre-tuned AARAFF Dipole Antenna was available at the time of broadcast and all was a go.
Lastly we needed to mount the antenna. Having no faith in my sense of balance I did the sensible thing and screwed the antenna into the birdhouse outside my kitchen window. The broadcast range wasn’t bad – not the 14.5 kilometres we had hoped for but we managed to reach Quadra and McKenzie and the top of Moss Street. My good friend Dustin is an arborist and he and a friend came over on the evening of our second broadcast to raise the height of the antenna. The Prometheus Radio Project has a great section on antennas, masts and towers but the rule is simply taller is better – given the length of the feed is not extended to far as this will change the frequency of the broadcast.
So in the end Fernwood Autonomous Radio is not as DIY as it may seam but it is quickly becoming a part of the arts and culture scene in Victoria. The community came together in the hoisting of the antenna and in many other ways. One of our listeners, a taxi driver and CFUV programmer gave us a recent report that the station coverage reached Lampson street in Esquimalt. We plan on getting another fifteen feet of clearance by erecting a mast for the antenna to sit on but for now we are happy with the coverage and will be making the jump to streaming in the new year. In the new year we will be streaming FAR991 online as well as terrestrially and podcasting should be streamlined by then as well.
This station will not last forever as the transmitter is only guaranteed until March (after this broadcasting will be a bit more sporadic) but I intend to pursue the possibility of building a 40 watt transmitter as outlined by irational.org. As long as their is a void in the ether of todays mass communication hegemony machine there will always be a community to step forward to work together to raise their voice.
I’m only 2/3 through your inaugural broadcast, but I’m very impressed. You should accept donations through bitcoins http://bitcoin.org/ It just requires listing a receiving address here, no credit card or Paypal issues involved, and would be great to provide micropayments to the artists. Also, how about considering taking calls by CB Radio? It can’t be shut down or censored like the outages in the Arab countries and it’s a good backup to the vulnerable internet and phone systems. Thanks for all your time and efforts.
Thanks Brian!
The bitcoin idea sounds great, everything has been out of pocket for the station so far and it’s not free for me to put this up. I’m sure the other artists would appreciate a bit of help too.
I haven’t looked into the CB route but that is definitely something to look into for the future. We’re starting out small but it’s gaining momentum!