Crosstown Traffic: KC5HWB-Ham Radio’s Forgotten Bands: 220MHz and 900MHz
Great blog post and discussion from Jason KC5HWB over at the Grapevine Ham Radio blog about 220MHz and 900MHz, the “Forgotten Bands” of ham radio:
When I was first licensed in 1994, the most inexpensive radio I could buy was the Radio Shack HTX-202 mono-band, 2 meter only, 12 memory channel HT. This radio sold brand new in the store for $189. You could also buy the 70 centimeter version of this radio, which had the same memory channels and features, for the same amount of money. Back then, if you wanted a dual-band HT, you were going to spend $300 or more. Today, however, anyone can buy a Chinese dual band for under $50. 20 years ago, if you wanted a 220mhz radio, you’d have to pay several hundred dollars. I don’t remember anything about 900mhz back then, the frequency spectrum belonged to us, but to my recollection there were little to no radios at all.
Today, you can buy a mono-band 1.25 meter radio from Anytone or TYT for under $200. Also, there are many 900mhz radios on the market, most of which are used, but many are obtainable for $100 or less. A good example of this would be the Kenwood TK-981 radio. I constantly see these radios sell used on eBay for $100-$125.
So the question is, why are these two bands forgotten? Today you can get a radio in either of these bands for a decent amount of money, and some people are using them, but they are not nearly as popular as the 2M and 40 bands in amateur radio. The 1.25 meter band is widely unused in the DFW area, and the band itself, being VHF, could be as reliable as 2 meters. The 900mhz band is becoming more popular in DFW, but radios are mostly purchased from used markets and surplus of businesses of local government agencies.
I have been told that 220MHz transmitters are difficult to include in multi-band radios because of the odd multiple of their frequency (50MHz, 150MHz, and 450MHz are easy multiples of each other. 220MHz doesn’t fit in this very well) and the difficulty in creating amplifier circuits and multi-band antennas that can accomodate this. There may be some truth to that but Jason argues that with modern software-defined radio and other newer technology that nowadays this should be easier. And he’s probably right about the easier part. But since there has been so little demand for 220MHz radios over the history of our VHF/UHF allocations, it’s just one of those bands we’ve forgotten about. So what would be some creative uses for this band that wouldn’t involve trying to get all of your ham friends to buy a special radio all at once? The FCC allows us, in §97.201 to use this band as an auxiliary link. From the Cornell University Law School Legal Information Institute website (47 CFR 97.201):
§ 97.201 Auxiliary station.(a) Any amateur station licensed to a holder of a Technician, General, Advanced or Amateur Extra Class operator license may be an auxiliary station. A holder of a Technician, General, Advanced or Amateur Extra Class operator license may be the control operator of an auxiliary station, subject to the privileges of the class of operator license held.(b) An auxiliary station may transmit only on the 2 m and shorter wavelength bands, except the 144.0-144.5 MHz, 145.8-146.0 MHz, 219-220 MHz, 222.00-222.15 MHz, 431-433 MHz, and 435-438 MHz segments.(c) Where an auxiliary station causes harmful interference to another auxiliary station, the licensees are equally and fully responsible for resolving the interference unless one station’s operation is recommended by a frequency coordinator and the other station’s is not. In that case, the licensee of the non-coordinated auxiliary station has primary responsibilty to resolve the interference.(d) An auxiliary station may be automatically controlled.(e) An auxiliary station may transmit one-way communications.
Which means (correct me if I am wrong) that we can use this for remote control links for repeaters, remote receiver backhaul links, and possibly one-way digital telemetry. I would think it most certainly could be used for special packet radio or APRS links. This would be a great place to send and receive data links from your Arduino or Raspberry Pi projects (perhaps using the Argent Data Systems Arduino Radio Shield, which I have been looking for an excuse to purchase since Scott introduced it a number of years ago) when the Xbee range just isn’t long enough.
And further, since this goes way back before many of my ham friends were licensed, I feel compelled to mention what happened in 1988 when a certain large shipping firm (who is now a big customer of mine) noticed that the 220MHz band was rather empty of hams (quote from Wikipedia):
In the late 1980s, United Parcel Service (UPS) began lobbying the FCC to reallocate part of the 1.25-meter band to the Land Mobile Service. UPS had publicized plans to use the band to develop a narrow-bandwidth wireless voice and data network using a mode called ACSSB (amplitude-companded single sideband). UPS’s main argument for the reallocation was that amateur use of the band was very sparse and that the public interest would be better served by reallocating part of the band to a service that would put it to good use.
In 1988, over the objections of the amateur radio community, the FCC adopted the 220 MHz Allocation Order, which reallocated 220–222 MHz to private and Federal Government land mobile use while leaving 222–225 MHz exclusively for amateur use. The reallocation proceeding took so long, however, that UPS eventually pursued other means of meeting their communications needs. UPS entered into agreements with GTE, McCall, Southwestern Bell, and Pac-Tel to use cellular telephone frequencies to build a wireless data network. With the 220–222 MHz band now left unused, the FCC issued parts of the band to other private commercial interests via a lottery in hopes that it would spark development of super-narrowband technologies, which would help them gain acceptance in the marketplace.
Use it or lose it, folks.
Any more comments about this? Take them over to Jason’s blog post and join the discussion!
(Published from DFW, Texas)