[amsat-bb] Fwd: Allocation of 433 434 MHz Band for Short Range Devices in VR2
My apologies for forwarding this but I need some help with the answers. You could write directly to Johnny or post to the reflector as is appropriate. >Date: Tue, 8 Mar 2011 08:37:19 +0800 (HKT) >From: Johnny Siu >Subject: Allocation of 433 434 MHz Band for Short > Range Devices in VR2 >To: "Edward R. Cole" > > > >Hello Edward, > > From my reading of your messages in Elecraft > mail reflector, I understand you are an active > operator in the UHF/SHF region. Therefore, I need to draw your expertise now. > >The allocation of 70cm band in Hong Kong is >430-431Mhz and 435-439.8Mhz - secondary amateur service. > >Office of Telecommunication Authority (OFTA) of >Hong Kong is now considering allocating >433-434Mhz for short range devices >(SRD). Clearly, this is not to the interest of >the amateur radio sector in Hong Kong and >deviated from IARU - region 3 band plan. > >I will take up the matter with OFTA on behalf of >the amateur radio sector in VR2 to defense the >70cm ham specturm. Before doing so, I would >like to draw some of your expertise: > >1. Is it common to have short range devices >within the 70cm band in other countries e.g. US? >2. Presumably, the short range devices are of >low RF power so that co-existence with ham >operation in the same band is possible. Is my understanding correct? >3. If my understanding in item 2 above is >positive, are there requirements for any guard >band between the SRD and ham channels? >4. Is there technical issues which I should highlight to OFTA? > >My ultimate aim is to demand OFTA to return the >band segment of 433-434Mhz to the amateur radio >sector (at least as secondary services) in >VR2. Spot frequencies co-exist with ham >operation are acceptable. Any information to >back up my argument will be appreciated. > > >Cheers, > >Johnny VR2XMC > 73, Ed - KL7UW, WD2XSH/45 == BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-1.4kw, 432-100w, 1296-testing*, 3400-winter? DUBUS Magazine USA Rep dubus...@hotmail.com == ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Re: [amsat-bb] Fwd: Allocation of 433 – 434 MHz Band for Short Range Devices in VR2
I think with a little research we will find that these frequencies are already in use by automobile tire pressure monitors on existing vehicles and maybe even garage door openers... Almost Part 95 type stuff if no... Roger WA1KAT On 3/7/2011 8:33 PM, Edward R. Cole wrote: >> Hong Kong is now considering allocating >> 433-434Mhz for short range devices >> (SRD). Clearly, this is not to the interest of >> the amateur radio sector in Hong Kong and >> deviated from IARU - region 3 band plan. >> Cheers, >> >> Johnny VR2XMC >> > > > 73, Ed - KL7UW, WD2XSH/45 ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Re: [amsat-bb] Fwd: Allocation of 433 – 434 MHz Band for Short Range Devices in VR2
Short Range Devices (SRDs) in 433-434 are bad news. The United Kingdom opened up 433/434 to SRDs in the 1990's. Automobile remote control key fobs used it - very short range, very low power stuff but the killer was the receivers. The Key Fob receivers had wide-open front-ends and collapsed in the presence of nearby RF. The result was that some UK Amateur 70cm repeaters were forced to shutdown to protect the unlicensed SRD's. The UK regulator Ofcom made it mandatory that applications for UK 70cm (430-440MHz) repeater licenses had to prove that they wouldn't cause "interference" to these unlicensed devices, eg wouldn't block wide-open RF front-ends! Following on from Automobile key fobs came a host of other low power SRD applications that were keen to use 433/434MHz. These have caused interference over a wide area, see Thames estuary SRD Interference on 433.500MHz http://www.g4uvj.btinternet.co.uk/isleofgrain.html SRD in 433/434MHz also impacts the Amateur Satellite Service. Manufacturers of 10 milliwatt walkie-talkies for 433/434 have cleverly run some leads through the battery compartment. If the user cuts these leads their 10mw 433/434MHz walkie talkie or base station gets converted into a 4 watt output transceiver that operates from 433.075 right up to 435.525MHz - well into our satellite allocation, see http://www.southgatearc.org/news/august2009/intek_drs5070_pmr446_radio.htm YouTube - Intek MT 5050 Export http://www.youtube.com/watch?v=Sgk5NDRP5sQ Industry needs a Globally allocated license exempt UHF allocation between 400 and 2400MHz - there isn't one !! - Global UHF license exempt spectrum is fragmented - Industry is currently trying to get 433-435MHz allocated as Global Unlicensed Spectrum so equipment can be sold anywhere. Belatedly Europe is attempting to allocate 915-921MHz (in-between European cell-phone frequencies) to SRD's. If 915-921MHz doesn't become the Global UHF SRD band then Amateurs will lose 433-435MHz for ever. Other URL's that may be of interest: Australia - SRD Interference causes Repeater to move http://www.southgatearc.org/news/jun2005/repeater_move.htm New Zealand 3.6 and 433 MHz SRDs http://www.southgatearc.org/news/august2010/nz_revised_gurl.htm Short range devices in the 433 MHz band http://www.southgatearc.org/news/august2008/short_range_devices_in_433mhz_band.htm 73 Trevor M5AKA ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Re: [amsat-bb] Fwd: Allocation of 433 434 MHz Band for Short Range Devices in VR2
At 07:07 AM 3/9/2011, Trevor . wrote: >Short Range Devices (SRDs) in 433-434 are bad news. Tell me about it! :/ >The United Kingdom opened up 433/434 to SRDs in the 1990's. >Automobile remote control key fobs used it - very short range, very >low power stuff but the killer was the receivers. Australia also allowed SRDs in the mid-late 1990s. >The Key Fob receivers had wide-open front-ends and collapsed in the >presence of nearby RF. The result was that some UK Amateur 70cm >repeaters were forced to shutdown to protect the unlicensed SRD's. >The UK regulator Ofcom made it mandatory that applications for UK >70cm (430-440MHz) repeater licenses had to prove that they wouldn't >cause "interference" to these unlicensed devices, eg wouldn't block >wide-open RF front-ends! This problem has been noted in certain locations, but they are not offered protection from this sort of interference here. >SRD in 433/434MHz also impacts the Amateur Satellite Service. >Manufacturers of 10 milliwatt walkie-talkies for 433/434 have >cleverly run some leads through the battery compartment. If the user >cuts these leads their 10mw 433/434MHz walkie talkie or base station >gets converted into a 4 watt output transceiver that operates from >433.075 right up to 435.525MHz - well into our satellite allocation, see Ouch! Haven't seen those here. >Australia - SRD Interference causes Repeater to move >http://www.southgatearc.org/news/jun2005/repeater_move.htm There's many examples of repeaters having to move. The problem for us here was that there was no limit put on the duty cycle of the SRDs. The most troublesome devices down here have been industrial crane controllers, which have a 100% duty cycle. I for one had interference from these from an industrial area 1-2km from my repeater. The ACMA effectively legislated that these devices don't exist, when it comes to protection from interference. The walkie talkies disappeared off the market quickly here. I think the well established UHF CB service out competed them, offering more power (200 mW - 5W) legally, and more features for a similar price, as well as compatibility with a larger installed base. The other big problem here is cordless headphones, which tend to drift up and down the band, and even outside the SRD band. 73 de VK3JED / VK3IRL http://vkradio.com ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Re: [amsat-bb] Fwd: Allocation of 433 – 434 MHz Band for Short Range Devices in VR2
Trevor wrote: > The UK regulator Ofcom made it mandatory that applications for UK > 70cm (430-440MHz) repeater licenses had to prove that they wouldn't > cause "interference" to these unlicensed devices, eg wouldn't block > wide-open RF front-ends! Unlicensed devices imposing restrictions to licensed users? I hope you are joking, otherwise you have a serious problem with Ofcom and your national society (RSGB?). 73! ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Re: [amsat-bb] Fwd: Allocation of 433 – 434 MHz Band for Short Range Devices in VR2
--- On Tue, 8/3/11, Miguel A. Vallejo, EA4EOZ wrote: > Unlicensed devices imposing restrictions to licensed users? > I hope you > are joking, otherwise you have a serious problem with Ofcom No I'm not joking, when devices are sold in large numbers Governments will protect them even if they are unlicensed. The UK now has 15 million automoblies using 433 MHz to open the doors and start the engine. Is the UK Government going to say to 15 million voters they've got to pay a lot of money to have a decent receiver installed or are they going to shut down a few Amateur repeaters ? That's the simple choice, no prizes for guessing which they choose. The same will hapen in any part of the world where SRD's are allowed on 433/434 MHz - it's the number of votes that count - doesn't matter what International Regs may say. 73 Trevor M5AKA ___ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
