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| Thread ID: 78503 | 2007-04-18 04:07:00 | Here's an odd-ball one..... | Billy T (70) | PC World Chat |
| Post ID | Timestamp | Content | User | ||
| 541983 | 2007-04-18 04:07:00 | I'm looking for a company that can supply an off-the-shelf radio transmitter/remote receiver system to control two devices simultaneously when up to 400 metres apart and often not line of sight i.e. with rising terrain or even a hill in between. The receiver output is required to simply toggle on or off a small relay in each unit, and there is no return communication path required. Cellular based systems are not a runner because very often these may be operating outside cellular coverage. The system would have to be secure against false triggering so some form of coded data signal would be essential. This would be especially important if, for example, the units were operating in frequency band inhabited by other users such as the HF or UHF CB bands. I am currently and actively searching for both "off the shelf" and custom solutions myself, but I figured that the PF1 knowledge-base is so wide that long before I find what I'm looking for, somebody else may very well already know of the perfect solution or the right company to contact. Cheers Billy 8-{) |
Billy T (70) | ||
| 541984 | 2007-04-18 05:24:00 | 400 m should be no problem . If you can make the code/decode circuitry, there's a fair range of frequencies you can use without specific(and paid) licencing( covered by "General User Radio Licences") . You are allowed "non-voice" use on channels 22 and 23 of the UHF PRS, at about 5W pep . There's the Short Range Device GURL (www . rsm . govt . nz/licensing/gurls/gurl-srd . html), with a range of frequencies (between 9 kHz and 246 GHz) and allowed powers, including 1W eirp in 26 . 95-27 . 3 MHz, (Australian 27MHz CB") though that's shared with the Amateur 11 m (telemetry/telecontrol) band . A "Fixed radio link" licence might not be portable . ;) Have a look at the PRS, FRL, SRD, GURLs on the MED web site (browse from the SRD one) . However, if you want to be legal, I'd guess that you are limited to using PRS, to get equipment which accords with . . . "Transmitters must conform to technical standards as prescribed in notices made under Regulation 32 (1) (b) of the Regulations . " |
Graham L (2) | ||
| 541985 | 2007-04-18 06:03:00 | Look for farm specialist suppliers, I remember a few years back I was at an ag field day in the NI, such devices were available for remotely switching small pumps etc. Something like this? www.gme.net.au |
godfather (25) | ||
| 541986 | 2007-04-18 06:51:00 | While not in NZ but close..try http://www.control-logic.com.au/ or from ebay Item no 250104071817 more to come.:) |
wmoore (6009) | ||
| 541987 | 2007-04-18 23:26:00 | This is proving a lot tougher nut to crack than I anticipated! Most of the prospects I have looked at are commercial/industrial control units that would cost thousands of dollars each. Use of channels 22 and 23 of the UHF PRS looks like a good option, but cost for a custom developed system would be too high given the limited numbers required. On reflection, an acknowledgement of receipt of commands would be very desirable and maybe an adaptation of commercial UHF PRS units with a "roger" facility would be viable, with the roger signal triggering the device switching as well as providing confirmation of receipt of commands. I'm going back to the client to see what their price/budget expectations are. Cheers Billy 8-{) |
Billy T (70) | ||
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