As the subject header says: a Motorola GP340 radio is reported to be capable of turning a Pieps DSP from Transmit to Off or Search:
http://lh6.ggpht.com/_7BAmdolYkPw/SW...patibility.jpg
This appears to be saying the same thing in German:
http://www.bergrettung.at/News-Detai...1;tt_news]=488
Whoa!! Good heads up. Jeeebus.
doh, double post.
Similar things can happen with the Barryvox. The switch is magnetic, and the speaker magnet in radios can cause it too turn on. Never was able to make it turn off though.
Which Barryvox: current Pulse or previous Opto 3000?Quote:
Originally Posted by snoboy
I showed this thread to a member of my ski patrol who is both an avalanche instructor and an electrical engineer.
His thoughts were:
"One of the comments seemed to imply that this was an issue with the field from the magnet in the radio speaker causing a magnetic switch in the transceiver to activate. My first reaction would be: Holy cow! What kind of powerful speaker do they use in that radio that they need such a powerful magnet. Also, magnetic reed switches tend to need pretty close proximity to a pretty strong magnet to activate unless they are specifically designed to be sensitive to weaker, further away magnetic fields. In general, I would say that it is likely that magnetic switches are used in a lot of transceivers because they provide an excellent and reliable way to maintain a waterproof interface between a mechanical activation mechanism and an electrical circuit. However, virtually every audio transducer these days, with some very few exceptions, uses a permanent magnet interacting with current through a coil of wire to produce acoustic energy. Things used to be pretty bad with stray magnetic fields around speakers until the use of CRTs and magnetic media with computers prompted a large movement to design such equipment with good magnetic shielding. I would have to say that it would take an extremely poor design to have a radio these days with sufficient stray magnetic field to be able to activate an external switch. On the other hand, it would take a fairly poor transceiver design to be that sensitive to stray magnetic fields. On the third hand, a lot of crap gets to us from, shall we say, less quality-conscious manufacturers, that may have extremely poor characteristics on either front. (This can apply all the way down to iPods and earphones.)"
His practical conclusion (which is the only part of all this I can thoroughly understand):
"The only sensible thing to do would be to do your best before heading out on any trip where your safety depends on such equipment to make sure that there is no detrimental interaction between any combination of your electronic devices."
And finally, his sidebar note:
"For an admittedly extreme example, one may be tempted to bring along say one of those shake-type flashlights that doesn't need a battery. I have a couple whose external magnetic field is so strong that it will suck an AA battery to its case from an inch or two away. Just having it in your pack would probably turn any use of a compass into an exercise in futility."
General statement to the issue
„ Warning: Motorola GP340 can turn Pieps to Off or Search “
In the recent years the performance of avalanche beacons has been improved significantly – like direction indication of Tracker (BCA) or 3rd-PIEPS-antenna. The performance is getting closer and closer to the limits given by physics to provide better “tools” for rescuers. But ALL avalanche beacons – also for former analogue models have on common sense: This are high sensitive devices, designed to work with magnetic flux lines with a scale of about 1:100.000 (50m range means about one-hundred-thousandth of the same signal strength of 1m distance).
Due to their nature, ALL of beacons are very sensitive against electrical and magnetical interference.
If a Ferrite-antenna is exposed to the field of an magnet (magnet of a speaker of a radio equipment in extremely close proximity, less than 5 cm), not only the signal strength (send AND receive) can be influenced significantly. Also the magnetic property of the Ferrite material is changed, due to the magnetic remanence – this can last a couple of minutes (up to 15 minutes). Depending on the strength and intensity of this influence, the impact on avalanche beacons can be slightly or significantly – it also need to be taken into account, that some beacons are working with compasses.
Due to this, it’s a recommendation from all manufacturers that minimum distances should be maintained between avalanche beacons and electronic, magnetic or metallic influences (like radios, mobiles phones, MP3-players, bunch of keys)! PIEPS recommends: • during SEND mode: min.15 cm • during SEARCH mode: min. 1,5 Meters
Furthermore, there are almost no other products ranges, where European standards are defined this tight. For instance, the maximum allowed signal strength of transmitting avalanche beacons is less than the maximum allowed electrical and magnetic noise level of all other products. Especially radios and mobile phones are barely limited (everybody knows the interference when a mobile phone starts ringing in the near a computer computer).
Additionally special standards for mechanical stress are at a unique level for avy beacons(6 drops to hard surface from 1 meter height – after that the beacons must be fully functioning and must be fully waterproofed). For this reason some manufacturers did choose a magnetic switch (reed contact) for ON/OFF and/or for SEND/SEARCH. Yes, theoretically with a very strong magnetic field you can override activate/deactivate this switch.
With the PIEPS-DSP you are not able to activate the magnet switch with the Motorola GP340 – as long as you are wearing it as instructed (beacons should be worn in the carrying harness or a trouser pocket – but always with the display towards you body).
Furthermore common known basic rules must be maintained:
„For years it’s common education standard, that minimum distances to radios, mobile phones and other electric- or magnetic influences to avalanche beacons must be maintained, independently from model and manufacturer and in all operation modes! This is common education standard for all rescue organisations!”
Mag. Walter Würtl Scientist, Mountain Guide
Official legal expert for mountain-rescue, avalanche awareness, avalanche excidents, avalanche protection Education instructor, Austrian Alpine Club Head avalanche instruction of Austrian-Mountain-Rescue-Organisation (until end of 2008)
Schober Michael, General Manager, PIEPS GmbH
Lebring, 16.01.2009
Opto 3000. Apparently there were some jackets with magnetic closures that could do it as well.Quote:
Originally Posted by Jonathan S.
As for your friend's comments, I guess there is some poor design, because I have seen it happen, with my own hands. Like I said, I couldn't get it to turn off which is something of a comfort I guess...
Then, I haven't occur this for use 340 and some extra battery for several years. Any way, 340 is a products popular to people.Quote:
"For an admittedly extreme example, one may be tempted to bring along say one of those shake-type flashlights that doesn't need a battery. I have a couple whose external magnetic field is so strong that it will suck an AA battery to its case from an inch or two away. Just having it in your pack would probably turn any use of a compass into an exercise in futility."
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lincoln
my battery:http://www.8eshop.com/two-way-radio-...a-hnn9008a.htm
I accept with information: a Motorola GP340 radio is reported to be capable of turning a Pieps DSP from Transmit to Off.
I must have posted this in some other thread, but I was able to replicate the Pieps problem even with refrigerator door magnets.
I never was able to find a jacket with magnetic closures, but I did find a pair of gloves with magnets: very weak, even though they're intended to keep the gloves together. Despite the glove magnets being so weak, they also caused the same problem in the DSP. (Has to be in very close proximity though, but given that the magnets were in the gloves...)