I was reading a model plane review in one of the RC magazines, and it was stated by the author that the particular flying club field where he was going to test fly banned JR receivers that were not of the double conversion type. JR receivers with the ABC&W system have been used all over the world for many years, and I have never heard of a any particular interference problems using this type of technology. Does anybody have any ideas why a model club would want to ban a proven system.
Ev- Yes, I know why a club might do that, as I'm twiddling my thumbs because the rulemakers in my club imposed such a ban of another, new but unrelated, technology. Ignorance. They don't understand it; somebody read somewhere 10-20 years ago that dual-conversion was the only Rx IF technology available to provide selectivity consistent with safety in the 1991-restructured R/C bandwidth allocation, and By God that's written in stone for eternity, Amen. JR, Berg, GWS and a few others, thankfully, don't buy into that dead gospel. OTOH, Some OF rulemakers do.
I'm in a club who prohibits a cell phone while in the pits and flight lines. They think the cell phone might affect the computers on the Radios we are using.... A bunch of morons..... I just smile and comply... I pick and chose my battles. Sparky
I suspect that Futaba got an anecdotal story or two about cell phones and computer radios, ran it through their legal department, and some golf playing lawyer came up with a statement. No science needed, no statistics to run, just a few words on paper with a vague warning.
Hmm.. Either you have a bad cell phone or a bad wireless phone. I constantly use one and the other rings so I answer it. The ONLY problem I have is when someone uses a microwave and I am on the wireless unit.
Not wanting to restart the cell phone debate, suggested reading =
we have a club member sporting a bad scar on his arm following accident caused when a Nokia cellphone & recent model TX were beside each other on bench, away from any unintentional movement of TX, and the large ST engine on his model went from idle to full power when cell phone started to ring. Motor went back to idle and all else normal again when ringing stopped. - Cell phones are now banned from our flight lines. - perchance relating to that sole cellphone's buzzer. regards Alan T. Alan's Hobby, Model & RC Web Links
Futaba were provided testaments of 8U transmitters being partially re-programmed by specific types of cell phones. I don't recall the details, but they were re-counted in the 8U and 9Z mailing lists a year or so ago.
The thing that caused Futaba to publish their recommendations was that the re-programming was reliably repeatable; that got their attention.
If anyone wants to google up the several threads on this issue, g'head.
OTOH, there's a pragmatic solution to the "cell phone issue" . . . . absent a demonstrated need to have an operating cell phone in the pits or on the flight line, they should be prohibited.
They should be prohibited for the same reason that many states are considering or have already enacted legislation prohibiting the use of hand-held phones while operating a vehicle : they are a known distraction.
Of all the places we don't need no steenkin' distractions, I'd like to think the flight line and the pits are right there at the top of the list.
And yes, I have two, a Motorola VT 60 and a Nextel i30sx. The Motorola has never exhibited any interference to anything I own, but you outta see what that Nextel does to the monitor if I key the thing !!
Both units stay in the car when I'm playing with my air-capable toys. That's 'cuz I _know_ Murphy is always waiting to spring a new trick on us, and I want to limit his opportunities as much as possible.
Think I'll start a new thread called 'common sense 0 Murphy 1'. Cheers, Fred McClellan The House Of Balsa Dust home.mindspring.com/~the-plumber AMA L180201 IMAA LM 090 NASA 6512 LHA 2 WB 233
Anyone can fly JR singles at our flying field - at the risk of losing their airplane or helicopter ! I did 2 or 3 times, then sold the R600 before I lost my plane. One glitch I got was full up elevator and full left aileron - don't know about the rudder - at 10' altitude just off the end of the runway while on approach. I have NEVER had a glitch with a Hitec dual. I have a Hitec single AM in a Sky Scooter that gets whacked several times per flight at our field.
Reason....... across the lake from our field is 'Broadcast Hill', where every TV station transmitter AND every FM radio station transmitter PLUS God only knows how many other radio service transmitters hung on the sides of those towers ! BTW, this is Dallas/Fort Worth area in North Texas.
That's a singular anecdotal story which is NOT borne out by others. If cell phones were a problem, we'd have reports like this coming in from ALL OVER the country... which we don't. It's kind of like flying commercial airlines. You hear of several crashes every year, but your statistical propability of dying in one of them is about nil compared to all the other ways you can die, including driving your car.
I fly at the same field and have watched the JR two step several times. Someone representing JR came to the field back in the mid 90s and did some testing with the ABC&W equipment. afterwards, they would send back their older dual conversion receivers to those that sent in the new ABC&W credit card units complaining of problems. People here replaced the ABC&W receivers with other dual conversion units and the problem went away.
In my experience, whenever someone gets "hit", 95% of the time that person is using a SC RX (I'm not knocking JR, but at my field, 99% of the time it is a JR SC with ABC&W). Banning an entire brand is a bit drastic, but I think it is an indication that more care is needed when using SC, most of our guys having such fly park flyers and usually fly at the far edge of the field.
You're talking about cordless phones, not cell phones. You probably wouldn't take one to the field, unless the field is 50 feet behind your house :)
And they can also use 27 mhz or 49 mhz, though most modern ones use the bands you mentioned.
Cell phones (the sort you get a bill for each month and can use anywhere in town), on the other hand, can use oodles of different frequency bands. None of them are anywhere near the frequencies used by our R/C stuff, but there's certainly some small possiblity of them interfering with the computer in certain radios under certain conditions.
| No blanket statement can be made concerning their relative "health" without | a ton more information.
| Anyone can fly JR singles at our flying field - at the risk of losing | their airplane or helicopter!
I'd suggest that there's nothing magical about single conversion vs. dual conversion, as suggested by this article --
(to be fair, it's written by somebody who sells single conversion receivers and claims they're as good or better as any dual conversion radios out there.)
... but I'm not going to argue with what appears to be a large amount of evidence that single conversion radios have problems there.
| Reason....... across the lake from our field is 'Broadcast Hill', | where every TV station transmitter AND every FM radio station | transmitter PLUS God only knows how many other radio service | transmitters hung on the sides of those towers ! BTW, this is | Dallas/Fort Worth area in North Texas.
Why wait for God to tell you what's out there? Look it up yourself.
though that doesn't include some of the things you'd probably be really interested in -- like pager and cell phone towers.
Here in Austin, there's been some reports of interference problems at Zilker Park. So I took my scanner out there, and found that there's some really strong FM data transmissions at 72.660, 72.860 and 72.960 mhz. They seem to have caused at least one plane to crash recently ...