Twisting long cable runs (1+ twist/inch @ 72MHz is more than adequate) allows all 3 leads to be subject to equal amounts of extraneous EMI/RFI. The result is all leads see the same rise/fall in extraneous energy. Although extraneous EMI/RFI may not be as prevelent on sailplanes (as say on an ignition equipped gasser), a pilot's logic should ALWAYS be to create an RF link that has as much headroom as possible between the TX and RX! Your system may never demonstrate (at least visibly) a communications anomoly, but why not take the known precautions and apply them?
It's unfortunate when people state "I don't, and it works...not a problem" implying there is not even an issue to begin with, especially when there have been many many situations solved by doing just what was recommended. I have performed tests in our antenna test range (see http://www.murandi.com) confirming that twisted leads do offer greater EMI/RFI immunity over typical OEM strip-cabling, and have solved real world problems in the same manner. I have also helped many others (especially in the large scale gas enviroment) solve long-lead issues by, amongst other things, twisting long leads. As far as why there are no OEM's suggesting actions to take regarding RF anomolies, why would they (the OEM) put themselves in a litigious position by doing so? More importantly is the fact that manufacturing components using strip cabling is significantly more cost-effective (the process is then automated) than twisted lead. As far as the JR-sponsored TOC pilot who flies both disciplines and chooses to ignore known ways of increasing the integrity of the RF link? It would indicate that indeed there is enough headroom present to operate (possibly) without (visible) anomolies. It would also support the OEM as proof that "their systems" are without fault. On the other hand, as a sponsored pilot, do you really think you or I are going to hear about any of the crashes that occur that relate directly to RF anomolies, especially if it were possible to increase system integrity by applying known and proven techniques that were ignored?? Well I have. Indeed there are some who did apply what I recommended, and they seem to be happy with the results. Bill Malvey wrote: > > On 2/10/03 8:29, "Randy Bullard" <[EMAIL PROTECTED]> wrote: > > > You guys are twisting your longer servo wires aren't you? Ma Bell has used > > this for many years to eliminate interference. > > I used to do this like a religion. Then I started flying large gassers. 10 > to 14 digital servos in a plane with a dual spark electronic ignition. Servo > extensions up to 48 inches long. I've just been using plain old flat JR 22 > ga servo wire without a single problem. > > I have a friend with and ASH-26 that has up to 8.5 foot flat wire runs, > again with no problems. > > I guess it is very application specific. But I have found that I do not need > to twist wires or do anything else as long as everything else is right with > eh radio and installation. > > I wonder why none of the radio manufacturers recommend twisted wire fro long > leads?? At least one TOC pilot is also an active scale glider pilot and I am > pretty certain that he does not use twisted wires in any of his planes, TOC > or large scale gliders. Oh yeah, he works for JR too so would likely know > what they recommend. > > Go figure. > > ~~~~~~~~~~~~~~~ > Bill Malvey > > > > RCSE-List facilities provided by Model Airplane News. Send "subscribe" and >"unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and >unsubscribe messages must be sent in text only format with MIME turned off. -- *~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~* Simon Van Leeuwen, Calgary, Alberta RADIUS SYSTEMS Cogito-Ergo-Zoom IAC25233*MAAC12835*IMAC1756*LSF5953*IMAA20209 *~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~* RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off.
