Peter Beeney Posted January 24, 2011 Share Posted January 24, 2011 Yes, I’m now reminded about the time I was checking my friend’s MPX IPD rx failsafe. I wanted to test the rx, so tx aerial up and walk away with the rx, servo and battery. To try and cut down the range I wrapped the aerial round the receiver and walked round the back of a hill, way out of line of sight. I’d just decided it wasn’t working properly, because I was so far away, when it suddenly operated! All ok. Took me nearly all the morning to walk back! Well, it certainly seemed like that anyway. PB PatMc, Is that a Yagi aerial? Directional, presumably? Edited By Peter Beeney on 24/01/2011 21:35:05 Quote Link to comment Share on other sites More sharing options...
Richard Putnam 1 Posted January 24, 2011 Author Share Posted January 24, 2011 Hi, The more this thread goes on the more interesting information comes to light! I had forgotten all about full range checking . Not a bad idea. I would never have thought of using the servo movement to clarify that all was well or the fail safe movement. It is funny that you mentioned Maynard Hill ,Peter as there is an article on him and his altitude records on page 62 of February 2011 RCM&E! He had to have a heater in with the receiver to keep it warm it cut in once he was above 15000Ft.. the record was set in 6th September 1970 at nearly 27,000Ft.and the record still stands. Imagine doing a range check! Long walk!! Richard. Quote Link to comment Share on other sites More sharing options...
PatMc Posted January 24, 2011 Share Posted January 24, 2011 Posted by Peter Beeney on 24/01/2011 21:27:36:PatMc, Is that a Yagi aerial? Directional, presumably? I think it is I'm going from memory. IIRC Maynard & a colleague adapted the aerial to use with a model Tx in the year before setting the record. Seems I remembered the altitude incorrectly I thought it was just under 30,000ft but at that height what's 3000ft between friends. Quote Link to comment Share on other sites More sharing options...
Peter Beeney Posted January 24, 2011 Share Posted January 24, 2011 Richard.I’ve not seen the mag, so that is indeed a coincidence! I think Maynard’s first record, of 13,000 ft, was in the early sixties, around 1963 time, and they used a military radar to read the distance. I can remember reading about it with great interest. Proportional radio then was real cutting edge stuff! If my memory is any good!Kraft was one of the American sets, this is what he may have been using, but I don’t know.PB Quote Link to comment Share on other sites More sharing options...
Former Member Posted January 25, 2011 Share Posted January 25, 2011 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
DH 82A Posted January 25, 2011 Share Posted January 25, 2011 Does no-one do a range check with the engine or electric motor running? Quote Link to comment Share on other sites More sharing options...
Steve W-O Posted January 25, 2011 Share Posted January 25, 2011 Posted by Eric Bray on 25/01/2011 12:13:44: In effect it works rather like the reflector in a car headlight - pushing all the light in one direction, only it is pushing the transmitted rf instead! I assume you are just using that to describe what it does, not to describe how it works? At least i hope so Because of all the variables, I think a full range check at least once a year is a must, even with 2.4GHz gear. Quote Link to comment Share on other sites More sharing options...
Peter Beeney Posted January 25, 2011 Share Posted January 25, 2011 Yes, Eric, from my now distant memory, the Yagi Array was a half wave dipole mounted on a beam with a 5% longer reflector behind it, and one, (or more) directors in front of it, each one getting 5% progressively shorter. This would be pointed toward the transmitter, and would be horizontally or vertically polarised, depending on the transmitting aerial. Also as I remember, the dipole itself would be 5% shorter than half-wave anyway. Half-wave for 27 MHz would be about 5.5 metres, so Maynard’s may have been quarter-wave, 2.75 metres long. Or even one eighth-wave, 1.575 metres long. I can also remember the course tutor saying that aerials were a black art anyway, just use whatever works best. I’m not sure he completely knew what he was talking about, but I certainly knew that I didn’t know what he was talking about! Is that any good for about 50 years ago? Amazing how I can remember totally useless information. Also apologies for wandering off track. I forgot where I was going! If there is any sort of problem then I would definitely try it with the motor running, I’ve seen the very seldom case of vibration, but range problems are very few and far between, in my experience anyway. It seems like one about every ten years. Also electric collywobbles are specific, not range related and seem to tend to individual models. But I have to say, as I’m mostly only trying to meddle with other people’s models, this is as I find it. Other people may find it different. PB Quote Link to comment Share on other sites More sharing options...
Richard Putnam 1 Posted January 25, 2011 Author Share Posted January 25, 2011 In answer to Rex " Does no one do a range check with the motor running". I do on electric because it is easy. But on I.C. I have to bow my head. No I very rarely do a check but maybe I should do one more often.. What about metal to metal vibration causing radio interference. Because it it is talked about I am sure it is a fact. But I just don't get it. I have never heard or seen the science to back it up. I do make sure I never have metal to metal linkages just to be on the safe side. Richard. Quote Link to comment Share on other sites More sharing options...
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