TX crystal changing story

Long post: A local boy named Noah was stricken with some form of Muscular Dystrophy and was in a wheel chair and had limited use of his hands but he could cradle a transmitter in his lap and push the sticks around. He played with a simulator at home and had his "coming at you" reflexes down pretty well. The fellow that taught me to fly was teaching him and his father, Rick to fly. Noah was priority; he didn't have much time left. The trainer was very cautious and rightfully so. The FBO at the local airport has given us permission to fly off of the Xed out runway. We tried to be really clear of the full scale and hangars. Flying time for Noah was limited and when he flew the trainer had to take it back often. Rick had bought his son at least two trainers and I think another kit was at home and they had two radios. One day while I was waiting for the windto calm and a buddy to show up Rick and Noah drove up. Without a word they started to set up a trainer. When I said, " Hello, ya need any help?" Rick told me that they were going to fly by themselves "crash or not". He explained that they were tired of not getting much stick time. Respecting his decision I watched. As it turned out the transmitter had dead batteries and the other trainer that was charged was not ready to fly. When it was evident he was not going to get that plane in the air I told him that if he let me get out my buddy cord I'd get him in the air. I could have sent him home for the other RX but I took it upon myself to change transmitter crystals. Yes, I'm a TX crystal changing Son Of a Biscuit eater! No one else was flying and I put everything back after were done. IMHO, no harm was done; I care not what any law says! (Or any internet user) I'll get back to Noah later.

I met a fellow this Cinco de Mayo that mentioned how he came about his computer 9ch JR. The hobby shop owner was showing it to him and he popped off " If it were on CH 39 I'd buyit right now!" LHS owner changed the crystal and bingo made a sale. IHMO this was irresponsible.This flyer is not a club member but might have been flying with us Thurs. if he'd shown up 15 min earlier. Whether or not his TX is off (freq. output) I do not know. To summarize my opinion on the subject: to change the TX crystal as I did was ok, to change the crystal the way the LHS owner did was not.

Have you ever had a flight that scared the begonias out of you? Maybe taking off with the ailerons reversed or on the wrong model on your TX? First flight on your first kit with the trims really off and the CG too far back? You get the plane down and you're shaking like a dog trying to crap a peach seed. Noah flew a 30+ minute flight in which I only took the plane back if it was diving straight down (and even then at the last moment or way over the hangars. When I finally landed I thought I was going to faint! It was a wild ride. We flew another 30+ minute flight and those two flights were more fun than he had had ever with a RC airplane. About two weeks later Rick saw me at the field at about 2PM and asked me if I minded giving Noah more flight time. He went and pulled him out of school to come fly with me. He'd been on the SIM a lot since the previous time and was 100% better, it was amazing.

Noah died shortly after that and when I paid my respects Rick thanked me again and told me how much that had meant to both of them. It was good for me too. True story, I'm proud, I admit it.

I'm sorry people let their feelings get hurt on the internet (usenet) but I get a kick sometimes out the rants. Life must be good if these little text msgs can get your dander up that much.



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*Great story!* Thanks, Mike - LeeH Still learning to land in a crosswind...

To reply substitute centurytel for nospam.

-- MK wrote:

Reply to
Lee Hopper


Great work. You have a right to be proud of what you did.


Tom Watson Sydney Australia

Reply to
Tom Watson

Good work with the boy,

However, I am concerned about your other comment "I met a fellow this Cinco de Mayo that mentioned how he came about his computer 9ch JR. The hobby shop owner was showing it to him and he popped off " If it were on CH 39 I'd buyit right now!" LHS owner changed the crystal and bingo made a sale. IHMO this was irresponsible." = not irresponsible.

All JR & Hitec Transmitters and receivers are centre tuned to 27, 29, 35,

36, 72 etc bands. Futaba TX and all RX are centre tuned except Futaba 72 MHz receivers which are tuned to either the top half or lower half of the 72 MHz band. ( Does anyone really believe the cost of systems is as cheap as they are if every set had to be individually tuned to a specific pair of crystals?)

Please note that whenever a customer visits any shop in this and almost every other country (only known exception is USA) and wishes to buy a new RC system, we ask the customer which brand, frequency and spot in that band the customer wants. We then simply insert the appropriate crystals at time of sale and check for correct operation at 2M range (aerial down). However, if TX or RX is second hand, aged or been dropped/crashed then one must have the tuning checked to confirm it is still within specification for that particular band.

regards Alan T.

Alan's Hobby, Model & RC Web Links

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In fact, from some messing around on te e-zone, it appreas that 35 and

36Mhz receovers are identical in many cases, with onbly a tweak to the nput voil (which the manufacture diesn't do) requirted to optimise.

Indeed some people have claimed to be able to retune 40Mhz receivers to

35 and vice versa.

Your info on TX'es is to the best of my knowledge accurate.

The only issues that have arisen in te UK is substituion of 3rd party crytsals in transmitters - these can resuklt in seriously 'off' frequencies.

I have a home built scanner and tried a 'no name' TX xtal in my trannies. WAY off. I suspect it was for a Sanwa or JR - I fly futaba.

THAT is the REAL danger. Using the wrong BRAND of transmitter cyrstal.

Receiver crystals seem to be completely interchangeable though.

Reply to
The Natural Philosopher

"Receiver crystals seem to be completely interchangeable though"

15 years ago I would have agreed, but no longer. Actual tech specifications are quite different with some brands. e.g. Hitec receiver crystals. We have tested interchange-ability many times on field and bench. Whilst other single conversion FM/AM RX crystals appear to work in Hitec RX, range will be severely compromised with noticeable glitching particularly in damp weather. This especially so with the Feather RX and HFS-O4MI+ (actually 5ch with switchable retract using Y in battery socket). Use only genuine Hitec crystals in a Hitec. GWS crystals can be interchanged with JR but other brands will degrade performance. Dual conversion crystals can not be interchanged. Hitec DC RX crystals on 35.36 & 40MHz have a frequency 10.7MHz ABOVE the nominal frequency whereas Futaba DC RX crystals are 10.7MHz BELOW nominal frequency. TX xtals are very different. e.g. Hitec FM TX xtals are cut at half nominal frequency whereas the Futaba FM TX xtals are cut at 1/3 nominal frequency.

Why risk hours of work etc., for a mere US$8 - US$10, use TX or RX manufacturers own label xtal.

regards Alan T. Alan's Hobby, Model & RC Web Links

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I don't know what all the fuss is about crystal changing. In Australia you either take the crystal that comes in a new radio set of have them swapped to your preference at the point of sale. However, The MAAA does recommend you have your radio set tested and certified by approved testers. Appropriate certification labels are applied to the back of the radio along with signatures and dates. Seems a much more logical thing to do than have some silly law about crystal changes.

Reply to
The Raven

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