ORIGINAL: bidrseed2
im going to do more checking today, but i also tried swamping checks. I left my jr 3810 on ch 72 ( im using ch 73 on the model) beside the aircraft and could ony get 12ft away. I could get further if the aerial was actually left lying as if it was within the wing! Any other posn wouldnt work.
Silver, so if i can get 30ft away before failsafe occurs, with the interfering tranny 1ft away from the model, is that a good check?
I was considering buying a JR synth module. Would that avoid the need to get tuning/alignment done by JRs service centre?
Not 1 foot from the model... 1 foot from the receiver antenna, parallel and or angled any relational position from the receiver antenna for the interfering trans. For the trans & receiver being checked the minimum is 10 feet, if you can get more than 10 feet away with your transmitters antenna removed / fully collapsed and with the interfering transmitter at full power, i.e. fully extended antenna and 1 foot or closer to your receivers antenna... then your sideband rejection / receiver blocking circuits in that receiver are tuned and working properly. Actually this test also checks your transmitters module for normal output, because it must be fairly strong to pass this test failsafe free. Obviously if you can get 30 feet away and or closer with the interfering transmitter all the better.
Keep in mind this swamp test is just a quick and dirty way to cut the wheat from the shaft...so to speak. When you get the feel of this test you can check many radios out in just a few minutes. You rarely will find any two with the same exact results. The swamp check does not take the place a proper range check especially with all on board EMI / RFI devices operating in your airplane. The swamp check just tells me if the transmitter & receiver are worth wasting any more time on.
You can buy the Synthesized transmitter & receiver modules JR, Futaba, or for that matter from any manufacture... sorry to say NO that doesn't insure a good R/F link. Buy whatever you like.. but you still must check them out. Actually the Synthesized modules must also be checked out on several channels as the range will vary from the low channels to the higher ones. Fact is I check my synth R/F modules out completely on whatever channels I plan to use.
One year at Superman I changed channels 3 times to find one no one else was on... each time I change channels I did a range check ECU operating to make sure it was OK.
NOTE: I have checked out three different JR Synth transmitter modules and have found their output to be higher than the crystal controlled versions. Why I'm not sure.. just noting what I have observed.
Lee H. DeMary
AMA 36099