Best Receiver
07-08-2002, 03:14 PM
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Best Receiver
Ok guys,
Getting close to finishing my MB339ARF and was wondering what receiver would be best. I have a JR 950S in my Roo and have been very happy with it, however, at Winimac I was told that using a single conversion receiver in jets is very risky.
I was just going to order another 950 or it's replacement the 955 but now I am wondering if I should go the 940 dual conversion route.
Whada think?
Thanks,
Randy
Getting close to finishing my MB339ARF and was wondering what receiver would be best. I have a JR 950S in my Roo and have been very happy with it, however, at Winimac I was told that using a single conversion receiver in jets is very risky.
I was just going to order another 950 or it's replacement the 955 but now I am wondering if I should go the 940 dual conversion route.
Whada think?
Thanks,
Randy
07-08-2002, 04:06 PM
#2
Real World Range Test!
Randy,
I am running the new 945 S- Dual Conversion (CH32) receiver which is the replacement for the 940S.
FWIW, I suffered a brain fart at the Denver Jet Rally and forgot to attach the Jet Team Libetrau whip antenna (~24" wire) to the top of my HotSpot. I flew a normal flight (around 12 minutes total run time and over 700 feet distance) without any apparent problems or lockout. The JetCat 120 with v4.0 ECU recorded 1 glitch for the entire flight which could have been milliseconds but nonetheless it recorded a hit. Normal count is Zero for this flight time. So I basically flew with 12" of receiver wire leading up to the antenna stub mounted to the top of the fuse behind the canopy. My ECU and fuel pump are mounted under the wheel well which puts them around 18"+ away from the receiver. It's mounted up front near the front tire (retracted).
My normal range checks on the ground with the antenna removed from my JR 8103DT is well over 300 feet with the Hotspot on the ground.
I've always run the 940S DC receivers in all my high end helicopters and DF's with no problems so far!
I am running the new 945 S- Dual Conversion (CH32) receiver which is the replacement for the 940S.
FWIW, I suffered a brain fart at the Denver Jet Rally and forgot to attach the Jet Team Libetrau whip antenna (~24" wire) to the top of my HotSpot. I flew a normal flight (around 12 minutes total run time and over 700 feet distance) without any apparent problems or lockout. The JetCat 120 with v4.0 ECU recorded 1 glitch for the entire flight which could have been milliseconds but nonetheless it recorded a hit. Normal count is Zero for this flight time. So I basically flew with 12" of receiver wire leading up to the antenna stub mounted to the top of the fuse behind the canopy. My ECU and fuel pump are mounted under the wheel well which puts them around 18"+ away from the receiver. It's mounted up front near the front tire (retracted).
My normal range checks on the ground with the antenna removed from my JR 8103DT is well over 300 feet with the Hotspot on the ground.
I've always run the 940S DC receivers in all my high end helicopters and DF's with no problems so far!
07-08-2002, 11:21 PM
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Hi Randy,
Go with the Multiplex RX they are the best in my book, I have used the JR-950s and they were Ok no complaints there.
Hope this helps you .................Johnny Hernandez
Go with the Multiplex RX they are the best in my book, I have used the JR-950s and they were Ok no complaints there.
Hope this helps you .................Johnny Hernandez
07-09-2002, 12:40 AM
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Watch that transmitter module also----
The receiver has to be tuned and aligned correctly no question, but don't forget if the transmitter module is weak, the best receiver in the world still won't give you the range your looking for. The fact is you can increase your range better and more sure by having a strong transmitter module. I know GP & Horizon will tell you modules are all the same but they are not, just as the new receiver you get will need to be checked out, don't assume it is any good till you know for sure!!
I have developed a simple quick three stage home checkout for a new receiver / transmitter combination.
1. Put the receiver in the freezer over night, next morning plug it in to some servos and make sure it works while still cold !
2. Same kind of a check "see if servos work and don't jitter" while placing the receiver on a vibration source.
3. Do a swamp check. With a second transmitter any frequency except the one your "in question system is on" wrap the receiver antenna around the second interfering transmitters fully extended antenna. Now with a JR transmitter, remove the antenna and walk away ---- you should be able to get 8 - 10 feet away! If you can't, unwrap the receiver antenna from the interfering transmitter's antenna and move it away as much as one foot. If you can't obtain lockout free operation with a Maximum of 1' and 10' ratio, then that transmitter / receiver combination is not worth wasting any further time on. Have it tuned and aligned until you can achieve at least that 1 and 10 ratio. Send it back to the factory if it fails any one of these three basic tests. If on the other hand you happen to have a combination that will achieve numbers like "wrapped" and 20 feet or more---- you've got a real winner setup, guaranteed to give you great range checks! At least on a baseline range check, but remember RFI can kill any good RF link in a heart beat----.
Lee H. DeMary
AMA 36099
I have developed a simple quick three stage home checkout for a new receiver / transmitter combination.
1. Put the receiver in the freezer over night, next morning plug it in to some servos and make sure it works while still cold !
2. Same kind of a check "see if servos work and don't jitter" while placing the receiver on a vibration source.
3. Do a swamp check. With a second transmitter any frequency except the one your "in question system is on" wrap the receiver antenna around the second interfering transmitters fully extended antenna. Now with a JR transmitter, remove the antenna and walk away ---- you should be able to get 8 - 10 feet away! If you can't, unwrap the receiver antenna from the interfering transmitter's antenna and move it away as much as one foot. If you can't obtain lockout free operation with a Maximum of 1' and 10' ratio, then that transmitter / receiver combination is not worth wasting any further time on. Have it tuned and aligned until you can achieve at least that 1 and 10 ratio. Send it back to the factory if it fails any one of these three basic tests. If on the other hand you happen to have a combination that will achieve numbers like "wrapped" and 20 feet or more---- you've got a real winner setup, guaranteed to give you great range checks! At least on a baseline range check, but remember RFI can kill any good RF link in a heart beat----.
Lee H. DeMary
AMA 36099
07-09-2002, 01:32 AM
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Lee,
How do you come up with this stuff?
I have always range checked my stuff with antenna out of the transmitter, with transmitter out at arms length and transmitter facing the model. I have never had a bad range check, and for that matter have never lost an airplane to a radio problem. I have used the 950S, the 940S, and the 955S in my jets with no problems. Oh by the way my most accurate range check is when I fly my airplane to the limits of my eyesight and still have control over it.
David Reid
How do you come up with this stuff?
I have always range checked my stuff with antenna out of the transmitter, with transmitter out at arms length and transmitter facing the model. I have never had a bad range check, and for that matter have never lost an airplane to a radio problem. I have used the 950S, the 940S, and the 955S in my jets with no problems. Oh by the way my most accurate range check is when I fly my airplane to the limits of my eyesight and still have control over it.
David Reid
07-09-2002, 01:35 AM
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Best Receiver
I just did your range check, I have a whip so I put the fully extended ant. of my other JR radio right next to it, then with my 10x ant. removed did a check, with the ecu on and armed. Got only 20' of room where I tried it and didnt have one lockout at all, guess thats good!?
07-09-2002, 02:31 AM
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A non Believer!
If you do enough of my little "Swamp checks" you'll find that no two receivers will checkout the same ------ and the bad one's will really stick out like a sore thumb. I said any transmitter will work for the swamp check, but the "best" kind is to use an older one that is AM modulation, (narrow band but AM)! I've got a little cheap Futaba transmitter I use just for this purpose ---------.
David if every radio you have checks out the same you only have one radio !! I am so sure of what I say because I've been doing this "stuff" so darn long, and have seen the damed-est things. If you will do this swamp check on every receiver you have, (I must have a dozen or more), every transmitter module, etc. etc. you will see what I am talking about. David I've never lost an aircraft to a radio failure either, but I don't assume anything. I also fly smack dab in a big metro area, with a lot of outside RF, and our field is as active as any in the country. Any day of the week you can go out to our field and find 12 to 15 pilots. And on the busy days, Sat, Sun, Wed, you can be sharing the flight line with 5 or 6 at a time, with 30 or so waiting or bull sh??ting on deck! If you haven't found a bad receiver / transmitter RF link you haven't seen very many! I have seen many systems I wouldn't put in my worst day to day beater much less a 7 --- 10 K bird.
Remember the swamp test is just a little quick and dirty check out, so I don't waste any time until it's tuned up !!
John yep sounds good, but remember on-board RFI is a completely separate bag of worms. I suppose David is going to tell us he's never seen any bad range checks from on-board RFI, and everything just works great all the time!! Hummm wonder what's in the water down there ------------ I'll bet David 10 bucks he won't collapse his antenna and do a limit of eye sight flight with say ( I think he's got a turbine F4 Phantom----would ya, now that would be a range check to beat all range checks??.
Lee --------
David if every radio you have checks out the same you only have one radio !! I am so sure of what I say because I've been doing this "stuff" so darn long, and have seen the damed-est things. If you will do this swamp check on every receiver you have, (I must have a dozen or more), every transmitter module, etc. etc. you will see what I am talking about. David I've never lost an aircraft to a radio failure either, but I don't assume anything. I also fly smack dab in a big metro area, with a lot of outside RF, and our field is as active as any in the country. Any day of the week you can go out to our field and find 12 to 15 pilots. And on the busy days, Sat, Sun, Wed, you can be sharing the flight line with 5 or 6 at a time, with 30 or so waiting or bull sh??ting on deck! If you haven't found a bad receiver / transmitter RF link you haven't seen very many! I have seen many systems I wouldn't put in my worst day to day beater much less a 7 --- 10 K bird.
Remember the swamp test is just a little quick and dirty check out, so I don't waste any time until it's tuned up !!
John yep sounds good, but remember on-board RFI is a completely separate bag of worms. I suppose David is going to tell us he's never seen any bad range checks from on-board RFI, and everything just works great all the time!! Hummm wonder what's in the water down there ------------ I'll bet David 10 bucks he won't collapse his antenna and do a limit of eye sight flight with say ( I think he's got a turbine F4 Phantom----would ya, now that would be a range check to beat all range checks??.
Lee --------
07-09-2002, 10:08 AM
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Best Receiver
Hey Lee, we'll be flying with David this weekend in Lumberton Mississippi. David, I'll help show that Lee! You take the F-4 way, WAY out to the limits of sight, low on the horizon for excitement, and I'll unscrew your JR antenna. We'll document it on video (even the brown stain on David's shorts!). That's put hair on your chest!
Make the big switch, MPX.
Make the big switch, MPX.
07-09-2002, 10:55 AM
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Tx module checks
Lee,
Is there any other definitive way to check out the Tx modules other than the test you mentioned? I'd like some kind of RF meter to see that the Tx does not have a weak output before I get started on the integrated airframe checks. All this testing with the antenna down heats up the modules.
Also why the difference in checks: The JR8103 recommends the range check with the antenna collasped, not off, like the 10X?
Jack
Is there any other definitive way to check out the Tx modules other than the test you mentioned? I'd like some kind of RF meter to see that the Tx does not have a weak output before I get started on the integrated airframe checks. All this testing with the antenna down heats up the modules.
Also why the difference in checks: The JR8103 recommends the range check with the antenna collasped, not off, like the 10X?
Jack
07-09-2002, 11:02 AM
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Originally posted by woketman
Hey Lee, we'll be flying with David this weekend in Lumberton Mississippi. David, I'll help show that Lee! You take the F-4 way, WAY out to the limits of sight, low on the horizon for excitement, and I'll unscrew your JR antenna. We'll document it on video (even the brown stain on David's shorts!). That's put hair on your chest!
Make the big switch, MPX.
Hey Lee, we'll be flying with David this weekend in Lumberton Mississippi. David, I'll help show that Lee! You take the F-4 way, WAY out to the limits of sight, low on the horizon for excitement, and I'll unscrew your JR antenna. We'll document it on video (even the brown stain on David's shorts!). That's put hair on your chest!
Make the big switch, MPX.
Lee ------
07-09-2002, 11:06 AM
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Yeah, well Lee you are correct. We are lucky in that regard (no big forest fire risk). But it'll be 99 degrees out there with 100% humidity and we'll all feel like crap after an hour. Just gotta keep under the tent as much as possible and wear that sunscreen.
07-09-2002, 11:51 AM
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Great replies all but....
Great replies all but....
I am still interested in why some people are saying that JR 950 single conversion receivers are not good to put in jets! This was told to me by several well know jet pilots at the Winimac jet event a few weeks ago (No I will not mention names). Why is the 940 or 945 dual conversion so much better. I was under the imporession that the JR ABCW&Y or what ever they call it, is supposed to be so good that they do not need a dual conversion receiver. This is not a slam against JR as I use JR is all by jets.
BTW, I get all my modules and receivers that fly jets tuned every year, just to make sure all are doing what they are supposed to be doing. Range has never been an issue with my Ram powered Roo and the 950 receiver. Ground checks are 300' plus with engine running or not and the plane sitting on the ground at a jet event with the antenna collapsed!
I am just looking to get the bets receiver for the job in my new MB 339.
CobraJet,
Do you think the range would have been less with the 950?
aptar,
I assume that this is with the TX collapsed and not off?
Jetflyer 24 and woketman,
I was thinking about the multiplex IPD receiver. I was over at Andy Low's shop a few months ago when I pick up the 339 and I noticed that he had one in his protype 339. He must trust thoes receivers an awfull lot to put it into his pre-production protype. I am just not convinced yet what there reliablity is and how well they will work with JR TX's. Maybe I will get one and install it in a gasser and see what hapens. As I recall the IPD receivers are about 1/2 the price of the JR receivers.
Lee,
What's with the freezer?!? Never hear of that one before
I do have Dave from D@M electronics do the vibration test every year when he tunes the TX and RX. A good idea incase there is any bad solder joints on the board.
I will try the swamp test maybe today when I get home from work, just to see what happens. I have several old radios that are out of tune (no longer used) that I can try this with.
David,
Did Vernon Montgomery ever get his TX back from Winimac?
Anybod know what the signal strenght is supposed to be on a good TX module? I have seen an RC Frequency scanner at Winimac that tells you what the signal is in db for each channel. That might be a good idea to check TX power in between yearly tunups.
Thanks,
Randy
I am still interested in why some people are saying that JR 950 single conversion receivers are not good to put in jets! This was told to me by several well know jet pilots at the Winimac jet event a few weeks ago (No I will not mention names). Why is the 940 or 945 dual conversion so much better. I was under the imporession that the JR ABCW&Y or what ever they call it, is supposed to be so good that they do not need a dual conversion receiver. This is not a slam against JR as I use JR is all by jets.
BTW, I get all my modules and receivers that fly jets tuned every year, just to make sure all are doing what they are supposed to be doing. Range has never been an issue with my Ram powered Roo and the 950 receiver. Ground checks are 300' plus with engine running or not and the plane sitting on the ground at a jet event with the antenna collapsed!
I am just looking to get the bets receiver for the job in my new MB 339.
CobraJet,
Do you think the range would have been less with the 950?
aptar,
I assume that this is with the TX collapsed and not off?
Jetflyer 24 and woketman,
I was thinking about the multiplex IPD receiver. I was over at Andy Low's shop a few months ago when I pick up the 339 and I noticed that he had one in his protype 339. He must trust thoes receivers an awfull lot to put it into his pre-production protype. I am just not convinced yet what there reliablity is and how well they will work with JR TX's. Maybe I will get one and install it in a gasser and see what hapens. As I recall the IPD receivers are about 1/2 the price of the JR receivers.
Lee,
What's with the freezer?!? Never hear of that one before
I do have Dave from D@M electronics do the vibration test every year when he tunes the TX and RX. A good idea incase there is any bad solder joints on the board.
I will try the swamp test maybe today when I get home from work, just to see what happens. I have several old radios that are out of tune (no longer used) that I can try this with.
David,
Did Vernon Montgomery ever get his TX back from Winimac?
Anybod know what the signal strenght is supposed to be on a good TX module? I have seen an RC Frequency scanner at Winimac that tells you what the signal is in db for each channel. That might be a good idea to check TX power in between yearly tunups.
Thanks,
Randy
07-09-2002, 12:34 PM
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Dual Conversion
Hey Randy, I was told by Horizon that we (turbines) should use the dual conversion Rx, but no explanation was given. I was also told by them that the Tx modules don't get weak (which I don't believe), but I'm no elctrical engineer of RF guru.
George
George
07-09-2002, 02:51 PM
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Geez
RANDY
do yourself a favor, If you're not sure about the Multiplex RX go for with the JR 950 S put it in your plane walk away from it see if everything works right and JUST FLY man, dont go crazy doing all that $**t that I'm reading here (no offense intended so back up ). I have quite a few Jets flying all the time NO QUEENS and if everything works properly while your engine is running at about 20 ft away with your antenna down, fly it man.
Multiplex RX are excellent for me I trust them in my Twin Turbine, and my single turbine jets and Knock on wood everything has been perfect, one of my jets is currently flying with a JR 950S for three yrs now with no problems at all.
Good luck Randy and Regards.........Johnny Hernandez
do yourself a favor, If you're not sure about the Multiplex RX go for with the JR 950 S put it in your plane walk away from it see if everything works right and JUST FLY man, dont go crazy doing all that $**t that I'm reading here (no offense intended so back up ). I have quite a few Jets flying all the time NO QUEENS and if everything works properly while your engine is running at about 20 ft away with your antenna down, fly it man.
Multiplex RX are excellent for me I trust them in my Twin Turbine, and my single turbine jets and Knock on wood everything has been perfect, one of my jets is currently flying with a JR 950S for three yrs now with no problems at all.
Good luck Randy and Regards.........Johnny Hernandez
07-09-2002, 03:06 PM
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Johnny,
Are you using the Multiplex receiver with a JR TX or the Multiplex TX?
I am gona be ordering something with in the next few days, just don't know what yet.
Thanks,
Randy
Are you using the Multiplex receiver with a JR TX or the Multiplex TX?
I am gona be ordering something with in the next few days, just don't know what yet.
Thanks,
Randy
07-09-2002, 03:37 PM
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Karlton (the MPX USA importer) has a sale about once a year and you can get them at an even better price. As for reliability, I have been flying brand M for 1.5 years now. I have three 9 ch IPD RXs and two 12 ch IPDs and have never yet had a problem in any way that was not operator error (my fault). Rock solid with far better range than I ever had with Futaba or JR (just my experience here after 29 years). I believe that Johnny uses the Graupner MC-24 TX with his MPX RXs. It is basically a Euro JR and will accept the USA JR TX modules. I gotta agree with Lee that I never take anything for granted with new equipment. I've been burned that way with both Futaba & JR in the past, luckily it was pre-turbine. But I am now paranoid. So every new MPX RX I buy, I have it shipped to Ernie Pritchard, the USA MPX repair tech in Arizona (great guy, fast turn around) for him to give it the once over. Just makes me feel better.
07-09-2002, 09:52 PM
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right on the $$
Woketman wrote:
I believe that Johnny uses the Graupner MC-24 TX with his MPX RXs. It is basically a Euro JR and will accept the USA JR TX modules.
thats my setup Randy, Woketman said it
Regards.........Johnny Hernandez
I believe that Johnny uses the Graupner MC-24 TX with his MPX RXs. It is basically a Euro JR and will accept the USA JR TX modules.
thats my setup Randy, Woketman said it
Regards.........Johnny Hernandez
07-10-2002, 01:04 AM
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Re: Great replies all but....
Lee,
What's with the freezer?!? Never hear of that one before
I do have Dave from D@M electronics do the vibration test every year when he tunes the TX and RX. A good idea incase there is any bad solder joints on the board.
I will try the swamp test maybe today when I get home from work, just to see what happens. I have several old radios that are out of tune (no longer used) that I can try this with.
David,
Did Vernon Montgomery ever get his TX back from Winimac?
Anybod know what the signal strenght is supposed to be on a good TX module? I have seen an RC Frequency scanner at Winimac that tells you what the signal is in db for each channel. That might be a good idea to check TX power in between yearly tunups.
Thanks,
Randy [/B][/QUOTE]
The freezer test will show up a bad "temp sensitive component right away" usually it will be the crystal. I have only found one bad crystal / receiver doing that test but shoot it only takes one night in the freezer ----- why not!
The 1 and 10 swamp test will tell you if the modules Tr & Rec are tuned relatively close, and rejecting outside interference properly, not bad information to know. At the same time it will give you an idea of the strength of your RF link, in comparison to other receiver / transmitter combo's you may have. It's takes a little time to develop a standard but my 1 and 10 works out fairly good.
As for the transmitter modules being all the same output (Horizon's comment) all I can say is bull Sh----t. I happen to have a JR 10 channel transmitter one of the first JR 10 channels manufactured. Long before Horizon even thought of selling and servicing JR radio's. Well the early straight 10 channel's meter was a relative RF meter, not a voltmeter! Then JR figured out there transmitter modules were so different in output and it showed on the meter, they decided to change the meter so it was just a volt meter. Cause anyone with a module that would only raise the meter to 3/4 instead of full or pegged reading would send the module back to be repaired. Ever wonder why the transmitter shows voltage on screen and has an analog volt meter also???? DA ----- it's cause they changed the RF meter so us user's wouldn't easily be able to tell when they shipped a weak transmitter module!!
Well I keep my older 10 channel just for the purpose of checking for weak trans modules. I have also found some of them mis-tuned to the antenna length! I have one that pegs the meter with three stages of the antenna collapsed, but when you fully extend the antenna the meter comes back down to 3/4 strength ---------Mike Byrd used to be with Circus Circus Hobbies (boy I'm dating myself now) the original importer of JR radios. He is a great R/C radio tech (Mike where are you???) well anyway I sent my second JR 10SX trans back in to him and he converted the volt meter back to an RF meter.
At any rate don't let Horizon try to tell you trans modules aren't different or get weak cause they do ------
When I really get into this it starts to piss me off, cause rarely if ever today can any of us get a trans module that actually puts out our legal limit of .75 milliwatts. Shoot most barely put out .5 milliwatt if that. They have done that so the three IM won't be a problem, with slightly loose receivers. Also they have reduced the output so the battery can run all of the electronics and last a longer time for the user at the field. Not all bad, and I'm not just talking about JR, Futaba does the same thing. If the transmitters would put out the full .75 milliwatt we would have no range problems but with loose receivers would start to see the 3IM thing crop up again. All in All I think the manufactures are doing what they can with the older technology, shoot in 20 years it hasn't changed. The problem today is the distributor's are plugging crystals in not matching dots!!, not match turning, just basically shoving them out the door. And for the most part getting away with it.
Futaba about a 1 1/2 ago was shipping there super synthesized modules out so far out of alignment you couldn't use big chunks of the 50 or so frequencies that should be available.
Nuff said on this subject for now, Randy to answer your question as to where you can get a signal strength meter??? I would think any good Ham outlet store should be able to point you to a inexpensive one. Or maybe someone will find where Mike Byrd is hiding out, and he could switch the volt meter back the way they were originally designed. The big problem is Horizon or GP will only use the book output transistors, and the book today is not even close to the legal limit. The lower output is, in part the key to the receivers of today working on the narrow band freqs as well as they do. With the outdated technology we are using I suppose, "it is a best we can do compromise" --------
Lee H. DeMary
AMA 36099
PS didn't mean to ramble but when I get started --------------
What's with the freezer?!? Never hear of that one before
I do have Dave from D@M electronics do the vibration test every year when he tunes the TX and RX. A good idea incase there is any bad solder joints on the board.
I will try the swamp test maybe today when I get home from work, just to see what happens. I have several old radios that are out of tune (no longer used) that I can try this with.
David,
Did Vernon Montgomery ever get his TX back from Winimac?
Anybod know what the signal strenght is supposed to be on a good TX module? I have seen an RC Frequency scanner at Winimac that tells you what the signal is in db for each channel. That might be a good idea to check TX power in between yearly tunups.
Thanks,
Randy [/B][/QUOTE]
The freezer test will show up a bad "temp sensitive component right away" usually it will be the crystal. I have only found one bad crystal / receiver doing that test but shoot it only takes one night in the freezer ----- why not!
The 1 and 10 swamp test will tell you if the modules Tr & Rec are tuned relatively close, and rejecting outside interference properly, not bad information to know. At the same time it will give you an idea of the strength of your RF link, in comparison to other receiver / transmitter combo's you may have. It's takes a little time to develop a standard but my 1 and 10 works out fairly good.
As for the transmitter modules being all the same output (Horizon's comment) all I can say is bull Sh----t. I happen to have a JR 10 channel transmitter one of the first JR 10 channels manufactured. Long before Horizon even thought of selling and servicing JR radio's. Well the early straight 10 channel's meter was a relative RF meter, not a voltmeter! Then JR figured out there transmitter modules were so different in output and it showed on the meter, they decided to change the meter so it was just a volt meter. Cause anyone with a module that would only raise the meter to 3/4 instead of full or pegged reading would send the module back to be repaired. Ever wonder why the transmitter shows voltage on screen and has an analog volt meter also???? DA ----- it's cause they changed the RF meter so us user's wouldn't easily be able to tell when they shipped a weak transmitter module!!
Well I keep my older 10 channel just for the purpose of checking for weak trans modules. I have also found some of them mis-tuned to the antenna length! I have one that pegs the meter with three stages of the antenna collapsed, but when you fully extend the antenna the meter comes back down to 3/4 strength ---------Mike Byrd used to be with Circus Circus Hobbies (boy I'm dating myself now) the original importer of JR radios. He is a great R/C radio tech (Mike where are you???) well anyway I sent my second JR 10SX trans back in to him and he converted the volt meter back to an RF meter.
At any rate don't let Horizon try to tell you trans modules aren't different or get weak cause they do ------
When I really get into this it starts to piss me off, cause rarely if ever today can any of us get a trans module that actually puts out our legal limit of .75 milliwatts. Shoot most barely put out .5 milliwatt if that. They have done that so the three IM won't be a problem, with slightly loose receivers. Also they have reduced the output so the battery can run all of the electronics and last a longer time for the user at the field. Not all bad, and I'm not just talking about JR, Futaba does the same thing. If the transmitters would put out the full .75 milliwatt we would have no range problems but with loose receivers would start to see the 3IM thing crop up again. All in All I think the manufactures are doing what they can with the older technology, shoot in 20 years it hasn't changed. The problem today is the distributor's are plugging crystals in not matching dots!!, not match turning, just basically shoving them out the door. And for the most part getting away with it.
Futaba about a 1 1/2 ago was shipping there super synthesized modules out so far out of alignment you couldn't use big chunks of the 50 or so frequencies that should be available.
Nuff said on this subject for now, Randy to answer your question as to where you can get a signal strength meter??? I would think any good Ham outlet store should be able to point you to a inexpensive one. Or maybe someone will find where Mike Byrd is hiding out, and he could switch the volt meter back the way they were originally designed. The big problem is Horizon or GP will only use the book output transistors, and the book today is not even close to the legal limit. The lower output is, in part the key to the receivers of today working on the narrow band freqs as well as they do. With the outdated technology we are using I suppose, "it is a best we can do compromise" --------
Lee H. DeMary
AMA 36099
PS didn't mean to ramble but when I get started --------------
07-10-2002, 02:17 AM
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Lee,
Nope Vernon's radio never showed up.
And......what really makes it bad is he lost his Bobcat on the Friday as well. Airplane had over 100 flights on it and had been throughly range tested both on the ground and in the air. Don't know what the problem was and he flew his Phantom afterwards. The good news was that we finally got him to "make the Switch" to JetCat. Expensive weekend!
DR
Nope Vernon's radio never showed up.
And......what really makes it bad is he lost his Bobcat on the Friday as well. Airplane had over 100 flights on it and had been throughly range tested both on the ground and in the air. Don't know what the problem was and he flew his Phantom afterwards. The good news was that we finally got him to "make the Switch" to JetCat. Expensive weekend!
DR
07-10-2002, 12:15 PM
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I made the switch!!!!
No not to Jet Cat but to Multiplex. I went to Electrodynamics yesterday and tried to order the 9ch IPD but Karlton was out of stock on them (whats up with that!) so I ordered the 12 ch instead.
Where should I have this thing tuned at? I am not sure D@M electronics or Pete Waters tunes these receivers.
Great thread guys!
Lot-o- lots of good information here!
I agree with Lee about the TX modules not being tuned! That was my problem when I bought a 'matched set' from Horizon. The TX was not matched to the RX and guess what? No rage at all. I would not have been able to fly a trainer plane with that combo as it came from Horizon!
I also have a few older JR Radios that do not have a module but do have the RF output meter instead of the voltage meter. It's kinda wierd when you first turn them on as the signal is in the red until you extend the antenna.
I know a few ham guys and will check with them for a cheap signal meter.
Lee, you keep mentioning .75 milliwatt. Do you mean .75 Watt? I was under the impressiuon that our little Tx's put out, or could put out, a full 3/4 watt.
Regarding the freezer test, do you think there is much chance of getting moisture in the electronic components due to condensation after taking these things out of the cold?
Thanks for all the good info, hopefully I will get the 339 done by Michigan Jets!
Randy
but to Multiplex. I went to Electrodynamics yesterday and tried to order the 9ch IPD but Karlton was out of stock on them (whats up with that!) so I ordered the 12 ch instead.Where should I have this thing tuned at? I am not sure D@M electronics or Pete Waters tunes these receivers.
Great thread guys!
Lot-o- lots of good information here!
I agree with Lee about the TX modules not being tuned! That was my problem when I bought a 'matched set' from Horizon. The TX was not matched to the RX and guess what? No rage at all. I would not have been able to fly a trainer plane with that combo as it came from Horizon!
I also have a few older JR Radios that do not have a module but do have the RF output meter instead of the voltage meter. It's kinda wierd when you first turn them on as the signal is in the red until you extend the antenna.
I know a few ham guys and will check with them for a cheap signal meter.
Lee, you keep mentioning .75 milliwatt. Do you mean .75 Watt? I was under the impressiuon that our little Tx's put out, or could put out, a full 3/4 watt.
Regarding the freezer test, do you think there is much chance of getting moisture in the electronic components due to condensation after taking these things out of the cold?
Thanks for all the good info, hopefully I will get the 339 done by Michigan Jets!
Randy
07-10-2002, 03:31 PM
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Veritech, Ernie Pritchard is THE Multiplex service guy. He is VERY knowledgable about the products and is just a great guy to talk to with fast turn around. E-mail me at [email protected] and I will get you his e-mail, physical address and phone numbers. I am at work right now and all that info is at home.