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I need your honest opinion.

Old 07-29-2011, 09:19 AM
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frisco2022
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Default I need your honest opinion.

I have been flying for many years and I still use 72mhz. I am now flying bigger more expensive planes which are gas and I want your opinion on switching to 2.4. My concern is that I have been using 72 without a problem until just recently I had a little problem with a glitch and almost lost the plane. Doing research on 2.4 I have been reading a lot on Brownouts and similar issues with low voltage levels. I have always used NiMH batteries without issues, maybe because I check them before each flight. It seems that 2.4 on paper is really great on paper but the reality of 2.4 is there are more problems than 72mhz, or so it seems. I have a 9303 with a Spektrum DM9 module which I have not used it yet until I have done some research. I know that everyone has there own thoughts on these two systems and I would like to hear them. Also if anyone has tips on power systems or anything else I would like to hear about it. I have always kept things simple and it has worked, I am just afraid putting in 2.4 and the receiver browning out on the first flight. I will appreciate all comments.
Old 07-29-2011, 10:21 AM
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JIMF14D
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Default RE: I need your honest opinion.

I cannot speak to the use of 2.4 systems in planes using gas engines as Ihave never used one. But Ihave been flying 2.4 systems in electric and glow planes for about 2 years now with never a glitch. My first system was a Spektrum dx6i which Iused for about 6 months while Iwas waiting for Hitec to come out with a 2.4 system. Inever had any brown out problems with theSpectrum Rx but there have been lots of reports of them in past years and they had a number of updates. But in two years at my field Ihave never seen anyone with Spektrum gear actually have a reported brown out.

I have been flying The Hitec A9 system with 6 and 7 channel Rx since March 2010 with no problems in both in EP and glow models over hundreds of flights. I have learned a few things since Istarted with 2.4:

There are two possible problems in any of these systems:
1. Loss of signal reception at the Rx due to improper antenna location or performance. This signal loss can cause the system to fail to follow the TX commands and do what some people call "lock out" where the system is frozen while the RX finds a good signal and restarts. Ihave never seen any signs of this problem while flying planes to the limit of my visual range.

2. Loss of Rx operation due to low RX voltage, causing the Rx to "reboot".
    [*]Like all RC system, one of the major keys to good operation is the proper sized and charged Rx battery.[*]The 2.4 RXs, at least for Hitec draw more current than the old 72 Mhz RXs[*]The Hitec Rxs have a great feature called the SPC port which allows you to operate the RX from a seperate battery or from the system battery but using a higher voltage to the Rx than is driving the servos. For example you can run your plane with a 3s 11.7 volt lipo, feed the lipo voltage into the Rx and run the servos from the nominal 5-6 volts provided by a BEC. With this configuration, the Rx will always get an adequate voltage even if you run down your LIPO to say 9 volts while flying. Your motor may stop but you will have control to make a "dead stick" landing that will all learned how to do with glow engines.[/list]
      [*]The Hitec A9 with 6 and 7 channel Rx include a Rx system telemetry capability which down links the RX input voltage to the Tx so you can see the state of your battery and also set an alarm if the battery goes below a set voltage. Iusually set my Rx battery alarm to 4.8 volts if I am not using a higher voltage via the SPC
        [*]Ihave seen situations were Iam flying 46-70 size glow models with a 4 cell ni-cad Rx/system battery (4.8 volts nominal) where if Islam the sticks around (think snap roll) that the battery alarm will beep and I can see on the TX after landing that the battery voltages has gone below 4.8 volts for a short interval. This is probably the result of too small a battery or a slight bind in a linkage or servo/surface. Ihave never had the RX brownout or lock up during these events. You can also run this test on the ground to give your system a check[/list][*]Ithink most of the new 2.4 systems include a failsafe function which causes the RX to set the surfaces to a user selected preset condition if there is a signal loss untill the signal link recovers. This probably helpful in benign flight condtions but is not going to save your model if you had a link drop just as you pitch up 3 feet above the ground for a 3D hover and the controls go to fail safe setting of nominal level flight trim and say idle throttle.[*]2.4 does not eliminate the need to have good wiring, switches, control horns, clevises, hinges, common sense and thumbs![/list]So I think much if the 2.4 "worry" is overstated. Install the systems properly, make sure your batteries are sized correctly, check them after each flight and range check your system often and you should be fine.

        PS:Ihave more faith in my 2.4 radio than Ido in my thumbs....
Old 07-29-2011, 10:27 AM
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DadsToysBG
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Default RE: I need your honest opinion.

I agree with the above. The only change is using a 6v system. Remember all 2.4 receivers now have a computer chip in them. Maintain your batteries and all the systems will work well. Most of the problems were consumer driven and the learning curve in the beginning.
I have been using 2.4 since day one in giant scale and jets without any problems. Dennis
Old 07-29-2011, 10:55 AM
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BuschBarber
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Default RE: I need your honest opinion.


ORIGINAL: frisco2022

I have been flying for many years and I still use 72mhz. I am now flying bigger more expensive planes which are gas and I want your opinion on switching to 2.4. My concern is that I have been using 72 without a problem until just recently I had a little problem with a glitch and almost lost the plane. Doing research on 2.4 I have been reading a lot on Brownouts and similar issues with low voltage levels. I have always used NiMH batteries without issues, maybe because I check them before each flight. It seems that 2.4 on paper is really great on paper but the reality of 2.4 is there are more problems than 72mhz, or so it seems. I have a 9303 with a Spektrum DM9 module which I have not used it yet until I have done some research. I know that everyone has there own thoughts on these two systems and I would like to hear them. Also if anyone has tips on power systems or anything else I would like to hear about it. I have always kept things simple and it has worked, I am just afraid putting in 2.4 and the receiver browning out on the first flight. I will appreciate all comments.
I have b
ee
n flying 72Mhz for 33 years. 2.4Ghz is a great replacement. I have not had a problem since I started using it 4 years ago.
Old 07-29-2011, 11:31 AM
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Ed
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Default RE: I need your honest opinion.

I have been flying Spektrum DSM2 in 6 giant scale aircraft for about 5 years now without a single glitch. Gas engines only. In fact it has eliminated glitches that I did have on 72 Mhz using Futaba. Never seen a brownout using it on 6 volts, 5 cells Nicd, or Nimh. Best system that I have ever owned in 54 years of flying R/C !

Ed
Old 07-29-2011, 11:56 AM
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ira d
 
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Default RE: I need your honest opinion.

I have been running Futaba 2.4 for about 3 years and using 4&5 cell packs nicad and nimh with no problems, I also have been using Airtronics 2.4
for almost a year with both 4&5 cell packs no problem. The brown out that you hear so much about is no longer an issue it was a problem that
JR Spektrum had on their early 2.4 systems but has been corrected.

I like 2.4 because you dont have to wait on channel being clear to fly and you dont have to worry about being shot down, Also the transmitter
uses less power to transmit on 2.4 than it does on 72mhz.
Old 07-29-2011, 02:10 PM
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Default RE: I need your honest opinion.

Like you I had been flying on 72 for several years and never really gave going 2.4 a real thought until I almost lost my gas model last year due to a very severe glitch. There and then I decided to join the 2.4 ranks, and using my trusty 8UAF Tx I simply installed a Futaba compatible 2.4 module and it's associated Rx powered by a 6 volt NiMh battery. So far I am extremely pleased with the performance, plus no more glitches. As the other posters have mentioned, the advantages of using 2.4 greatly outweigh using 72. Make the switch as I am certain that you will be very pleased with the results.

Karol
Old 07-29-2011, 03:06 PM
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frisco2022
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Default RE: I need your honest opinion.

I cannot thank you enough for your advice, I will make the switch for sure. I guess my next question is what type of battery should I use. Right now I an using a 6v NiMH battery. On other posts I have read that some receivers reboot when the voltage gets around 3v. I find that pretty hard when you are running a 6v battery I assume, unless you never check it. All the servos are analog not digital and I am not doing 3D, this is a warbird.
Old 07-29-2011, 03:14 PM
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Ed
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Default RE: I need your honest opinion.

That's fine, stay with 6 volts, and for extra security, use parallel packs of adequate capacity. Go to " Reds Battery Clinic " and scroll down to Parallel Packs.





Old 07-29-2011, 03:17 PM
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BuschBarber
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Default RE: I need your honest opinion.


[quote]ORIGINAL: frisco2022

I cannot thank you enough for your advice, I will make the switch for sure. I guess my next question is what type of battery should I use. Right now I an using a 6v NiMH battery. On other posts I have read that some receivers reboot when the voltage gets around 3v. I find that pretty hard when you are running a 6v battery I assume, unless you never check it. All the servos are analog not digital and I am not doing 3D, this is a warbird.
[/quote
Now that many are using Digital servos, which draw more current than Analog, there is more of a chance that the current draw, on the Rx battery, can cause a voltage drop large enough to Reboot the Rx.

I use 2cell LiPo or LiFe Rx batteries, with 6v Regulators, depending upon the servo choice.
Old 07-30-2011, 05:40 AM
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karolh
 
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Default RE: I need your honest opinion.


ORIGINAL: frisco2022

I cannot thank you enough for your advice, I will make the switch for sure. I guess my next question is what type of battery should I use. Right now I an using a 6v NiMH battery. On other posts I have read that some receivers reboot when the voltage gets around 3v. I find that pretty hard when you are running a 6v battery I assume, unless you never check it. All the servos are analog not digital and I am not doing 3D, this is a warbird.
Rich and others on this forum convinced me to change my Rx batteries from 4.8volt 700mA Nicads to a higher capacity when I upgraded my radio from 72 to 2.4. I initially switched to using a 6.0 volt 1650 mA NiMh, however I now intend to use A123 1100mA packs.

Karol
Old 07-30-2011, 07:17 AM
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rmh
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Default RE: I need your honest opinion.

If you can stand the weight - use 2300ma genuine A123-
and read up on em . these cells are totally UNLIKE anything you have used before .
1 they will hold a charge -on the shelf -for many months
2 they will supply all the power your setup calls for - whether or not you intended that to happen!!!!
2 you can NOT use any of the battery check devices you used for NIMH- they are worthless for these cells
5 buy a A123 charger with internal balancer .
6 learn to use it
7 get a meter which you can put in line from battery to rx- and use it faithfully when setting up your model- use an old NIMH in place of the A123 when doing the setups - these will show power problems easily- the A123 will just keep on adding power -which is what you want -after the model is setup.
Finally - these are the best cells you can buy - well worth the price if you setup the model to use them
properly
Old 07-30-2011, 07:42 AM
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karolh
 
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Default RE: I need your honest opinion.

Thanks for your welcomed pointers and yes I do agree, these cells are nothing like I have ever encountered before. Recognising this, I have been in discussion with Richard at Wrong Way RC who has been very helpful, and has given lots of valuable information regarding their care etc. I really can do without the additional weight of a 2300 mA pack, and as my setups consists mainly of analog servos and no 3D flying, the 1100 mA pack should suit my needs okay.

Karol
Old 07-30-2011, 09:49 AM
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flycatch
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Default RE: I need your honest opinion.

I'll start by saying 72mhz is not dead. Many and I'm one of them still fly on this frequency. The reason I stayed on this frequency is simple a matter of convience and economics. I use nothing but JR top of the line receivers and transmitters. RC manufactures switched over to the new frequency to decrease cost and increase sales. They accomplished both but failed to do the R&D. Now you the consumer suffer the consequencses. The same thing occured on 72mhz until they released PCM receivers. Standard FM receivers just won't work in a high RF noise environment.
If you operate with low end 72mhz equipment I would make the switch to 2.4 but if you have a 72mhz transmitter capable of SPCM transmission don't switch. Purchase compatible receivers to match the transmission signal and you won't experience the dreaded "glitch" problem. I flew glow powered helicopters for many years and never had a glitch that I was aware of.
Old 07-30-2011, 06:15 PM
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Default RE: I need your honest opinion.

Been flying 2.4 in turbine powered aircraft since 2.4 first came out. Not one problem.
Old 07-31-2011, 03:20 AM
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flyerdave
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Default RE: I need your honest opinion.

Diddo flycatch,
I have been flying my Futaba 9CAP with 149DP PCM recevers and have never had a glitch or problem whatsoever. I cannot force myself to drop this system and go 2.4 and guess what,since only three of us are left at the field who fly 72mhz,I never have to wait for a frequency pin. I guess I'll make the switch someday, but right now, I see no reason to change.
Old 07-31-2011, 06:48 AM
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DougV
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Default RE: I need your honest opinion.

Here's some good info about A123 packs: http://hangtimes.com/a123_batteries_for_giants_faq.html

Depending on the model, I use LiPos, A123's or LiFe packs.

By the way, I made the change to 2.4 when it first came out with Jets, Helis, planes and boats and never looked back.

Doug.
Old 07-31-2011, 08:38 AM
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rmh
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Default RE: I need your honest opinion.

Other than the economics of it - using 72 for flying is really one of the least safe links for flying
If you live in the boondocks - where there are no other uses of 72- then sure- use it.
Old 07-31-2011, 02:39 PM
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JCINTEXAS
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Default RE: I need your honest opinion.

The decision to go with A123 batteries is a good one. I used NiMh batteries for about 2 years, and they worked well......until I let a couple of battery packs sit unused in my shop for several months. NiMh batteries need to be regularly charged and cycled and not left sitting unused. A123 batteries don't have this shelf-life problem. A fully charged 2S A123 battery will put out about 7 volts and I was worried that I would need a voltage regulator. No problem. I and many others use 2S A123 receiver packs without a regulator, and they work just fine. I've been flying Futaba 2.4 FASST radios for almost 4 years, and I run all digital servos. In my opinion, 2.4 GHz radios are the best and most reliable radios we have ever had, and A123 batteries are the best receiver batteries (airborne packs) available.
Best Regards and Happy Flying
JC (FASSTFLIER) AMA3240

Old 08-01-2011, 03:01 PM
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frisco2022
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Default RE: I need your honest opinion.

Thank you all for the responses, I just purchased a spektrum 7010 receiver to go with the module I have. Hope it all works!!!!
Old 08-01-2011, 06:20 PM
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Default RE: I need your honest opinion.

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