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Old Nov 12, 2012, 10:30 AM
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Spring type battery holders are not a good solution with rechargeable batteries. Corrosion can easily set in on the spring/battery terminal interface (dissimilar metals). At least with disposable batteries, the spring contacts are scraped clean occasionally when the batteries are replaced and, obviously, the new batteries have clean contact ends. Not so with rechargeable batteries that live their entire lives in a battery holder because they never have to be removed until they ultimately fail. Solder your rechargeable cells directly...
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Old Nov 12, 2012, 11:25 AM
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2.4 rx's have lots of blind spots due to antenna orientation, more or less depending on your rx set up. Ive found these blind spots several times and the same one a couple of times. now i run dual sats in everything and dont have the problem anymore.
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Old Nov 12, 2012, 12:06 PM
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Interesting - I did some more research found your original thread on Eneloop RX packs. I guess you have have changed your tune on the validity of your original testing setup after all...
Not really
Theyare still 1 C cells and unless you are using very low power consumption servos - they can easily fade on you
My original tests on high drain servos were a typical load for a large IMAC model The A123 (the real thing) are still ,easily the best choice.
for higher loads
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Old Nov 12, 2012, 12:22 PM
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Interesting topic here!! I've had exactly 3 loss of contact issues with my Spektrum receivers in last 3 yrs,, one resulted in loss of a plane,,, all 3 in incidents were with DSM2 receivers operating near a large microwave repeating tower. So far have not had ANY issues with DSMX10,, I suspect my 3 incidents were related to interference from microwave tower and lack of robustness of DSM2 :-(. Just my theory
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Old Nov 12, 2012, 12:40 PM
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Originally Posted by Airman74 View Post
all 3 in incidents were with DSM2 receivers operating near a large microwave repeating tower.
The problem was still probably a brown-out. In many years of running this stuff, I've never seen a case where I was SURE that interference was the cause, but I've seen hundreds of cases of brown-out problems.
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Old Nov 12, 2012, 06:34 PM
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The problem was still probably a brown-out. In many years of running this stuff, I've never seen a case where I was SURE that interference was the cause, but I've seen hundreds of cases of brown-out problems.
Hmmm.... Let me get this straight. DSM2 (which has brown-out detection) was being used in an environment with a significant source of 2.4Ghz interference, but somehow it is still likely that brown-outs were responsible for the incidents.
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Old Nov 12, 2012, 07:05 PM
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Hmmm.... Let me get this straight. DSM2 (which has brown-out detection) was being used in an environment with a significant source of 2.4Ghz interference, but somehow it is still likely that brown-outs were responsible for the incidents.
Jasmine will make a claim like that, but he very often does not back it up with any fact at all. Mostly because he cannot and he knows it. Getting to be quite common, really...
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Old Nov 12, 2012, 07:27 PM
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and when it comes to common - I see an expert here .
As all have noted - it helps to have some factual info when attempting to make a rebuttal
I see nothing here which makes J2601's comment implausable
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Old Nov 12, 2012, 07:55 PM
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Hmmm.... Let me get this straight. DSM2 (which has brown-out detection) was being used in an environment with a significant source of 2.4Ghz interference, but somehow it is still likely that brown-outs were responsible for the incidents.
YES. I'm saying flying near a microwave tower doesn't change the chance of having a brown out and it's worth checking because it's the most common cause of failures with 2.4Ghz systems. That is, don't assume you don't have a brown out problem simply because you think you've identified a likely cause, when you have no hard evidence for that cause other than coincidence.
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Old Nov 12, 2012, 08:01 PM
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YES. I'm saying flying near a microwave tower doesn't change the chance of having a brown out
Even though it's been demonstrated that you won't/can't, it would be wonderful if you backed that up with fact, please...for once... Preferably via directly "footnoting" Spektrum design.
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Old Nov 12, 2012, 09:58 PM
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Here Stanley -you take this hammer -----and when I nod my head --
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Old Nov 12, 2012, 10:12 PM
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YES. I'm saying flying near a microwave tower doesn't change the chance of having a brown out
But it does increase the change of a lockout - especially with DSM2...

Quote:
Originally Posted by jasmine2501 View Post
and it's worth checking because it's the most common cause of failures with 2.4Ghz systems.
It is easy enough to check considering that DSM2 has brownout detection.

Quote:
Originally Posted by jasmine2501 View Post
That is, don't assume you don't have a brown out problem simply because you think you've identified a likely cause, when you have no hard evidence for that cause other than coincidence.
There is no reason to assume that it was a brownout - especially when you have no evidence of that. There were factors involved that make it at least reasonable to consider that a lockout was a likely cause.
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Old Nov 13, 2012, 08:14 AM
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Brownout has now become the standard excuse for any system failure in 2.4GHz.

That is strange, as it is just a myth that 2.4GHz systems in general are more prone to brownouts than MHZ systems.
A myth, put forward in order to put those few systems in a better light that really have a problem with low voltages.
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Old Nov 13, 2012, 08:31 AM
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Brownout has now become the standard excuse for any system failure in 2.4GHz.

That is strange, as it is just a myth that 2.4GHz systems in general are more prone to brownouts than MHZ systems.
A myth, put forward in order to put those few systems in a better light that really have a problem with low voltages.
I have to call you on that -
Past experiences with 72/50/53 mhz show voltage drop is far less of an issue.
None of those will require resetting even if voltages drop below servo operating voltage levels . Servos will slow and operation can become unflyable -but the rx do not stop trying to process.
I used to fly stuff weighing over 40 pounds and I did a lot of checking on battery requirements to keep the huge control surfaces operating.
When 2.4 hit the scene -the power requirements was one of my first questions .
The myth
I know of no myth but factually ALL the 2.4 radios will stop processing info at voltage levels where servos become inoperable . You may see a few tenths volt differences between brands but all of the rx stop and must reset at some point around 3 volts.
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Old Nov 13, 2012, 08:54 AM
TRB
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I posted this in another thread and just thought it would be interesting to put here. I was having glitch problems on a 72MHz radio due to a weak BEC so I tried scoping the radio voltage rails while moving the control surfaces. The BEC was terrible, but I also found that 2 standard Futaba servos will still suck 4AA Nimh batteries down nearly 1/2 a volt even with no servo binding.

I personally do a lot of robotics and know how big of a deal a good power supply can be for digital circuits, and what kind of funky problems can manifest. I personally did not know how much current RC servos can draw under load. All those years I flew big planes on 4AA Nicad packs, and never thought about it. I'm not sure I consider even a dedicated 4AA pack good enough anymore. I think if I flew big planes I would run a 2xA123 or 5x1/2A cells or something maybe with a good linear 5V regulator.
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