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Nov 02, 2012, 05:38 PM
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richard hanson's Avatar
Security through obscurity--
No?
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Nov 02, 2012, 05:40 PM
Registered User
Quote:
Originally Posted by richard hanson
Security through obscurity--
No?
What are you referring to? "Security through obscurity" refers to relying on an algorithm remaining unknown in order to maintain security.
Nov 02, 2012, 05:49 PM
AndyKunz's Avatar
Quote:
Originally Posted by richard hanson
You do know that DSMX has various hopping arrangements which are peculiar to a specific tx.

each DSMX tx has a GUID which is it's own and utilizes 23 channels.
I don't know how many different GUID sequences (tx) are used
The GUID is 32 bits. That's 4 billion different possibilities.

Andy
Nov 02, 2012, 05:51 PM
AndyKunz's Avatar
Quote:
Originally Posted by jsipprell
I think they mean "adaptive" in the same way Hitec means it; analyze the environment at bind time and avoid congested areas of the band but once everything is up and running the channels in use don't change. (Hitec actually requires you to activate a special "mode" for this).
Not at all. DSM2 would pick 2 clear frequencies X MHz apart and use them. DSMX uses 23 frequencies spread out across all 80 sort-of evenly.

Andy
Nov 02, 2012, 05:53 PM
Registered User
Quote:
Originally Posted by AndyKunz
The GUID is 32 bits. That's 4 billion different possibilities.

Andy
Bit of a stretch to call those GUIDS (as per RFC 4122).
Nov 02, 2012, 05:55 PM
Registered User
Quote:
Originally Posted by AndyKunz
Not at all. DSM2 would pick 2 clear frequencies X MHz apart and use them. DSMX uses 23 frequencies spread out across all 80 sort-of evenly.

Andy
Hmm, I must have been confusing Hitec's scheme with Spektrum's.
Nov 02, 2012, 06:07 PM
AndyKunz's Avatar
My code-to-the-RFC days are hopefully over for good!

Andy
Nov 02, 2012, 06:41 PM
Registered User
richard hanson's Avatar
Quote:
Originally Posted by jsipprell
What are you referring to? "Security through obscurity" refers to relying on an algorithm remaining unknown in order to maintain security.
I took editorial liberty with the meaning
But - the random distribution of the Tx - does help the cause.
None of the users ever knows which guid they have -
Nov 02, 2012, 07:02 PM
Suspended Account
Quote:
Originally Posted by jsipprell
No, DSMX hops constantly. You can actually prove this by forcing a Spektrum transmitter into DSMX mode (after binding a receiver in DSM2 mode) and noting how you'll have brief moments of "jittery" control whenever the transmitter happens to hop on to one of the two DSM2 frequencies.
How does one "force" a Spektrum TX into DSMX mode in that situation?
Nov 02, 2012, 07:18 PM
Registered User
if the radio and RX support DSMX it will bind in DSMX mode
also with in DSMX mode you can pick 1024/22ms or 1024/11ms modes
my helis are all set to 11ms since they are all digital servos
Nov 02, 2012, 07:29 PM
Suspended Account
Quote:
Originally Posted by Elios000
if the radio and RX support DSMX it will bind in DSMX mode
also with in DSMX mode you can pick 1024/22ms or 1024/11ms modes
my helis are all set to 11ms since they are all digital servos
Changing servo speed doesn't answer the question of binding a TX/RX in DSM2 mode and then "forcing" the TX into DSMX mode to observe the described "jittery control". I'd actually like to see that, myself...
Nov 02, 2012, 07:32 PM
AndyKunz's Avatar
Quote:
Originally Posted by jsipprell
No, DSMX hops constantly. You can actually prove this by forcing a Spektrum transmitter into DSMX mode (after binding a receiver in DSM2 mode) and noting how you'll have brief moments of "jittery" control whenever the transmitter happens to hop on to one of the two DSM2 frequencies.
You mean like this?

https://www.rcgroups.com/forums/show...postcount=1368

I'm glad to see somebody actually read my post and tried it!

Andy
Nov 02, 2012, 07:34 PM
Suspended Account
Quote:
Originally Posted by AndyKunz
You mean like this?

https://www.rcgroups.com/forums/show...postcount=1368

I'm glad to see somebody actually read my post and tried it!

Andy
Wow, you *can* answer questions without being vague and circuitous!

And, thanks for "listening".
Nov 02, 2012, 07:37 PM
Registered User
richard hanson's Avatar
Andy - you have rx in place of tx on one sentence
Nov 02, 2012, 08:20 PM
AndyKunz's Avatar
Where? It's late Friday night, I'm on vacation, and I can't see it.

Andy


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