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Old Dec 17, 2012, 02:32 AM
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Originally Posted by pmackenzie View Post
You might get away with it because the power output from the receiver is lower, and it does not transmit as much information so the duty cycle is lower.
Duty cycle is lower indeed, but power is the same (give or take the loss of the extra antenna switch).
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Old Dec 17, 2012, 03:24 AM
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Quote:
Originally Posted by pmackenzie View Post
You might get away with it because the power output from the receiver is lower, and it does not transmit as much information so the duty cycle is lower. All of which means less heat that has to be dissipated.

But not a good idea to operate it without a load to take away the RF energy.
Actually, hardware they are the same.
Both antennas being equal 2dB, you see close RSSI values for both direct and return signal.
Pulse peak power matters for range, duty cycle affects only data quantity you can transmit. And there are more bytes in RC stream than telemetry stream.
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Old Dec 17, 2012, 08:10 AM
Ride, Surf, Fly, Sleep
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Guys,

Has anyone come across a successful hack to get the DHT-U to output any received CPPM?

Just spend an hour searching the web without success - wondering now if I should just pull out the mulitmeter and scope and start probing....
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Old Dec 17, 2012, 08:38 AM
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DHT-U is a transmitter / display, it doesn't receive anything than telemetry data.
CPPM is at the other side of the link.
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Old Dec 17, 2012, 09:56 AM
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Originally Posted by renatoa View Post
DHT-U is a transmitter / display, it doesn't receive anything than telemetry data.
CPPM is at the other side of the link.
You are of course right mate - long day, I'm tired

What I meant to say is I have a small PIC module I'm using to access and decode CPPM at the 4ch RX and I'm also now writing some code ofor it to act as a hub to send back data through the RX data port.

Is there any hack you know of at the DHT-U end to provide access to the transmitted user-encoded frames?
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Old Dec 17, 2012, 07:16 PM
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I got my Frsky diy unit today and have already mounted it into my 7CAP. with the Rx in the basement workshop I was able to go up stairs and even while holding the Tx antenna I didn't get any beeps. Putting it into Range check mode I got single beeps right away. Must be alot of interference in the basement. My 3 way switch is a little flakey. In the 1 way position it will bump out to the middle very easily.
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Old Dec 17, 2012, 11:10 PM
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United States, CA, Novato
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Quote:
Originally Posted by davecrash View Post
I got my Frsky diy unit today and have already mounted it into my 7CAP. with the Rx in the basement workshop I was able to go up stairs and even while holding the Tx antenna I didn't get any beeps. Putting it into Range check mode I got single beeps right away. Must be alot of interference in the basement. My 3 way switch is a little flakey. In the 1 way position it will bump out to the middle very easily.
The switch has no effect once the module is powered up. So you should be fine even if it changes position when flying. You can ground test this to confirm.

-Wayne
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Old Dec 18, 2012, 04:00 AM
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Originally Posted by quincross View Post
Is there any hack you know of at the DHT-U end to provide access to the transmitted user-encoded frames?
Unfortunately not, the DHT-U keeps the serial data for itself, it doesn't forward it further. If you need access to the data you'll need one of the other modules.
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Old Dec 18, 2012, 05:51 AM
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Originally Posted by Rotozuk View Post
The switch has no effect once the module is powered up. So you should be fine even if it changes position when flying. You can ground test this to confirm.

-Wayne
That's good to know. I can get other switches so not a big deal either. I was thinking about a 3 position slide switch. Less likely to accidently move it.
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Old Dec 18, 2012, 06:04 AM
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I mounted the LED/Bind switch board, and the option switch, on top of my Futaba 7 channel. A little hot glue holds in the LED/bind switch board good. I was able to use the old 72mhz antenna base to work with the 2.4ghz antenna too.

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Old Dec 18, 2012, 10:14 AM
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If you only use d series rxs than you can just take the switch off. I chucked mine in my tool box if I ever need to update the firmware
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Old Dec 18, 2012, 10:29 AM
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Originally Posted by jrod155 View Post
If you only use d series rxs than you can just take the switch off. I chucked mine in my tool box if I ever need to update the firmware
That's interesting. I usually tell customers to wrap the switch in electrical tape and secure it somewhere inside. If they ever have a need to do firmware the switch is still there. Didn't know you could remove the switch and have it function correctly.
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Old Dec 18, 2012, 10:34 AM
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Originally Posted by Kilrah View Post
Unfortunately not, the DHT-U keeps the serial data for itself, it doesn't forward it further. If you need access to the data you'll need one of the other modules.
Thanks - Yeah, I kind of suspected that - I'm going to open the case and do some probing around, with a bit of luck I'll find separate TX/RX and processing/display boards. If so I'll try and lift the datastream from that, if not....DFT or DHT here I come....
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Old Dec 18, 2012, 11:07 AM
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The serial line is there, but used different in many ways:
- no more RS232, no max circuit for logic translation, it is now TTL serial, and available as an USB plug
- the code use it for firmware updates
- it outputs some cryptic non documented info when in normal service, if performing a data acquisition the module GUID can be found in the stream, amongst other unrecognizable binary data.
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Old Dec 18, 2012, 12:17 PM
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Ireland, Donegal
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Anyone ideas why my D8R-II is beeping on A1 (alarm on) and showing about 4.1v on switch on, the voltage slowly rises until the alarms go off and may settle about 5.1 This can take about 20secs.
It is connected to a 4 cell pack so nothing to do with a ESC or BEC. Servo pin voltage is pack voltage from switch on so again nothing to do with supply.
I think in the past I may have accidentally with a screwdriver shorted some combination of the RX TX Grn A1 A2 pins on the side.
I have opened the case but don't see any component burnt, seems like to me like a cap charging up.
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