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Dec 13, 2012, 02:52 AM
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Cesco's Avatar
Quote:
Originally Posted by kha
drop the frame rate even more.
I did get your code to have a look.

I do not think about dropping framerate or channels, but about not transfering data that has not changed. Most of the channels wont change at all, so we do not need to transfer them every 20ms. Obviously the the TX needs to select the channels and send an additional mapping indicator to the RX.

A 20ms 4 byte message could consist of:
8 bit chan X
8 bit chan Y
4 bit X mapping
4 bit Y mapping
8 bit checksum

where x-mapping says in which of the 16 channels the X data has to go in the receiver.


btw could you store a windows exe for rfm22calc?
Last edited by Cesco; Dec 13, 2012 at 03:16 AM.
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Dec 13, 2012, 03:54 AM
Registered User
Tried that too, but if you lose a couple of frames it won't work, so every channel will need updates every now and then increasing bandwidth again.
Also added problem, if you try to move everything at once there will be a huge delay.
Preamble and header still make up a lot of data, so won't be able to really drop speed.
Increased sensitivity is in the noise floor, so no effect will be seen. And if it isn't in the noise floor it will be only 1-2 dB increase which is very marginal for the added inconveniences..
Dec 13, 2012, 04:01 AM
Registered User
Cesco's Avatar
Quote:
Originally Posted by Rownald
Increased sensitivity is in the noise floor
Based on my HAM experience i totally disagree on that.

Have a look at WSJT or similar developments, which work WAY below the noise floor. In other words the "noise floor" depends on BW (bandwidth).
Less speed = less BW = less noise.
Dec 13, 2012, 04:08 AM
Registered User
Based on practical experience with OpenLRS I disagree with you, while it may still be possible to receive a signal that is in the noise floor the RFM22B seems to do this not so well compared to the software that you named. During range testing I lost signal when the signal strength got to around noise floor.
Dec 13, 2012, 02:56 PM
Registered User
bingo17's Avatar
Quote:
Originally Posted by Rownald
Based on practical experience with OpenLRS I disagree with you, while it may still be possible to receive a signal that is in the noise floor the RFM22B seems to do this not so well compared to the software that you named. During range testing I lost signal when the signal strength got to around noise floor.
Also keep in mind noise floor changes with area, day of time, etc..
What dbm level is noise floor in your area or what is your baseline rather?
Dec 13, 2012, 03:04 PM
Registered User
My noisefloor is around -105 to -100 dBm
Dec 13, 2012, 03:27 PM
Registered User
bingo17's Avatar
Quote:
Originally Posted by Rownald
My noisefloor is around -105 to -100 dBm
Wow that is low, 90 - 95 here and sometimes as high as 85dbm

regards
Dec 14, 2012, 01:54 AM
Registered User
Cesco's Avatar
in anticipation of my orange module i did order this 0.5W module, not pin compatible to original and VCC is higher.
http://www.goodluckbuy.com/2500m-hig...le-500mw-.html

Then i did try to get a price from hoperf for the 1W module. Hoperf does not seem to be a retailer, this might get complicated, and 10 minimum order.
http://www.hoperf.com/rf/fsk/RFM23BP.htm
Dec 14, 2012, 03:03 AM
throw new IOPilotException();
IceWind's Avatar
Try to reach out to this guys: http://rf-store.com/
They don't have it currently listed but you never know.

That's where I got my RFM22B, they sell any quantity and the prices are reasonable.
Only thing that might be expensive is the shipping.
Dec 14, 2012, 03:43 AM
fast
fmkit's Avatar
Quote:
Originally Posted by Cesco
in anticipation of my orange module i did order this 0.5W module, not pin compatible to original and VCC is higher.
http://www.goodluckbuy.com/2500m-hig...le-500mw-.html

Then i did try to get a price from hoperf for the 1W module. Hoperf does not seem to be a retailer, this might get complicated, and 10 minimum order.
http://www.hoperf.com/rf/fsk/RFM23BP.htm
received GLB 0.5w module without any documentation,
got it working but never used because of high heat even in low power mode

RFM23BP 1w module works very well, I have some 20pc on hand, if you want to experiment get one $25 shipped, add $3 for PCB
Last edited by fmkit; Dec 14, 2012 at 04:38 AM.
Dec 14, 2012, 04:54 AM
Registered User
RoboSerg's Avatar
So anyone did a range check with stock antennas ?
Dec 14, 2012, 09:16 AM
Registered User
Quote:
Originally Posted by RoboSerg
So anyone did a range check with stock antennas ?
I have not received mine yet. I refuse to pay 30 bucks for shipping so its on the slow 3.99 shipping boat.
Dec 14, 2012, 08:12 PM
hjukhjuk
gooby's Avatar
Ugh, once again Hobbyking is pathetic when it comes to keeping products in stock.
Dec 15, 2012, 12:45 AM
Suspended Account
This UHF system does not look to be plug and play at all
Dec 15, 2012, 01:07 AM
kha
kha
openLRSng haxor
Quote:
Originally Posted by David22
This UHF system does not look to be plug and play at all
Yes it is not plug and play but there is a few firmwares that make it very close. All you need is a 3v3 ftdi or any other usb to ttl serial adapter to prigram it.

I'm workking on one and I hope I have the binding stuff done on Tuesday after that is in it will behave pretty much like any of the shelf system.


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