Author Topic: preliminary measurements for Lora RFM95/ MoteinoMega.  (Read 2127 times)

hatchett

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preliminary measurements for Lora RFM95/ MoteinoMega.
« on: February 04, 2016, 04:57:15 PM »
I finally got some time to do some informal measurements in the lab for this system. After doing a little field testing i found the range a little underwhelming compared to our FSK radios at similar output powers and frequency. I used the lowest and slowest of the preset Modem settings and set the RF power to 23dbm. I used the Radiohead simple Client/server setup to ping pong packets. So today, in the lab i measured the output power directly and found that the maximum output power we could get was 17dbm at a 23dbm power setting this offset tracked with all power settings. I did a quick sensitivity check and found that the RSSI readings on the server were not correlated to actual input levels. there was a bit of leakage from the single RF shielded chamber the other chambers were being used today so i will perhaps come in and do some very careful measurements of the sensitivity this weekend. when doing range testing i found that the link was lost at less than -100 dbm RSSI setting which is, of course, not close to the calculated sensitivity level given the settings. Any ideas about the low output power readings?  one other thing, has anyone put together a schematic for these modules? i looked around and did not find one on the Hope Radio site. i roughed in the RF input network but decided to see if someone has a schematic already before i start measuring component values.

WhiteHare

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Re: preliminary measurements for Lora RFM95/ MoteinoMega.
« Reply #1 on: February 04, 2016, 05:25:57 PM »
Thanks for your post!

Were you using a <1% duty cycle?  See:  https://lowpowerlab.com/forum/index.php/topic,1495.msg10443.html#msg10443

I don't know that it would matter, but aside from power level, did you change any of the other radio parameters?  If you're otherwise out of ideas, maybe it would be worth trying some of the other predefined configurations to see if there are any measurable differences?
« Last Edit: February 04, 2016, 05:28:45 PM by WhiteHare »