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CC2500 output power settings
- vlad_vy
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07 Dec 2017 04:55 - 07 Dec 2017 04:56 #66371
by vlad_vy
CC2500 output power settings was created by vlad_vy
Why CC2500 output power has these settings?
0xC6, // -12dbm
0x97, // -10dbm
0x6E, // -8dbm
0x7F, // -6dbm
0xA9, // -4dbm
0xBB, // -2dbm
0xFE, // 0dbm
0xFF // 1.5dbm
Why not to use settings similar to CYRF6936?
0x60, // -30dbm
0xA0, // -25dbm
0x46, // -20dbm
0x57, // -15dbm
0x97, // -10dbm
0xE7, // -5dbm
0xFE, // 0dbm
0xFF // 1.5dbm
0xC6, // -12dbm
0x97, // -10dbm
0x6E, // -8dbm
0x7F, // -6dbm
0xA9, // -4dbm
0xBB, // -2dbm
0xFE, // 0dbm
0xFF // 1.5dbm
Why not to use settings similar to CYRF6936?
0x60, // -30dbm
0xA0, // -25dbm
0x46, // -20dbm
0x57, // -15dbm
0x97, // -10dbm
0xE7, // -5dbm
0xFE, // 0dbm
0xFF // 1.5dbm
Last edit: 07 Dec 2017 04:56 by vlad_vy.
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- Fernandez
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07 Dec 2017 07:48 #66372
by Fernandez
Replied by Fernandez on topic CC2500 output power settings
No idea myself about the registers, but i think there has been discussion about it in the past?
From my side, what I can confirm and reported in the past is that for my module Range Check for Frsky (or lowest power setting using Deviation Frsky), has much much more emission power compared to the original Frsky Range Check with original equipment. With my homebrew field strength meter, it has see still significant emitted power ! while the original frsky range check I almost measure no field strength with my meter. (however I can't give any absolute nrs) So range check function in deviation Risky is useless.
Maybe Frsky disable the complete PA in range check ? It may also be that there are diffences in the PA/LNA stages between modules? Myself I have the unshielded cc2500 module,"skyartec", it is not anymore listed at Banggood.
From my side, what I can confirm and reported in the past is that for my module Range Check for Frsky (or lowest power setting using Deviation Frsky), has much much more emission power compared to the original Frsky Range Check with original equipment. With my homebrew field strength meter, it has see still significant emitted power ! while the original frsky range check I almost measure no field strength with my meter. (however I can't give any absolute nrs) So range check function in deviation Risky is useless.
Maybe Frsky disable the complete PA in range check ? It may also be that there are diffences in the PA/LNA stages between modules? Myself I have the unshielded cc2500 module,"skyartec", it is not anymore listed at Banggood.
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- vlad_vy
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07 Dec 2017 08:03 #66373
by vlad_vy
Replied by vlad_vy on topic CC2500 output power settings
Frsky has -30dBm for range check (30 times for distance). Futaba has -20dBm for range check (10 times for distance). Spektrum has -30dBm for range check (30 times for distance).
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07 Dec 2017 12:38 - 07 Dec 2017 12:41 #66375
by Fernandez
Replied by Fernandez on topic CC2500 output power settings
Yes that could be however I can just see from field strength meter comparing my original Frsky DHT-U to Deviation Frsky D protocol, that in rangecheck, deviation has way more emitted power than original Frsky DHT-U. So I believe there is some issue at least in power.
Further between protocols there seem also big differences in field strength, from what can remember Frsky and Flysky were the strongest on the meter. So 100mW for one protocol not give same signal on the meter than for the other protocol.
Further between protocols there seem also big differences in field strength, from what can remember Frsky and Flysky were the strongest on the meter. So 100mW for one protocol not give same signal on the meter than for the other protocol.
Last edit: 07 Dec 2017 12:41 by Fernandez.
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07 Dec 2017 14:14 - 07 Dec 2017 14:28 #66380
by vlad_vy
Replied by vlad_vy on topic CC2500 output power settings
Tested new output power values (without antenna gain):
Protocol S-FHSS (CC2500)
Deviation__current____changed
150mW = 57.17mW = 57.17mW
100mW = 51.79mW = 51.79mW
30mW = 32.68mW = 14.22mW
10mW = 20.87mW = 4.25mW
3mW = 10.66mW = 1.28mW
1mW = 6.96mW = 0.38mW
300uW = 4.25mW = 0.16mW
100uW = 3.05mW = 0.05mW
Protocol S-FHSS (CC2500)
Deviation__current____changed
150mW = 57.17mW = 57.17mW
100mW = 51.79mW = 51.79mW
30mW = 32.68mW = 14.22mW
10mW = 20.87mW = 4.25mW
3mW = 10.66mW = 1.28mW
1mW = 6.96mW = 0.38mW
300uW = 4.25mW = 0.16mW
100uW = 3.05mW = 0.05mW
Last edit: 07 Dec 2017 14:28 by vlad_vy.
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07 Dec 2017 15:03 #66382
by Fernandez
Replied by Fernandez on topic CC2500 output power settings
hmm not so clear how do you get to these output levels? yyou measured them or did you calculate and used fixed gain for PA?
The max power setting 57.17mW is also much lower than the 100mW which is tyical for RC systems?
The max power setting 57.17mW is also much lower than the 100mW which is tyical for RC systems?
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07 Dec 2017 15:15 #66383
by vlad_vy
Replied by vlad_vy on topic CC2500 output power settings
Measured by ImmersionRC RF Power Meter on antenna connector.
It's normal output power for CC2500. Futaba T14SG has 60-65mW output power at antenna connector. Moreover, it doesn't include antenna gain 2.1 - 3.0dBi. 100mW output power = power + antenna gain. 60mW = 18dBm, 18dBm + 2.1dBi = 102mW.
It's normal output power for CC2500. Futaba T14SG has 60-65mW output power at antenna connector. Moreover, it doesn't include antenna gain 2.1 - 3.0dBi. 100mW output power = power + antenna gain. 60mW = 18dBm, 18dBm + 2.1dBi = 102mW.
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07 Dec 2017 15:44 #66385
by Fernandez
Replied by Fernandez on topic CC2500 output power settings
yes but antenna gain is pretty useless for the average flyer who do not take care of pinting antenna. So practically we can fly as far as the lowest radiated direction area of the antenna.....
Anyway i think your change make sense, I can check it for Frsky D-series esecially range check as I beleive is important to have it low power equally to real frsky, whic is currently not.
it could be debated to otherwise to make just a scale without mentioning the RF ower in mW. but rangecheck, low, medium, normal, highest. or whatever just nr 1-10
Anyway i think your change make sense, I can check it for Frsky D-series esecially range check as I beleive is important to have it low power equally to real frsky, whic is currently not.
it could be debated to otherwise to make just a scale without mentioning the RF ower in mW. but rangecheck, low, medium, normal, highest. or whatever just nr 1-10
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- vlad_vy
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08 Dec 2017 13:14 #66412
by vlad_vy
Replied by vlad_vy on topic CC2500 output power settings
New output power values can be used with Nightly Builds.
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