315mhz/433mhz transmitter
 

On 7/23/2012 12:30 PM, Jeff Liebermann wrote:
On Mon, 23 Jul 2012 11:54:01 -0500, John S
wrote:

On 7/23/2012 11:21 AM, Jeff Liebermann wrote:
On Mon, 23 Jul 2012 08:56:41 -0500, John S
wrote:

On 7/23/2012 1:28 AM, Jeff Liebermann wrote:
On Sun, 22 Jul 2012 23:21:12 -0700, Jeff Liebermann
wrote:

FCC 15.209
http://louise.hallikainen.org/FCC/FccRules/2012/15/209/
200 uv/meter maximum, measured at 3 meters. That works out to about
-46dBm ERP or about 12 milliwatts into a unity gain antenna.

Sorry, brain damage.
The -46dBm should be 10.8dBm ERP

Hmmm... my calculator says P = 12 nanowatts.

Your calculator is correct. My -46dBm is wrong. It was late, I was
multitasking, the phone range, I was tired, etc. Sorry for the
muddle.
+10.8dBm converts to 12 mw.

12 nw is -49 dBm. Why are you still using 12 mw?

The 12mw is correct. The -46dBm was my mistake. It should
have been about +10.8dBm.

http://www.rapidtables.com/convert/power/dBm_to_mW.htm

Then... I find a 433MHz radio that delivers +20dBm (100mw).
http://www.sparkfun.com/products/10153
By my reading of 15.209, that's overpowered unless operating with a
miserable -9dB gain antenna.

The antenna would have to have -69 dB gain for 100 mw to radiate 12
NANOwatts.

Nope. Use 12 milliwatts or 10.8dBm please. Loose the -46/49dBm.


From the document you posted, P*G/(4*Pi*D^2) = E^2/(120*Pi)

Let G = 1, D = 3, E = 200uV then

P*1/(4*3.14*3*3) = (200e-6)^2/377 and

P/113 = 40e-9/377 so that

P = 113 * 106e-12 giving

P = 12e-9

This looks like NANOwatts to me.

315mhz/433mhz transmitter
 

On 7/23/2012 12:30 PM, Jeff Liebermann wrote:
On Mon, 23 Jul 2012 11:54:01 -0500, John S
wrote:

On 7/23/2012 11:21 AM, Jeff Liebermann wrote:
On Mon, 23 Jul 2012 08:56:41 -0500, John S
wrote:

On 7/23/2012 1:28 AM, Jeff Liebermann wrote:
On Sun, 22 Jul 2012 23:21:12 -0700, Jeff Liebermann
wrote:

FCC 15.209
http://louise.hallikainen.org/FCC/FccRules/2012/15/209/
200 uv/meter maximum, measured at 3 meters. That works out to about
-46dBm ERP or about 12 milliwatts into a unity gain antenna.

Sorry, brain damage.
The -46dBm should be 10.8dBm ERP

Hmmm... my calculator says P = 12 nanowatts.

Your calculator is correct. My -46dBm is wrong. It was late, I was
multitasking, the phone range, I was tired, etc. Sorry for the
muddle.
+10.8dBm converts to 12 mw.

12 nw is -49 dBm. Why are you still using 12 mw?

The 12mw is correct.

Please show your work.

315mhz/433mhz transmitter
 

On 7/23/2012 12:30 PM, Jeff Liebermann wrote:
On Mon, 23 Jul 2012 11:54:01 -0500, John S
wrote:

On 7/23/2012 11:21 AM, Jeff Liebermann wrote:
On Mon, 23 Jul 2012 08:56:41 -0500, John S
wrote:

On 7/23/2012 1:28 AM, Jeff Liebermann wrote:
On Sun, 22 Jul 2012 23:21:12 -0700, Jeff Liebermann
wrote:

FCC 15.209
http://louise.hallikainen.org/FCC/FccRules/2012/15/209/
200 uv/meter maximum, measured at 3 meters. That works out to about
-46dBm ERP or about 12 milliwatts into a unity gain antenna.

Sorry, brain damage.
The -46dBm should be 10.8dBm ERP

Hmmm... my calculator says P = 12 nanowatts.

Your calculator is correct. My -46dBm is wrong. It was late, I was
multitasking, the phone range, I was tired, etc. Sorry for the
muddle.
+10.8dBm converts to 12 mw.

12 nw is -49 dBm. Why are you still using 12 mw?

The 12mw is correct. The -46dBm was my mistake. It should
have been about +10.8dBm.

http://www.rapidtables.com/convert/power/dBm_to_mW.htm

Then... I find a 433MHz radio that delivers +20dBm (100mw).
http://www.sparkfun.com/products/10153
By my reading of 15.209, that's overpowered unless operating with a
miserable -9dB gain antenna.

The antenna would have to have -69 dB gain for 100 mw to radiate 12
NANOwatts.

Nope. Use 12 milliwatts or 10.8dBm please. Loose the -46/49dBm.


Oh, I see.

You used 100 MILLIvolts (not MICROvolts) in your calculation! That's how
you wound up with MILLIwatts rather than (NANOwatts).

315mhz/433mhz transmitter
 

On 7/23/2012 12:30 PM, Jeff Liebermann wrote:
On Mon, 23 Jul 2012 11:54:01 -0500, John S
wrote:

On 7/23/2012 11:21 AM, Jeff Liebermann wrote:
On Mon, 23 Jul 2012 08:56:41 -0500, John S
wrote:

On 7/23/2012 1:28 AM, Jeff Liebermann wrote:
On Sun, 22 Jul 2012 23:21:12 -0700, Jeff Liebermann
wrote:

FCC 15.209
http://louise.hallikainen.org/FCC/FccRules/2012/15/209/
200 uv/meter maximum, measured at 3 meters. That works out to about
-46dBm ERP or about 12 milliwatts into a unity gain antenna.

Sorry, brain damage.
The -46dBm should be 10.8dBm ERP

Hmmm... my calculator says P = 12 nanowatts.

Your calculator is correct. My -46dBm is wrong. It was late, I was
multitasking, the phone range, I was tired, etc. Sorry for the
muddle.
+10.8dBm converts to 12 mw.

12 nw is -49 dBm. Why are you still using 12 mw?

The 12mw is correct. The -46dBm was my mistake. It should
have been about +10.8dBm.

http://www.rapidtables.com/convert/power/dBm_to_mW.htm

Then... I find a 433MHz radio that delivers +20dBm (100mw).
http://www.sparkfun.com/products/10153
By my reading of 15.209, that's overpowered unless operating with a
miserable -9dB gain antenna.

The antenna would have to have -69 dB gain for 100 mw to radiate 12
NANOwatts.

Nope. Use 12 milliwatts or 10.8dBm please. Loose the -46/49dBm.


Oh, I see.

You used 200 MILLIvolts (not MICROvolts) in your calculation! That's how
you wound up with MILLIwatts rather than (NANOwatts).

315mhz/433mhz transmitter
 

On Mon, 23 Jul 2012 12:41:32 -0500, John S
wrote:

From the document you posted, P*G/(4*Pi*D^2) = E^2/(120*Pi)
Let G = 1, D = 3, E = 200uV then
P*1/(4*3.14*3*3) = (200e-6)^2/377 and
P/113 = 40e-9/377 so that
P = 113 * 106e-12 giving
P = 12e-9
This looks like NANOwatts to me.

Well, that looks right. I'll do the short version:

From Pg 29.
http://transition.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet63/oet63rev.pdf

Assuming a 0dBi gain antenna:
Power = 0.3 FS^2
where
FS = field strength in Volts/meter
P = Watts
Plugging in:
Power = 0.3 * (200 uV/m)^2 = 0.3 * (200*10^-6 V/m)^2
Power = 0.3 * 4*10^-8 = 12*10-9 = 12 nano watts.
Argh... You're right.

However, that can't be the correct maximum power. It's much too low
to be useful.

Digging out a cheat sheet from:
http://www.ti.com/lit/an/swra090/swra090.pdf
CEPT (European) 1e and 1e1 are 10mw and 1mw respectively.
However, digging down to the FCC stuff on Pg 11, I find that the specs
are really in FCC 15.231(b).
http://louise.hallikainen.org/FCC/FccRules/2012/15/231/
and are approx 11,000 uV/meter. Grinding the numbers again...

Assuming a 0dBi gain antenna:
Power = 0.3 FS^2
where
FS = field strength in Volts/meter
P = Watts
Plugging in:
Power = 0.3 * (11000 uV/m)^2 = 0.3 * (11000*10^-6 V/m)^2
Power = 0.3 * 0.000121 = 36 milliwatts.

Thanks for catching my mistake and I'll double check the numbers
(again) when I get home from some service calls.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

315mhz/433mhz transmitter
 

On 7/23/2012 4:03 PM, Jeff Liebermann wrote:
On Mon, 23 Jul 2012 12:41:32 -0500, John S
wrote:

From the document you posted, P*G/(4*Pi*D^2) = E^2/(120*Pi)
Let G = 1, D = 3, E = 200uV then
P*1/(4*3.14*3*3) = (200e-6)^2/377 and
P/113 = 40e-9/377 so that
P = 113 * 106e-12 giving
P = 12e-9
This looks like NANOwatts to me.

Well, that looks right. I'll do the short version:

From Pg 29.
http://transition.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet63/oet63rev.pdf

Assuming a 0dBi gain antenna:
Power = 0.3 FS^2
where
FS = field strength in Volts/meter
P = Watts
Plugging in:
Power = 0.3 * (200 uV/m)^2 = 0.3 * (200*10^-6 V/m)^2
Power = 0.3 * 4*10^-8 = 12*10-9 = 12 nano watts.
Argh... You're right.

Thanks for that concession.

However, that can't be the correct maximum power. It's much too low
to be useful.

Well, maybe.

Digging out a cheat sheet from:
http://www.ti.com/lit/an/swra090/swra090.pdf
CEPT (European) 1e and 1e1 are 10mw and 1mw respectively.
However, digging down to the FCC stuff on Pg 11, I find that the specs
are really in FCC 15.231(b).
http://louise.hallikainen.org/FCC/FccRules/2012/15/231/
and are approx 11,000 uV/meter. Grinding the numbers again...


Yes, but you are reading only part of the regulations. These are
PERIODIC radiators. Please read the whole thing and tell me how often
and for what period you can transmit.


Thanks for catching my mistake and I'll double check the numbers
(again) when I get home from some service calls.

Very well. Please point out the pertinent parts that allow this
(undisclosed) mode of operation.

315mhz/433mhz transmitter
 

On Mon, 23 Jul 2012 19:14:28 -0500, John S
wrote:

However, digging down to the FCC stuff on Pg 11, I find that the specs
are really in FCC 15.231(b).
http://louise.hallikainen.org/FCC/FccRules/2012/15/231/
and are approx 11,000 uV/meter. Grinding the numbers again...

Yes, but you are reading only part of the regulations. These are
PERIODIC radiators. Please read the whole thing and tell me how often
and for what period you can transmit.

Ummm... let's set some ground rules first. With all due respect, if
your interest is learning something about FCC rules-n-regs, how the
stuff works, how to make it all play together, how to grind the
numbers, and where to find pieces, I'll bust my posterior to supply
you with direction and/or answers. However, if your intent is make me
jump through hoops, burn my time, or supply information that you could
easily excavate on your own, please find someone else to play your
game. I don't mind being wrong, being told I'm clueless, or doing
research. I do mind wasting my time.

See the last paragraph of 15.231
http://louise.hallikainen.org/FCC/FccRules/2012/15/231/
In addition, devices operated under the provisions of this
paragraph shall be provided with a means for automatically
limiting operation so that the duration of each transmission
shall not be greater than one second and the silent period
between transmissions shall be at least 30 times the
duration of the transmission but in no case less than 10
seconds.

The method of modulation is not specified. Whatever modulation method
is chosen must comply with 15.231(b)(3)(c)
The bandwidth of the emission shall be no wider than 0.25%
of the center frequency for devices operating above 70 MHz and
below 900 MHz. For devices operating above 900 MHz, the emission
shall be no wider than 0.5% of the center frequency. Bandwidth
is determined at the points 20 dB down from the modulated carrier.

At 433MHz, that yields about 1MHz bandwidth which is adequate for most
anything between on-off keying to perhaps frequency hopping spread
spectrum.

Thanks for catching my mistake and I'll double check the numbers
(again) when I get home from some service calls.

Very well. Please point out the pertinent parts that allow this
(undisclosed) mode of operation.

Sorry, but undisclosed modes are by definition undefined and therefore
not codified in the FCC rules-n-regs.


--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com
# http://www.LearnByDestroying.com AE6KS

315mhz/433mhz transmitter
 

On 7/23/2012 4:03 PM, Jeff Liebermann wrote:
On Mon, 23 Jul 2012 12:41:32 -0500, John S
wrote:

From the document you posted, P*G/(4*Pi*D^2) = E^2/(120*Pi)
Let G = 1, D = 3, E = 200uV then
P*1/(4*3.14*3*3) = (200e-6)^2/377 and
P/113 = 40e-9/377 so that
P = 113 * 106e-12 giving
P = 12e-9
This looks like NANOwatts to me.

Well, that looks right. I'll do the short version:

From Pg 29.
http://transition.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet63/oet63rev.pdf

Assuming a 0dBi gain antenna:
Power = 0.3 FS^2
where
FS = field strength in Volts/meter
P = Watts
Plugging in:
Power = 0.3 * (200 uV/m)^2 = 0.3 * (200*10^-6 V/m)^2
Power = 0.3 * 4*10^-8 = 12*10-9 = 12 nano watts.
Argh... You're right.

However, that can't be the correct maximum power. It's much too low
to be useful.

Digging out a cheat sheet from:
http://www.ti.com/lit/an/swra090/swra090.pdf
CEPT (European) 1e and 1e1 are 10mw and 1mw respectively.
However, digging down to the FCC stuff on Pg 11, I find that the specs
are really in FCC 15.231(b).
http://louise.hallikainen.org/FCC/FccRules/2012/15/231/
and are approx 11,000 uV/meter. Grinding the numbers again...

Assuming a 0dBi gain antenna:
Power = 0.3 FS^2
where
FS = field strength in Volts/meter
P = Watts
Plugging in:
Power = 0.3 * (11000 uV/m)^2 = 0.3 * (11000*10^-6 V/m)^2
Power = 0.3 * 0.000121 = 36 milliwatts.


..3 * .000121 = .000036 or 36 MICROwatts.

Thanks for catching my mistake and I'll double check the numbers
(again) when I get home from some service calls.


You're welcome again.

315mhz/433mhz transmitter
 

On 7/23/2012 10:38 PM, Jeff Liebermann wrote:
On Mon, 23 Jul 2012 19:14:28 -0500, John S
wrote:

However, digging down to the FCC stuff on Pg 11, I find that the specs
are really in FCC 15.231(b).
http://louise.hallikainen.org/FCC/FccRules/2012/15/231/
and are approx 11,000 uV/meter. Grinding the numbers again...

Yes, but you are reading only part of the regulations. These are
PERIODIC radiators. Please read the whole thing and tell me how often
and for what period you can transmit.

Ummm... let's set some ground rules first. With all due respect, if
your interest is learning something about FCC rules-n-regs, how the
stuff works, how to make it all play together, how to grind the
numbers, and where to find pieces, I'll bust my posterior to supply
you with direction and/or answers. However, if your intent is make me
jump through hoops, burn my time, or supply information that you could
easily excavate on your own, please find someone else to play your
game. I don't mind being wrong, being told I'm clueless, or doing
research. I do mind wasting my time.

Your condescending attitude is noted.

See the last paragraph of 15.231
http://louise.hallikainen.org/FCC/FccRules/2012/15/231/
In addition, devices operated under the provisions of this
paragraph shall be provided with a means for automatically
limiting operation so that the duration of each transmission
shall not be greater than one second and the silent period
between transmissions shall be at least 30 times the
duration of the transmission but in no case less than 10
seconds.

This paragraph is part of paragraph (e) which allows only

260-470 1,500 to 5,000^1 150 to 500^1
^1Linear interpolations.

so that, with interpolation to 433, it works out to about 4383 uV/m.

This, then, allows .3*(4383e-6)^2 or about 5.76 microwatts for 1 second
out of every 30 seconds. Or, for 1/3 second out of every 10 seconds, but
never more frequently.


Thanks for catching my mistake and I'll double check the numbers
(again) when I get home from some service calls.

You're welcome (again).

315mhz/433mhz transmitter
 

On 7/23/2012 11:21 AM, Jeff Liebermann wrote:

Then... I find a 433MHz radio that delivers +20dBm (100mw).
http://www.sparkfun.com/products/10153
By my reading of 15.209, that's overpowered unless operating with a
miserable -9dB gain antenna. From the manufacturers web pile at:
http://www.hoperf.com/rf_fsk/
they offer +10, +13, and +20dBm outputs and claim they all meet ETSI
and FCC regs. I dunno about that.


Well, I can't argue with the fact that they are being produced. If they
really meet the FCC regulations, I have been unable to prove it. I have
looked all over the FCC site under part 15 and never found an area that
allows such power.

If you ever find it, I would appreciate a link to it.