315mhz/433mhz transmitter
 

hi
i'm just new to this field and i need some help on it and i appreciate any help...
my aim is to make a 315 or 433 transmitter and receiver so what ics is the best for that and where can i buy them and so for the antennas(but i would like to build them)...
thanks

315mhz/433mhz transmitter
 

On Thu, 19 Jul 2012 23:20:02 +0000, foxbrain
wrote:


hi
i'm just new to this field and i need some help on it and i appreciate
any help...
my aim is to make a 315 or 433 transmitter and receiver so what ics is
the best for that and where can i buy them and so for the antennas(but i
would like to build them)...
thanks


For the antenna use a piece of wire, a length of lamda/4 is fine.

w.

is it a straight wire or curved ? shouldn't i look at it's impedance and make matching with it ?
what about it's ICs

315mhz/433mhz transmitter
 

foxbrain wrote:

'Helmut Wabnig[_2_ Wrote:
;793671']On Thu, 19 Jul 2012 23:20:02 +0000, foxbrain
wrote:
-

hi
i'm just new to this field and i need some help on it and i appreciate
any help...
my aim is to make a 315 or 433 transmitter and receiver so what ics is
the best for that and where can i buy them and so for the antennas(but i
would like to build them)...
thanks-


For the antenna use a piece of wire, a length of lamda/4 is fine.

w.

is it a straight wire or curved ? shouldn't i look at it's impedance and
make matching with it ?
what about it's ICs

If you want meaningfull replies, you need to ask meaningfull questions.

What do you intend to transmit, modulation type, power levels, etc.?

i want to make a remote control for 3 relays using the encoders/decoders: pt2262 and pt2272 , it doesn't mine what kind of modulation...
i recently found these 2 ics : u2741b and ata3741 . but what kind of antenna do i need? is there any other thinks i have to know?

315mhz/433mhz transmitter
 

On 7/20/2012 9:44 AM, foxbrain wrote:
'Helmut Wabnig[_2_ Wrote:
;793671']On Thu, 19 Jul 2012 23:20:02 +0000, foxbrain
wrote:
-

hi
i'm just new to this field and i need some help on it and i appreciate
any help...
my aim is to make a 315 or 433 transmitter and receiver so what ics is
the best for that and where can i buy them and so for the antennas(but i
would like to build them)...
thanks-


For the antenna use a piece of wire, a length of lamda/4 is fine.

w.

is it a straight wire or curved ? shouldn't i look at it's impedance and
make matching with it ?
what about it's ICs




Use lots of ICs. It doesn't matter which ones. Just put a lot in.

315mhz/433mhz transmitter
 

On Sat, 21 Jul 2012 14:02:29 +0000, foxbrain
wrote:


i want to make a remote control for 3 relays using the
encoders/decoders: pt2262 and pt2272 , it doesn't mine what kind of
modulation...
i recently found these 2 ics : u2741b and ata3741 . but what kind of
antenna do i need? is there any other thinks i have to know?

Yes, thinkalot.

Why not buy such a thing as this he

http://tinyurl.com/c2pku44


w.

315mhz/433mhz transmitter
 

On Thu, 19 Jul 2012 23:20:02 +0000, foxbrain
wrote:

i'm just new to this field and i need some help on it and i appreciate
any help...
my aim is to make a 315 or 433 transmitter and receiver so what ics is
the best for that and where can i buy them and so for the antennas(but i
would like to build them)...

This sounds like a school class project. If so, we should not be
doing your homework as you will not learn anything.

Some general direction:
http://www.linxtechnologies.com/en/products/modules/kits
http://www.rfsolutions.co.uk/acatalog/RF_Development.html
http://www.ti.com/tool/cc1101dk433
http://www.radiotronix.com/products/proddb.asp?ProdID=216
etc. Google for "433 MHz development kit". These development kits
are NOT cheap, but will give you a clue as to what's involved in the
product development.

For antennas, Google for "433 MHz antenna". There are plenty to
choose from. Most likely, a 1/4 wave wire whip antenna will be
sufficient.

For antenna design help, Google for "433 MHz antenna design". This
might be useful for comparing different types of antennas:
http://www.ti.com/lit/an/swra161b/swra161b.pdf

i want to make a remote control for 3 relays using the
encoders/decoders

There are also commerical products that do roughly what you propose.
Reverse engineering the design and using similar components for your
project is possible:
http://www.ebay.com/itm/170740349762
http://www.ebay.com/itm/170854388957
etc...


--
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
 

foxbrain wrote:

i want to make a remote control for 3 relays using the
encoders/decoders: pt2262 and pt2272 , it doesn't mine what kind of
modulation...
i recently found these 2 ics : u2741b and ata3741 . but what kind of
antenna do i need?

How would anyone here know that as it depends on what kind of range you
exepect to get.

The simplest antenna would be a quarter wavelength piece of wire.

is there any other thinks i have to know?

Probably.

thanks that helped...
BTW i'm making a project for my own not any kind of homework.
i have one more question : if i wanted to make my device have a bigger range like 500-1000meters should i put an amplifer before the antenna?
i should change the antenna in to yagi shouldn't i?

315mhz/433mhz transmitter
 

On Mon, 23 Jul 2012 00:08:53 +0000, foxbrain
wrote:

BTW i'm making a project for my own not any kind of homework.

Ok, you're off the hook.

i have one more question : if i wanted to make my device have a bigger
range like 500-1000meters should i put an amplifer before the antenna?
i should change the antenna in to yagi shouldn't i?

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.

This should explain how it all works:
http://transition.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet63/oet63rev.pdf
See the calcs on Pg 29.

Claims 500 meters:
http://www.sparkfun.com/products/155
At 10mw, this is close to maximum legal. Anything more than that and
you're going to start interfering with wireless weather stations, car
alarms, etc.

--
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 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

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

so depending on the equation in :
http://transition.fcc.gov/Bureaus/En...3/oet63rev.pdf
i should make the power the much larger i can but not more than 10mw
and so for the gain , and decrease the E (v/meter)....
thanks

315mhz/433mhz transmitter
 

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.

315mhz/433mhz transmitter
 

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.

That is wrong, 10mW ERP is what these lowpower devices are allowed
to transmit.

315mhz/433mhz transmitter
 

On 7/23/2012 9:12 AM, Rob wrote:
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.

That is wrong, 10mW ERP is what these lowpower devices are allowed
to transmit.


If so, then more than 200uV/m is allowed. Do the calculation as Jeff
supplied:

quote
This should explain how it all works:
http://transition.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet63/oet63rev.pdf
See the calcs on Pg 29.
/quote

315mhz/433mhz transmitter
 

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.
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. 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.

--
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 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?

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.

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.


I don't either. This is a question I've had for years.

315mhz/433mhz transmitter
 

On Mon, 23 Jul 2012 12:53:12 +0000, foxbrain
wrote:

so depending on the equation in :
http://tinyurl.com/c86y6q6
i should make the power the much larger i can but not more than 10mw
and so for the gain , and decrease the E (v/meter)....

Not exactly. When adding a bigger antenna, you will need to decrease
the transmit power to keep the field strength (V/meter) constant.

For example, assume that +12dBm tx power and 0dBm (unity) gain antenna
is the maximum legal. If you replace the unity gain antenna with an
+8dBi gain yagi, you will need to reduce the transmit power down to
+4dBm output to stay withint the maximum field strength requirement.

Note that you can calculate your maximum range if you know the various
numbers.
http://wireless.navas.us/index.php?title=Wi-Fi#Link_Calculations
http://www.terabeam.com/support/calculations/som.php



--
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 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.

--
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 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.

315mhz/433mhz transmitter
 

On Tue, 24 Jul 2012 09:10:20 -0500, John S
wrote:

On 7/23/2012 4:03 PM, Jeff Liebermann wrote:
(...)
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.

Oops and thanks (again). I keep fudging the numbers (unintentionally)
to what I think they should be, instead of what they are. Very
embarrassing.

Microwatts doesn't seem to make sense as there are products being sold
that advertise 10mw and 100mw output power levels. Obviously they are
not being certified under Part 15. However, I can't find another US
service on 433MHz that qualifies (except ham radio). FCC frequency
allocations table is of no use:
http://ecfr.gpoaccess.gov/graphics/pdfs/er27ja12.018.pdf
433MHz is an ISM band, but only in region 1 (Europe) and not in region
2 (US).
http://en.wikipedia.org/wiki/ISM_band
My guess(tm) is that the higher power 433MHz devices can only be sold
in Europe. Yet, that's not apparent on any of the sites selling
433MHz data radios.

"FCC Compliance testing Using the MICRF112"
http://www.micrel.com/_PDF/App-Notes/an-55.pdf
Page 9 has the calcs for a typical key fob transmitter.
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.

I'll do some more reading and checking, hopefully tonite. Paying work
comes first. My appologies (again) for my multiple screwups.

--
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 Tue, 24 Jul 2012 10:34:16 -0500, John S
wrote:

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.

Unless I missed something, you're correct. I can't find anything in
the US rules (except Part 47 ham radio) that allows milliwatt level
operation on 433MHz. It is allowed in Europe under CEPT rules to 10mw
at 10% max duty cycle:
http://www.ero.dk/47DA77DD-A2B7-4DD2-8288-3900A875B3F6?frames=no&
(MS Word Document). Nothing that allows 100mw but possibly in another
foreign country.

I've only done certifications for 900MHz, 2.4GHz, and 5.7GHz, FCC
15.247 hardware. The 433MHz stuff is new to me. FCC 15.247 allows 1
watt into 6dBi.
http://louise.hallikainen.org/FCC/FccRules/2012/15/247/


--
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 7/24/2012 12:12 PM, Jeff Liebermann wrote:

Microwatts doesn't seem to make sense as there are products being sold
that advertise 10mw and 100mw output power levels. Obviously they are
not being certified under Part 15. However, I can't find another US
service on 433MHz that qualifies (except ham radio). FCC frequency
allocations table is of no use:
http://ecfr.gpoaccess.gov/graphics/pdfs/er27ja12.018.pdf
433MHz is an ISM band, but only in region 1 (Europe) and not in region
2 (US).
http://en.wikipedia.org/wiki/ISM_band
My guess(tm) is that the higher power 433MHz devices can only be sold
in Europe. Yet, that's not apparent on any of the sites selling
433MHz data radios.

It appears that we have both looked very hard and have come to the same
conclusion. I now wonder if the US suppliers are unaware of the region
1/region 2 thing.

"FCC Compliance testing Using the MICRF112"
http://www.micrel.com/_PDF/App-Notes/an-55.pdf
Page 9 has the calcs for a typical key fob transmitter.
36 microwatts.

I saw that. Lower left corner of page 4 says that continuous operation
is allowed. Where do they get that?

315mhz/433mhz transmitter
 

On 7/24/2012 12:23 PM, Jeff Liebermann wrote:

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.

Unless I missed something, you're correct. I can't find anything in
the US rules (except Part 47 ham radio) that allows milliwatt level
operation on 433MHz. It is allowed in Europe under CEPT rules to 10mw
at 10% max duty cycle:
http://www.ero.dk/47DA77DD-A2B7-4DD2-8288-3900A875B3F6?frames=no&
(MS Word Document). Nothing that allows 100mw but possibly in another
foreign country.

Yeah, my conclusion as well.

315mhz/433mhz transmitter
 

John S wrote:
On 7/24/2012 12:12 PM, Jeff Liebermann wrote:

Microwatts doesn't seem to make sense as there are products being sold
that advertise 10mw and 100mw output power levels. Obviously they are
not being certified under Part 15. However, I can't find another US
service on 433MHz that qualifies (except ham radio). FCC frequency
allocations table is of no use:
http://ecfr.gpoaccess.gov/graphics/pdfs/er27ja12.018.pdf
433MHz is an ISM band, but only in region 1 (Europe) and not in region
2 (US).
http://en.wikipedia.org/wiki/ISM_band
My guess(tm) is that the higher power 433MHz devices can only be sold
in Europe. Yet, that's not apparent on any of the sites selling
433MHz data radios.

It appears that we have both looked very hard and have come to the same
conclusion. I now wonder if the US suppliers are unaware of the region
1/region 2 thing.

Here in Europe, 10mW ERP is allowed on 433 MHz. This of course does
not mean that all devices have that much power. I can understand that
a 13dBm transmitter device is allowed with an inefficient antenna and
still result in 10mW ERP or less. 100mW seems to be a bit off the
scale, who would want to waste that much power.

Unfortunately, "allowed" and "in use" are different things. It is
allowed to used 10mW handy talkies on 433 for unlicensed use, but in
reality those users have the wellknown Chinese devices (Wouxun etc)
that output 4 watts. Or they use a 50W standard HAM mobile transceiver.
Without license. On the amateur bands.

315mhz/433mhz transmitter
 

In article ,
Jeff Liebermann wrote:

My guess(tm) is that the higher power 433MHz devices can only be sold
in Europe. Yet, that's not apparent on any of the sites selling
433MHz data radios.

"FCC Compliance testing Using the MICRF112"
http://www.micrel.com/_PDF/App-Notes/an-55.pdf
Page 9 has the calcs for a typical key fob transmitter.
36 microwatts.

I've run into interference in a local shopping mall parking lot, which
is sufficient to almost completely block 433 MHz car keyfobs from
working. It comes from a local noodle restaurant, which uses a
wireless order-taking system... from the sound of the transmissions
over the air, I think the central node is polling the hand-held order
entry units 3-4 times per second (well in excess of the Part 15
periodic radiator limit). It's quite audible for about a city block
around the restaurant, in at least some directions.

I got a look at one of the handheld terminals, and did not see any
sort of FCC licensing or type-acceptance sticker.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

315mhz/433mhz transmitter
 

On 7/24/2012 1:16 PM, Dave Platt wrote:
In article ,
Jeff Liebermann wrote:

My guess(tm) is that the higher power 433MHz devices can only be sold
in Europe. Yet, that's not apparent on any of the sites selling
433MHz data radios.

"FCC Compliance testing Using the MICRF112"
http://www.micrel.com/_PDF/App-Notes/an-55.pdf
Page 9 has the calcs for a typical key fob transmitter.
36 microwatts.

I've run into interference in a local shopping mall parking lot, which
is sufficient to almost completely block 433 MHz car keyfobs from
working. It comes from a local noodle restaurant, which uses a
wireless order-taking system... from the sound of the transmissions
over the air, I think the central node is polling the hand-held order
entry units 3-4 times per second (well in excess of the Part 15
periodic radiator limit). It's quite audible for about a city block
around the restaurant, in at least some directions.

I got a look at one of the handheld terminals, and did not see any
sort of FCC licensing or type-acceptance sticker.


Why am I not surprised? I think this could get out of hand just as the
27 MHz band did. There is a slight difference here. The military has an
interest in the 70 cm band, so this may become very interesting. Note
that near some military bases, some gadgets are becoming next to useless
already.

315mhz/433mhz transmitter
 

On Tue, 24 Jul 2012 12:57:33 -0500, John S
wrote:

On 7/24/2012 12:12 PM, Jeff Liebermann wrote:

Microwatts doesn't seem to make sense as there are products being sold
that advertise 10mw and 100mw output power levels. Obviously they are
not being certified under Part 15. However, I can't find another US
service on 433MHz that qualifies (except ham radio). FCC frequency
allocations table is of no use:
http://ecfr.gpoaccess.gov/graphics/pdfs/er27ja12.018.pdf
433MHz is an ISM band, but only in region 1 (Europe) and not in region
2 (US).
http://en.wikipedia.org/wiki/ISM_band
My guess(tm) is that the higher power 433MHz devices can only be sold
in Europe. Yet, that's not apparent on any of the sites selling
433MHz data radios.

It appears that we have both looked very hard and have come to the same
conclusion. I now wonder if the US suppliers are unaware of the region
1/region 2 thing.

I still have some more reading to do, and ask a few experts. However,
offhand, methinks there's a problem.

"FCC Compliance testing Using the MICRF112"
http://www.micrel.com/_PDF/App-Notes/an-55.pdf
Page 9 has the calcs for a typical key fob transmitter.
36 microwatts.

I saw that. Lower left corner of page 4 says that continuous operation
is allowed. Where do they get that?

It's there, although I had to read it several times before I found it.
http://louise.hallikainen.org/FCC/FccRules/2012/15/231/
See section (e):
Intentional radiators may operate at a periodic rate exceeding
that specified in paragraph ...

The field strength is limited to about 4500 uV/meter. There's also
some notes on the topic on Pg 14 of the TI app note:
http://www.ti.com/lit/an/swra090/swra090.pdf

--
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 7/24/2012 2:41 PM, Jeff Liebermann wrote:
On Tue, 24 Jul 2012 12:57:33 -0500, John S
wrote:

On 7/24/2012 12:12 PM, Jeff Liebermann wrote:

Microwatts doesn't seem to make sense as there are products being sold
that advertise 10mw and 100mw output power levels. Obviously they are
not being certified under Part 15. However, I can't find another US
service on 433MHz that qualifies (except ham radio). FCC frequency
allocations table is of no use:
http://ecfr.gpoaccess.gov/graphics/pdfs/er27ja12.018.pdf
433MHz is an ISM band, but only in region 1 (Europe) and not in region
2 (US).
http://en.wikipedia.org/wiki/ISM_band
My guess(tm) is that the higher power 433MHz devices can only be sold
in Europe. Yet, that's not apparent on any of the sites selling
433MHz data radios.

It appears that we have both looked very hard and have come to the same
conclusion. I now wonder if the US suppliers are unaware of the region
1/region 2 thing.

I still have some more reading to do, and ask a few experts. However,
offhand, methinks there's a problem.

"FCC Compliance testing Using the MICRF112"
http://www.micrel.com/_PDF/App-Notes/an-55.pdf
Page 9 has the calcs for a typical key fob transmitter.
36 microwatts.

I saw that. Lower left corner of page 4 says that continuous operation
is allowed. Where do they get that?

It's there, although I had to read it several times before I found it.
http://louise.hallikainen.org/FCC/FccRules/2012/15/231/
See section (e):
Intentional radiators may operate at a periodic rate exceeding
that specified in paragraph ...

Yes, but continuing with paragraph (e) includes the last paragraph which
you quoted earlier:

quote you

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.

/quote you

And this last paragraph is part of FCC paragraph (e).

There is nothing in that section which allows continuous transmission.


The field strength is limited to about 4500 uV/meter. There's also
some notes on the topic on Pg 14 of the TI app note:
http://www.ti.com/lit/an/swra090/swra090.pdf

It is parroting paragraph (e). Nothing new nor informative there.

I'm enjoying this, Jeff. Finally, I have someone with which to kick this
around and learn something. I'd really like to get to the bottom of this
whole thing.

315mhz/433mhz transmitter
 

On 7/24/2012 3:37 PM, John S wrote:

I'm enjoying this, Jeff. Finally, I have someone with which to kick this
around and learn something. I'd really like to get to the bottom of this
whole thing.


Should we take this somewhere else? I wonder if anyone else is
interested. Maybe Rob? What do you think? If it benefits only three
people, is it worth it?