very small low power simple transmitter (ideally single chip)?

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I'd like to build a very small, low power RF transmitter circuit that
is small and light enough (and cheap enough not to worry about) to be
attached to a cats collar.
I just want it to transmit either a constant or pulsed carrier (pulsed
prob best for battery life) of a known frequency, that I can monitor
with a receiver and DF antenna.

There must be single chip transmitters about these days?

Anyone suggest suitable circuit?


Re: very small low power simple transmitter (ideally single chip)?


On 18 Aug 2006 02:00:21 -0700, in sci.electronics.design "megoodsen"

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something like this?

http://www.jbgizmo.com/page4.html


martin

Re: very small low power simple transmitter (ideally single chip)?



martin griffith wrote:

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Yes exactly thanks!


Re: very small low power simple transmitter (ideally single chip)?





**  Groper alert  !



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 **  Lotsa luck  -   that schem is fake.

 Cat collar transmitters and receivers are commercially available.

 But only absolute fuckwits buy them.

Go ahead  -  make my day.





........  Phil



Re: very small low power simple transmitter (ideally single chip)?



megoodsen wrote:
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Yep, that's a good transmitter circuit.  If you need longer batery
life, you can add a 74HC14 and set it up as a short pulse oscillator,
say 10 seconds on, a minute or two off.


Re: very small low power simple transmitter (ideally single chip)?


One more Q..

Where might I source in a suitable small crystal for operation at
somewhere between 144 and 146MHz?

ta


Re: very small low power simple transmitter (ideally single chip)?


On 18 Aug 2006 02:51:44 -0700, in sci.electronics.design "megoodsen"

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http://www.jbgizmo.com/index.html
see http://www.jbgizmo.com/page25.htm
for using overtones


martin

Re: very small low power simple transmitter (ideally single chip)?


...and I'm sure you have the ham radio license required for transmission in
this band?  And if you do, why are you asking the question in the first
place?

Jim


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Re: very small low power simple transmitter (ideally single chip)?



RST Engineering (jw) wrote:
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If it's under 100mW, is that not legal?

Mark


Re: very small low power simple transmitter (ideally single chip)?


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   No. it has to be on specified band segments.  Wade through CFR 47 for
all the regulations for the US.  Most other countries have similar
regulations and laws.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
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Re: very small low power simple transmitter (ideally single chip)?


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No. For Part 15 rules (unlicensed operation), see
http://www.access.gpo.gov/nara/cfr/waisidx_05/47cfr15_05.html

which says, in part....

Subpart C_Intentional Radiators

Sec. 15.209  Radiated emission limits; general requirements.

     (a) Except as provided elsewhere in this subpart, the emissions from

an intentional radiator shall not exceed the field strength levels

specified in the following table:

------------------------------------------------------------------------

                                                              Measurement

          Frequency (MHz)                Field strength         distance

                                       (microvolts/meter)       (meters)

------------------------------------------------------------------------

0.009-0.490......................  2400/F(kHz)                      300

0.490-1.705......................  24000/F(kHz)                      30

1.705-30.0.......................  30                                30

30-88............................  100 **                             3

88-216...........................  150 **                             3

216-960..........................  200 **                             3

Above 960........................  500                                3

------------------------------------------------------------------------

According to the above, you are allowed 200 uV/m at 3 meters.

This is equivalent to 13 nanowatts of isotropically radiated power.

Cheers,
John


Re: very small low power simple transmitter (ideally single chip)?



John - KD5YI wrote:
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I guess that makes my 500 milliwatt, 560,000 Gigahertz transmitter
illegal!!!

(LED flashlight)

Luhan


Re: very small low power simple transmitter (ideally single chip)?


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See how that screws up the natural flow of the threae? Sheesh!

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Only if they can receive it on their FSM! ;-)

Cheers!
Rich



Re: very small low power simple transmitter (ideally single chip)?


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Read Title 47 and decide for yourself. In the meantime, I will ask them if
there is a reward for reporting lawbreakers such as yourself.

John



Re: very small low power simple transmitter (ideally single chip)?


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   snipped-for-privacy@fcc.gov is the address to report suspected illegal use of RF
equipment to the FCC.  I contacted them to ask where to report the
people spamming cell phone jammers and snipped-for-privacy@fcc.gov is where I was
told to make reports.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
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Re: very small low power simple transmitter (ideally single chip)?


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My comment was in the same vein as Luhan's. I should learn how to put in
smiley faces, I guess.

If I were to report Luhan, I would also have to report all those other
lawbreakers who drive around with their headlights on.

Re: very small low power simple transmitter (ideally single chip)?


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   I wasn't suggesting you report him.  Like I said, it is the link if
there is a real need to report anything to the FCC.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
We've slightly trimmed the long signature. Click to see the full one.
Re: very small low power simple transmitter (ideally single chip)?


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In what state is it illegal to turn your headlights on?

Thanks,
Rich


Re: very small low power simple transmitter (ideally single chip)?


The state of insobriety?

Jim




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Re: very small low power simple transmitter (ideally single chip)?



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And even less, if your antenna has gain, right? Because it still has to
be < 200 uV/m at 3 meters, looking right up the throat of the antenna,
right?

So, what's the deal with those RF modems with thousands of meters' range?
Are they, like, pre-licensed or something?

And will a signal that weak reach an RC airplane that's, say, 300m away?
<google...>
Anyway, here's some frequencies:
http://www.modelaircraft.org/Comp/frequency.htm

Cheers!
Rich


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