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Blocking RF from intentional radiators

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  Blocking RF from intentional radiators Don Y <blockedofcourse@foo.invalid> - 2017-02-06 00:40 -0700
    Re: Blocking RF from intentional radiators whit3rd <whit3rd@gmail.com> - 2017-02-06 00:56 -0800
      Re: Blocking RF from intentional radiators Don Y <blockedofcourse@foo.invalid> - 2017-02-06 02:19 -0700
        Re: Blocking RF from intentional radiators Robert Baer <robertbaer@localnet.com> - 2017-02-08 20:22 -0800
    Re: Blocking RF from intentional radiators piglet <erichpwagner@hotmail.com> - 2017-02-06 11:57 +0000
      Re: Blocking RF from intentional radiators "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-02-06 06:51 -0600
      Re: Blocking RF from intentional radiators Don Y <blockedofcourse@foo.invalid> - 2017-02-06 06:52 -0700
        Re: Blocking RF from intentional radiators Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-06 07:55 -0700
          Re: Blocking RF from intentional radiators Don Y <blockedofcourse@foo.invalid> - 2017-02-06 12:38 -0700
            Re: Blocking RF from intentional radiators Tim Wescott <seemywebsite@myfooter.really> - 2017-02-06 14:18 -0600
              Re: Blocking RF from intentional radiators Don Y <blockedofcourse@foo.invalid> - 2017-02-06 14:39 -0700
                Re: Blocking RF from intentional radiators Jon Elson <jmelson@wustl.edu> - 2017-02-06 17:10 -0600
                  Re: Blocking RF from intentional radiators Don Y <blockedofcourse@foo.invalid> - 2017-02-06 17:06 -0700
                    Re: Blocking RF from intentional radiators Jasen Betts <jasen@xnet.co.nz> - 2017-02-07 04:12 +0000
                Re: Blocking RF from intentional radiators Jasen Betts <jasen@xnet.co.nz> - 2017-02-07 04:05 +0000
            Re: Blocking RF from intentional radiators Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-06 14:56 -0700
              Re: Blocking RF from intentional radiators Don Y <blockedofcourse@foo.invalid> - 2017-02-06 15:18 -0700
          Re: Blocking RF from intentional radiators Robert Baer <robertbaer@localnet.com> - 2017-02-08 20:41 -0800
        Re: Blocking RF from intentional radiators Robert Baer <robertbaer@localnet.com> - 2017-02-08 20:32 -0800
      Re: Blocking RF from intentional radiators Phil Allison <pallison49@gmail.com> - 2017-02-06 06:39 -0800
    Re: Blocking RF from intentional radiators John Larkin <jjlarkin@highlandtechnology.com> - 2017-02-06 08:28 -0800
    Re: Blocking RF from intentional radiators Jeff Liebermann <jeffl@cruzio.com> - 2017-02-06 09:23 -0800
      Re: Blocking RF from intentional radiators Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-02-06 09:30 -0800
      Re: Blocking RF from intentional radiators Don Y <blockedofcourse@foo.invalid> - 2017-02-06 11:52 -0700
        Re: Blocking RF from intentional radiators Jeff Liebermann <jeffl@cruzio.com> - 2017-02-06 11:31 -0800
          Re: Blocking RF from intentional radiators Don Y <blockedofcourse@foo.invalid> - 2017-02-06 12:49 -0700
            Re: Blocking RF from intentional radiators John S <Sophi.2@invalid.org> - 2017-02-06 14:07 -0600
            Re: Blocking RF from intentional radiators "nuny@bid.nes" <Alien8752@gmail.com> - 2017-02-06 12:09 -0800
              Re: Blocking RF from intentional radiators Don Y <blockedofcourse@foo.invalid> - 2017-02-06 13:37 -0700
                Re: Blocking RF from intentional radiators "nuny@bid.nes" <Alien8752@gmail.com> - 2017-02-06 14:35 -0800
                  Re: Blocking RF from intentional radiators Don Y <blockedofcourse@foo.invalid> - 2017-02-06 15:59 -0700
            Re: Blocking RF from intentional radiators Jeff Liebermann <jeffl@cruzio.com> - 2017-02-06 17:56 -0800
        Re: Blocking RF from intentional radiators George Herold <gherold@teachspin.com> - 2017-02-06 12:03 -0800
          Re: Blocking RF from intentional radiators Don Y <blockedofcourse@foo.invalid> - 2017-02-06 13:31 -0700
            Re: Blocking RF from intentional radiators George Herold <gherold@teachspin.com> - 2017-02-06 13:29 -0800
              Re: Blocking RF from intentional radiators Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-02-06 13:32 -0800
              Re: Blocking RF from intentional radiators Don Y <blockedofcourse@foo.invalid> - 2017-02-06 15:01 -0700
                Re: Blocking RF from intentional radiators Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-06 15:07 -0700
                  Re: Blocking RF from intentional radiators Don Y <blockedofcourse@foo.invalid> - 2017-02-06 15:13 -0700
                    Re: Blocking RF from intentional radiators Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-02-06 14:28 -0800
                      Re: Blocking RF from intentional radiators Don Y <blockedofcourse@foo.invalid> - 2017-02-06 15:31 -0700
                    Re: Blocking RF from intentional radiators Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-06 15:59 -0700
                      Re: Blocking RF from intentional radiators Don Y <blockedofcourse@foo.invalid> - 2017-02-06 17:08 -0700
                        Re: Blocking RF from intentional radiators pcdhobbs@gmail.com - 2017-02-08 16:36 -0800
                    Re: Blocking RF from intentional radiators Clifford Heath <no.spam@please.net> - 2017-02-07 10:26 +1100
        Re: Blocking RF from intentional radiators whit3rd <whit3rd@gmail.com> - 2017-02-06 13:05 -0800
          Re: Blocking RF from intentional radiators Don Y <blockedofcourse@foo.invalid> - 2017-02-06 14:22 -0700
            Re: Blocking RF from intentional radiators kevin93 <kevin@whitedigs.com> - 2017-02-06 13:39 -0800
              Re: Blocking RF from intentional radiators Don Y <blockedofcourse@foo.invalid> - 2017-02-06 15:12 -0700
            Re: Blocking RF from intentional radiators whit3rd <whit3rd@gmail.com> - 2017-02-06 14:43 -0800
              Re: Blocking RF from intentional radiators "nuny@bid.nes" <Alien8752@gmail.com> - 2017-02-06 16:29 -0800
        Re: Blocking RF from intentional radiators Jasen Betts <jasen@xnet.co.nz> - 2017-02-07 04:19 +0000

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#446382 — Blocking RF from intentional radiators

How can I economically, simply and reversibly inhibit the
RF link to a GDO?  Short the antenna?  Slip it in a
grounded copper tube?  etc.

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#446385

On Sunday, February 5, 2017 at 11:40:48 PM UTC-8, Don Y wrote:
> How can I economically, simply and reversibly inhibit the
> RF link to a GDO?  Short the antenna?  Slip it in a
> grounded copper tube?  etc.

Pop it into a shortbread tin.   Or a metal filing cabinet.
Isn't there a sensitivity knob, that you can just turn down?

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#446386

On 2/6/2017 1:56 AM, whit3rd wrote:
> On Sunday, February 5, 2017 at 11:40:48 PM UTC-8, Don Y wrote:
>> How can I economically, simply and reversibly inhibit the
>> RF link to a GDO?  Short the antenna?  Slip it in a
>> grounded copper tube?  etc.
>
> Pop it into a shortbread tin.   Or a metal filing cabinet.

It must still be operational -- I just want to disable the
"wireless" control.

> Isn't there a sensitivity knob, that you can just turn down?

I doubt it (I don't have extensive research on the various
makes/models available).  And, if so, it would probably be an
internal adjustment (trimpot).

I'm looking for something simple that I can tell folks to
do:  e.g., "slip a length of 1/4" copper tubing over the
antenna wire and short the tubing to the GDO's chassis.

But, it has to be a reliable means of disabling "RF" from
being processed by the receiver, regardless of the location
of the XMTR!

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#446964

Don Y wrote:
> On 2/6/2017 1:56 AM, whit3rd wrote:
>> On Sunday, February 5, 2017 at 11:40:48 PM UTC-8, Don Y wrote:
>>> How can I economically, simply and reversibly inhibit the
>>> RF link to a GDO? Short the antenna? Slip it in a
>>> grounded copper tube? etc.
>>
>> Pop it into a shortbread tin. Or a metal filing cabinet.
>
> It must still be operational -- I just want to disable the
> "wireless" control.
>
>> Isn't there a sensitivity knob, that you can just turn down?
>
> I doubt it (I don't have extensive research on the various
> makes/models available). And, if so, it would probably be an
> internal adjustment (trimpot).
>
> I'm looking for something simple that I can tell folks to
> do: e.g., "slip a length of 1/4" copper tubing over the
> antenna wire and short the tubing to the GDO's chassis.
>
> But, it has to be a reliable means of disabling "RF" from
> being processed by the receiver, regardless of the location
> of the XMTR!
   Well, what if you are within 5000 feet of the Xmitter? 500 feet? 50 feet?
   If you are close enough, you will find that Faraday shielding is 
virtually worthless.

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#446393

On 06/02/2017 07:40, Don Y wrote:
> How can I economically, simply and reversibly inhibit the
> RF link to a GDO?  Short the antenna?  Slip it in a
> grounded copper tube?  etc.

Isn't the whole point of grid dip oscillators that they are mild 
radiators. What is the desired action?

piglet

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#446396

"piglet" <erichpwagner@hotmail.com> wrote in message 
news:o79o8s$lq9$1@dont-email.me...
> On 06/02/2017 07:40, Don Y wrote:
>> How can I economically, simply and reversibly inhibit the
>> RF link to a GDO?  Short the antenna?  Slip it in a
>> grounded copper tube?  etc.
>
> Isn't the whole point of grid dip oscillators that they are mild 
> radiators. What is the desired action?

I think he meant "GPS Disciplined Oscillator".

(It's ambiguous, and undefined, so for once, I'm not saying you're "wrong on 
the Internet". :^) )

Tim

-- 
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Contract Design
Website: http://seventransistorlabs.com 

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#446402

On 2/6/2017 4:57 AM, piglet wrote:
> On 06/02/2017 07:40, Don Y wrote:
>> How can I economically, simply and reversibly inhibit the
>> RF link to a GDO?  Short the antenna?  Slip it in a
>> grounded copper tube?  etc.
>
> Isn't the whole point of grid dip oscillators that they are mild radiators.
> What is the desired action?

Garage Door Opener

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#446416

On Mon, 6 Feb 2017 06:52:45 -0700, Don Y <blockedofcourse@foo.invalid>
wrote:

>On 2/6/2017 4:57 AM, piglet wrote:
>> On 06/02/2017 07:40, Don Y wrote:
>>> How can I economically, simply and reversibly inhibit the
>>> RF link to a GDO?  Short the antenna?  Slip it in a
>>> grounded copper tube?  etc.
>>
>> Isn't the whole point of grid dip oscillators that they are mild radiators.
>> What is the desired action?
>
>Garage Door Opener

My garage door opener has a slide switch at the inside wall control
that locks the opener from RF operation.
		
                                        ...Jim Thompson
-- 
| James E.Thompson                                 |    mens     |
| Analog Innovations                               |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| STV, Queen Creek, AZ 85142    Skype: skypeanalog |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |

     Thinking outside the box... producing elegant solutions.

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#446446

On 2/6/2017 7:55 AM, Jim Thompson wrote:
> On Mon, 6 Feb 2017 06:52:45 -0700, Don Y <blockedofcourse@foo.invalid>
> wrote:
>
>> On 2/6/2017 4:57 AM, piglet wrote:
>>> On 06/02/2017 07:40, Don Y wrote:
>>>> How can I economically, simply and reversibly inhibit the
>>>> RF link to a GDO?  Short the antenna?  Slip it in a
>>>> grounded copper tube?  etc.
>>>
>>> Isn't the whole point of grid dip oscillators that they are mild radiators.
>>> What is the desired action?
>>
>> Garage Door Opener
>
> My garage door opener has a slide switch at the inside wall control
> that locks the opener from RF operation.

That would be ideal.  But, if the receiver is in the power head,
then you'd not be able to purchase such a switch as an aftermarket
item to achieve the desired functionality -- you'd need another
control lead or other means of encoding the switch's position
onto the signal pair that normally actuates the opener.

As the Rx antenna is typically just a short length of wire protruding
from a hole in the case, its hard with JUST access to it to ensure NO
RF makes it into the receiver (e.g., if the user stood directly below
the opener and activated his remote).

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#446453

On Mon, 06 Feb 2017 12:38:47 -0700, Don Y wrote:

> On 2/6/2017 7:55 AM, Jim Thompson wrote:
>> On Mon, 6 Feb 2017 06:52:45 -0700, Don Y <blockedofcourse@foo.invalid>
>> wrote:
>>
>>> On 2/6/2017 4:57 AM, piglet wrote:
>>>> On 06/02/2017 07:40, Don Y wrote:
>>>>> How can I economically, simply and reversibly inhibit the RF link to
>>>>> a GDO?  Short the antenna?  Slip it in a grounded copper tube?  etc.
>>>>
>>>> Isn't the whole point of grid dip oscillators that they are mild
>>>> radiators.
>>>> What is the desired action?
>>>
>>> Garage Door Opener
>>
>> My garage door opener has a slide switch at the inside wall control
>> that locks the opener from RF operation.
> 
> That would be ideal.  But, if the receiver is in the power head, then
> you'd not be able to purchase such a switch as an aftermarket item to
> achieve the desired functionality -- you'd need another control lead or
> other means of encoding the switch's position onto the signal pair that
> normally actuates the opener.
> 
> As the Rx antenna is typically just a short length of wire protruding
> from a hole in the case, its hard with JUST access to it to ensure NO RF
> makes it into the receiver (e.g., if the user stood directly below the
> opener and activated his remote).

If it's got a plastic case, then you probably need to wrap the whole 
thing in metal.

Maybe put a tin can over the antenna, grounded to the power head casing?  
I give you no guarantees, but it may work.  If you're lucky you'll find 
something that telescopes well enough to make nice contact so you can 
just reach up and slip it over.

My experience with RF and cheap devices is that it doesn't work when you 
want it do, but it _will_ reliably work when you'd really rather it 
didn't.

-- 

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

I'm looking for work -- see my website!

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#446472

On 2/6/2017 1:18 PM, Tim Wescott wrote:
> On Mon, 06 Feb 2017 12:38:47 -0700, Don Y wrote:
>
>> On 2/6/2017 7:55 AM, Jim Thompson wrote:
>>> On Mon, 6 Feb 2017 06:52:45 -0700, Don Y <blockedofcourse@foo.invalid>
>>> wrote:
>>>
>>>> On 2/6/2017 4:57 AM, piglet wrote:
>>>>> On 06/02/2017 07:40, Don Y wrote:
>>>>>> How can I economically, simply and reversibly inhibit the RF link to
>>>>>> a GDO?  Short the antenna?  Slip it in a grounded copper tube?  etc.
>>>>>
>>>>> Isn't the whole point of grid dip oscillators that they are mild
>>>>> radiators.
>>>>> What is the desired action?
>>>>
>>>> Garage Door Opener
>>>
>>> My garage door opener has a slide switch at the inside wall control
>>> that locks the opener from RF operation.
>>
>> That would be ideal.  But, if the receiver is in the power head, then
>> you'd not be able to purchase such a switch as an aftermarket item to
>> achieve the desired functionality -- you'd need another control lead or
>> other means of encoding the switch's position onto the signal pair that
>> normally actuates the opener.
>>
>> As the Rx antenna is typically just a short length of wire protruding
>> from a hole in the case, its hard with JUST access to it to ensure NO RF
>> makes it into the receiver (e.g., if the user stood directly below the
>> opener and activated his remote).
>
> If it's got a plastic case, then you probably need to wrap the whole
> thing in metal.
>
> Maybe put a tin can over the antenna, grounded to the power head casing?
> I give you no guarantees, but it may work.  If you're lucky you'll find
> something that telescopes well enough to make nice contact so you can
> just reach up and slip it over.
>
> My experience with RF and cheap devices is that it doesn't work when you
> want it do, but it _will_ reliably work when you'd really rather it
> didn't.

That's exactly the problem I've been facing with my experiments.
The things that you *think* would work all seem to fall down
in unpredictable ways.

Tuck the antenna into the case so none of it is "exposed".  Nope.
Too much of the case (cover) is plastic.

Ground the (loose end of the) antenna.  Nope.

Slip a narrow dia copper pipe (like a soda straw) over the antenna,
threading it carefully into the hole in the case through which it
protrudes, then ground that.  Nope.  (too much of a "service loop"
within that can't be adequately shielded).

Encase the opener in a metal shield.  Nope.  Chain/screw drive needs
a means of getting out of the enclosure along with power cord
and *wired* connections (wall mounted pushbutton, infrared detector)
getting in.  (also, looks like shit!  This was just an exercise to see
how extreme I would have to get to block the signal)

Discipline yourself NEVER to use the remote (i.e., HIDE it) still
leaves that function active.

[Our old opener had a 12 or 14b code -- DIP switch.  When we moved in, I
set it to something "random" -- for certain interpretations of "random".
Neighbor replaced their opener in roughly the same timeframe.  And,
wondered why *his* garage door kept acting of its own accord.  Until,
one day, he watched us pulling into our driveway and HIS door CLOSING
coincident with ours OPENING!]

[A *really* old opener we had some 40 years ago would trip when we
vacuumed the bedroom floor -- located immediately ABOVE the opener]

Unfortunately, the "wireless remote" is considered such an ESSENTIAL aspect
of a garage door opener that it never occurs to the folks designing the
receiver(s) to include a provision that disables the remote.  E.g., set
code to "INVALID".

This is true of many wireless devices -- that also have valid functionality
with the wireless aspect disabled.  Try to give a stranger directions on
how to turn off the WiFi on their router:  what make/model?  what is the
downstream IP address of the router?  does it have a web-enabled management
console?  do you know the password?  etc.  At least many laptops have discrete
SWITCHES to enable/disable the wireless without resorting to BIOS settings
and "apps"!  (of course, these aren't standardized so its still a challenge
to come up with generic instructions...)

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#446496

Don Y wrote:


> Unfortunately, the "wireless remote" is considered such an ESSENTIAL
> aspect of a garage door opener that it never occurs to the folks designing
> the
> receiver(s) to include a provision that disables the remote.  E.g., set
> code to "INVALID".
What is it, exactly, that you are trying to do?

Do you want to permanently disable the RF remote?  If so, and it is one of 
the learning-type units, just press the learn button and then don't trigger 
any remotes for it to listen to.  (Possibly you might have to press the 
learn button at the end to inform it there are no more remotes to learn.)
that should clear the memory of any remote signatures.

If it is one of the really old units where you cut wires to set the remote 
code, then you might have to cut a circuit component to disable the 
reciever.  If it has a tuning slug in a coil, you could take the slug out.

I'm just guessing what you are trying to do.  If you want to TEMPORARILY 
disable the remote, that could be harder, if the unit was never designed 
with that in mind.  You could rig an extension cord, and unplug it when you 
don't want the RF to work, but then you'd have to plug it in to run it 
manually.  (Only good idea I can come up with is is an RF jammer, a little 
noise source placed right near the receiver, and plugged into a wall socket, 
when you want no remote control.)

Jon

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#446517

On 2/6/2017 4:10 PM, Jon Elson wrote:

> I'm just guessing what you are trying to do.  If you want to TEMPORARILY
> disable the remote, that could be harder, if the unit was never designed
> with that in mind.

Exactly.  Who buys a remote controlled garage door opener and DOESN'T
want the remote feature operable?!

> You could rig an extension cord, and unplug it when you
> don't want the RF to work, but then you'd have to plug it in to run it

People would find that tedious.

> manually.  (Only good idea I can come up with is is an RF jammer, a little
> noise source placed right near the receiver, and plugged into a wall socket,
> when you want no remote control.)

This is the option that I am currently pursuing.  But, without knowing the
make/model of folks' GDO's, I can't be guaranteed to know the correct
frequencies, etc. to overload the front end.

So, my approach is to use the *existing* remote as the "jammer"! But, set
to a "different" code (this is problematic for learning controllers!  how
do you pick a different code for the REMOTE after telling the GDO your
*correct* code -- which is done by using the REMOTE?!), affix it to the
power head with the button locked in the depressed position.  I.e.,
continually broadcast the "wrong" code in such close proximity
to the receiver that the "correct" code could never be recognized.

[No idea how to guarantee this!  Guy up the street works for Chamberlain
so I will touch base with him to see if he can get me some of the inside
scoop]

But, the battery in the remote will quickly die (ok, grab phantom power
from the series connection to the wall mounted pushbutton to power
the transmitter, indefinitely).

And, the frequencies used are not licensed for "continuous transmission"
so I'm probably tempting fate with this as a final solution.

[But, I may learn enough from it to concoct a legitimate alternative
based on the same principles -- maybe at much lower power levels (to
fall below the licensing requirements) and direct connection to the
antenna lead...]

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#446598

On 2017-02-07, Don Y <blockedofcourse@foo.invalid> wrote:
> On 2/6/2017 4:10 PM, Jon Elson wrote:

>> manually.  (Only good idea I can come up with is is an RF jammer, a little
>> noise source placed right near the receiver, and plugged into a wall socket,
>> when you want no remote control.)

> So, my approach is to use the *existing* remote as the "jammer"!

illegal.  you nned to reduce power significantly so as not to jam your
neighbours also...

-- 
This email has not been checked by half-arsed antivirus software 

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#446597

On 2017-02-06, Don Y <blockedofcourse@foo.invalid> wrote:
> On 2/6/2017 1:18 PM, Tim Wescott wrote:
>
> That's exactly the problem I've been facing with my experiments.
> The things that you *think* would work all seem to fall down
> in unpredictable ways.
>
> Tuck the antenna into the case so none of it is "exposed".  Nope.
> Too much of the case (cover) is plastic.
>
> Ground the (loose end of the) antenna.  Nope.
>
> Slip a narrow dia copper pipe (like a soda straw) over the antenna,
> threading it carefully into the hole in the case through which it
> protrudes, then ground that.  Nope.  (too much of a "service loop"
> within that can't be adequately shielded).
>
> Encase the opener in a metal shield.  Nope.  Chain/screw drive needs
> a means of getting out of the enclosure along with power cord
> and *wired* connections (wall mounted pushbutton, infrared detector)
> getting in.  (also, looks like shit!  This was just an exercise to see
> how extreme I would have to get to block the signal)
>
> Discipline yourself NEVER to use the remote (i.e., HIDE it) still
> leaves that function active.

connect the antenna to the driven end of the microcontrollers crystal?

-- 
This email has not been checked by half-arsed antivirus software 

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#446475

On Mon, 6 Feb 2017 12:38:47 -0700, Don Y <blockedofcourse@foo.invalid>
wrote:

>On 2/6/2017 7:55 AM, Jim Thompson wrote:
>> On Mon, 6 Feb 2017 06:52:45 -0700, Don Y <blockedofcourse@foo.invalid>
>> wrote:
>>
>>> On 2/6/2017 4:57 AM, piglet wrote:
>>>> On 06/02/2017 07:40, Don Y wrote:
>>>>> How can I economically, simply and reversibly inhibit the
>>>>> RF link to a GDO?  Short the antenna?  Slip it in a
>>>>> grounded copper tube?  etc.
>>>>
>>>> Isn't the whole point of grid dip oscillators that they are mild radiators.
>>>> What is the desired action?
>>>
>>> Garage Door Opener
>>
>> My garage door opener has a slide switch at the inside wall control
>> that locks the opener from RF operation.
>
>That would be ideal.  But, if the receiver is in the power head,
>then you'd not be able to purchase such a switch as an aftermarket
>item to achieve the desired functionality -- you'd need another
>control lead or other means of encoding the switch's position
>onto the signal pair that normally actuates the opener.
>
>As the Rx antenna is typically just a short length of wire protruding
>from a hole in the case, its hard with JUST access to it to ensure NO
>RF makes it into the receiver (e.g., if the user stood directly below
>the opener and activated his remote).

Have you examined the wall switch?  What brand of GDO?
		
                                        ...Jim Thompson
-- 
| James E.Thompson                                 |    mens     |
| Analog Innovations                               |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| STV, Queen Creek, AZ 85142    Skype: skypeanalog |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |

     Thinking outside the box... producing elegant solutions.

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#446483

On 2/6/2017 2:56 PM, Jim Thompson wrote:
> Have you examined the wall switch?  What brand of GDO?

GDO is just an example case of the problem I'm trying to address.
(but, THIS opener has no provisions for that; I'm not keen on wandering
over to neighbors' houses just to see if I can BREAK their openers!  :> )

It was a perfect "test case" for me:  it's already installed, in place,
doesn't require any prototyping or bench space, etc.

"How would/could I prevent the remote from affecting the opener?"

The approaches (outlined in previous post) that I *thought* would
have a marked effect on the opener's operation -- given that it
is often "finicky" in its INTENDED role -- were alarmingly
INEFFECTIVE!  Like shorting a power line in an attempt to trip a
breaker/blow a fuse and, instead, finding the fuse holding
but the wire getting hot!

"What do I have to do to force this NOT to work -- yet, ensure I
can return it to its normal state?"

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#446967

Jim Thompson wrote:
> On Mon, 6 Feb 2017 06:52:45 -0700, Don Y<blockedofcourse@foo.invalid>
> wrote:
>
>> On 2/6/2017 4:57 AM, piglet wrote:
>>> On 06/02/2017 07:40, Don Y wrote:
>>>> How can I economically, simply and reversibly inhibit the
>>>> RF link to a GDO?  Short the antenna?  Slip it in a
>>>> grounded copper tube?  etc.
>>>
>>> Isn't the whole point of grid dip oscillators that they are mild radiators.
>>> What is the desired action?
>>
>> Garage Door Opener
>
> My garage door opener has a slide switch at the inside wall control
> that locks the opener from RF operation.
> 		
>                                          ...Jim Thompson
...also, do not forget the power switch...

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#446965

Don Y wrote:
> On 2/6/2017 4:57 AM, piglet wrote:
>> On 06/02/2017 07:40, Don Y wrote:
>>> How can I economically, simply and reversibly inhibit the
>>> RF link to a GDO? Short the antenna? Slip it in a
>>> grounded copper tube? etc.
>>
>> Isn't the whole point of grid dip oscillators that they are mild
>> radiators.
>> What is the desired action?
>
> Garage Door Opener
>
   Color of a different horse.
   Not megawatts, just mere milliwatts.
   Firstly, the LO in Garage Door Openers are not well shielded; may we 
presume you "do not care" about that aspect, only the receiver aspect?

   Almost any kind of an input shorting scheme should reliably inhibit 
reception.
   Also, changing the LO frequency will inhibit practical functionality.

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#446413

piglet wrote:

>
> > How can I economically, simply and reversibly inhibit the
> > RF link to a GDO?  Short the antenna?  Slip it in a
> > grounded copper tube?  etc.
> 
> Isn't the whole point of grid dip oscillators that they are mild 
> radiators.
>

** LOL -  that's what I initially thought " GDO " stood for. 

 Then I realised the poster was narcissistic, piece of shit TROLL.

 
 

....  Phil 

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