"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...
No. Well, maybe. Hell, why don't you just extend the existing wire antenna to the outside and treat it like a long wire antenna.
It might work. Or it might make the receiver oscillate :).
Most of this VSWR is due to the fact that the small antenna has a high (capacitive) reactance. Tuning it out with a loading coil, you only have a smallish resistance mismatch and hence much lower VSWR.
You tune out the capacitive -j707 ohms with a loading coil +j707 ohms and you only have to worry about the resistive 1.52 ohms. To match this to a 50 ohm input, the impedance ratio would be 1.52:50 or 1:33 or less than 1:6 turns ratio.
A few cm long "rubber duck" (normal mode helix) is a reasonably efficient antenna for 433 MHz.
But only for certain values of "reasonably" :).
...Jim Thompson
OK Jim, What is the model # of your opener, Let's find out what the output circuit looks like. Here's a few,
Mike
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Door is a sheet-metal sandwich with the insulation between the two metal panels. Walls are foil-backed exterior sheathing plus foil-backed drywall inside.
Dramatic range improvement.
[snip]How about this... Drill hole in door, fit water-tight thru-hole BNC connector, attach rubber ducky antennas to each side. Would that be enough of a "window"? ...Jim Thompson
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| James E.Thompson | mens |
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I love to cook with wine. Sometimes I even put it in the food.
Genie Model 2024
Can you simply buy a 433MHz receiver that has a relay output? ...Jim Thompson
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| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
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I love to cook with wine. Sometimes I even put it in the food.
Well, it has half a chance of working, and half a chance of making things worse. It depends on which side of the dipole you poke through the wall. Half-baked is usually the result of half-way solutions and half-ass kludges. The reason I can only offer half a reply is that I have not seen anyone build a working antenna like that, which should be a clue as to how well it might work. If you're going to drill a hole in the wall, you might as well put the entire antenna outside. However, if you insist on doing it wrong, just make sure you put the half of the dipole that goes to the coax center conductor outside the garage, and the grounded half of the dipole inside the garage. With foil backed insulation in the wall acting as a ground plane, no RF will radiate from the grounded half of the dipole, giving you a better than half-way possibility of making this technical abomination work.
1/4 wavelength at 433 MHz is about 17.5 cm.Incidentally, the problem with attaching a bigger/better/outside antenna is that it MIGHT detune the receiver. If it's a crude TRF (Tuned RF) receiver, where all the selectivity is one tuned circuit connected directly to the antenna, any changes in antenna configuration is going to create a problem. As Mike K suggested, you'll need to look at the schematic to see if there's any isolation between the antenna and the tuning.
Beware of engineers bearing screwdrivers (and tuning tools).
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
They're all over eBay in many different configurations.
The problem will be getting one that is compatible with your cars Homelink remote. That means you'll need to buy both the receiver and transmitter because the transmitter is needed to program the Homelink thing. However, if you're not going to use Homelink, then it's not an issue.
Also, methinks we might be wrong about the frequency. The Genie 2024 runs on 390 MHz or possibly 315 MHz frequency. Genie got into problems in areas where the military was using 390 MHz for something. I'm not sure as I couldn't find any specific references. I could lookup what it does by the FCC ID number, or you could just hang a frequency counter near the trasmitter and see what frequency the remote belches.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
Cell phones are used for that, too.
Luckily, some fraction of bomb builders blow themselves to bits before they are finished.
-- John Larkin Highland Technology, Inc jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Don't assume that just because someone is a terrorist/ freedom fighter (Delete to taste) that they are stupid.
The information is readily available with a simple google search, the bad guys also have computers, and are quite often *very* competent in their use.
-- Tciao for Now! John.
John Williamson scribbled...
Should you start searching for such info, you'll soon be getting unexpected visitors
Not if I search for "How do I increase the range of my garage opener". Maybe you were daft enough to search for "How do I trigger a bomb by using a garage opener"? (Hint:- a relay is involved for the simple method).
Anyway,in the OP's case, it's simple. Move the aerial to the outside of the screened metal box he's just put it in, or use the foil on the door as the aerial.
-- Tciao for Now! John.
Looks like about 9 wires to move the control circuit board, includes the receiver, outside.
I got that pdf from here
I didn't find a schematic.
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As I understand it, the cell phone is also the device of choice for long range garage door openers. I know someone who has a system that lets him dial in through his house phone, which then activates a motor and it's open by the time he gets there. So far as I know, his garage door hasn't exploded yet.
I have a whole set of tuning tools, in their original pocket protector. (I grew up in a Radio/TV repair shop in the late 50's, when there were IF cans aplenty :-) ...Jim Thompson
-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at
Looks like this will do it...
or this one is cheaper...
...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
The iphone 4S did have a design glitch where the way some held it was a problem in that regard. The others are fine.
That's a lot of speculation and maybes. How about he look at what he has and goes from there. I'll bet it is one of the single chip code hopping solutions from any one of a bunch of manufacturers and I doubt that it will be a super- regen anything. And, he didn't say that he cared if the FCC might not like the mod.
Where?
I'm curious how you calculate these values?
Does that leave two wires a crook could short to open the door? Important not to forget the "other" reason for a door opener...
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