Looking to ID antenna on this little electronic

[Rusty Bumper]

This may seem insignificant to you but I am not spending the $ they want for a new name brand one.
This is an aftermarket opener for my Liftmaster. It has poor range but at least it will work as I am on the other side of the door.
Can any of you identify the antenna on it? I am hoping I can add a length of wire to get more range out of it. .....unless adding a length won't work for a transmitter.
Thanks for your help.
Rusty

 

[PCustoms]

I don't see an antenna loop

Odds are you can't just add a wire, as the chip is tuned for a specific antenna

 

[American Locomotive]

The antenna is the light green trace running around the entire outer edge of the circuit board.

I'd probably try putting a new battery in it before soldering more antenna onto it.

 

[Metal-Marc]

This may seem insignificant to you but I am not spending the $ they want for a new name brand one.
This is an aftermarket opener for my Liftmaster. It has poor range but at least it will work as I am on the other side of the door.
Can any of you identify the antenna on it? I am hoping I can add a length of wire to get more range out of it. .....unless adding a length won't work for a transmitter.
Thanks for your help.
Rusty

LoL

That's not how this works.

 

[wyliesdiesels]

Theres no antenna connector so im not sure how youre gonna add an antenna onto that

 

[Metal-Marc]

I am hoping I can add a length of wire to get more range out of it

before soldering more antenna onto it.

not sure how youre gonna add an antenna onto that

You can't. This is a tuned circuit, you can't just solder wires in there hoping to improve anything. You won't.

Like AL said, try a fresh battery.

 

[PCustoms]

The antenna is the light green trace running around the entire outer edge of the circuit board.

I'd probably try putting a new battery in it before soldering more antenna onto it.

Yep

It's exactly what I was looking for, just missed it.

As myself and others have said, it's a tubes circuit you can't add to it.

 

[Innovate1]

You say it is aftermarket. Maybe buy a real liftmaster remote or a better third party one. Someone once said you can always make something a little cheaper and a little worse - the Chinese are experts at that.

 

[mikedodge]

You get what you pay for.
They're usually not all that expensive to begin with.

 

[Rusty Bumper]

Thanks for your help every one!
A new ones (both factory transmitters failed early) were too expensive and the price point on these were such that I could order one for the 2 vehicles as well as the 4 wheeler.
I think I will put in a new energizer battery and then be more thankful that I don't have a manual garage door.

 

[American Locomotive]

I mean if these transmitters are super cheap, you could just try soldering a length of wire to somewhere on that ring antenna on the PCB. It will either make things better, or make it worse. Probably not much to lose.

 

[dogdog]

First find out what is the transmitting frequency. Then find out the antenna wire length needed and find out the resistance is that antenna to match the impedance if the circuit. I think that is the terms use. Some ham guy will probably jump in to give you more info. Maybe also check if your receiver can take a better antenna?

 

[RPH]

Couple things I noticed. This is a tuned resonant circuit. Any change can and will affect its response to signal.
Best to use a scope that can identify the frequency for tuned circuit.
The red capacitors on the board are coupling caps for the ac signal. The trace acts as the inductive part of the antenna. To enlarge the antenna loop the coupling caps will need to change due to increase in the inductive element.
Also, with the chip number, all I could find was surface mount but no 14 pin units.
N channel mosfet is described.
So, to do the job, you need to remove the blue circled capacitor. Now you have an open loop. Add your extended antenna wire, calculate the inductance change from original. With that information you can calculate the capacitor changes with the three caps. The blue circled cap has to be in series with new antenna lead when connecting to board.
Antenna design is a complex mathematical effort and hope for the best. In other words be ready to tune the circuit.
Good luck.

 

[Metal-Marc]

Good luck.

Yeah good luck.

Unless you're an RF engineer and do this for a living, you will not improve anything.

Unless you have experience, you will damage the board trying to remove SMD components or solder them back on.

Nothing wrong with experimenting, but once OP starts to fiddle with this board, it will be toast.

 

[dogdog]

https://nz.apexelex.com/specs/rf_ics_ism_band/RF60.pdf

probably easy to do, cheap for experiment, easy since it have some sort of automatic tuning on chip, but still have to find out your transmitter frequency, easiest is to find the FCC ID on the shell of that transmitter. ALL transmitting/receiving devices have FCC ID sold in the US. Even if everything is redacted out, transmitting frequency is still there. buy the right antenna design on your center freqency will give you optimal transmission range. I got bunch of SMA connectors on ebay for cheap, antenna, well... dependent on your frequency. I believe all garage door transmitters are in 40's 300s 400s or 900s MHZ those... you can certainly be "Sepcial" of cause.

use https://FCC.IO to search, if you don't have "special equipment to measure.

 

[Rusty Bumper]

If it is not as simple as "yeah, just solder a 3" copper wire here", then I am good with the current range, albeit short.
I truly appreciate all of your replies. This is a great group to go to for answers.

 

[dogdog]

If it is not as simple as "yeah, just solder a 3" copper wire here", then I am good with the current range, albeit short.
I truly appreciate all of your replies. This is a great group to go to for answers.

it's not that complicated, just have to know what you are doing.

 

[infinkc]

Thanks for your help every one!
A new ones (both factory transmitters failed early) were too expensive and the price point on these were such that I could order one for the 2 vehicles as well as the 4 wheeler.
I think I will put in a new energizer battery and then be more thankful that I don't have a manual garage door.

Liftmaster has excellent customer service, I’m sure if you contact them they would replace them.

 

[Metal-Marc]

it's not that complicated, just have to know what you are doing.

Knowing what you're doing is the complicated part.

 

[acer66]

Knowing what you're doing is the complicated part.

Man that made me laugh out loud.
Thank you.

 

[Blueshound_GJ]

Harsh crowd here!

OP, why not try the other end - the motor assembly should have a 12" or so wire sticking out as an antenna. Try bending it up, down, or sideways to try for better reception.

 

[Rusty Bumper]

Harsh crowd here!

OP, why not try the other end - the motor assembly should have a 12" or so wire sticking out as an antenna. Try bending it up, down, or sideways to try for better reception.

You're thinking outside the box! I believe I saw a yellow wire hanging down as the antenna from the drive motor/box on the wall.

 

[dogdog]

You're thinking outside the box! I believe I saw a yellow wire hanging down as the antenna from the drive motor/box on the wall.

First find out what is the transmitting frequency. Then find out the antenna wire length needed and find out the resistance is that antenna to match the impedance if the circuit. I think that is the terms use. Some ham guy will probably jump in to give you more info. Maybe also check if your receiver can take a better antenna?

Lol

 

[rockettauto]

Yep. Only two real ways to gain range on the transmitter. Switch to unidirectional antenna or add power ie amplifier.

You could add a parabolic reflector to either end with no circuitry involved. Still more practical to do on the receiver end. You'd have to experiment with the direction it's aimed though, its likely it receives more from a direction that is not toward the door.

Plenty of places online to calculate a parabola and plot it's shape and choose it's focal distance, which is where you'd want the receiver antenna to hang out. Then it's up to you to approximate it. I'd do something in a half tube shape for the length of the wire.

Or in a half hearted attempt just slip a couple of these over your receiver antenna along with providing a way to stiffens it so it stays in the focal zone.

https://www.amazon.com/dp/B073W928GJ/?tag=atomicindus08-20

 

[Blueshound_GJ]

Aluminum foil can also be fashioned into a crude reflector at minimal cost. If there's a DirecTV antenna around it would be a decent form. Trial and error of course

 

[dave*99]

I did the calculations. Here is the result. This is a scene from the Donner party so I think I got great reception

 

[walta]

Some of us think we understand electronic and how they work and have success but I am convinced radio frequency circuits run on pure magic things that you thought of as insulators are suddenly capacitors and moving a wire 1/16 of an inch makes a huge difference.

Antenna design is a black art onto itself. Bigger is not necessarily better.

If you are unhappy with this knock off find another.

At least consider the possibility that you have tried 5 different transmitters and they all preform poorly maybe it is not a transmitter problem. Local interference from another source would not be uncommon and wireless alarm sensors are notorious offenders and a receiver fault is possible.

 

[dave*99]

LED bulbs make a lot of RF noise too. Are there any nearby or in the GDO itself?

 

[Rusty Bumper]

LED bulbs make a lot of RF noise too. Are there any nearby or in the GDO itself?

I put led in my jeep where the this is located, but they are not on while in use.

 

[dave*99]

Mostly the ones powered by AC make noise.

How was performance with the original Chamberlain transmitters?

 

[Rusty Bumper]

How was performance with the original Chamberlain transmitters?

As far as I remember the range was good. But they were then intermittent and I went through a lot of batteries thinking it was the battery. Then they (2) did not work at all after about 18 months. I threw them in the trash. I believe replacement were north of $45. This was about 5 years ago and I have been using these $12 replacements ever since.

 

[dave*99]

How old is the GDO?

 

[Rusty Bumper]

LiftMaster 8500. They are about 10 years old.

 

[ybnormal]

Bigger is not necessarily better.