Lost sensor contact

So the weather station has been up and running for a while now but something has been bothering me. About twice per hour I get a “lost sensor contact” message from the software. Occasionally, it looses contact for a few hours at a time before it comes back.

I think it is because the sensors are around 50′ away through 3 brick walls and the fact that the receiver is located in my shack which can be a noisy RF environment at times.

The solution? A external antenna hack…

The unit in question, a WH-1081 weather station.

An SMA fly lead. I will cut the plug end off.

The back removed.

Original antenna and receiver board.

Hole for SMA socket

SMA socket installed and connected to the receiver board. I connected the ground of the coax to the battery ground.

All put back together.

The finished result.

I put a spare 60cm long 434Mhz antenna on the top to test and so far, after 3 hours, it has not lost sensor contact once.

12 Replies to “Lost sensor contact”

  1. Hello, I’ve noticed improvement consultants in the distance from the transmitter to the receiver?
    I am working on this issue and I need to have greater range, need to get up to 900 feet (100 meters).
    I placed an external omnidirectional antenna at the transmitter 433 mhz and arrived at a range of 130 meters.

    Very good job, very neat

    Regards, Paul

  2. Thanks Paul, it has been working great for me.

    I only modified the receiver though so that the transmitter stayed within its licence free specification.

    Matt.

  3. Very nice, a neat job. I have the same problem and will try this fix.
    Can you recommend a place to buy the 60 cm antenna? I’m in the US.

    Thank you.

  4. Hi Steve and thanks.

    It does work very well and, most importantly, is perfectly legal as you are only upgrading the receive part of the equipment.

    Any Ham radio handheld antenna designed for the 70cm (430Mhz) band would work well. Just make sure that it has the right connection on the antenna for your socket.

    The antenna I used was a Intek KA-505-LN that I had laying around.

    Matt.

  5. THanks, i had a signal problem, and with this i fix that

    very good job!

    Regards. GUido

  6. Hello,

    Great little bit of information on here. I have been wondering on how to do this for ages. Just need to buy a UHF antenna. Do you know how to do this on the unit that sends the data? It would be a great help. Also if you have any videos on youtube can you let me know please

  7. I have not looked at the transmitter unit. Modifying the transmitter would make it unlicensed and therefore illegal to use and it could also damage the waterproofing of the unit.

    With a good antenna on the receiver, you should not have to do the antenna on the transmitter.

    Matt.

  8. Ahh right okay thank you. I didn’t know about that licence. So I am guessing then a UHF Linear Amp would be a big no no. I’m guessing a low powered repeater system would be okay though? I see that there are such things out there but they cost a lot of money. Would you say this is the way to go?

    Thanks for the reply

    Jacques

  9. I have had the same problem and a Google search led me here, I didn’t have the parts you used and so I have installed a temporary aerial from an old broken child’s remote controlled car.
    So far I now have a good connection and so I’m going to source the parts you used and hopefully that will be an end to the signal dropout.
    I think the receiver should come with an external aerial socket!

  10. Great work. I’m glad that it’s working for you. The random “Lost sensor contact” message is very annoying!

  11. in my case it was already enough to simply lead the red wire-antenna through a whole in the casing and straighten it out.

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