Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
Can you identify your outdoor transmitter model # please?
It is rather hard to find as replacement items go, and a model # for it would help considerably in the search I have already done to some extent (and found nothing so far.)
(Sorry to have disappointed you.)
Since you would obviously prefer that someone else help you, I have Opted Out, opening the case to other Experts in this case.
Different expert here.
In case you were not aware, Sharp no longer makes or markets (sells) weather stations of this type, so finding replacement parts - such as the remote transmitter - can be VERY difficult.
But if you really like this particular system, you can still find similar systems for sale online, at places like Amazon and eBay. I have a link to a listing on Amazon below for a similar system (SPC595 I believe), and that transmitter MAY work with your system.
Click here for listing --> http://amzn.to/2elhfbM
Also, if you scroll DOWN on that listing you may see OTHER more modern weather systems - from other manufacturers - that have similar features and at a lower cost.
NOTE: The makers of these systems that have been around for a LONG TIME are companies like LaCrosse Technology & Ambient Weather.
I hope this helps. Please let me know what you find or if you have any more questions.
Take Care, Greg A.