Replaced new battries, only inside temp come on. ouside transmitter seams to be transmitting but temp does not show

It is the transmitter to an atomic clock and temperature display. It is in the window to collect the data from the satellite and pass it to the clock.
SkyScan Atomic Clocks - Customer Support, User Manuals ...https://skyscanatomicclocks.comThe SkyScan® Atomic Clock automatically sets itself to the correct time and date by receiving and decoding the NIST radio signal with an internal receiver. It ensures daily accuracy to the fraction of a second by refreshing the signal each day.‎User Manuals · ‎Daylight Saving Time · ‎Support Desk · ‎Quick Reference Guide for...

Or a Lacrosse Weather Station part

Skyscan – La Crosse Technologyhttps://www.lacrossetechnology.com › pages › skyscan
Ordering Replacement SkyScan Temperature Sensors To order a replacement sensor for your item, please locate your model number in the list below and click ...

SkyScan (tx6u/86722alu) 433mhz Temperature Transmitter ...https://www.ebay.com › ... › Weather Stations
Item description "The La Crosse TX6U works outdoors by sensing temperature and transmitting that information to an indoor station. It can transmit to a base up to 80 feet away. Multiple sensors can be assigned a number so that it will be clear which information from which sensor is displayed."
US$28.66 · ‎In stock

You are using a wireless system that transmits signals between the outdoor sensor and the indoor receiver. They are not a perfect match. You cannot make adjustments, thus if your lucky, the factory matched up the devices prior to the sale. You may contact Lacrosse for a replacement outdoor temperature device.

Sometimes, you have to remove all the batteries in the transmitter and receiver and wait a few minutes before the next step.

Then you replace transmitter batteries first and within 30 seconds, get the batteries installed in the receiver. This allows the receiver to link up with your transmitter. Both units need to be reset this way. You'll see the temperature and any other information the transmitter provides come up in a few minutes. This works with my La Crosse weather station. Using the reset buttons without removing power will not work. My nieghbour has a weather station from another manufacturer and this is also the only way that his will link up.

The clock actually receives the radio signal on it's own, you don't need to transmit the time to the clock on your own.

Seems to be a consistent problem with Skyscan. I have the 88800 model and my outdoor transmitter isn't transmitting the temperature either. We've replaced the batteries in both the transmitter and clock and nothing for outdoor temp. It's only been used for 9 months.