I get 2 bars less than friend who has a Pearl-both t-mobile
I used to get at least 1 more bar until 3-4 months ago
upgraded software
changed to new sim card
no improvement
is there a way to add an external antenna?
Thanks for any help with this!

Are you checking the two devices side by side at the same time and same location? If you are comparing in different locations, then it is an unfair comparison.

Can't add an external antenna if there isn't a place for it.

It is a pretty old device. Probably getting close to the end of its life. Maybe time for a new device ?

Yes, we checked them side by side in multiple places.
Are you saying there is no place to attach an external antenna to a 7100t? There is a small square opening just above the release button for the battery cover (under the cover) that I was hoping was an antenna port.
I'm assuming the internal antenna is the problem. Is it repairable or replaceable? I'd like to wait til my contract is up to get a new one.

Repair would probably cost more than the device is worth. Check with your carrier and see what they have to say.

I am not a 7100 expert. The 7100i might have had an external antenna of sorts.

I did a quick Google search on "7100 external antenna" and turned up a few hits, but I don't know if they are in stock or if they would even work. So Google

The 7100i had an external antenna but most iden devices did. There is no way to attach any external antenna to the 7100t.

Time to face the facts. It's time for a new BlackBerry!