Whoops, I'm a little behind on my Slovenian. It's the Ložu valley, where Snežnik Castle is located. All my late wife's relatives were (and are) from the Stari trg pri Ložu area and the Postanja area. I don't remember traveling through your town but there are so many villiages in the area I lost count.
We went from Postanja to Piran and Porto Roz (or Porto Benton, a better description) so we were certainly in your area.
I am from the USA in the state of Alabama, which is in the southeast part of the country. My wife was also from the USA but she was half Slovenian as her grandparents on her father's side both came for Slovenia to the USA in the early 1900's. We had a great time in Slovenia - the country is beautiful and the people are so friendly. But, we are straying far from radios.
I guess TETRA did win out then. I thought it would since it seems to be almost the EC standard now. The antenna in the link looks fine assuming you got it with an SMA adapter. If you're using a SMA to BNC adapter, you're putting a lot of strain on the antenna connection and probably losing some signal strength.
If you head towards Postanja and use close call, you should pick up some local services. The SŽ was operating on VHF around 165 mHz when I was there were forest rangers (don't know the correct term in Slovenian) on UHF. I don't think there are many scanner listeners in Slovenia so anything you come up with will help others in Slovenia. I did notice that there was some hostility about having a scanner near the Croatian border so take care.