Banjo Uke Tuning 'Issue'

I've just acquired my first banjo-uke and absolutely love the sound of it but I've got the following tuning 'issue'...

With the open strings in tune... for first few frets, say 1st to 3rd, the fretted notes are considerably sharp, for the higher frets, say 10th to 12th, the fretted notes are (slightly) flat, and for the frets in the middle the fretted notes are just about right. This is the same for all the strings and the degree of flatness/sharpness is pretty much indep of the string.

To add to my confusion, the bridge seems to be in the wrong place... distance from but to 12th fret is 17.2 cm but distance from 12th fret to bridge is around 18.2 cm. To my mind that should make all the fretted notes flat but the 'flatness' should increase as I move towards the 12th fret...

I appreciate there's a few posts on these sorts of problems but I couldn't find any posts with exactly this issue or with any solutions for me...

At present my solution is to capo around 4th fret and play from there. For these frets it's pretty much in tune (to my ears at least) and I love the sound up there anyway. But uncapo'ed it sounds pretty rough and wouldn't be in tune with other instruments

The saddle on these instruments is floating so its up to you to set it properly. The distance from nut to saddle should be the distance from nut to 12th fret x 2 + compensation. If I've read you correctly you have 1 cm of compensation! That's way too much. Bring the compensation back to 2 to 3 MM and try setting the instrument up again.

My banjo ukulele is a temperamental beast too. Make sure that the strings are sliding easily through the nut slots.

Anthony

Once I got my B/U intonation set up right,I used a pencil
to draw on the head (vellum) both sides of the bridge.
Only faint pencil lines,but I can quickly visually check that
the bridge has not moved!

Cheers guys ... after some in-depth harmonic analysis (!) I think there's a prob at the nut - effectively lengthening the strings a little beyond the end of the fretboard ... so that when fretted it's sharp ... the bridge is out on purpose to compensate and flatten everything off.

Anyway I think it's the nut so my solution is to detunethe strings and capo at the 1st fret... this takes the nut out of the equation and is working fine so far ... then I might be able to place the bridge a bit better ... then think about what to do about t'bridge

I'm loving playing it (and also secretly enjoying the dark arts of 'tuning')

The nut being out of place is more common than you would hope. I've sent several ukulele's off to luthiers to have the nut placed correctly.

Anthony

Having said thinking what to do with the bridge, I experienced similar scenario with my DRUMJOLELE, that is, as I pick and twick hard the strings I noticed that the bridge slides creating unwanted sound. Since the head is not made of lamb skin I found the double sided (very thin like teflon) tape very handy. This also ensures the rule of thumb "nut to 12th x 2" plus the sideways movement.