I see the center pin on a typical N connector is pretty small

How much power could it hold at HF and also uhf/vhf
frequencies? Assuming a modern day high quality N connector??

The power handling capability of a connector is determined by both its voltage
limit and its current limit, whichever of the two is more constraining.

The N connector voltage limit is usually stated to be 500V (peak), corresponding
to an RF power of 2,500W over 50-Ohm impedance. Please note that the 500V limit
applies to the extreme environmental and conditions (e.g. temperature, humidity)
so, for a normal usage, the connector would well withstand more than 500V.

Conversely, I was never able to find a specification for the N connector current
limit. This will actually depend on the usage conditions, i.e. whether a
round.the-clock broadcast service, or an intermittent amateur service. With a
power of 2,500W, the rms current through the connector would be about 7A (at 50
Ohm), a value that, given the size of the inner pin, I would consider well
tolerable for amateur service. For a broadcast service instead it would perhaps
be safe not to exceed 1,000W at VHF, or somewhat less at UHF.

The other thing i pondered is that it seems the don't make
Pl259/so239 connectors for hardline, so what do guys use typically for
higher power DIN?

The PL259 connectors are low-cost connectors that are simply unknown in the
professional world. Main reasons a
- they do not offer a controlled impedance across the connector length
- they are not sealed, and hence offering no protection against humidity
- the ground connection is unsafe. If the connector does not remain well
tigthened under all operational conditions, one can never be sure on the
continuity of the ground path.

For hardlines there is a good choice of connectors, see
http://www.surplussales.com/connectors /HardLConnIndex.html

73

Tony I0JX