Robert11 wrote:
Hello,

Should have asked this also in my previous post re 50 or 75 ohm coax, but
I guess it is probably better to start a different thread.
New at this, so please pardon these very basic type of questions.

For a receiving only application, 30 MHz on down:
Putting up a new Inverted-L receiving antenna.

Radio, Balun, Lightning Arrestor use the 259 type of plug which I guess is
nominally for 50 ohm systems.

I can go with 75 ohm BNC connectors for the main coax run, but am pretty
well stuck with the
259 type for the already purchased units I noted above.

Intuitively, I guess I would like (all) 75 ohm connectors if I am using 75
ohm coax.

But, for 30 MHz and lower listening, would I even notice any difference,
probably ?

No. You wouldn't even if you were transmitting.

Is any received signal lost, or reflected back, at these 75-50 ohm junctions
?

No significant amount. The length of the discontinuity is extremely
short compared to a wavelength, and it's not a terribly bad
discontinuity. You'd be hard pressed to measure the difference at HF,
even with very good equipment. (Of course, you could see it with a high
speed TDR, but that's not an HF measurement.)

Roy Lewallen, W7EL