RG213U cable joins

[delatbabel]

Hi all,

One for the radio/tech heads to answer maybe.

I'm looking at fitting a VHF antenna for the AIS unit out the back, and I already have a run of RG213U cable that goes through a conveniently located and sealed through-hull in about the right place. The problem is that the ends of the RG213U have become frayed and slightly corroded. I cut back the cable somewhat and found good clean corrosion free wiring inside at each end, all good so far. I haven't electrically tested the cable but I'll do that before I proceed.

Using that existing cable would have the tremendous advantage of not having to cut the through-hull, since the cable itself appears to be permanently sealed in place, epoxied over, etc. The downside is that I would have to put a couple of joins into the run of cable to achieve that, one before the radio and one on the outside of the boat before the antenna.

Is the signal loss that I'm going to get running through a couple of additional PL259 plugs and cable joiners going to be excessive, to the point where I need to run an entire new length of cable? Or should things be OK using the existing cable and joiners?

[linnupesa]

Delatbabel

The connector loss would be so small as to be hardly measurable, quite likely much less than 0.2 or even 0.1db That means if it were an audible signal you'd be unable to detect any differences at all, even with a few connectors added.

Try to not to get globs of solder onto the male PL259 center pin outside, as that enlarges the diameter which could then physically distort the mating SO239 socket. That one has flexible tines or sides to grip the pin securely. Besides, solder is a poor RF conductor, unlike the often silver plated connector surfaces. ( it's a vanity thing with RF, superficial and surface mostly )

The AIS runs around 162 MHz or general marine VHF frequency channels and it seems you are talking about a very short cable run anyway. Long cable runs would introduce more loss than a few added connectors, especially as frequency goes up.

At 500Mhz you might notice a little loss and at 1 or 2 GHz it'll be increasing a lot which could become an issue for radar. Below 100Mhz it should only be defective or poorly made connections you should be concerned with. At HF ssb even wiring nuts are acceptable in a pinch, so you always keep at least one pair of those aboard, right?

Ivo s/v Linnupesa ( radio hamster station KI6S )