Antenna whips

Brian D · Nov 15, 2020

You can by whips off of ebay. I did that for some HF whip antennas I had. Just in case I cut them too short. I would think that if you use anything other than an antenna whip, it might look like a coat hanger on your 74 Ford.

Don S/V ILLusion · Nov 15, 2020

The trick is picking the correct length if you don’t have the old one to compare. While the resonant length is easy to calculate, the base loading coil length varies between manufacturers which changes the physical length of the whip. If there is no loading coil, it’s straight-forward.

Brian D · Nov 15, 2020

Vesper might also sell you a replacement whip. Might be a little higher in price than a generic whip. Your call.

jssailem · Nov 15, 2020

Bob, my experience with Vesper has been excellent... Just remember they are in NZ, different time zone and day, which can make the response time little confusing at times.

Brian D · Dec 8, 2020

It depends on the actual length of the original whip. Do you now the model number of the broken antenna? Most are 36" so it shouldn't be a problem. As I mentioned, I replace my whips with generic whips and had no issues. So the worst that could happen is it won't work as well as the real antenna. I don't think that will be an issue. Look up you antenna and see what the sales brochure says. If it indeed says 36" whip, then a generic whip will work.

Now for the potential show stopper. If you cannot get the old whip out of the base then all this is moot. Check to make sure you can remove the set screw and remove the carcass of the old whip. If you can't then you will need to replace the entire antenna.

Good luck

jssailem · Dec 8, 2020

Bob S said:
I had no problem with the VHF or AIS all season.

that you know of. Perhaps you had use but I am guessing that with the whip gone your range should be limited.

Your Vesper software has the ability to tell you the antenna VSWR.

VSWR

The voltage standing wave ratio (VSWR) is defined. VSWR is a measure of the reflected power on a transmission line. VSWR is a function of the characteristic impedance of the transmission line and the impedance of the antenna. VSWR specs (specifications) are introduced, along...

www.antenna-theory.com

For a radio (transmitter or receiver) to deliver power to an antenna, the impedance of the radio and transmission line must be well matched to the antenna's impedance. The parameter VSWR is a measure that numerically describes how well the antenna is impedance matched to the radio or transmission line it is connected to.

jssailem · Dec 8, 2020

Every thing "boat" is a project, and a learning experience for me.

dLj · Dec 8, 2020

Our society has become a use and throw - building and\or working on things from a fundamental level is now becoming further and further from our perspectives. Boats have never arrived to the "remove component X replace with new" type mentality that the majority of our society has grown used to. This all adds to the feeling of "project" when doing work on boats...

dj

Don S/V ILLusion · Dec 8, 2020

Bob S said:
Anyone see a problem with the 3’ 3mm from McMaster?

Go for it. The radio can't read the brand name on the whip.
Just for peace of mind, I'd put a VHF SWR meter or even better, an antenna analyzer on the rig when done to verify a reasonable match. The former is both cheaper and pretty straight forward.

jssailem · Dec 8, 2020

Don S/V ILLusion said:
an antenna analyzer on the rig when done to verify a reasonable match.

His Vesper Software has that included. Just have to know what it is and use it.

Ken Cross · Dec 8, 2020

Don S/V ILLusion said:
Go for it. The radio can't read the brand name on the whip.
Just for peace of mind, I'd put a VHF SWR meter or even better, an antenna analyzer on the rig when done to verify a reasonable match. The former is both cheaper and pretty straight forward.

The issue here is once the mast goes up it becomes really difficult to adjust the length for a good VSWR. It would be way less trouble to get the right part or replace the whole antenna.

FastOlson · Dec 8, 2020

After well over a decade of use the ss whip fell out of our masthead antenna. I found it on deck one day.
Next haulout we replaced the whole antenna assembly. The bottom loading coil was showing UV damage and age.
As Ken tried to point out, it's a looooong way up there and I would add that doing this work from a bosuns chair is not easy.
When the yard did this replacement while the boat was hauled for a bottom job, they used their 4-wheel electric Man Lift, and the guy could work on it up-close with no problem... I got billed for about a half hour of time.
Seemed like a really good deal!

Don S/V ILLusion · Dec 8, 2020

Ken Cross said:
The issue here is once the mast goes up it becomes really difficult to adjust the length for a good VSWR. It would be way less trouble to get the right part or replace the whole antenna.

I understand but you don’t need to wait until after you raise the mast to check.

While height, orientation and proximity to nearby objects will affect SWR, that doesn’t mean you can’t tune it for minimum SWR; only that the minimum you see at ground level will be higher than when erected. Just tune for minimum SWR as the optimum antenna length won’t change.