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foojin · 06-12-2019, 10:23

Hope this is not too stupid of a question, but my understanding of the KISS ground is that it is a bunch of wires cut to 1/4 wavelengths. What is the difference between it and grounds such as the MFJ-1932?

There are many other ground systems that seem to be based on the same principle. Is there something about the KISS that makes it better suited to marine conditions and use?

Brian.D · 06-12-2019, 11:05

The KISS is enclosed in a black tube so you cannot see how the wires are formed. The theory is that the wire length and the way they are bent and the way they are taped to each other make for the perfect counterpoise for marine use.

Save your money. Before you purchase either the KISS or the MFJ, read this. You might be surprised how easy it is to make your own KISS. Also, after reading that you should read this.

foojin · 06-12-2019, 12:12

Brian,

Thanks. Read both the links. Fascinating.

Sitting here thinking, well, maybe I should connect to both random pieces of wire and a thru-hull. How could I possibly go wrong?

Another question... Also read Michael Jefferson's paper on SSB installation. Is there a lot of value in products such as lightning arrestors, line isolators and SWR meters? The reason I ask is other than Jefferson's paper I can find little discussion of them on marine forums and other websites.

Brian.D · 06-12-2019, 13:00

SWR meters without a doubt. One can always use that as a metric as to how the system is performing. When one starts to see a change (for the worst) in the SWR then one can assume that some maintenance might be in order. The other two, that is really a safety call. Just remember that the tuner might not be able to tune all the frequencies you want to use. So keep data on the bands you operate on.

Another thought. If you plan on going the route of a vertical dipole for single band operation, you might want to get an antenna analyzer to ensure it is tuned to the band you want. Not a major requirement but just a thought.

transmitterdan · 06-12-2019, 14:39

SWR is important. But it isn’t proof that the KISS is working. A resistor will have really good SWR but it cannot transmit very far. This is one way a KISS style ground system improves SWR. The more lossy the ground system the better the SWR.

ohgary · 06-12-2019, 19:27

Quote:

Originally Posted by transmitterdan

SWR is important. But it isn’t proof that the KISS is working. A resistor will have really good SWR but it cannot transmit very far. This is one way a KISS style ground system improves SWR. The more lossy the ground system the better the SWR.

Since most marine SSB stations are using a tuner SWR is pretty unimportant. The tuner will make the radio happy. Get the antenna legnth as long as possible and thats the best you can do. A 40 ft boat with a backstay antenna with a 50ft mast is going to give you 53ish feet of antenna, actually close to 48ft when you get the wire above your head. Most marine tuners will work on all marine freq with this size antenna. How much power goes out is going to be based on freq in use. That becomes the big question.

Brian.D · 06-12-2019, 21:16

ohgary, are you including the feed from the tuner when you say "get the wire above your head"? If not, then you are not calculating the length of the antenna correctly. Just saying...

As for the SWR and turner, if the tuner is not working correctly the SWR will be high. At home I have a MFJ Automatic Antenna Tuner and a SWR meter between it and the radio. There are frequencies that will not tune on my 106' wire antenna and the SWR lets me know right away.

The discussion was about the KISS vs and MFJ-1932. We should stay the course of the OP's question and not deviate.

MJH · 07-12-2019, 09:53

Quote:

Originally Posted by foojin

Hope this is not too stupid of a question, but my understanding of the KISS ground is that it is a bunch of wires cut to 1/4 wavelengths. What is the difference between it and grounds such as the MFJ-1932?

There are many other ground systems that seem to be based on the same principle. Is there something about the KISS that makes it better suited to marine conditions and use?

I am not familiar with the MFJ-1932 but I have the KISS installed on my boat and tested to Hawaii and back with oustanding results. We cruisers are tight with our money because we have so many ongoing issues to deal with. But for the current price of $149 I don't see any reason to f*** around playing with something else. Get it done, scratch the item off your To-Do list and move on.

~ ~ _/) ~ ~ MJH

waterman46 · 07-12-2019, 16:51

The MFJ is an almost true radial system - 8 wires of 14' length each, designed to be used on land in a 360 degree pattern. Those wires should actually be much longer if you want it to be an ideal ground on frequencies below the 15 meter ham band. Won't fit on a boat that way unless you have a rather large catamaran. KISS is just 1/8 of this system as they only can extend in one direction on a boat, but does have some advantage if you happen to be using a frequency which is very close to 1/4 wavelength of one of those internal wires in the KISS.

Not sure why anyone would pay for a KISS ground. Make your own using a bunch of wires of various lengths, ideally the longest should be 1/4 wavelength on the lowest marine frequency you want to operate on, and easier to install as you can snake them along, avoiding the many obstacles inside the hull. If you want do it scientifically, make one wire 1/4 wavelength for each of the marine and/or ham bands, subtracting the length from the junction point to your antenna tuner.

Auspicious · 08-12-2019, 03:41

Quote:

Originally Posted by foojin

Hope this is not too stupid of a question, but my understanding of the KISS ground is that it is a bunch of wires cut to 1/4 wavelengths. What is the difference between it and grounds such as the MFJ-1932?

There are many other ground systems that seem to be based on the same principle. Is there something about the KISS that makes it better suited to marine conditions and use?

The KISS-SSB is a reasonable (perhaps 90%) solution as a counterpoise. It's biggest advantage is that the very good mechanical construction means it will still be a 90% solution in ten years. The MFJ is going to corrode relatively rapidly and performance will deteriorate. You can do better than the MFJ with perforated twin lead you can buy in bulk and cut yourself. That will work better than the KISS for a while (a year? two?) and then need to be replaced.

Quote:

Originally Posted by foojin

Sitting here thinking, well, maybe I should connect to both random pieces of wire and a thru-hull. How could I possibly go wrong?

You aren't wrong. Counterpoise and ground are different things. Read up on single-point ground and on ground loops. In short, you want a single path to a single ground for everything on the boat.

Quote:

Originally Posted by foojin

Is there a lot of value in products such as lightning arrestors, line isolators and SWR meters? The reason I ask is other than Jefferson's paper I can find little discussion of them on marine forums and other websites.

Quite different things. Lightning arrestors are old wives' tales. Tens of thousands of volts, hundreds of thousands of amps are not going to follow little green wires (we call those wires "fuses"); they are going everywhere. Line isolators (trivial to build - you don't need to buy) help reduce common-mode radio frequency interference (RFI). SWR meters are great tools. I like the Daiwa CN-801HP since it works for HF and VHF. As has been noted, all it will tell you is that the tuner is making a match. They don't say anything about how well the antenna is performing.

Quote:

Originally Posted by ohgary

Get the antenna legnth as long as possible and thats the best you can do.

No. You want to avoid antenna lengths that are an integral multiple of a half wavelength at frequencies of interest. For an end-fed wire multiples of a half wavelength have very high impedance and tuners will struggle to make a match. The arithmetic is not difficult but it is tedious. I built a spreadsheet http://AuspiciousWorks.com/AntennaLength.xlsx that tests at band edges and center band with 5% margin (you can adjust that). It turns any band label red if the antenna is an unfortunate length. Remember the antenna length begins at the tuner antenna stud and includes the GTO-15 lead wire as well as your antenna.

I'm okay with the KISS-SSB. Avoid the GAM/McKim slide on antenna. Insulated backstays, alternate backstays, and whips are fine.

foojin · 09-12-2019, 14:56

Quote:

Originally Posted by Auspicious

You aren't wrong. Counterpoise and ground are different things. Read up on single-point ground and on ground loops. In short, you want a single path to a single ground for everything on the boat.

I didn't realize, if I am now realizing correctly, that an antenna ground and a ground for the boat's electrical system were the same things. Of course, makes me wonder in my ignorance why I could not attach the tuner ground to my boat's central electrical ground which is connected to wires that fan out through the boat.

Quote:

Originally Posted by Auspicious

You want to avoid antenna lengths that are an integral multiple of a half wavelength at frequencies of interest.

My understanding, as well. I will look at your spreadsheet. Does a 15-foot length of GTO-15 in the lazarette, wrapped in a foot-long bundle, count as 15 feet of antenna. If so, sounds like an easy cheat.

transmitterdan · 09-12-2019, 15:48

I would not recommend to connect the tuner ground to the battery minus. I would simply connect it to a below the waterline through hull close to the tuner. Use a wide copper strip at least 2.5” wide. 4 inches wide is even better. You want the tuner ground to connect to the water as easily as possible.

You can create some interference issues by mingling DC and RF ground.

transmitterdan · 09-12-2019, 15:50

It’s not a great idea to make loops out of the GTO cable. This can interfere with the tuner’s automatic functions. Best to just run the GTO wire straight from the tuner to the vertical radiator.

S/V Illusion · 09-12-2019, 15:52

Quote:

Originally Posted by foojin

I didn't realize, if I am now realizing correctly, that an antenna ground and a ground for the boat's electrical system were the same things. Of course, makes me wonder in my ignorance why I could not attach the tuner ground to my boat's central electrical ground which is connected to wires that fan out through the boat.

My understanding, as well. I will look at your spreadsheet. Does a 15-foot length of GTO-15 in the lazarette, wrapped in a foot-long bundle, count as 15 feet of antenna. If so, sounds like an easy cheat.

What you call an “antenna ground” or the “boat’s ground” are synonymous but recognize neither is an effective counterpoise which is what this thread asks originally. Many confuse ground with counterpoise.

Regarding coiled wire, the subject of inductance is something you probably don’t want to study so suffice it to say a coiled wire electrical length will be different than its physical length. It’s the electrical length which is important here so coiled wire is not a direct substitute for length.

Assuming you have metal seacocks, just run some random lengths to a few and you will have a counterpoise more effective than the latest magic dust gadgets like the KISS or its clones.