KISS counterpoise vs MFJ-1932

[foojin]

Hmm. How does one score 99% on their ham exam, yet know nothing about radio operation, either ham or SSB? Good at remembering, understanding not so much.

Thanks to all for the input and study ideas. Getting a bit closer.

[Brian.D]

Since the discussion has seemed to morphed to antenna lengths...

I spent month doing research, looking for formulas, spreadsheets, what have you. Nothing matched. Everyone had a plan better than the previous. So I gave up. Then, I found this page. I looked at the chart and said I need column C. 35' is what I chose and it worked like a char. I now have a 106' (qth) but will be going back to 35'.

[Auspicious]

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.

In principal you can (and probably should) consider all the grounds on your boat: HF, VHF, DC, AC safety ground, lightning, galvanic bonding. In the best of worlds each ground would be independent until they come together at a single point ground. Along the lines of "one ring to rule them all." This is how we did/do things on military ships where maximizing safety and minimizing interference is a priority.

Most recreational boats don't even approach this standard. VHF ground, DC ground, bonding, and lightning are intermingled in multiple locations which can lead to ground loops, conducted interference, and higher than necessary noise floors. Unless you're doing a complete rewire it simply isn't worth the effort to remediate. That doesn't mean not doing the best you can particularly during repairs and new installations.

The single point ground can be anywhere. It's an arbitrary choice. Once made the decision has implications that ripple through the rest of the boat electrical system. The connection to a sintered metal plate is a good choice. So is a sea cock. A mushroom-style thruhull is less wonderful as the electrical connection is difficult; note that hose clamps are stunningly bad electrical connectors.

Originally Posted by foojin

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.

It works but not entirely predictably. As others have noted the coil of wire forms an inductance which is added to the load seen by the tuner. The wire in the coil does count for length and length has its own impedance (resistance and inductance). The tuner just switches capacitance and inductance to try making a match. A lump of extra inductance doesn't help matters. However, if a straight run of GTO-15 to the antenna drops you on top of an integral multiple of a half wavelength on a desired band it can't hurt to try. You could calculate the inductance of the coil https://sciencing.com/calculate-wind...r-7502845.html and even model the whole boat in EZNEC or another antenna modeling software package. Frankly trial and error is likely to be faster unless you have another reason for engaging in a science project.

Modeling the entire boat, at least mast and rigging, in addition to the antenna will demonstrate the expected mild directivity aft that most boats exhibit.

Originally Posted by transmitterdan

I would not recommend to connect the tuner ground to the battery minus.

They come together somewhere, on or off the boat. If you have interference issues the general solution is to put a DC block in the RF ground on its way to the single point ground.

Originally Posted by S/V Illusion

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.

This is a common point of confusion. A radio installation really should have both a counterpoise and an RF ground. It'll work with just one or the other but better with both.

Originally Posted by Brian.D

Since the discussion has seemed to morphed to antenna lengths...

I spent month doing research, looking for formulas, spreadsheets, what have you. Nothing matched. Everyone had a plan better than the previous. So I gave up. Then, I found this page.

I'm surprised you had trouble. Discussions on the impedance of end-fed wire antennas are common. Most versions of the ARRL Antenna Book are good. The U Del link you offered is fine although limited to ham bands. We're all making the same calculations - my spreadsheet at https://AuspiciousWorks.com/AntennaLength.xlsx relieves the tedium of calculation and addresses both ham and marine bands. The only thing you have to change is the antenna length in cell B3. If you have particular interest in higher frequency bands (shorter wavelengths) you might reduce the safety margin in cell G9. Otherwise just avoid red labels on bands of interest to you.

I built the spreadsheet to support the West Marine rigging department. Fortunately I retained the rights so I can share it.

[foojin]

Originally Posted by Auspicious

This is a common point of confusion. A radio installation really should have both a counterpoise and an RF ground. It'll work with just one or the other but better with both.

Going to ask about wires if I might, further drifting from my OP.

Let's say you run one connection from the tuner ground to, let's say, a metal thru-hull as your RF ground, using copper foil that is 2"-4" wide.

If I throw a counterpoise into the mix, I suppose I can run a second connection from the tuner ground to the counterpoise. In this case, should I use copper foil or is round wire okay. I know the connection is provided with the KISS, but not if I go with another solution.

The manual for my SSB shows the ground connections from the auto tuner and the transceiver going to a common ground (the thru-hull in the case above). Is round wire suitable for transceiver-ground connection even if I used copper foil for the run from the tuner to the ground?

[Auspicious]

Originally Posted by foojin

Going to ask about wires if I might, further drifting from my OP.

You may ask anything you like young Padawan.

It's been a long day, and I'm immersed in Star Wars as the latest movie is looming and my wife wants to watch all the ones already out before we go see the new one.

Originally Posted by foojin

Let's say you run one connection from the tuner ground to, let's say, a metal thru-hull as your RF ground, using copper foil that is 2"-4" wide.

The underlying issue is something called skin effect. The higher the frequency the greater the proportion of RF current that flows close to the surface of the conductor. This is why commercial microwave uses waveguide--all skin and no insides. Even at HF frequencies this has a measurable effect. At VHF it is more signficant, which is why old rooftop TV antennas used tubing for elements. Some VHF antennas in fiberglass radomes use tubing also. It's all a case of "every little bit counts."

Lets not lose sight of the fact that the radiating element is a wire of some kind - backstay or similar.

Anything you can do to reduce the net impedance of your connection to ground is worth doing, so copper foil as short a run as possible from the tuner ground lug to your RF ground/single point ground is a good practice. That this makes a DC block easier, if necessary for you, is a bonus. Wire for counterpoise is fine. In theory, considering velocity factor if tuning counterpoises is appropriate but in the real world for agile radios (vice commercial single frequency) it doesn't matter. You could tune counterpoises to 7268, 8152, and 14300 and feel better about yourself.

Originally Posted by foojin

The manual for my SSB shows the ground connections from the auto tuner and the transceiver going to a common ground (the thru-hull in the case above). Is round wire suitable for transceiver-ground connection even if I used copper foil for the run from the tuner to the ground?

*sigh* You have an Icom. I love those guys. I really do. Great equipment. Just let the radio ground stud float-no connection. The radio ground connects to the tuner through both the tuner control cable and the coax shield. The tuner should be grounded. Connecting the radio ground stud to ground leads to a ground loop.

Hope this helps.

[Stenn]

I presume many of us have in-board engines. I see no mention of attaching the antenna ground to the transmission housing or engine block, which would then be connected through the solid propeller shaft to sea water, wouldn't it ? Why deal with clamping to a seacock/through-hull when we could use an actual bolt on the transmission housing and a lug on a ground strap ?

[S/V Illusion]

Originally Posted by Stenn

I presume many of us have in-board engines. I see no mention of attaching the antenna ground to the transmission housing or engine block, which would then be connected through the solid propeller shaft to sea water, wouldn't it ? Why deal with clamping to a seacock/through-hull when we could use an actual bolt on the transmission housing and a lug on a ground strap ?

You are conflating RF counterpoise and DC grounding.

Someone might come along who wants to explain or you could read about the distinction yourself.

[Auspicious]

Originally Posted by S/V Illusion

You are conflating RF counterpoise and DC grounding.

And frankling RF counterpoise with RF grounding.

[waterman46]

Originally Posted by Stenn

I presume many of us have in-board engines. I see no mention of attaching the antenna ground to the transmission housing or engine block, which would then be connected through the solid propeller shaft to sea water, wouldn't it ? Why deal with clamping to a seacock/through-hull when we could use an actual bolt on the transmission housing and a lug on a ground strap ?

You can certainly connect the RF ground from the antenna tuner to the engine and let the shaft and prop ground it to sea. But this leaves the system more susceptible to RF noise, especially from the alternator. You can try this but if you notice alternator noise in the receiver, a better solution, if you want a sea ground, is to use a separate grounding plate for RF only, or at least connect to a metallic thru-hull fitting.

The RF grounding system should be DC isolated from direct connection to sea to minimize electrolysis. For HF(marine/Ham SSB) use several ceramic capacitors in parallel to create a 1uF capacitor between the sea ground (engine, plate, thru-hull, whatever) and the radio/tuner ground. The capacitor can be anywhere along the radio ground connection. See Stan Honey's article explaining this.


http://www.glsbc.com/files/marinegroundingsystems.pdf

The KISS ground, MFJ-1932 wires or a homemade equivalent, can also be connected to the tuner ground at the same time. No need for capacitors there, as those wires will not be in contact with anything else.

Usually, the more ground wires you can connect will be better, but each connection should be tested to check if it introduces noise from any of your on-board sources.

[Auspicious]

Originally Posted by Stenn

I presume many of us have in-board engines. I see no mention of attaching the antenna ground to the transmission housing or engine block, which would then be connected through the solid propeller shaft to sea water, wouldn't it ? Why deal with clamping to a seacock/through-hull when we could use an actual bolt on the transmission housing and a lug on a ground strap ?

1. Hose clamps are stunningly bad electrical/RF connections. Drill and tap for 10-24 and use a machine screw.
2. Engine block is not a great ground point, especially if you have a shock absorbing coupling after the transmission.

[Stenn]

Thanks Ausp...yes, I agree, tap and screw...IF I was using a seacock...

My engine/transmission has no flexible coupling, just solid steel and iron, directly coupled to solid stainless steel prop shaft (1983 Universal 5411 Diesel)...though I did also run a lugged ground from a transmission housing bolt to one of my cutlass bearing strut bolts too.

[Stenn]

Thanks Illusion, I do realize there's a difference between straight electrical/DC ground and RF counterpoise ground...

I was all ready to go with making a counterpoise, or even buy a KISS-SSB, until I read the article by well-known authority (Greg/Gary..I don't remember) saying just run your tuner ground to seawater ground...he and other very experienced friend did A/B testing of KISS, random wire, a 2 seawater grounds, found seawater ground noticeably better than KISS, etc...so put me back to square one and my transmission bolt question.

[Brian.D]

That would be Gordon West. He has an article discussing the merits of seawater ground. Very good. His testing proved it better than the 100 sqft of copper in the bilge.

You can also build your own counterfeit KISS. You can find the info here.

[Stenn]

THANKS Brian, Yes, that's the "G" I was remembering....

...and thanks for the how-to link !

So...is there a point to doing both, seawater ground AND capacitive counterpoise ?

[Brian.D]

Well, look at it from a different perspective: it won't hurt.