weak power output

Nov 26, 2008
1,966
Endeavour 42 Cruisin
I have an Icom M600 and a new AT140 tuner with a short wire to my backstay.
2 straps to bronze ground plate.
Power is from a 900 amp bank via 8 ga wire.

When transmitting I only draw 3 to 4 amps. Reports are that my signal is clean but weak.

Could be a lot of things, looking for some of the more likely culprits. Power connections all look good. Where to look first?
 
Feb 17, 2006
5,274
Lancer 27PS MCB Camp Pendleton KF6BL
First thing I would check would be corrosion on the power connectors (you already mentioned that). Corrosion will cause resistance which will cause the power to drop greatly resulting in a lower voltage. Next check to see if your battery's voltage is dipping on keydown. I don't think it is the tuner unless the tuner is not tuning and thus getting a high SWR. If that is the case, then the radio is reducing its power output to prevent .damage to the finales. And then there is the connection at the backstay. Could be corroded cause the tuner to give false readings.

So three things. (1) Clean all the power cable connects. (2) Check to see if the tuner is actually tuning and not giving a false SWR reading at the radio. (3) Check to see that the physical connection to the backstay is not corroded.
 
Nov 26, 2008
1,966
Endeavour 42 Cruisin
Checked connections for power and the antenna, clean and tight.
Hear tuner click when tuning.
 
Feb 17, 2006
5,274
Lancer 27PS MCB Camp Pendleton KF6BL
Have a dummy load? If so, place it on the output of the rig and fire into that. See if the current draw goes to 20amp at 100 watts. I would do the same for the output of the tuner.
 

KD3PC

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Sep 25, 2008
1,069
boatless rainbow Callao, VA
You may want to make sure that the AT140 is in fact configured to work with the M600, there are some switches internal to the M600 for "non AT 120" tuners..

Backstay "antenna" is insulated from the rest of the rigging and the coax properly attached and terminated? Gnd straps are actually at system ground (no voltage between)?

your current draw (lack thereof) is telling you something is amiss...

Check your power settings, you may be on low power.

I would drop back - remove the tuner and transmit to a small vertical temporarily mounted on the rail, connected to a short piece of coax and see what the reports say. Then look at current and reports. If all is good, then add tuner to this set up and verify correct operation, same checks - then add existing coax to the system, this way you KNOW what works and what doesn't

You will get varied reports, as many contacts may be further or closer than your antenna is designed for. Hams are notorious for giving good "reports" and then asking time and again for repeats and fills.
 
Nov 26, 2008
1,966
Endeavour 42 Cruisin
Dip switch settings are correct in M600.

Power is set to hi.

Backstay insulated at the top. Ant wire GTO is only a few feet long and clamped on by backstay chainplate.

Ground straps at system ground...where do I measure this?

I'll see what kind of long wire antenna I can fab to use directly out of the M600. But if I can find a dummy load, that would accomplish the same thing, right?

Been dealing with this for a while, on SSB nets with reliable operators I continually get similar reports of clean but weak tx. Not on ham bands.

Thanx
 

KD3PC

.
Sep 25, 2008
1,069
boatless rainbow Callao, VA
Backstay lower end should be insulated from chain plate...you want the segment between there and the mast head end to be the radiator -separate, electrically from the rest of the rigging, coax ground should then clamp/attach to the short stub that would attach to the chain plate.

Ground straps should show little to no resistance when a DMM is used, between those straps and other boat grounds. Many use a ground plate on the exterior of the hull, others may use a large metallic mass/plate/ground plane as low in the bilge as is practical. Some will use the engine, or prop shaft as "ground". You want ALL of that ground to be at the same potential (no voltage between the various grounded bits and plates and straps). Similarly all connections should be clean, tight and and zero resistance between those connections and equipment ground studs or connections.

The dummy load will eliminate the rig (and the tuner, on the next step, test) as being faulty, if you can see a dramatic increase in current as you transmit, briefly. Then add the tuner in, and retransmit in to the dummy load, you should still see a current increase as you transmit and a quick reduction when you release the microphone. Make sure your dummy load will handle the power, within the timeframe you need....most are rated for seconds.

Similarly, you should see a reduction in Voltage at the battery/source as that current rises. Perhaps 13.6vDC dropping to 11.8-12.5vDC...if the battery/source drops much below that, you may have a weak/dead cell or bad battery. You could check this in your current configuration...just place your DMM across the battery/source and see what voltage drop you see on transmit.
 
Mar 20, 2012
3,983
Cal 34-III, MacGregor 25 Salem, Oregon
Backstay insulated at the top. Ant wire GTO is only a few feet long and clamped on by backstay chainplate.
Thanx
what about the insulator at the lower end of the backstay?.... inside the hull of my boat, the backstay chainplate has a ground strap connected to it.... even if yours does not have a ground strap, its a good idea to use an insulator between the stay and the chainplate anyway.
 
Feb 17, 2006
5,274
Lancer 27PS MCB Camp Pendleton KF6BL
You can also try an alternate backstay just for testing in lieu of a vertical. A length of wire about 43 feet connect to the tuner and raised with a halyard (14 ga. should work just fine). One other test to try is a vertical dipole cut for 14300 for testing on the MMN. I know this is a lot of testing but one of these suggestions will pin down what is wrong.

Also (more stuff... LOL), disconnect your GTO from the tuner and connect to one side of DMM. Connect other side of DMM to anything metal that is gounded (like another chain plate). Should read 0, zero, nada, or better any indication that there is no resistance what so ever. If you get any value, then yes, you will have a difference of potential and that is not good.

When I saw you mention chainplate I too was concerned that it is somehow grounded. This is why I suggest the alternate backsatay.
 
Nov 26, 2008
1,966
Endeavour 42 Cruisin
Backstay chainplate is thru bolted to transom and is not 'wired' to anything. Tuner antenna goes to chainplate bolt. Chainplate goes thru teak toerail to backstay turnbuckle and then backstay.
 
Feb 17, 2006
5,274
Lancer 27PS MCB Camp Pendleton KF6BL
You know, I got to thinking more about this. When you measured your current draw, were you using data or SSB? Data causes the radio to go into constant key while SSB only peaks power when certain conditions are met. If you measured while doing a voice test, then yes, you will only peak current at certain levels.

I have performed the same test at home to see how much current I will draw in data and voice. While using 100 watts of data, the rig was using 20 amps @12vdc. When I changed power levels, the current went down accordingly. I like to use JT65 at home. When I start sending my data, I adjust my output for 30 watts and on the watt meter, it shows 30 watts constant. However, when I use 100 watt voice, I would peak maybe 20 watts at most and the current would be a couple of amps.

With that in mind, can your test your current draw while using data or CW (if you have that mode). If not, you will need to have something to have the radio produce a constant steady carrier, maybe AM mode (if you have that). If you do not have data, then something that will produce a steady tone into the mic for a few seconds.

For all we know, your rig could be working just fine. It could be nothing more that propagation as mentioned above.

Just another thought.
 
Nov 26, 2008
1,966
Endeavour 42 Cruisin
No data and no CW.

Tested by shouting a 'tone' for 5 seconds.

This has been going on for about 6 months. I would check in every morning on cruiseheimers ssb net and consistently was weak. Other boats nearby would be heard fine but I was always weak. When propagation was poor I just couldnt be heard. So relative to a lot of other boats, I was always at the low end of the spectrum.
Thnx
 
Feb 17, 2006
5,274
Lancer 27PS MCB Camp Pendleton KF6BL
Ok... sorry, but just trying different ideas.

Are you sure you are in J3E and not R3E? I am sure you are, but just need to check. R3E is reduced or variable carrier. And, the other mode that is available on the radio is H3E, which is SSB with full carrier, similar to AM. If you key down on H3E the radio should produce a carrier with no modulation unless you talk. That should produce a tone basically.
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
Your antenna ground is to what? If you ground the antenna to the sea AT the antenna base this works best. The simple test is taking a woven copper strap off the antenna coax shield at the point where the center coax wire goes to the backstay. Throw the other end in the water. I've seen some pretty long ground plane straps to bornze grounding plates. Those long runs act as part of the antenna and can (depends on the actual routing) really give some interesting radiation patterns (mostly straight up which you don't want).
Also, the ground plane for sea water is only about 0.1 wavelengths deep into the water so if you ground plated is 6' down on the keel that does not help much. The ideal ground plane is a long metal fin launched from a location VERY NEAR the end of the coax to antenna connection. The fin pierces the water on all angle of heel.
 
Nov 26, 2008
1,966
Endeavour 42 Cruisin
My ground strap os attached to the ground lug of the tuner as per the Icom tuner instructions
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
not the tunner grounding strap the antenna ground plane.
I'm talking about the antenna not the tunner. You know the ground plane raidials for land lubbers. those radials are infinate in number and length with you ground the coax shiled coming off the antenna coax connection to the sea with a short braided strap.
What I hear you saying is the coax cable runs up to the antenna and the center wire gots to the backstay and the shiled goes where? it needs to be supplying a ground plane for the antenna. If you try and use the tunner ground that means the ground plane actuall starts pretty far from the "base" of the antenna. Ask yourself would you put the ground plane radials 15 feet away from the base of your land antenna????? I'd expect no distortion but very little power from such a configuration.
 
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
AND
you will not be able to load up the antenna as there is no ground plane to "push off" of