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Author Topic: Icom IC7000 power issues working /MM  (Read 3242 times)
GOUDURIX
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Posts: 222




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« on: August 31, 2017, 06:51:55 AM »

Switched from yaesu FT897D to an Icom 7000 for /MM use on my sailing boat 3 years ago because of the better receiver and IF-DSP features of the IC7000. I really have the impression I am poorer at DX with the IC7000 (ok not A/B testing and years apart) getting a decent signal out. The antenna and ground system in the sailing boat and the ATU remained the same.
When on shore power (boat's service batteries on the battery loader in the marina) the voltage will easily be 14V or more.
When transmitting voice and mike gain well set to not overshoot ALC and with reasonable VSWR < 1.5:1,  I get 100W out.
When sailing and service batteries under medium load (GPS and chart plotter working) my voltage is 12.5-12.6V and power is halved.... (as read on the rigs power meter).
I've read about the voltage sensitivity of the IC7000 but it seems a bit extreme?

I'll do more standardized testing on dummy load and with regulated power supply at 12V - 12.4V - 12.6V -13.8V with both rigs.

But I guess i'd rather install a voltage booster in the boat than returning to the Yaesu FT897D and its noisy receiver?

Jan
ON3ZTT
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WA3SKN
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Posts: 6497




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« Reply #1 on: August 31, 2017, 03:36:30 PM »

Make sure you have good, low loss connections.
The IC7000 shows specs of 13.8 volts +/- 15%... thats 11.73 to 15.87 volts.  And with 22 amp current draw at 13.8 volts comes to a resistance of .62727 Ohms when transmitting (theory).  It does not take much of a poor connection to get the voltage near the cutoff point.
However, the meter reading does indicate it is in the proper range.  What is the power source?

-Mike.
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KC1BMD
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Posts: 608




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« Reply #2 on: August 31, 2017, 05:09:34 PM »

"...under medium load (GPS and chart plotter working) my voltage is 12.5-12.6V and power is halved..."

Where exactly are you measuring the radio's input voltage? Are you using the power fused cable supplied by iCOM? I've heard of connections at the fuse deteriorating and dropping voltage. Measure the voltage at both sides of the fuse and see if there is any drop. Check it directly at the rig too. It could be that with load your voltage is dropping at the rig more than you think. The IC-7000 is not quite as tolerant to low voltage as some other rigs. You could also try cleaning the connections at the fuse. According to the input voltage vs. power output chart in AB4OJ's Icom IC-7000 Frequently Asked Questions (FAQ), it would be down to 50% power at 10.5V.
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GOUDURIX
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Posts: 222




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« Reply #3 on: September 01, 2017, 12:05:09 AM »

Thanks for both your replies. I am aware of the bad original fuse holders of the Icom power cable. On the boat I am using the Yaesu's power cable and the fuse contacts are clean and OK.
On the boat the power cable is connected directly to the 180 Ah service batteries (gel type; Deca, well charged with intelligent chargers both on shore power or alternator).
I tested at home QTH last night on the power supply. Short power cable; measured voltage at the power supply.
Tested on dummy load; voice and on 20m and 17m. Mic gain well into ALC range. Compressor off.
At 13.8V the Icom is putting out around 80V - Yaesu FT897 90W.
At 13.0V Icom 75W and yaesu 85-90W
At 12.6V Icom 65-70W and Yaesu 85-90W
At 12.0V Icom 60W and Yeasu 85-90W
I see no voltage drop on the power supply when transmitting (that will surely be different on battery power on the boat and will measure that).

I will re-do the test on the boat

Will however recheck the power connections.

1) on shore power battery charger on
2) on service batteries 1 hour after switching off the shore power charger

First impression is that indeed the Icom 7000 is really dropping power rapidly with voltage going down that real boat life situation 12.0-12.4 volts under load and the Yaesu FT897D remains quite stable down to 12.0V

That is a pity. The Icom's receiver and IF-DSP filtering is quite needed on a boat with all its possible interferences. The Yaesu however is sturdy and has a seperate Digital mode where digital gain can be set specifically eg for Winlink digital mode.

Jan
ON3ZTT

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GOUDURIX
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Posts: 222




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« Reply #4 on: September 04, 2017, 05:57:19 AM »

Been testing /MM in the sailing boat.

I had an original Yaesu power cord  about 2.5m long connected directly to the service battery posts instead of at the mains connector in the boat's switch panel.

Measuring voltage drops at 100W in CW:
- lost 1.3 to 1.4V at the transceiver
- voltage down about 0.5v at the main connector posts in the switch panel.
The same happens standalone on the 180Ah service battery bank (at about 13.0V unloaded  and when 35 amp the shore power loader is on and unloaded voltage was about 14.2V.

So it seems I have quite some resistive loss in the power cable. I thought it had better (automotive) fuse holders than the Icom 7000 original one.

I then removed the 2.5m supply cable from the battery posts; shortened it to about 0.6 m and connected to the switch pannel main power posts.
With this I am still measuring about 0.8V drop at 100w in CW. It seems that also the longer cable gave losses....

I will try to find better fuse holders or HD fuses used in boating - whatever type of fuses (25A) that can allow a very low loss connection.

Jan
ON3ZTT


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KC1BMD
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« Reply #5 on: September 04, 2017, 02:08:59 PM »

The voltage drop seems somewhat high to me. Maybe someone with a similar setup could comment. I haven't measured my IC-7000 input voltage (on a small shack switching supply) but I should check it out of curiosity.
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GOUDURIX
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Posts: 222




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« Reply #6 on: September 05, 2017, 12:03:42 AM »

I have now rechecked the Yaesu FT897 home QTH on the regulated PS and using an original yaesu power cord that incorporates 2 automotive-style fuse holders also. I also see about 0.4 to 0.5 voltage drop over those fuses.
They are the real issue. (although not as bad as the 1.3 V drop I saw on the boat) Cleaning their contacts doesn't seem to solve it.

Any better 25 or 30A fuses solutions?

Either these type of DH fuses used in yachting
http://www.nauticexpo.com/prod/craftsman-marine-bv/product-37808-406527.html



(maybe solder de power leads to it) or solder the power vcable leads to the automotive style fuses now common in HAM tcvr power cables?

Jan
ON3ZTT
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WA3SKN
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« Reply #7 on: September 06, 2017, 09:00:10 AM »

Depending on the length of run, you might want to use 6 gauge to the radio and then just a short pigtail to the radio.  It can help a lot with wire losses, both power and return leads.

-Mike.
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GOUDURIX
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Posts: 222




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« Reply #8 on: September 07, 2017, 12:27:03 AM »

Tnx Mike. makes a lot of sense, I was thinkng to do so. Remains the fact that using 6 gauge will greatly limit the wire losses, but the critical point remains the tiny contact surface between the fuse holder and the fuse contact lips.

I had a heavier gauge wire on the feed to my old Kenwood TS850 and fuse holders that look the same automotive style but somewhat bigger size. I only measure 0.3V loss at the tcvr side of the fuse.

So I'll try out both: gauge 6 wire and solder the fuses in.
0.3V loss doesn't really bother me normally but on the boat evary loss is an issue when under sail and batteries already under medium to heavy load (fridge, nav electronics, ...)

Tnx



Jan
ON3ZTT
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VE3FMC
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Posts: 33




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« Reply #9 on: September 09, 2017, 05:06:00 AM »

Hi Jan

One thing you should do with the fuses in the power cable for the IC-7000. Pull them out, clean them well and put them back in.

I had an issue with the power output dropping on the IC-7000 I owned. I had stored it for awhile, put it back on the desk. Power level was way down. Did some research and came across the fuse issue.

Sure enough, pulled them out, cleaned them, put them back in and the power output was back to normal.

Good Luck, Rick VE3FMC
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GOUDURIX
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Posts: 222




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« Reply #10 on: September 13, 2017, 03:32:57 AM »

Hi Rick,

I have done that. Cleaned with special cleaning fluid. Sanded & polished the contact surface. Not helping a lot. I guess it is a combination of  the typical wire gauge (about 12 or 14 gauge) and the limited contact surface in the automotive style fuse holders.

I will now test 6 gauge wire and solder the fuses into both gauge 6 power leads.

I want to get below 0.3V loss over the feedline.

Regards

Jan
ON3ZTT
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NR4C
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Posts: 466




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« Reply #11 on: September 14, 2017, 11:50:08 AM »

Run fat cable directly from battery to radio.  I recommend #10 or #8.  Feel cable and connectors while transmitting to look for heat.  Heat is wasted energy.  the cable may get a bit warm under load for long time. I have some PowerPoles that get hot under a 20 Amp load.  A shot of DeOxit helped a lot in this case.

...bc nr4c
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VA7CPC
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« Reply #12 on: September 15, 2017, 09:14:33 PM »

Depending on the length of run, you might want to use 6 gauge to the radio and then just a short pigtail to the radio.  It can help a lot with wire losses, both power and return leads.

-Mike.

I used 6-gauge wire on my boat.  It worked nicely -- an IC-706mkIIg could put out 100 watts peak, SSB phone, from the house battery bank.

If you compute the voltage drop over a realistic cable run, it's what you need for 20 amps and a few tenths of a volt drop.  There are table for that, in the West MArine catalog and other places.

Also, I used Boeshield T-9 on my fuse connections.  Never had any trouble.

.     Charles
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GOUDURIX
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Posts: 222




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« Reply #13 on: September 18, 2017, 03:50:37 AM »

Hi,

have tested with 6-gauge wire and both automotive style fuses solder into the + and - line.

Tested with 1.20m long 6gauge wire leads on the stabilised power supply at 13.8V:
- at full 100W in CW
- no voltage drop measured at the power supply
- "only" 0.2V drop at the transceiver best result ever. That loss must surely be over the fuses not the 6 gauge wire.....

I'll install these feedlines in the boat. And probably a voltage booster

Jan
ON3ZTT
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KC1BMD
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Posts: 608




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« Reply #14 on: September 19, 2017, 04:58:49 AM »

Nice work -persistence paid off! I don't own any of these products but they get decent reviews and appear to have a marine solution too: N8XJK Marine Booster
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