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Author Topic: ic7000 shuts down???  (Read 1501 times)
AE5KH
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Posts: 29




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« on: February 22, 2013, 02:52:19 PM »

Setup... Mobil IC7000 with a Little Tarheel II. tuning mode rtty or cw.

I get the antenna to tune just fine at 20m and 10m but when I try and tune to 40m the radio shuts down when I key up to hear the increase in noise.

 
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K6AER
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« Reply #1 on: February 22, 2013, 03:08:39 PM »

Does the radio shut down when you reduce the RF output?

There is a chance that RF is coming back to the radio via common mode currents on the outside of the coax line.

Is the antenna resonate and what is the installation like?

Do you have choke beads on the coax at the antenna feed point?
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AE5KH
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« Reply #2 on: February 22, 2013, 05:55:05 PM »

It still shuts down even if I reduce the RF out to 1%.

The antenna is mounted to the side rail of a F250 truck.

I do not have beads on the coax, only on the control wire for the antenna itself.

This seems to be only on 40m and below, it tunes to 20m and above just fine.
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K6AER
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« Reply #3 on: February 22, 2013, 09:39:12 PM »

Where is the B+ connected in the truck for the radio?
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AE5KH
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Posts: 29




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« Reply #4 on: February 22, 2013, 09:53:02 PM »

Sorry maybe I am supposed to know this but what is "B+"? If you are refering to the positive power it is run straight from the drivers side battery terminal, actually both negative and positive wires are run from the battery?
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KB5ZSM
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Posts: 70




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« Reply #5 on: February 22, 2013, 10:15:29 PM »

I also have the IC7000 and have had that happen. When the car is running - No Problem, but with the engine off - Big problem. It's the voltage drop between your battery and your radio. Mine was fixed by replacing the radio cable with 8 gauge wire (and fuses at the battery end). Also look in to "Power Boosters". They should help resolve your problem also.

Good Luck & 73s,
Win
KB5ZSM
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WN2C
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Posts: 430




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« Reply #6 on: February 23, 2013, 03:12:33 AM »

Go to K0bg.com and read Allan's web page on bonding, and chokes.  Oh and by the way, did you put in that little screw on the seperation cable at the radio head?  That is I assume you have the head off the radio.  Allan's site has a lot of usefull info for the HF mobileer.

Rick  wn2c
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K3GM
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Posts: 1767




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« Reply #7 on: February 23, 2013, 08:14:17 AM »

Another item of great importance:  If the control head is separated from the radio, you must install the small metric screw to secure the connetor to the control head body.

Another thing that helped for me was to attach a short ground braid from the ground screw on the 7000 to the nearest ground point on the vehicle's body.
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WN2C
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Posts: 430




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« Reply #8 on: February 23, 2013, 06:47:28 PM »

There is also 2 small ferrite chokes that come with that separation cable.  Use them, one as close to the head as you can and one close to the radio body.  If you don't have any chokes on the coax, you should.  Try a 3/4 inch split ferrite FT 31(I believe, some one check me on this) make a small coil(abt 3 turn or 4 turns)and place over coax.  Tie wrap it so it won't open.  Use 2 splits if necessary.  More bonding will help too.  What are you using to bond the antenna to the vehicle?

It has been said by a very knowledgeable mobileer (Don Johnson) that HF mobile takes a lot of work to make it work and a lot more work to keep it working.
Let us know how you are making out.

Rick  wn2c....Proud user of Scorpion Screwdriver antenna and IC-7000
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W9MMS
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Posts: 118




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« Reply #9 on: February 23, 2013, 09:08:42 PM »

It seems that you're having an affair with " Common Mode Current "
Have you choked off ( minimum of 10 turns around a mix 31 ferrite ) the Control Cable at
the feed point of the Antenna?

http://www.k0bg.com/common.html

Pay attention to "Proper RF choking"

http://www.k0bg.com/controllers.html

NB:  Inadequate choking will affect the input impedance, and thus the antenna's efficiency.



((((73)))) Milverton.

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VA7CPC
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Posts: 2358




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« Reply #10 on: February 23, 2013, 11:20:49 PM »

If I remember right, the Ic-7000 power cable has two cylindrical glass fuses in it.  They are notorious sources of trouble.  So:

a) keep them corrosion-free by using contact cleaner and/or silicone dielectric grease;

b) or, replace them with "blade-type" automotive fuses (30 amp is probably right).

.               Charles
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VE3FMC
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Posts: 983


WWW

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« Reply #11 on: February 24, 2013, 03:44:43 AM »

If I remember right, the Ic-7000 power cable has two cylindrical glass fuses in it.  They are notorious sources of trouble.  So:

a) keep them corrosion-free by using contact cleaner and/or silicone dielectric grease;

b) or, replace them with "blade-type" automotive fuses (30 amp is probably right).

.               Charles

No the Icom 7000 has the blade fuses in it which are notorious for bad connections which will cause the power output to drop. I replaced mine with glass fuses.
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VA7CPC
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« Reply #12 on: February 24, 2013, 08:48:58 AM »

. . .

No the Icom 7000 has the blade fuses in it which are notorious for bad connections which will cause the power output to drop. I replaced mine with glass fuses.

Oops . . .

Anyway, you should check the "DC +" voltage _at the rig_, and ensure that you don't have a problem with voltage drop when transmitting.

.           Charles
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WD5GWY
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Posts: 391




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« Reply #13 on: February 24, 2013, 09:23:46 AM »

Another item of great importance:  If the control head is separated from the radio, you must install the small metric screw to secure the connetor to the control head body.

Another thing that helped for me was to attach a short ground braid from the ground screw on the 7000 to the nearest ground point on the vehicle's body.
This is probably the cause of the problem. I have seen this exact problem occur because
the small screw was missing. It is very easy to overlook.
Also, low voltage when the engine is not running will have similar effects. The IC-7000 is much
less forgiving of voltage drop (despite what the manual says) compared to the older 706 radios.
james
WD5GWY
 
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W9MMS
Member

Posts: 118




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« Reply #14 on: February 24, 2013, 11:47:02 AM »

. . .

No the Icom 7000 has the blade fuses in it which are notorious for bad connections which will cause the power output to drop. I replaced mine with glass fuses.

Oops . . .

Anyway, you should check the "DC +" voltage _at the rig_, and ensure that you don't have a problem with voltage drop when transmitting.

.           Charles

Charles, the Radio works just fine on 10 and 20m.
That rules out  Voltage drop.


((((73)))) Milverton
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