CG-3000 Auto ATU woes

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M0XXQ
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CG-3000 Auto ATU woes

Unread post by M0XXQ »

There seems to be a fault with the unit, basically it will no longer tune on 160M and 80M, I have used the ATU with the guidelines in the manual e.g. TX power 100W or less, using non-halfwave resonant antenna lengths and it has been a very good ATU until today when it started exhibiting problems during a 160M SSB QSO, the VSWR shot up and the band went quiet, checked all feeders and connections by replacement and the problem persists. Strange behaviour , the VSWR comes down to around 1.5:1 using an FM carrier, it fluctuates up and down a few points, on RX almost no band noise almost like the antenna has been disconnected, then switch to SSB and the VSWR shoots back up to infinity.
Note that this behaviour is only apparent on 160,80 and 40M.

I have done a reset, left it powered down for a couple of hours and the problem hasn’t went away – I can still match the antenna on the high bands e.g. 20M and up, for reference the antenna is a 120 ish foot Longwire and decent ground system.
Has anyone had similar issues?
VK5TM
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Re: CG-3000 Auto ATU woes

Unread post by VK5TM »

Found this on QRZ.com, but it doesn't explain why it tunes the higher bands.
I own one of these CG-3000 ATU's and it does work great but there is a weakness within it. The center conductor feeding the Antenna lead is of a lower gauge than it should be.Mine actually burned that wire. Mine now has a heavier gauge wire and problem is solved.
If it is the typical relay switched matching component type, may be a dicky relay?
M0XXQ
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Re: CG-3000 Auto ATU woes

Unread post by M0XXQ »

Problem fixed, poor build quality!
I re-flowed several solder joints and tightened up the loose HV antenna terminal, back in business.
VK5TM
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Re: CG-3000 Auto ATU woes

Unread post by VK5TM »

Wasn't made by MFJ by any chance? :twisted:
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M0HJO
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Re: CG-3000 Auto ATU woes

Unread post by M0HJO »

Im looking at buying one Rob, with a long bit of wire to get on top band.

John.
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M0XXQ
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Re: CG-3000 Auto ATU woes

Unread post by M0XXQ »

M0HJO wrote: Sat May 30, 2020 10:23 am Im looking at buying one Rob, with a long bit of wire to get on top band.

John.
They are good mate, really for the money.
I would honestly recommend an Inverted L, get one of those 12M telescoping fiberglass poles, run 40 feet of wire up the pole, tape it as you telescope each section and the remainder of the wire horizontal keeping the end away from tress, buildings of possible.
I work all over the UK with a respectable signal, I have also worked Eastern Europe and have a regular net on 1920 with the Irish lads.
Note that you will need either lots of short radials e.g. 32 short radials or 2-3 resonant counterpoise wires at 130 feet.
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M0HJO
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Re: CG-3000 Auto ATU woes

Unread post by M0HJO »

M0XXQ wrote: Sat May 30, 2020 10:45 am
M0HJO wrote: Sat May 30, 2020 10:23 am Im looking at buying one Rob, with a long bit of wire to get on top band.

John.
They are good mate, really for the money.
I would honestly recommend an Inverted L, get one of those 12M telescoping fiberglass poles, run 40 feet of wire up the pole, tape it as you telescope each section and the remainder of the wire horizontal keeping the end away from tress, buildings of possible.
I work all over the UK with a respectable signal, I have also worked Eastern Europe and have a regular net on 1920 with the Irish lads.
Note that you will need either lots of short radials e.g. 32 short radials or 2-3 resonant counterpoise wires at 130 feet.
How much wire do you get out mate, I'm thinking I can get about 40ft up then around 100 to 120 in one line.

John.
Glad to be Here.
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M0XXQ
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Re: CG-3000 Auto ATU woes

Unread post by M0XXQ »

M0HJO wrote: Sun May 31, 2020 9:59 pm
M0XXQ wrote: Sat May 30, 2020 10:45 am
M0HJO wrote: Sat May 30, 2020 10:23 am Im looking at buying one Rob, with a long bit of wire to get on top band.

John.
They are good mate, really for the money.
I would honestly recommend an Inverted L, get one of those 12M telescoping fiberglass poles, run 40 feet of wire up the pole, tape it as you telescope each section and the remainder of the wire horizontal keeping the end away from tress, buildings of possible.
I work all over the UK with a respectable signal, I have also worked Eastern Europe and have a regular net on 1920 with the Irish lads.
Note that you will need either lots of short radials e.g. 32 short radials or 2-3 resonant counterpoise wires at 130 feet.
How much wire do you get out mate, I'm thinking I can get about 40ft up then around 100 to 120 in one line.

John.
Thats similar to my config John, 40 foot up and 90 odd foot horizontal.
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M0HJO
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Re: CG-3000 Auto ATU woes

Unread post by M0HJO »

M0XXQ wrote: Sun May 31, 2020 10:04 pm
M0HJO wrote: Sun May 31, 2020 9:59 pm
M0XXQ wrote: Sat May 30, 2020 10:45 am

They are good mate, really for the money.
I would honestly recommend an Inverted L, get one of those 12M telescoping fiberglass poles, run 40 feet of wire up the pole, tape it as you telescope each section and the remainder of the wire horizontal keeping the end away from tress, buildings of possible.
I work all over the UK with a respectable signal, I have also worked Eastern Europe and have a regular net on 1920 with the Irish lads.
Note that you will need either lots of short radials e.g. 32 short radials or 2-3 resonant counterpoise wires at 130 feet.
How much wire do you get out mate, I'm thinking I can get about 40ft up then around 100 to 120 in one line.

John.
Thats similar to my config John, 40 foot up and 90 odd foot horizontal.
cool beans!
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M0VMT
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Re: CG-3000 Auto ATU woes

Unread post by M0VMT »

I like mine warned in a pan :D
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