Trim tabs move when transmitting on VHF?

[Fisherdv]

I noticed today when I hit the transmit button on the VHF radio my electric Lenco trim tabs move. Every time I hit button in 25W mode. What the heck

[Chief of the Boat]

Collusion?   

[Fisherdv]

Very strange

[Chief of the Boat]

Could it have something to do with the tabs resetting to retract with no power?  Does the 25 watt mode draw enough current to retract them?

[Fisherdv]

That's a good point COB, they run on a 30A fuse and I connected them to the same fuse panel in the cuddy as all the other accessories. The auto retract for the tabs is connected to the trim gauge on/off with the key. Maybe I should isolate the tabs and connect them in the back off the battery with the 30A fuse

[Chief of the Boat]

Did this happen with engine running?

[Fisherdv]

Yes, only does it when VHF is transmitting at 25W, doesn't do it in 1W mode

[Chief of the Boat]

I would try to wire the VHF directly to the battery (Fuse protected) and see what happens.

[neild]

"Are you there HAL... Do you read HAL?.. Open the pod bay doors HAL."

[DevMah]

That's a good point COB, they run on a 30A fuse and I connected them to the same fuse panel in the cuddy as all the other accessories. The auto retract for the tabs is connected to the trim gauge on/off with the key. Maybe I should isolate the tabs and connect them in the back off the battery with the 30A fuse

Check your connections first... if it was working before then is not the wire or fuse.
Put a voltmeter across the fuse panel operate the radio in 25w mode see if the voltage drops below 12.
Make sure you are on the fuse for the trim tab.
My first guess loose or corroded connection.

If you always had this problem then you size the run to the helm inadequately.


Dev

[Fisherdv]

Boat is new, no corrosion. Connections are good. Just added trim tabs and first time transmitting on the radio with them. Cable run is 8 gauge to the acc fuse box in the cuddy

[Salmon King]

I noticed today when I hit the transmit button on the VHF radio my electric Lenco trim tabs move. Every time I hit button in 25W mode. What the heck

😱‼️
Don't have a solution for you....this sounds like you might want to call the trim tab or vhf manufacturer for assistance.

[DevMah]

Boat is new, no corrosion. Connections are good. Just added trim tabs and first time transmitting on the radio with them. Cable run is 8 gauge to the acc fuse box in the cuddy

Check the voltage at the fuse going to the trim tab while using the VHF at 25W.
I am thinking you are either getting a  voltage drop or spike.

Do you have the new all in one electronic switch? If so is the antenna wire close to it or the wires of the switch?

Dev

[Kimbrey]

Sounds to me you are getting a voltage drop when you key the mic to the point it's keying the auto retract.
Is the battery charged?
I know you said all your connections are good but do you have a good tight connection on the battery posts?  Good tight connections on the battery switch?
Are you running one or two batteries?

[Threeweight]

+1 on the voltage drop.  What gauge wiring do you have going from the switch panel to the radio?  What gauge wire do you have running from the stern to the helm? What brand is the radio?

I had a cheap Cobra VHF my dealer threw in when I bought my Hewes.  Late last summer, I was chatting with a buddy on the tuna grounds with it when I noticed that every time I keyed my mic on 25w, my fish finder screen would show a band of static.  Didn't do it on 5w.  Upgraded my wiring from the fuse block to the radio, installed new fuse, same thing.  My primary radio (Standard Horizon) didn't create this problem. 

Replaced Cobra with another SH, and problem went away.  My guess is the cheap radio had a short in it somewhere.

[AJFishin]

I was told to have dedicated ground & power wires connected straight to the battery with a inline fuse.
That's how I have mine connected.

[Salmon Hobo]

We can't rule out the old sea tale of "Ghost Tabs"

[Fisherdv]

Battery connections are tight,
8 gauge wire from battery switch in back, to acc fuse panel up front
Single battery
Radio is a Standard Horizon with built in GPS and DSC, good radio
Switch panel to radio I want to say 12 or 14 gauge

[Fisherdv]

Only happens in 25W mode, does not do it in 1W mode, I agree on the voltage drop
AJFISHIN, I was trying to avoid a rewire but I just might have to
I was trying to wait to go to a dual battery set up until another year or two till the single I have now needs replacing so I can buy both batteries at the same time

[Threeweight]

What's the antenna brand, and what kind of antenna connector do you have?

Something is causing a voltage drop when you transmit.  Your radio should pull about 7 amps at 25 watts transmit, with the set up you describe that should not be enough to cause an issue, unless you have a bad connection somewhere or a short of some kind.

[Fisherdv]

4' glass Shakespeare antenna
Single battery, straight to a blue seas on/off switch. Acc fuse panel connected off the battery switch

[Fisherdv]

My acc fuse panel in the cuddy has FF, trim tabs, VHF, lights pretty much all acc wired to it. I'm not sure of its max rating (I would guess about 100A) but I suspect that fuse panel my be over loaded. Although if I add up all fuses I'm still under 100A. I just may have to do a dual battery set up and rewire sooner than later

[DevMah]

My acc fuse panel in the cuddy has FF, trim tabs, VHF, lights pretty much all acc wired to it. I'm not sure of its max rating (I would guess about 100A) but I suspect that fuse panel my be over loaded. Although if I add up all fuses I'm still under 100A. I just may have to do a dual battery set up and rewire sooner than later

I think is more than the fuse box I think you may have the conductor undersized for the helm feed.

Are you sure it is 8 AWG.... I think my original was 10 AWG... not sure but I Pulled a new 6 AWG to th hem.


Dev

[Fisherdv]

Yes, says 8 AWG, I just checked to make sure

[Fisherdv]

I remember reading a while back ago about people blowing fuses transmitting. Maybe it's more of a current draw than we really think