Do ferrite clamps help on the 12V power wire?

[weccwwe]

Hi All,

I have a 50Amp/15Volt Power supply that I have been using to power 2 base transceivers on my desk. The power supply is about 4 feet away from the transceivers.

Would clamp-on type ferrites on the 12V lines to the transceivers help to lower the RF? The more on the lines, the better? (Like 3 or 4 in a row, on each + and - )

Regards

 

[prcguy]

Hi All,

I have a 50Amp/15Volt Power supply that I have been using to power 2 base transceivers on my desk. The power supply is about 4 feet away from the transceivers.

Would clamp-on type ferrites on the 12V lines to the transceivers help to lower the RF? The more on the lines, the better? (Like 3 or 4 in a row, on each + and - )

Regards

For HF just using a few snap on types does nothing, you have to use the right ferrite mix and the right number of turns . A proven combination for HF is an FT-240-31 mix ferrite toroid and wrap 9 turns of both the + and - wires through the core. In other words place the + and - wires together as a pair and wrap them together through the core.

For VHF/UHF its easier as three #43 mix or Laird 28mix snap on cores can make a noticeable improvement and you run the +/- pair of wires through each core with all the cores tight in a row. Place the ferrites as close as possible to the power supply and if its a switching type do the same for the AC power cable.

 

[weccwwe]

Thank you for the awesome answer, prcguy, going to order up those parts now, quick question, on the HF toroid, 9 turns of both +&-, is it through the same toroid?, so only one is needed?

Vhf/ugh, how many turns at each of the 3 toroids?

This is my power supply: https://www.amazon.ca/gp/aw/d/B07ZPB55NM/ref=ya_aw_od_pi

 

[prcguy]

Thank you for the awesome answer, prcguy, going to order up those parts now, quick question, on the HF toroid, 9 turns of both +&-, is it through the same toroid?, so only one is needed?

Vhf/ugh, how many turns at each of the 3 toroids?

This is my power supply: https://www.amazon.ca/gp/aw/d/B07ZPB55NM/ref=ya_aw_od_pi

For HF, one toroid, both wires together side by side as you wrap them through the common core. For VHF/UHF just clap on three snap on ferrites in series. If the hole is big enough you can use just one and wrap three turns through it but most snap on cores only have about a 1/2" hole. Each time the wire passes through the hole its considered a turn.

 

[weccwwe]

Thank you for the great help, prcguy.

Regards

 

[K3DMY]

Thank you for the great help, prcguy.

Regards

Switching power supplies are notoriously noisy, especially the ones made in China. PI type L/C filters at both the AC input and DC outputs are a big help. I have had noise levels as high as 0.5 V P-P. Grounding of all your equipment is a must.

 

[weccwwe]

Thank you K3DMY

 

[merlin]

Last 5 years, I use the HP server PSUs like this:

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Looking at them with a spectrum analyzer, there is no detectable emissions.
However, HF/MF, you can get noise from power service, so ground the supply and radios.
These crowbar at 62 amp, they take a simple mod to turn on, a simple mod to adjust 13.6 volt.
They are stiff, fixed voltage, but you can add a 50 amp meter. Binding posts for connections and put them in a project box.
I tap off of mine with a variable buck converter that runs my bench LED lights. Even with that, no significant noise.