Problem with SSB Icom and Spectra Watermaker

[jpiebrig]

John, sorry I have made a mistake. I took off the label on the control panel (nothing written on it except Catalina 300) and under it is a MPC-5000.
So nothing to do with the control panel, it is the good one.
And it was not a new MPC-5000 control panel but a different version of the MPC 5000 control board with a battery backup. The battery backup allows the MPC board to retain its last operating state when the system is powered down for up to 5 days.
But I don't need that.

[daddle]

I have a Spectra with all the options and it does not interfere with any radio at any time.

The idea to power the SSB (or anything) directly from the battery is a popular misconception. Even though it probably solves problems in many cases it is not the proper solution. The proper solution is to fix all the corroded connections and components between the battery and the SSB and all other devices. Those are the problem in nearly all cases. Good connections and reasonably sized wires are the key.

Super-sizing wires is also a popular fallacy.

[transmitterdan]

Originally Posted by jpiebrig

John, sorry I have made a mistake. I took off the label on the control panel (nothing written on it except Catalina 300) and under it is a MPC-5000.
So nothing to do with the control panel, it is the good one.
And it was not a new MPC-5000 control panel but a different version of the MPC 5000 control board with a battery backup. The battery backup allows the MPC board to retain its last operating state when the system is powered down for up to 5 days.
But I don't need that.

If you are sure the water maker is putting noise on the 12V power supply then putting a properly designed inductor and capacitor PI filter on the 12V input to the water maker may help. It needs to be right at the water maker and not back at the battery or breaker panel. To figure out what component values and ratings you need will require someone with a decent theoretical understanding of RFI and current ratings of inductors. But it is possible to fix this problem. Seek out help from a boater near you that is also an amateur radio operator. They should be able to recommend a suitable filter for your water maker.

Dan

[jpiebrig]

I will not be able to test with some capacitors before Saturday. Some priority works prior to departure .
I tell you later.

[Mata'irea]

We circumnavigated with an identical problem. Icom 802, 12VDC Spectra Catalina 300 w/ MPC5000. Tried lots of fixes and discussed w/ Spectra on at least one ocassion. In the end our fix was to turn off the MPC when not in use. Not ideal but it "solved" the problem.

[SoonerSailor]

This does not have to be as complicated as transmitterdan implies.

With ferrites on the cables, and capacitors shunting to ground/negative, you are creating a low pass filter. You can do this with ferrites alone or capacitors alone, but they will work even better in concert. Mix31 ferrite toroids and 0.1 mFd (plus or minus an order of magnitude) RF capacitors will do this with a frequency cutoff low enough that spurious HF signals will be suppressed. No complex calculations are needed for this application.

If it is the control head creating the noise, you want the ferrites and capacitors on the cable as close to the head as possible. If it is the main unit, you will want them on both the power leads AND the cable going to the control head as close to the main unit as possible.

Very strange that your Spectra is radiating but others don't have the problem.
Let us know how it all turns out.

Chip

[transmitterdan]

It does require some thought to ensure that the ferrite is not saturated by the DC current drawn by the watermaker. This is one reason ferrites don't always work even though they should at first glance. Plus most 0.1uF capacitors will become resonant and thus ineffective above about 5MHz so a proper filter will use more than one capacitor value in parallel to avoid resonances. I did not want to drop into a theory discussion as it seldom helps in these kinds of threads. A local HAM with SSB experience should be able to help resolve this quickly.

Dan

[Tellie]