WFCO Converter RF Interference. Solutions/alternatives?

Hi.  I've searched the forums here for 'WFCO' and 'interference' and didn't turn up any discussions concerning the beastly RF interference that these units seem to put out.

I have a Starcraft 2106 pop up camper that came factory equipped with an Elixir 25 amp converter.  After boiling the original battery dry with the simple one-stage charger that the Elixir had, I changed the battery our for an AGM, and soon after that the converter died (thankfully before it managed to ruin the AGM battery, as well).

I searched the web and found the WFCO 8725 unit recommended as an upgrade/replacement for the Elixir 25, so I ordered one and after a lot of grief caused by the different arrangement of the AC in/out routing, lack of a metal case ground, etc. finally got the beast installed.  Imagine my surprise when I find that the unit when powered, knocks my weather radio out, interferes with the AM receiver in my tow vehicle when I approach the camper, and worst of all, it pretty much wipes out the ham bands up through 10 meters with squegging noises every few kilohertz. Even from an antenna 50 feet away, the noise peaks at S9 or more.

The user manual (and web site advertising) claim FCC Class B.  Of course, you know how much that tends to mean in this day and age, but wait, there's more! (sound like a knife commercial, yet?)

The manual states, and I quote:

"This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules.  These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment." (my emphasis).

Commercial?  That is Class A, which is less stringent than Class B.

It gets better:

"Operation of this equipment in a residential area is likely to cause harmful interference in which cause[sic] the user will be required to correct the interference at his own expense."

Well, they were right.  Hopefully, someone here has met the enemy (WFCO) and conquered it somehow, or found a better alternative (that fits the oriignal Elixir 25 form factor, doesn't boil my battery, and is much better behaved, RF-wise).

Thanks for any advice/help you can give.  I use this camper for our radio club's Field Day (ARROW/W8UM joint exercise) , and without a solution to this, we will have to forgo having 12V-supplied shore power for the duration of the contest, except from the pre-charged battery.  We can run the air conditioning and other AC accessories direct from an extension cord from the site generator(s), but obviously, this is all sub-par compared to just being able to plug the 30 amp pop up camper drop into the generator and going from there.

73,

Dave, N8SBE

Dave,

IF you can get a few ferrite beads on the power input line and on the coax right at the radio, that will help the conducted emissions.  This did help my AM band somewhat although not much for 80 meters and above.  For the ones radiated, I have no idea.  You will find most if not all the converters/chargers for RVs are RF NOISE generators and you will get NO help from the manufacturers other than what you have already read.  My advice is to get a good power supply and add what is required to make it a battery charger on your own.  The cost of in line filters for the current and the necessary shielding of the converter is nearly prohibitive.

"Operation of this equipment in a residential area is likely to cause harmful interference in which cause[sic] the user will be required to correct the interference at his own expense."

Some of my neighbors were not thrilled when I informed them of this law and worked with them to reduce the noise in the neighborhood.  Try it in an RV Park.  Lots of fun.  NOT!!!!!!

The RF emissions regulations in the US suck!! 

I have an expensive Xantrex inverter/charger and I have to have the charger off when ever I operate any low band radios except the AM band and then it must be a strong signal or it is painful to listen to it.  I turn the charger off when using the radios.  Now I somehow have to figure a way to remember to turn it back on at O'dark 30 when I quit operating and am half asleep.

Not much help but if you should come across something, a lot of us would like to know about it.

A linear power supply like the Astron RS-35A won't generate RFI and can be used to replace your converter   They aren't that expensive.

link here

Jim,

Now you have my thinking cap working...

I have an MFJ 25A 'MightyLite' switching power supply, which I use as my desktop supply for my IC-7000 and has been pretty clean, RFI-wise.

I used to have an Astron, but let it go with my IC-735 when I sold it last year.

I also have a West Mountain Radio PWRgate PG40s, which I got originally to use in my tow vehicle (a Durango) to put together a floating charger-type setup under the rear load floor hatch, but gave up on the idea and just ran really heavy wire from the PDC in the engine compartment to the rear compartment, where the body of the IC-7000 goes.  So the PWRgate is essentially surplus at the moment.

I could wire it up in the camper with the 25 amp supply, but the WFCO converter is always powered when the main AC breaker is switched on.  I'd like to leave that breaker turned on normally, because is feeds shore power to all the AC outlets in the camper.  There is a separate AC breaker for the air conditioner circuit, but there is a single outlet dedicated for the air conditioner.

I'll think on this some more to see what may come of it.  One idea would be to gut the WFCO and put the MFJ switcher supply in its place with the PWRgate PG40S, using the existing 12VDC fuse panel for distribution.  The only downside would be the fan on the MFJ supply.  It is always running when the supply is on, and is noticeable in a quiet room.

73,

-- Dave, N8SBE

There is a rather good book on the subject published by the American Radio Relay League Inc (www.arrl.org) but I can give you a few suggestions

First, there are two paths for interference. Is your weather radio powered by

1: 120vac
2: self contained battery
3: 12 volt system in house?

If 3 you could have common mode interference via the power line. filter devices on the power line can improve this

If it's 1: then ... Same tihng, only you want to put the filters on the 120 volt side of the WFCO

If 2, (Mine is a 1/2/3 model. I'm not sure just what is powering it now, I think 3)

Make sure the case of the converter is WELL GROUNDED to the chassis, not just the negative output lead but the case itself.

That would be my first suggestion

I'd suggest a Progressive Dynamics, however where Mine, seems to be as silent as a battery.... Others have not reported the same level of interference (ZERO)

John,

The weather radio has internal batteries, and also an AC-powered 'wall wart'.  I find that the interference when running on batteries is greatest when the radio is placed near one of the camper's AC outlets when the converter is powered on.  Unfortunately, as I move the radio around, the signal (from the Southfield transmitter to my home in Ann Arbor) varies enough to not make comparisons of locations in the pop up very useful.

I've placed ferrite cores on all AC lines, except the main 30 amp one, because it is too big to get one of my clamp-on cores around.  I've also placed cores on all 4 of the DC lines coming out of the converter.  As far as I can tell, they've no effect.  If they had had some effect, then it might be that most/some of the interference is being conducted, but it would appear that it is mostly being radiated from the converter board itself.

I'd like to ground the converter cabinet, but the durn thing is made of plastic, unlike the Elixir.  The Elixir had a much nicer setup, with a large grounding bar on the back of the cabinet for DC ground, chassis ground, and AC neutral tie point.  In the WFCO unit the chassis ground just goes through a hole in the back of the plastic chassis, and then to a ground bar in the AC breaker junction box.  Everything is plastic-mounted.

Now that I'm considering gutting the WFCO and putting a quiet switching supply (I've been reading all the QST switching supply product reviews on the ARRL web site this evening) and PWRgate PG40S in, I wish I had not discarded the Elixir cabinet.  I'd rather build it all into that metal cabinet.  It would also leave me with a working WFCO that I could substitute back if I couldn't get the supply/PWRgate design to work satisfactorily.

One thing I noticed after looking through all the product reviews -- it is essentially impossible to get a supply that is quiet RF-wise and also quiet fan-noise-wise.  The two most quiet RF-wise supplies have relatively noisy fans that run continuously.  The only exception was the Alinco DM-330MV, which being a bit of an overkill, is not to pricey, and has a nice feature that allows me to preset the voltage with a recessed back panel control (I need 14.5 V to use the PG40S with an AGM battery), and lock it in with a switch on the back panel.  Unfortunately, even though the fan is temperature controlled, and is very quiet when it runs, the heat sink on the supply gets 'untouchable' hot when the supply is run at 21A output for some period of time.  That could be very problematic for a build-in situation, if I'm trying to replace the WFCO in its current location.

The product reviews point out that even for the supplies that make some amount of RF noise, that it mostly occurs when the supply is outputting more power (21A versus 1A), so for the purpose of the review, in receive mode, the noise is much less.  In a camper, though, if the battery is charging heavily (10A or so), and the furnace is running, you could encounter that higher noise level, even if receive mode.  My assumption here, also, is that whatever transceiver you might be using would be plugged into one of the camper AC outlets, and would have its own (hopefully quiet) switching supply.

Still cogitating....

73,

-- Dave, N8SBE

John,

Looking over the Progressive-Dynamic site, I notice the Intelli-Power 4000 series all-in-ones come closest to replacing what I have, although the required cutout is 1 inch taller.  Is this the system you are running that is so RF-quiet?

73,

-- Dave, N8SBE

Have you tried 20m lately.. Just finished with nice qso with Jack in San Vicente-Alicante in Spain. I used PSK 31.

   And all that with my vertical in the backyard on the ground, about 10W RF into the antenna. There is hope.

73 carson FL 28.0 N.

My system is a PD-9180 with charge wizard

As I said mine is 100% silent, rf wise, but others have reported noise

So, Take this with a large grain of sodium chloride if you will please

I have not been on 20 lately, I"ve not been on much of anything as I've been busy busy busy

If the ground ever thaws, maybe I can get the hole dug for my antenna mount and finish up the low band installation here in the house.  The RV one, I am flat on my *#% as I haven't been able to work out the mechanism to lift the antenna.  The remote part was easy but the mechanical is hard for me.  I need a mechanical engineer for a couple of hours with a computer drawing program.  :'(  I hope to get one Sunday over coffee.