i should bring up that trying to isolate and cure rfi is a royal bit*#. we don't know if it is airborne or hardwire bound. we don't also know if it is just the controller or is it something else such as that particular radio. we must remember that the antennas are not located at the radio, but are most likely outside up in the air on a mast. finding and remembering these things does help in a cure as it's not always enough to just say the controller did it, what now? ground system differences or faulty grounds can also lead to problems so this is part of my reasoning to say to try to interpose or switch components from other sites to find out some of these particulars in narrowing down the causes. for example, if you take that controller that is at the site that has interference and place it at a good site and the interference goes away then i'd say look for a different cause. interchanging radios in a similar fashion helps to know if it is the radio's fault.(which i doubt, but you never know)
as was mentioned, caps and ferrite cores should be located inside the controller if possible, but at the very minimum as close to it as possible to help elilminate conducted interference through the wires and to stop the wires from acting like antennas. does the interference go away if you disconnect the coax cable from the radio? if so, then the interference is airborne and if not it's going through your dc wiring. it's alot of detective work and that's 1/2 the battle. the other half is getting rid of it, but it becomes easier to do when you know how it gets from point a(to be determined) to point b(the radio).

I've got a thread going at Outback's forum- http://www.outbackpower.com/forum/viewt ... 1848#11848

As for our pv's, they are mounted for summer sun angle and straight south. They contribute very little in the winter as they are often covered with ice or buried in snow.

ok ak. many seem to be saying as i in general and that you have to determine how it gets to the radio. power wires, antenna, or both. i didn't notice it said and maybe i overlooked it, but did you try disconnecting the antenna to see if the rf noise stays present even if only at a lower intensity? ground loops are also very possible too.
on a different note is my asking you of the usage during those winter months. do you still use the radios at that time of year? if yes, then what is powering them during those times of solar power blackout?

Techs that were on site used a handheld radio to sniff and could hear the noise inside and outside in close proximity to the hut, so pretty certain it's radiated. Also, it's actually breaking the squelch of the radio. See the outback thread, we have a new theory that we may have an accidental antenna in the form of a drain wire that's in the cable runs to the PV panels.

except for you finding that extra wire it all sounds like my advice in tracking it down. keep us informed here as well as your posts over there if you would. for the record, i have radio experience as an amateur radio operator.
gee, you think he noticed?

Niel,
Yes, it's obvious you know your way around radios. Your advice was definitely of help, and I want thank you for it. Everyone sees things from a slightly different angle, and that's why it's good to hear from others like you. Everything is still speculation until we get back to the mountain.
To answer your previous question regarding our other power source. Yes, the radios operate year-round, 24/7. If they're not up 98% of the time, we take a financial hit on our maintenance contract. Needless to say, solar has been turned off at these sites until we resolve the issue.
Our other power source is redundant propane fired internal combustion generators. They are diesel engines retrofitted to burn gaseous propane. The engines spin 3 phase generators whose output is fed to a rectifier cabinet and converted to 24vdc. The system is rather unique in the aspect that the generator output is regulated by a control loop monitoring the dc, after it has been rectified. In addition, there are seperate controllers for each generator which monitor the battery charge level and call the generators to start only when batts are depleted. A charging profile is then completed with bulk and taper segments. A PLC acts as the master or "mother" controller, and allows only one engine at a time to respond to the low voltage "call to start", toggling between the two so they both get exercised. In addition, each engine's controller also controls environmental dampers/fans to regulate hut temperatures, and the PLC has the ability to override/control these elements as well, should the engine controllers fail to do so.
Extensive sensor wiring monitors voltages, current draw, rpm's, charge current, temperatures, oil pressure, smoke, fire, fuel levels, weather, as well as data from various site loads, and all is reported back to a master station over microwave links/telco circuitry where the data is recorded into a database for analysis. This circuitry also allows for manual engine control and modification of operating parameters in response to site specific conditions.
The "on demand"nature of the system works well with the solar. In summer, the engines rarely see a "call to start" condition, saving lots of $ in propane cost.

Since it sound like your having large costs shuting down your solar, I would suggest you purchase at least ONE WX-MPPT from xantrex before your next visit to debug. Since it has Class B FCC certification you know, worst case it will fix the issue, if all else should fail and by the sounds of it, even at 600.00 each, it cheaper than having to haul in fuel

At that frequency, a majority of the EMI could be common mode noise (current) coming out of the leads of the unit. some things to try:

Ferrite beads--They make lossy split ferrite beads (like those bumps on cords for computers/digital electronics) that you can clamp on each pair of signal wires (or entire groups of wires--especially +/- heavy current wire pairs, don't put individual wires through separate inductors, large currents will saturate the cores--making them useless, and the added differential inductance can cause signal/stability issues; doing pairs only blocks the common mode noise but keeps signal quality high and circuit stability unaffected). Don't put ferrite beads on your lightening ground connections--it will just make those ground runs more inductive and not pass lightening strikes to ground as well.

Look at the catalog for size and frequency range covered. You want "lossy" ferrite beads designed for emissions control so that they convert the RF energy into heat. There are also larger solid rings you can wrap an extra turn of cable through that can help too. It has been too many years for me to remember vendor names/part numbers but here is a search that may help.

http://clusty.com/search?query=ferrite+filters+beads

Shielded cable--using braided shielded cable (with the jacket grounded back at the noise source--MX60 metal case) will help too. Generally, only the first 10' or so (longer will not hurt) needs to be grounded. The capacitance of the braid will short out most of your RF to ground.

You can get various braided "socks" (some can be wrapped around existing cable) or get the wide flat braid used for grounding applications--it is hollow and you can pull your wires through the hollow center section and build your own braided cable harness.

In the old days, you could also get old braided conduit from ships/navy surplus too.

Regular solid conduit will work fine too (grounded at source of noise). I would not trust flex conduit (spiral type) unless you do your own testing first (needs solid ground connection entire 10'--spiral connections along length may not work as well).

-Bill

i'm not criticizing the second opinions you are getting, but just reafirming how it parallels my advice. yes, i can overlook something so no problem in more minds at work. that's why you initially posted as you're not dumb, but you can overlook something too.
that's quite a nice system you guys devised there. i do have to agree with solar guppy and the owner in that you should order at least one new xw controller if your next bout with tackling the rfi doesn't pan. time is essential and you want a good working system there. yes, there are costs, but it could be more costly otherwise as the system has been compromised by this rfi. at the very least you would have a backup controller and the cure now would allow you time to play with the causes/cures of the interference at a more relaxed pace.

Thanks for all the input. I've got some split ferrite chokes in hand, and just got approval to buy a Xantrex. Might get to the mountain by the end of this week.