News:

To visit MidNite Solar click this link www.midnitesolar.com

Main Menu

KID RF Hash

Started by Tobit, June 05, 2020, 01:57:22 PM

Previous topic - Next topic

Tobit

I'm loving my KID but it sure generates a lot of hash into my ham radios when in charge mode.  I've been experimenting with a lot of filters and ferrite chokes but it remains.  It is the only device in my cabin that generates hash.  Ham radio is an essential part of my off-grid life but it makes weak signal morse code reception difficult.

Would the Classic operate any cleaner?

Vic

#1
Hi Tobit,

As you know,   MPPT CCs  are,   essentially  Switching power supplies,   and are fairly large ones,   at that.

Most of the emissions are Conducted on the PV,   and to some extent,  the battery cables connecting to the CC.

It sounds like you have tested where there emissions are coming from,   by turning the KID,  OFF,   and noting the change in emission levels.   Inverters also often create RFI.

Ferrite Common Mode chokes on these cables are generally the first thing to try.    For HF,  Mix 31 ferrite cores seem to work well for HF frequencies.   Try winding several "turns" of the PV cables through a type 31 clamp-on (if you have large ones),   or through a donut toroid core,   very close to the CC,  if you can.

Isolating antennas from proximity to the PV arrays,   above ground power cables,   etc  will often reduce the emission levels,   if you have the room,   away from the power system location.

Here is a Link to a very long Thread,  from the Wind-Sun Forum,   on RFI:
https://forum.solar-electric.com/discussion/4685/radio-noise-from-pv-system/p1

Also,   K9YC has a number of articles on his site on using Common Mode Chokes,   and RFI Reducgtion:
www.audiosystemsgroup.com/RFI-Ham.pdf

EDIT:  The following should be the Common Mode Choke Cookbook:
http://k9yc.com/RFI-Ham.pdf

Please DO let us know how you are doing on this   ...

More later   73,   GL,   VIc

Off Grid - Sys 1: 2ea SW+ 5548, Surrette 4KS25 1280 AH, 5.25 KW PV, Classic 150,WB, Beta Barcelona, Beta KID
Sys 2: SW+ 5548s, 4KS25s, 5.88 KW PV, 2 ea. Classic 150, WB, HB CC-needs remote Monitoring/Control, site=remote.
 MN Bkrs/Bxs/Combiners. Thanks MN for Great Products/Svc/Support&This Forum!!

Tobit

Thanks Vic, it's definitely a work in progress.  Hard to isolate much in a 12x18' cabin but I'm trying.  No inverters here, trying to keep everything 12VDC.  I am also living by candlelight.  LOL.

Hash is definitely narrowed down to the KID when in Bulk or Absorb mode, not so much in Float.  PV array is negligable and already cleared up with several turns on big 3" mix 31 cores.

Tobit

Honestly, it isn't that bad but I moved to the middle of the woods so I'd have no noise so I'd like to clean it up as much as possible.  :)

boB

Quote from: Tobit on June 05, 2020, 03:35:38 PM
Honestly, it isn't that bad but I moved to the middle of the woods so I'd have no noise so I'd like to clean it up as much as possible.  :)

I hear you there !   Are you on HF that you have the noise or VHF/UHF.   Typically the noise is OK on VHF/UHF.

Here in the city HF is impossible because of all the appliances and neighbor's noise.

Ferrite common mode chokes on the battery and PV input lines are the first thing to try like Vic mentioned.  Right next to the Kid.  As close as possible.

If you have a large enough toroid, I would run both battery and both PV lines through the same toroid if it is large enough.

Keep us posted.

K7IQ
K7IQ 🌛  He/She/Me

Tobit

#5
Quote from: boB on June 05, 2020, 05:27:34 PM
I hear you there !   Are you on HF that you have the noise or VHF/UHF.   Typically the noise is OK on VHF/UHF.

If you have a large enough toroid, I would run both battery and both PV lines through the same toroid if it is large enough.

Keep us posted.
It is all HF though the worst is on 6M where I need the band clean.

I hadn't considered running both the PV and battery lines through the same roid.  Because of the PV distance, I run 6 ga. from the combiner box to the breaker in a Big Baby box and then 10 ga. to the KID.

I want to try a couple 3" ID mix 31 rings next but they are a bit expensive.  Maybe next month.

boB

Quote from: Tobit on June 05, 2020, 05:36:48 PM
Quote from: boB on June 05, 2020, 05:27:34 PM
I hear you there !   Are you on HF that you have the noise or VHF/UHF.   Typically the noise is OK on VHF/UHF.

If you have a large enough toroid, I would run both battery and both PV lines through the same toroid if it is large enough.

Keep us posted.
It is all HF though the worst is on 6M where I need the band clean.

I hadn't considered running both the PV and battery lines through the same roid.  Because of the PV distance, I run 6 ga. from the combiner box to the breaker in a Big Baby box and then 10 ga. to the KID.

I want to try a couple 3" ID mix 31 rings next but they are a bit expensive.  Maybe next month.


OR a separate one just for the battery cables ?

BTW, are these birdies at single frequencies or are you seeing wideband hash ?



K7IQ 🌛  He/She/Me

Tobit

Quote from: boB on June 05, 2020, 06:38:52 PMOR a separate one just for the battery cables ?

BTW, are these birdies at single frequencies or are you seeing wideband hash ?
6M is the worst, but also a problem on 160, 80, and 40M where I have very sensitive beverage antennas.

Attached is the waterfall hash on 6M, the blue lines go away when I shut off the breaker connecting the KID to the battery bank.

Vic

#8
Hi Tobit,

Thanks for the added info on your system,   and for the pic of the radio screen.

Since you have no inverter,   your 7300 is probably connected directly to the radio.   Have you tried disconnecting the antenna coax from the radio?   What effect does this have on the level of the RFI ?

Have you tried a common-mode choke on the battery cables from the KID,   or,   on the 12 V  DC cables,  right at the radio itself?

Believe that you may not have a lot of ferrites available,   but,   you might try moving the ferrite on the PV least,  to the battery side of things,   to see what happens.

What is the separation between the 6M antenna and the PV array/s?   If you have a  rotatable directional 6M antenna,   do you see a reasonable change in the RFI levels  when the antenna is rotated>

Thanks for any added info.73   Vic
Off Grid - Sys 1: 2ea SW+ 5548, Surrette 4KS25 1280 AH, 5.25 KW PV, Classic 150,WB, Beta Barcelona, Beta KID
Sys 2: SW+ 5548s, 4KS25s, 5.88 KW PV, 2 ea. Classic 150, WB, HB CC-needs remote Monitoring/Control, site=remote.
 MN Bkrs/Bxs/Combiners. Thanks MN for Great Products/Svc/Support&This Forum!!

Tobit

Vic, disconnecting the antenna has no affect on the hash. 

Primary antenna is a 125' doublet fed with 600-ohm ladder line 60 feet in the air above the PV array below,  the ladder line is fed  off at a right angle to the other side of the property to avoid the array but I'm not sure of the distance.  I have large coax to a 4:1 voltage balun before coming into the cabin.  I will soon be replacing this with a hyrbid 4:1 and 1:1 balun to allow for easier matching and better common mode chocking via the 1:1 balun.  I do have some common mode choking on the feedline now but it could be better.

At this point, I think I need to invest in larger mix 31's on the KID to allow for more turns.  To me, it still seems to be more of a KID problem under charging than a PV input issue. 

boB

Quote from: Tobit on June 05, 2020, 07:11:19 PM
Vic, disconnecting the antenna has no affect on the hash. 

Primary antenna is a 125' doublet fed with 600-ohm ladder line 60 feet in the air above the PV array below,  the ladder line is fed  off at a right angle to the other side of the property to avoid the array but I'm not sure of the distance.  I have large coax to a 4:1 voltage balun before coming into the cabin.  I will soon be replacing this with a hyrbid 4:1 and 1:1 balun to allow for easier matching and better common mode chocking via the 1:1 balun.  I do have some common mode choking on the feedline now but it could be better.

At this point, I think I need to invest in larger mix 31's on the KID to allow for more turns.  To me, it still seems to be more of a KID problem under charging than a PV input issue.


If you removed the antenna and the RFI is still there, it may be entering either through the battery lines OR through the case itself.

If it is through the battery cable, then the #31 material may reduce it enough to get by with.  That is one of my favorite materials too.

How close is the Kid to your radio ?

And, can you take a spectrum shot of it with the Kid breaker turned OFF ?  That would give a baseline measurement.

I see that the spikes your analysis is showing are most likely at repetitions of the Kid's switching frequency which is somewhere around 35 kHz



K7IQ 🌛  He/She/Me

Vic

#11
Quote from: Tobit on June 05, 2020, 07:11:19 PM
Vic, disconnecting the antenna has no affect on the hash   ...

   ...   At this point, I think I need to invest in larger mix 31's on the KID to allow for more turns.  To me, it still seems to be more of a KID problem under charging than a PV input issue.

The more work (the greater the KID's output current) that is being done,   the larger the level of the RFI hash should be.  Suppression on the battery cables twix the CC and the battery,   can cause an increase in voltage drop,   often due to an increase in cable length increase for the  cable in the ferrite.   This can have a larger impact on 12 V systems.   Just another tradeoff.  So try to use the largest cable that is practical,   between the CC and the battery,  if you need a CM choke there.

Do not know the source of your ferrites,   but,   IMO,  KF7P.com (Chris,  IIRC)  seems to have a fairly wide selection and very reasonable prices of most of them   ...  I have no business relationship with them,   just a happy customer.

73,  Thanks,     Vic
Off Grid - Sys 1: 2ea SW+ 5548, Surrette 4KS25 1280 AH, 5.25 KW PV, Classic 150,WB, Beta Barcelona, Beta KID
Sys 2: SW+ 5548s, 4KS25s, 5.88 KW PV, 2 ea. Classic 150, WB, HB CC-needs remote Monitoring/Control, site=remote.
 MN Bkrs/Bxs/Combiners. Thanks MN for Great Products/Svc/Support&This Forum!!

Tobit

Two photos attached:

KID in "Resting" mode
KID breaker to battery shut off

One thing to note that I had not noticed earlier, as I am usually running weak signal digital modes with the sound turned off, when in resting mode, there is a pulsing noise during receive.

Vic, I've been buying my roids from Palomar Engineers  They've seemed to be very reputable and reliable over the years.

Tobit

Sorry for the overly large size on the "off" image, I thought I resized it.

Vic

Hi Tobit,

What did you do to get the KID to Rest?   Looks like the Converter in it is still running,  in the first pic.

Fine on Palomar.   Recently,   some have said that they are not responding to messages/orders   ...   may well be CoVid related.

Thanks,   Vic
Off Grid - Sys 1: 2ea SW+ 5548, Surrette 4KS25 1280 AH, 5.25 KW PV, Classic 150,WB, Beta Barcelona, Beta KID
Sys 2: SW+ 5548s, 4KS25s, 5.88 KW PV, 2 ea. Classic 150, WB, HB CC-needs remote Monitoring/Control, site=remote.
 MN Bkrs/Bxs/Combiners. Thanks MN for Great Products/Svc/Support&This Forum!!