It was Suppose to Work! | Fixing my RFI in the Shack | 1:1 Common Mode Choke at the Ant Feedpoint

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It was Suppose to Work! | Fixing my RFI in the Shack | 1:1 Common Mode Choke at the Ant Feedpoint

Рет қаралды 1,036

Күн бұрын

I'm troubleshooting as to why am I now getting RFI after moving my 40m skyloop and also cutting 21 feet 9 inches off the wire. I decided to move my Balun Design 1:1 Common Mode Choke to the Antenna Feedpoint. It's suppose to reduce CMC right? Watch the video and find out.
Thank you for watching!
#cmc
#Skyloop
#rfi
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Пікірлер: 25

@QRP700 8 ай бұрын

If your shack is directly under antenna you are within the field of the radiating antenna which is highly likely causing the problem therefore you will not eliminate the RF without relocating antenna from above your equipment. 73 de Aiden EI8HJB

@DarrenN4VFR 8 ай бұрын

That's good to know, yeah I'm below the antenna maybe about 30 feet away.

@QRP700 8 ай бұрын

Hey Darren, I thought I would also add that it is good to have a RF field strength meter to test field strength in the shack. You can also use it to check if RF is on the outer casing of equipment. While monitoring RF field strength meter Turn down power and If problem goes away as reading is going down It is due to proximity of antenna. I also found that If you have any antennas close by you need to choke them as well because RF couples onto them and follows the coax into shack. I also had to put ferrites on power supply to equipment as well. I hope this helps you out. 73 De Aiden EI8HJB

@lamontwolverton8959 8 ай бұрын

I've had great luck my enhansing my ground system with all stainless hardware, multiple earth grounds and AC shielding, but I'm sure you have investigated that, good luck! Laughed at the HOA statement, hit a nerve 😀

@DarrenN4VFR 8 ай бұрын

Thanks still working on it. Going to attack my Mic input and Powered Speaker system since it's only when I transmit that I hear RFI going through my speakers and headset without the Monitor on.

@HamBandit 8 ай бұрын

Hey darren! just wanted to say this it might help. Your going after common mode currents but that is not your issue. your dealing with amplifer Location. move your amplifier away from your TUNER and radio. I had the same issue. i moved my amplifier about 18 feet away and the RFI disappeared it took a longer jumper but it worked for me. Your getting RFI bubbles from the antenna above and from the amplifer located below. Give that a try hope that helps.

@DarrenN4VFR 8 ай бұрын

Yeah man, I agree, it's not CMC issue. I really don't have much coax nor place unless I put the amp in the laundry room which the wife won't allow me. In my Florida QTH, yeah, I moved the Amp & Tuner as far away from my Computer, Audio Interface, and Microphone however, I didn't get RFI issues there but did that anyways. I'll try to add more FT240-31 torroids and attach the speaker & mic cables.

@g0fvt 8 ай бұрын

Common mode current can still be an issue since with the choke at the feedpoint the entire coax is still in a strong RF field. It can sometimes be worth having a common mode choke at the shack too. Of course if you are right under the antenna the field strength can be very high. As for avoiding certain parts of your station being near the computer, many broadcast systems are set up with a laptop directly connected, but as amateurs we don't have the luxury of having purpose built sites for gear. Your rooftop tour did show a few possible paths for unwanted RF current, I obviously don't know the issue that is causing your problem. I too have had issues with RFI, generally all attributable to common-mode current, it often is far worse on a specific band. It is great when you do get it resolved and often the solutions will help your received noise levels too. Good Luck 73

@DarrenN4VFR 8 ай бұрын

I'll do a Common Mode Current test by removing my ground/shield coupling on the PL239 at the back of my Tuner to see if the noise floor decreases when I remove the ground. If there are no changes, then there is no presence of CMC.

@ernie6544 8 ай бұрын

Install ferrites on the speaker power supply line

@DK5ONV 8 ай бұрын

Good Job. Stopp interfering yourself 💯😍👌

@DarrenN4VFR 8 ай бұрын

Thank you Uncle Guenter.

@alessandroconcas 8 ай бұрын

Hi, have already use a usb isolator? ferrite on coax and ugly unun are, in my system, more efficient than rf choke...

@greglyons2402 8 ай бұрын

I wonder is your shack on the top floor? If so, your problem may be from your antenna now being too close to your shack. I had the same problem my shack is on the second floor and the antenna is right above my shack Raised it up 10 feet and the issue went away even running high power no issues now. I know you can't raise yours back up but just a thought.

@DarrenN4VFR 8 ай бұрын

My shack is on the 1st floor. The antenna is on the 3rd floor (Roof). I have to climb a tall ladder to get up there. I've got it nearly eliminated, video will be posted after Christmas.

@greglyons2402 8 ай бұрын

@@DarrenN4VFR Oh ok I wasn't sure good to hear that I know that it can drive a person crazy sometimes trying to find it lol Looking forward to the video hope you guys have a great Christmas

@TahoeMtnMan 8 ай бұрын

Have you considered a remote tuner?

@DarrenN4VFR 8 ай бұрын

I don't want to place my Palstar HF Auto on the roof in an enclosed container. Still need to run DC power up there. It's okay. I'll deal with what I have right now.

@N1SEP- 8 ай бұрын

How do you have your equipment grounded, meaning your amp and radio?

@DarrenN4VFR 8 ай бұрын

My Anan's ground is going to 2 places, my desk's grounding bus and also my Mercury Lux. My tuner is grounded to my desk's grounding bus. Then my grounding bus goest through the junction box access to a grounding rod maybe 8' deep.

@N1SEP- 8 ай бұрын

I’m curious to the Anan going two places? All equipment needs to go directly to ground bus in order to prevent a ground loop.

@N1SEP- 8 ай бұрын

I’m also curious as to how long your wire to the 8’ ground is?

@DarrenN4VFR 8 ай бұрын

@@N1SEP- I would guess about 4-5 feet from the shack through the wall and straight down to the grounding rod.

@DarrenN4VFR 8 ай бұрын

@@N1SEP- I'll disconnect the ground from the Anan to the Amp and go straight to the grounding bus.