Reducing HF Noise Using Antenna Phasing With The MFJ-1026
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- čas přidán 11. 09. 2024
- I get a lot of questions regarding HF noise from the local Amateur Radio Operators and wanted to do something on what I am doing to reduce the HF noise on 40 Meters that I think is coming from a neighbor's house. This is only one of many solutions when you can't get to where the noise generator is to try to fix / reduce it's unwanted signal.
Stew, thanks for the video. I’ve been looking for ways to reduce noise. Jeff KF0BPN
Glad to help
Stu
AG6AG
Forgive me if I'm wrong but if the Main Antena Gain is lower than the maximum (10) it seems to me that you're also attenuating the receiving signals, no? 73 de PY5CL
Hi Carlos,
Yes, you are reducing the signals across the board, but by combining the two antennas you are able to lower general noise and around your signal of interest.
I'm not an expert on phase and diversity when it comes to antenna arrays, but from what I've managed to gleam from the literature, the phase of the two antennas can reduce the unwanted signal why allowing the wanted signal to poke through.
I was actually kinda surprised that it works as well as it does!
Stu
AG6AG
@@AG6AG Thank you! I also have the 1026 for many years and still have some difficulty to tune it. Lately has started a terrible power line noise here that I can't get rid of, I think my auxiliary antenna is not good for capturing noise. Sorry my poor english.
Stu: What are you using for an auxiliary antenna? Main antenna? I have been thinking of getting one of these. My noise floor on 40 meters is similar to yours. My main antenna is a fan dipole (80-40-20-15-10M). Thanks!
Hi Bob!
Well, the Aux Antenna is a CHA-250b and the Primary is an fan dipole (80-40-20-15-10M). You can use about any Aux antenna you want. There is lot's of info regarding the type and configuration of the Aux antenna in the docs for the MFJ-1026. One glaring note I need to make... Make sure the interference is coming from something you don't have control over. If you wait a bit I will be coming out with a video on testing for local noise.
Stu
AG6AG
@@AG6AG LOL! I guess I shouldn't have scrapped the CHA-250 after all...!
Will check out those docs. Have been putting ferrites on most everything in the shack, hasn't changed much. Tried the test for common-mode noise on the coax, and that's apparently not the problem either. Will be looking forward to your next video. :-)
You can use just about anything that receives for that Aux antenna. As a matter of fact, the primary and aux antenna should be the same polarity. I used the vertical because it was in the air already, but I'm thinking of putting up a long wire or un-matched dipole for the aux antenna in the near future. Remember, you only need "ears" on the aux antenna... It doesn't need to be resonant like a transmit antenna...
Stu
AG6AG
@@AG6AG Hi, Stu - I bought one of these and am waiting for the receive antenna (a MFJ 40-20-10-6M dipole) to get here from GigaParts. In the meantime, I tried it with the little wimpy antenna it came with, and it actually knocked about 1-1/2 to 2 S-units off the noise floor on 40 meters. Quick question - would I connect the "TX GND" jack on the FTDX-3000 to the T/R control jack on the MFJ device? From the manual, that would appear to be the right choice but just wanted to make sure. Thanks!
Hi Bob,
Yes, the TX GND Jack on the FTdx3000 should go to the T/R Control Jack on the back of the MFJ.
Stu
AG6AG
great video thank you 73
Glad you enjoyed it
Stu
AG6AG
I get similar noise floor on 30m, been looking into one of these for a while but not decided yet.
Hi Steve,
It's a tough call as to whether to invest the money... Trying to use the internal antenna was not the hot ticket for me, which means I have a HF multi-band tied up to the device.
I would exhaust all the other less expensive options before spending the money on this... It worked well for me, but it doesn't work in all cases and like I said, you will most likely be tossing at very least a receive only HF antenna at the problem as well.
Let me know if you decide to try it and how it works, or if you find a better solution!
Stu
AG6AG