line noise s7

KB4OIF

I have a S7 line noise most of the time on my 6600M. I have tried everything I can think of to mitigate it. Read through the manual and tried a few things. what is the best way to tone it down?????

KB4OIF

John

Stan VA7NF

More information please:

What do you define as line noise - Is this external power distribution line noise and how did you identify it as such?

Can you run your 6600M off a battery and turn off the whole house power, to identify if the noise is from within or outside your home?

What bands and do you have any directional antenna, for any or the highest frequency band displaying that noise? If so can you identify in which direction the signal is the strongest?

Is it a repeating noise (birdie) or a spectrum flat base noise?

Your note said "most of the time" Can you expand on that

What is your shack RF grounding like? Is the 6600M chassis connected to: A) a dedicated ground and how far away is it: B) floating i.e. not grounded: C) somehow connected to your AC safety ground

What is(are) your feedline(s) like and are they ferrite filtered? Are they grounded at home entry?

Can you post an image of the panadapter displaying that noise?

There are so many ways noise can get in. If you can answer these questions the group may be able to give you suggestions.

I personally have a portable SW (boom-box) receiver and a National Radio DF loop plus a sniffer antenna that I chase down various noise sources.

If you have AM broadcast stations repeated on short wave this is an entirely different problem.

Regards (73)

WX7Y

What mode and Bandwidth is the radio in, The Flex is Different than most radio's in that the S meters uses the full receive bandwidth to give you the calibrated S meter reading.

To see what your actual S Meter noise level is when hunting for noise that may not actually be there go to CW Mode and set the RX Filter to 50 HZ. This should give you a much lower S meter reading then the wider SSB filters.

John KB4DU

The Wide Band noise system was specifically developed to reduce line noise. A noisy power transformer near the Austin facility was the inspiration for this feature. It can be very effective on the correct type of noise. There are YouTube videos that show its effect. Unfortunately it doesn’t affect the various noise types at my QTH. Not the right type of noise.

Flex uses a 500 hz bandwidth as its standard for noise measurements.

Also, as mentioned above, the flex S meter is calibrated, showing the signal level at the antenna terminals. Most traditional radios S meter readings are neither calibrated or linear, so meter reading comparisons to the flex are not meaningful.

David Decoons, wo2x

If it is power line noise, then try the WNB at a level of 93. I find that to be very effective here on dry windy days when the power line arcing acts up.

I have videos on my YouTube channel showing an almost 20 dB drop in noise floor.

73

Dave wo2x

KB4OIF

Stan. don't know if it's EXTERNAL line noise. Tested with a battery and the noise is still there. hooked my hex beam to it and did a 360. A TINY due south. I am 3 miles from the gulf of Mexico to my south. Not a birdie. Spectrum flat base noise??????? It SEEMS to go down slightly at night. Dedicated ground about 3 feet from the window feed thru. 2 x 20 foot copper pipes down into the ground water level connected together with 1 inch braid. 1/2 in braid to the window feed thru. 1/2 inch braid about 3 feet to the 6600M. Commercial RF choke in line before the coax goes thru the feed thru.

Bert. 2.7 bandwith. I run SSB 95 percent of the time.

John. wide band Noise blank on the Flex has no affect on it.

David. I am going to go thru the video's one more time to see if I missed anything.

KB4OIF

John

Trucker

Does it go away when you disconnect your antenna? I have an S7 noise floor on 40 meters. I have yet to find the source. Living in the city is the biggest problem. When we lived in the county 40 was mostly S3 to S4. Plus, solar activity plays a part in creating band noise. Some things we cannot do anything about. Good luck.

James

WD5GWY

If SmartSDR had Phase Cancelation with Diversity reception you could use a second antenna to cancel out the noise. MFJ sells a device that can do something similar.

John KB4DU

If the WNB doesn’t affect the level, it’s probably not line noise. Next test I suggest is power the flex with battery and turn off the house at the main breaker. If the noise persists then it’s probably external and not much you can do about it. I’ve not found grounding to have much effect on external noise. Did you previously have a radio installed?

Stan VA7NF

Thanks John for all the information, as per KB4DU, your reply re battery didn't say if your house power was turned off while your 6600M was on battery; so no direct confirmation it is external.

Thanks for the beam info, I'm assuming 40M is on the beam, and that is not giving a significant level difference.

IF your 40M panadapter display was taken this morning, around the time of your note OR taken during daylight hours them I'm sorry to suggest you are hearing Sun noise - BUT you mentioned it is only slightly quieter at night and there are many stations displayed suggesting there may be some propagation at your time of the photo.

Note: your bandwidth at the S-Meter reading was 2700Khz. Standard background noise is calibrated at 500Hz so 2700/500 is 5.4 (round to 6X or 2 s-Units) means your 500Hz corrected level is around S5

If a) this was taken during daylight and a slight gain to the south, and with current sun activity (sun sports and recent CME activity) this may be normal background.

b) you didn't confirm when on battery, your house power was shut down; so we cannot confirm it is entirely external

c) you earlier said it is slightly quieter at night, possibly inferring this sample was during the day.

d) Since I live in Western Canada (49.5 degrees North) my daylight hours are quite different and the sun is fairly low in the sky, so I cannot make a direct comparison to your local conditions.

So far my guess is natural noise. Can any others (KB4DU?) take any comparative readings; I recognize a rotatable 40M quad is not easy to replicate for comparisons. I would expect a 2 element 40 to show more directivity if it were an earth based noise source, and that antenna probably picks up more signal than just a dipole so your readings are above the "typical" 40M level.

Please prove me wrong with conflicting data, especially about your home power during battery time and any difference in the background levels.

Stan

VE7ATJ_Don

Hi John... I know it doesn't help with your problem, but to let you know you are not alone, I have an S7 noise level regularly on 40m here on the West Coast of Canada (Vancouver Island). I suspect it's just 'local noise' as I'm running a ground mounted vertical and only very occassionally does it drop to S5.

In my previous home, I did find that my refridgerator was a considerable source of noise on 40m. Line filters (on both ends) mitigated it a bit, but the best solution was to turn off the fridge while I wanted to use 40m. Not the best solution, but I just never told my wife :-)

KB4OIF

Ok. Un hooked the antenna. there was a 2 foot long cable attached that I can't get to with my back problems. It has 2 ferrite cores on it. The noise went to S3 .

I am going to do the test with the batterty today without the power being on. It will take me an hour to get everything turn back on and set back up.

No the 40 meter antenna that I am using is NOT on the beam. Beam is a Hex beam 6-20. OCF for 10,15, 20 and 40. SWR is flat on 40. 20 is close to being flat. 15 and 10 is 4.6 SWR. don't use those.

KB4OIF

John

Trucker

An S3 indication with the antenna disconnected is normal. The meter at that point is showing the level of each bin being generated by the hardware. S Meter readings on the Flex Radio never drop to zero.

James

WD5GWY

Stan VA7NF

Thanks for the info John. With 2Khz+ bandwidth that no antenna S3 is normal. It does eliminate that any rogue signals are coming in via the ground system.

KB4OIF

going to have to wait till my back calms down before I do the Power off test.

KB4OIF

John

KB4OIF

sorry it took so long. Life got in the way. Power off test. Same as before.