Whooshing noise.

Josh
Posts: 10
Joined: Sat Oct 06, 2018 9:28 am

Whooshing noise.

Postby Josh » Sun Oct 07, 2018 11:01 pm

Hey all,

This is something I've noticed with my old Flex 5000a (my previous radio), but I think that was a genuine noise being picked up by the antenna. This time I'm hearing the noise whichever antenna I select and even without it being connected, so I presume it is some artifact generated internally.

Just curious as to whether anyone else has noticed similar anomalies or even whether it is a setting on the radio that may alter where they are placed.

I'm still a bit of a novice with the technicalities of the radios. I know that it does disappear if I change the ADC; Though, I don't entirely understand about the ADCs. I don't know whether I can chose ADC2 for the main antenna or whether this is more for sampling or splicing.

Josh.
Attachments
whooshing.png
whooshing.png (806.62 KiB) Viewed 1286 times
N9VX
Posts: 12
Joined: Sun Apr 09, 2017 7:38 pm

Re: Whooshing noise.

Postby N9VX » Mon Oct 08, 2018 2:49 am

What radio are you hearing this on?

Joe N9VX
Josh
Posts: 10
Joined: Sat Oct 06, 2018 9:28 am

Re: Whooshing noise.

Postby Josh » Mon Oct 08, 2018 8:12 am

Sorry, I left out that vital piece of info. It's the Anan 8000.
User avatar
w-u-2-o
Posts: 1305
Joined: Fri Mar 10, 2017 1:47 pm

Re: Whooshing noise.

Postby w-u-2-o » Mon Oct 08, 2018 11:19 am

Can't help you on the whooshing noise, except to say my 8000 doesn't do that. The simplest explanation is that it is coming from your power supply.

As for understanding the ADCs and whatnot, see this post:

https://apache-labs.com/community/viewtopic.php?f=6&t=2644

It wouldn't be a bad idea to at least glance at the "sticky" posts in the various forums and sub-forums here.

73,

Scott
Josh
Posts: 10
Joined: Sat Oct 06, 2018 9:28 am

Re: Whooshing noise.

Postby Josh » Mon Oct 08, 2018 11:40 am

I have to admit I did find the post on ADCs and it makes total sense now I've read it.

Well.. Interesting. I have two PSUs. I will try the other one and see whether that generates the same noise. If it does the same could it be that both are generating the noise ? Hard to say, I guess. I'd imagine others aren't getting a similar noise anywhere. It is also just below 40 meters. In fact, it was in the 40 meter band at first but has migrated just below it.

The Flex 5000a doesn't seem to suffer the same noise. The only similar noise seems to be one picked up on the antenna, as changing antennas gets rid of the noise.

I do search the forums before I post, but I couldn't see anything posted on this. Perhaps it is unique to me. :-/
K9RX
Posts: 224
Joined: Fri Apr 14, 2017 3:47 pm

Re: Whooshing noise.

Postby K9RX » Mon Oct 08, 2018 1:30 pm

Josh,

Not sure if this is what I see - but it looks very similar. If you did a wider display I could tell better. I see these all over the place and had assumed they're interference signals from somewhere outside my property. I can peak them in a particular direction often and lower antennas generally don't pick them up (I mostly see it using the 135' high 20 or the 90' high 15 monobanders, see a small fraction of the signal using the 4 element SteppIR at 37'). I was thinking they're either from the ubiquitous vampires or Plasma TV's (I live in an older rural area).

Let me know if you track it down. One of these days I intend to do the same. But they've not been too much of a nuisance, yet.

Gary
Josh
Posts: 10
Joined: Sat Oct 06, 2018 9:28 am

Re: Whooshing noise.

Postby Josh » Mon Oct 08, 2018 1:49 pm

Interesting... I have a few that the antenna picks up, but if I set up another antenna I can use diversity for those.

The noise I posted before is actually below the noise floor on top band and the one on 40 meters disappears below the background noise. I had the antenna so it wasn't tuned. THey seem to read around S4-5 on the meter, but this is just below the noise floor on 160.

I also dropped the voltage slightly on the PSU and it also dropped in frequency.

They do appear to get louder as I go lower. The strongest being around 300Khz. It is quite possible that it is a product of the PSU; However, I don't seem to get it in the same place on the Flex5000A. In fact, the ones I get on the Flex are only those that the antenna is picking up.

I know that this is related to another post, but it could be relevant; The PSU makes a horrendous noise when sending the two tone test above 50 watts. I'm wondering whether there is a connection between the issue with the PSU picking up something from the rig and the rig picking up noise from the PSU?

I did try another PSU and the noise was slightly lower in freq (could be a voltage difference). I also noticed that when I dropped the key the noise moved back up in frequency very quickly. Only by a few Hz.
K9RX
Posts: 224
Joined: Fri Apr 14, 2017 3:47 pm

Re: Whooshing noise.

Postby K9RX » Tue Oct 09, 2018 2:00 pm

I too have it there on the lower bands but it is lost in the noise when the antenna is connected. I primarily see it on the upper bands - 15 and above. It is quite strong at times up there and I see 86Khz between "hill tops" (referencing your picture) or subsequent peaks. I'm pretty sure its external to my shack - it peaks at about 45° (this using a relatively sharp lobed 6 element long boom monobander) and the house is at ~135°.

If I could figure out what is causing it I could then at least have something to 'ask' the neighbors about when I try to find the source.

Gary
Josh
Posts: 10
Joined: Sat Oct 06, 2018 9:28 am

Re: Whooshing noise.

Postby Josh » Tue Oct 09, 2018 7:39 pm

I think the one I have in the pic is either being generated by my PSU or the radio itself. I'd like to think it is the PSU. Are you running a switch mode PSU too?

Thankfully they seem to be swallowed by the noise when tuned up. Though, I have seen a few that are being received on the antenna. I think my next step is to get Diversity working with a secondary antenna to null out some of this QRM.

Be interested to know what is generating those noises. I'd imagine it's a switch mode somewhere.

Josh.
K9RX
Posts: 224
Joined: Fri Apr 14, 2017 3:47 pm

Re: Whooshing noise.

Postby K9RX » Wed Oct 10, 2018 1:11 pm

I am using the RD Power 1KW supply ... I never run more than about 80W with my 8000 (if more than that needed I use the amp). It is a switcher but very quiet, at least RF-wise.

You can find a spot that has this issue on the waterfall and pan - then have someone sit there while you go and shut off circuit breakers at your mains box ... I use FRS radios and my wife ... I was unable to effect a change for this one this way - however I did find that my 19 SEER Heatpump (very high efficiency) was causing lots of garbage when the fans come on (inverter driven) ... so when it gets cooler in the fall I'll go up in the attic and try ferrites. Might have to resort to a line filter as well or instead.

Gary
K9RX
NC3Z
Posts: 70
Joined: Sun Oct 29, 2017 8:57 pm
Location: Merritt, NC

Re: Whooshing noise.

Postby NC3Z » Mon Oct 29, 2018 11:40 am

Josh,

Just ran upon your post here, I just posted a identical one viewtopic.php?f=17&t=2922

2 other hams so far say they have the same exact issue. But I got reply's saying it was my power supply (even though I ran the test using a battery, and I always use linear supplies). Or that it was caused by me using 0dB attenuation on 160M, even though I have a very low noise RX antenna system.

Apache says it is caused by the harmonic of the main SMPS used on the Orion MKII card and there is nothing they can do.
Gary NC3Z

Return to “Everything Else: Antennas, Relays, Switches, Power, Grounding, Cooling, etc.”