Diagnostic software for flex

IZ2ODM

Hello guys,
it's been a few weeks now that I have a lot of QRM and looking the panadapter is not clear if it is due to the high level of QRM ( domestic , led or something like that) or some problem of Flex. 
Panadapter show a sort of "wall" from 14.050 to 18.100 Mhz ...also close to 7 Mhz . IS there some diagnostic software in order to check Flex for RX section ? Maybe some filters are damaged...Thanks and

73 de IZ2ODM

WA2SQQ

Post a photo of what you are seeing.

Mack

Please run this test. Disconnect all antennas from the Flex and connect a dummy load or short the ANT 1 connector. Does the interference remain? If so, try unplugging wall warts or trying a different power supply. It's VERY unlikely this is a Flex hardware issue.

Mack
W4AX
Alpha Team

IZ2ODM

Thanks Mack I'll try and let you know...
73
Roby

IZ2ODM

ok. Test executed with dummy load . Noise disappear , also without any load (dummy) or antenna or ground connected. This sound good.

For WA2SQQ see photos.

IZ2ODM

Tim - W4TME

Yes, very good.  The noise is external of the radio.  Now comes the challenge of finding it and seeing if you can mitigate it.

IZ2ODM

This last photo show with dummy load-->no noise

IZ2ODM

noooo..... Good for radio but it will be hard to find.In your opinion is right a "specific noise" or a general high QRM ?

Mack

It will likely be a bit difficult to find but based on the signal strength it's probably within your home. Here's the way I would approach the problem:
1) Identify which circuit breaker the Flex and computer are connected to. Leave this breaker on.
2) Turn off each other breaker ONE AT A TIME to see if the noise disappears. If and when you identify the circuit then go unplug any transformer or appliance until you locate the source. 
3) If you cannot find the offending circuit then the only breaker left to test is the one with the Flex Radio and computer. Find a 12 volt batter to power the Flex and use a laptop or iOS device to connect to the radio which is running on battery power. Finally turn off the break on your radio/computer and see if the noise goes away. 
4) If you don't find the issue after following ALL of these steps then check back here and I'll discuss how to find noise issues outside your house.

Mack
W4AX
Alpha Team 

Tim - W4TME

Could be a motor noise.  I do not recall ever seeing anything like this before.

Jim K4JAF

Is the noise your seeing constant all the time or does it come and go during the day?
Also do the noise spikes within the wide band noise vary in amplitude and frequency?

G8ZPX

That noise is almost certainly either VDSL broadband or PLT / PLA adaptor noise. The signature is very familiar to me and obviously quadrature digital signalling. The very deep notched at 17.6 and 14 MHz are pre-coded notches where the box of trick is being prohibited from TX'ing.

G8ZPX

That noise is almost certainly either VDSL broadband or PLT / PLA adaptor noise. The signature is very familiar to me and obviously quadrature digital signalling. The very deep notched at 17.6 and 14 MHz are pre-coded notches where the box of trick is being prohibited from TX'ing.

IZ2ODM

It will be hard to find...Thanks G7BCX

IZ2ODM

Just a couple of questions , in case of VDSL broadband noise how far from my ant/radio can be in order to capture noise ? I have a cabinet  of  Thelephone company 40mt from my ant but frankly speaking it is there by many years . Same question for PLT adapter , how fare can be from my shack? Thanks for any reply .

Roby IZ2ODM

IZ2ODM

Always the same Jim during the day/night 24h or almost when i'm on the shack/radio

John - K3MA

You might want to look at this document.  The spectrum looks very similar to yours.  You can also search for RSGB VDSL Interference.

John K3MA

http://rsgb.org/main/files/2017/08/2017-RFI-Update-RSGB-Convention.pdf

Steve G1XOW

http://g1xow.uk/   scroll down a page or two for lots of images of VDSL QRM to see how devastating it is.

Stan VA7NF

Thanks John for this RSGB reference. 
The frequency range directly matches Roby's spectrum display, with the U2/D3 indicating VDSL service > 50Mbps. 
In NA we used to have problems with the cable TV and internet which were helped by better RG-6 and good unbalanced transformers.  Home telephone wiring can make excellent antenna systems.
The RSGB document looks good for a club presentation, with permission.

Manfred HB9FLU

VDSL or PLC

73 de Manfred

IZ2ODM

Thanks John and Stan . Read immediately and , frankly speaking, what it is showed seems totally similar at mine. Sorry for following and **** question ; It is not a matter of good filter? I mean...if I 'd use something like 4O3A bandpass filter may I solve something ?

Iz2ODM Roby

Stan VA7NF

Roby, unfortunately no filters on your receive will work; the interference signal is on your receive frequency.
 In the RSGB presentation they talk about line balance and underground.  The RF signal is part of the DSL architecture so it will exist.  Our problem is keeping that signal away from radiating to our antenna. 
That is by perfecting the line balance (makes it a non radiating feed line), covering it with a shield such as shielded telephone cable or grounded metal conduit, or suppressing the radiated signal (underground).  Any user that adds a telephone extension with a loose wire has just made a whole house transmitting antenna.

Stan VA7NF

Second thought.
if the upload frequencies are stronger than the download then the interference source is near the user side (your own VDSL modem), if the other way (D1/D2/D3 stronger than U1/U2 - see presentation for exact frequencies) then it is communications company near their hub.
Your spectrum display is just abound the 20M band, and looks like your antenna (resonant I assume around 20M) is more sensitive in that range.
Try a different antenna (or loosen the connector so only the centre makes contact) and take a 0-14Mhz spectrum view.  That should show the different frequencies and their strengths.