Grounding receiver ??

[HZainon]

Do you connect some kind of ground wire to your shortwave receivers?
I am currently using an old ICOM ICR71E.  It has a connector for Ground / Earth wire at the back.
I am wondering, if some sort of connection should be made to the Ground post.
But how?  Connection to what.  This was my question I couldn't answer clearly.
What is the reason for grounding your receivers?
Does grounding your radios improve DX reception?

HI. I read the conversation very carefully. I am a SWL from Rome, Italy.
I've read everything written about receiver grounding.
I live on the third floor of a building. I have three receivers, Racal 3712 and a WJ 8711 and a JRC 515. On the roof of the building an ALA1530LN and 25mt of cable. I tried to test with the PL connector with only the central pole and nothing changes. I think then the noise I have is derived from outside and not from inside. I put all the ferrites to the electrical cables and antennas.

I can't put a copper stake in the ground.
I try to connect the receivers separately to the heating water pipe.

What do you think?
Thanks in advance
Maurizio

[ChrisSmolinski]

Do you connect some kind of ground wire to your shortwave receivers?
I am currently using an old ICOM ICR71E.  It has a connector for Ground / Earth wire at the back.
I am wondering, if some sort of connection should be made to the Ground post.
But how?  Connection to what.  This was my question I couldn't answer clearly.
What is the reason for grounding your receivers?
Does grounding your radios improve DX reception?

HI. I read the conversation very carefully. I am a SWL from Rome, Italy.
I've read everything written about receiver grounding.
I live on the third floor of a building. I have three receivers, Racal 3712 and a WJ 8711 and a JRC 515. On the roof of the building an ALA1530LN and 25mt of cable. I tried to test with the PL connector with only the central pole and nothing changes. I think then the noise I have is derived from outside and not from inside. I put all the ferrites to the electrical cables and antennas.

I can't put a copper stake in the ground.
I try to connect the receivers separately to the heating water pipe.

What do you think?
Thanks in advance
Maurizio

The primary reason for grounding a receiver is safety.  While it can (rarely) improve reception by reducing noise, this is usually not the case. Sometimes grounding can increase noise. What is good/necessary for electrical safety is not always good for radio reception.

A water heater pipe, especially on the third floor, is probably not a good RF ground. It could even be a very very bad RF ground or a source of additional noise. Sometimes they can be a dangerous "ground" to use, if connected for example to a natural gas line.

Most of the time, noise pickup is due either to the antenna itself picking up the noise signals, or common mode currents on the transmission line (coax cable typically). In the latter case, ferrite or other common mode choking can reduce or eliminate these currents.  In the former case, there is nothing(*) you can do to eliminate the noise. There's no magical devices that can distinguish "noise" from "real signals".

(*) You can (sometimes) use phasers to mix the signals from two antennas, and adjust the relative amplitude/phase so that you can reduce/eliminate (generally) at most one noise/RFI source. Requiring retuning as you change frequency, or the noise source changes.

[NJQA]

If I can add on to what Chris and others have already said…

Much of the confusion over grounding is rooted in not understanding why you are doing this.  There are probably a half dozen different goals someone might be pursuing in “grounding”, and what you do to accomplish them may be in conflict with each other.  Examples include (but are not limited to):

* Electrical Safety
* Lightning Protection
* EMI Control
* Hum prevention
* Antenna counterpoise needs

I see people make mistakes grounding their station all the time when they mix these up.

For instance, in the US, the National Electric Code (NEC) has a section that states a grounding conductor is not required to be larger than #6 gauge.  However, this is in a section that deals with electrical safety.  #6 was chosen because that was enough to ensure that safety devices like circuit breakers would function normally.  Larger wire was unnecessary for that purpose.  Lightning protection, however, is covered in another document.  #6 would be inadequate for that purpose; you would want a larger conductor to ensure most of the surge current went down that path rather than alternate grounding paths.

Ufer grounds are another example.  In the US they are allowed for electrical safety grounding.  I wouldn’t want to use that as a means for lightning protection grounding though.  I would be worried that the heat generated from the lightning surge would cause entrapped moisture in the concrete to vaporize and explode the concrete.

Adding to the confusion are frequency dependent effects.  An adequate grounding design for 60 hz probably has problems at 6 MHz.

When designing a grounding system for my station, I would start with an NEC compliant implementation for electrical safety.  Then I would address changes for lightning protection.  I would follow that with any measures necessary for EMI control, ensuring that I didn't compromise any steps taken for the first two.

[~SIGINT~]

Hi Maurizio,

Could you describe the type of noise you are receiving? It could very likely be emanating from the main power lines or neighbour.

The Wellbrook 1530LN is an excellent antenna and is very sensitive. In my case, it was too sensitive and overloading the input to my SDR receiver. When troubleshooting, I inserted a variable attenuator at the input to the SDR and discovered that once I inserted approx 10 dB of attenuation my overload issue started to disappear. Further investigation lead me to discover that I was getting overload from local AM stations which I could see well past 5 MHz on the receiver. My fix was to insert a Flamingo AM notch filter at the input of the SDR. That cured 90% of my issues. I would not expect the Racal, WJ nor the JRC to suffer from input overload. I have owned similar models of these receivers and they all have very good input overload protection and band-pass filters.

An interesting EMI issue I had from my previous location was the emanation of noise from the SCR motor control and break system associated with the elevators in a neighbouring building. I could "hear" the elevator start, speed up, slow down and stop. From the research I did, this is not so uncommon in older buildings where the system was upgraded and they used the existing electrical ground (wire running to a water pipe). That is apparently a no no. These systems are supposed to have a dedicated ground to suppress EMI.

I presume that you do not have a rotator on the loop? Potentially being able to null out that interference by steering the loop in the appropriate direction would be of great benefit. A weak signal is still better than no signal or a pile of noise.