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De-noising the active magnetic receiving antenna.
pa0nhc 20180308

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This antenna performs as good as its noise free grounding and its noise free installation location is.
Installing without proper grounding is useless.

            Grounding.
If no measures are taken :
RF noises induced onto the OUTside of the coaxial cable screening, can travel to the antenna unit PCB ground surfaces. From there they will travel through the INside of the coax cable towards the receiver input. And will there be heard.

By grounding the antenna PCB ground surfaces, noises induced onto the coax mantle can be blocked by the mantle current choke L6 on the antenna PCB.

For minimal noise hinder, the ground surface of the antenna unit MUST be connected onto a noise-free grounded mast. 
Do NOT ground the coax line.
 
The receiver will automatically be grounded to that same mast too, via the screening of the coax cable.
For best signal-to-noise ratio, the receiver and all connected equipment then may NOT be connected to any extra (mains-safety) ground.
Construct a dedicated grounding at the antenna mast,
 
If grounding via the antenna mast is impossible, the receiver MUST be grounded for safety reasons.
BUT noises on the coax outside will then not be blocked from the antenna. The received signal-to-Noise ratio will be bad.
TIP : A low-Z noise-free ground possibly can be made by a connection to the steel reinforcement of concrete structures.
            Coax.
Use THIN (1.6 - 2.8 mm) coax. This can be wound several times loosely through the big holes in BIG ferrite clamps. Reason :
 
3x though a ferrite hole = 9x more effective than 1x
 
Do not worry about cable losses, they are neglect able on these low frequencies. The coax losses at these low frequencies are very low, and the active magnetic antenna circuits are designed for low VSWR.

Ferrite material and application.
This newer version antenna unit already contains a ferrite ring mantle current choke on the PCB. This makes connecting the coax to the antenna easier.

- For de-noising cables, use ferrite clamps or ring cores with a high Ui value, for instance :
            Conrad orderNr 1086902, 1086901, 500623 of 1086873).
- Wind thin coax several times LOOSELY through the big hole of the ferrite clamp.
3x though a ferrite hole = 9x more effective than 1x
CHECK for a well closed clamp. Both halves should lay in flat contact to each other.

- Install a ferrite core over the coax at the tuning unit.
- Install ferrite cores at the receivers antenna plug and at the receiver-output of the tuning unit.
- Install a ferrite core near the receiver over the mains cable.
`        OR
- If a separate power supply is used, install a ferrite core near the receiver over the DC supply cable.

- Install several ferrite cores over the coax between the antenna unit and the tuner unit, divided over the whole coax cable.
        OR
- Burry the coax cable into the soil.

At your own risk.
ONLY if :
1. The antenna unit is well grounded with the antenna mast
and
2. Your mains power system is equipped with automatic ground leak switches :

You then could disconnect any (mains-safety) ground at the receivers power supply.