SAQ reception system

[F5VLB]

I use two electrodes of 2m long buried underground, 100m apart and oriented 285°. I feed an usb sound card UMC202HD from Behringer and decode with spectrum lab. Very noisy here in Brittany France due to proximity of a water pump station and the speed controller regulators radiating a lot of interferences as one can see on the picture. Anyway a faint signal was decoded.
73’s Jean Marie F5VLB
https://www.facebook.com/groups/earthprobes

saq reception

Topic

[g4bip]

Oh and PS – hoist it up high on an insulated pole. This works by measuring the E field between the plate and ground – a metal pole will just short out this field!
73s

[rich.g.williams]

So if I understand correctly the setup you are using (E-field probe) is receiving/measuring the potential difference between the 15 x 15cm copper PCB panel and Ground (Earth). The PCB panel being isolated/insulated a few metres above ground. The potential difference being created by the vertical E-field component from SAQ.

That sounds like a very good setup.

I’m thinking about where physically to put the FET and the wiring geometry of how to connect back to the Ground (Earth) reference potential. This arrangement seems to be something like a vertical rod antenna.

[g4bip]

As has been noted there is a lot of noise in ground connected systems. I would suggest using an E-field probe. There are various designs around but its very small and consists of a 15 x 15cm copper PCB panel connected to the gate of a high impedance FET amplifier. This is followed by a simple emitter follower that produces a low impedance output into a regular laptop sound card. No tuning requires as this is a totally broad band E-Field amplifier. I use the SAQ Panoramic Receiver software which has excelent digital filtering to 50Hz and covers from DC to about 22Khz. There are versions that can cover higher if your sound card can handle fast sample rates.

I hope this helps and I was getting very good copy last summer and all ready and waiting for this one on Sunday.
73s G4BIP

[Jean Marie POLARD]

Good evening Rich, have a try ! if you do try, you don’t know. Earth probes antenna (epa)works even when the soil is dry. I have done tests during summers, in RX and TX mode, even on 8.25kHz (yes 8270 Hertz). For more information come on https://www.facebook.com/groups/earthprobes there is a files section with plenty of pdf about the topic.
Good luck, and keep us informed.
73’s Jean Marie F5VLB

[rich.g.williams]

“two electrodes of 2m long buried underground, 100m apart and oriented 285°” That’s a good idea, does the ground need to be fairly dry for that to work? I’m assuming your electrodes are measuring the small potential difference created by the SAQ E-Field component. I have tried a 10m circular loop of insulated wire placed on the ground and it works well for some VLF transmitters but not SAQ (because SAQ M-Field is horizontal).

I will experiment with your setup next time SAQ transmits, I can easily get an electrode (Ground Rod) separation of 25m minimum.

[rich.g.williams]

Hello Jean Marie,

Yes I will try it thanks, I have two good Earth connections about 24m apart and in the direction of SAQ. I live about 2.3Km away from Wenvoe Transmitting Antenna, Cardiff, Wales, it transmits VHF and UHF so it is a consideration. For certain this antenna configuration will pick up less interference from Lightning storms.

8270 Hertz that’s amazing! This VLF can propagate well and its easy to build analogue and digital bandpass filters for such low frequencies so narrow band Morse code can carry messages a long way.

Best regards,

Richard

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