I have made a few changes to the power supply lead filtering. Both the power lead and the data lead to the modem now each run in their own copper tube shield from the lower part of the cabinet to the top of the cabinet with an external exit (outside on top) The modem is mounted externally on top of the cabinet and has a metal screen over it with the comms antenna poking out through a hole in the side of that shield box. The comms cable and power cable attach to the modem externally. At the lower end of the modem power cable in the cabinet each line of the cable has three passes through a ferrite ring ,the windings inverse on opposite sides of the ring. There is also a binocular core with the 5 volt receiver supply wires passing through it. All this in an attempt to remove spurs and random noise from the receiver, there will be more sophisticated filtering to follow. The Listening Post is being run from the mains 240 volt supply via an extension lead from the house, with the battery charger keeping the battery on float at about 13 volts. I would rather run the system at 12 volts as it means a lot less energy lost in the linear 5 volt regulator for the receiver.
LIstening post -update
- Thread starter VK3EB
- Start date
Hi Ray. The manuel re boot worked ok. Some remote control of the system could be handy in case I were not contactable. This morning I placed Denys 5 volt reg back into the circuit because my lin. 5 v reg I think has stopped , so there is more noise on the RCVR. I will try to sort a few things out later, happy listening Ray. The system generally seems to work well. Last night I heard just about every listed NDB for example.
Generated by Dens switching reg, my linear reg failed I think.
VK3EB
Member
Bill secures counterpoise 20cm above ground on insulated stakes, counterpoise is directly under the longwire.
Counterpoise - a much neglected idea, basically the other half of an antenna system, helping to reduce ground losses when transmitting and usually tuned.
On our SDR system Bill notice a big improvement on sig to noise. In effect we now have two grounds, one the earth (big metal box) and two, the counterpoise (insulated ground wire that has capacitance to the long wire) now the fun bit is what earth to what parts in the chain.
Counterpoise - a much neglected idea, basically the other half of an antenna system, helping to reduce ground losses when transmitting and usually tuned.
On our SDR system Bill notice a big improvement on sig to noise. In effect we now have two grounds, one the earth (big metal box) and two, the counterpoise (insulated ground wire that has capacitance to the long wire) now the fun bit is what earth to what parts in the chain.
VK3EB
Member
Regulator Plasmatroncs PL20
plasmatronics.com.au
Plasmatronics - Solar Power Regulators
Plasmatronics designs and manufactures solar charge controllers, pv hot water controllers and off-grid energy diverters and electronic regulating and metering devices for solar power systems.
VK3BLD
Member
What is the URL for the SDR?
Go back to page 1 and read thru the texts to find the access. Good luck.
Renamed to https://listen.sadarc.org it will be upgraded to Dallas's WEB-888 sdr which will provide for 13 receivers rather than the current limit of 4 receivers.