My main location, at 5B Cyprus, lies just outside the most densely populated area of the city, not far from the airport, near the sea, in a residential area with little QRM.
Little does not mean null and in fact I am also a victim of the human QRM and some disturbances of various kinds, although not very intense.
My main reception antennas for the low bands (below 30m) are two crossed active loops that can vary between two-way loops, crossed loops or phase-shifted loops.
the loops are created in 10mm diameter aluminum tube, square in shape, 120cm on the side for a 480cm torpedo perimeter, installed at a height of 7m from the terrace below and directed as follows:
loop1 – EU / NA + MO
loop2 – AS / JA + SA
The signal received by the loops is managed by the board designed by LZ2AQ which transfers the RF reign via FTP cable, I use 30m CAT 6 S-FTP cable for the route from the antennas to the station.
Approaching the spring / summer period and with an absence of almost two months from home (E6ET DXpedition + work) that will bring me to turn on the radio physically in 5B in May (I spent active remotely activating the home station but without the possibility of using the receiving antennas remotely) I thought about perfecting the reception system.
The changes that I thought are the following:
- raise the pole that supports the 1 / 2m loops
- review the electronic card for managing signals and controls
- remake the box at the station including selectable bandpass filters and a block choke before the splitter that sends the signal to RTX and SDR
The first two points are simple, for the third you have to work a bit and here begins my article!
First we have to assemble the bandpass filters, I have chosen QRP filters looking that I need them only in RX and I dont have to give them power.
The filters are very small and the toroids to be wrapped decidedly disproportionate to my hands.
I will make five filters (30-40-60-80-160m) and will be selected by a relay board where the 30m filter will always be active to reduce intermodulations even when one of the others is inserted, considering that from the 30m band I have no risk any QRM coming to the RX system.
… to be continued.. i’m working 🙂