0-10 MHz receive over UTP?
For a long time I had the idea to use UTP (Unshielded Twisted Pair) cable for my receive antenna, the K9AY or anything else. Advantages is that there are 4 pairs of twisted cable available in one cable and therefore there is no need for a control cable. Even switching the preamp can be done via the same cable. Or use the remaining pairs for an RS485 communication to switch antennas, attenuators or preamps.
This cable is available cheap in the computer networking business.
For a long time nothing happened until in the German magazine Funkamateur, DK7ZB published a balun for a delta loop. I recalculated the balun for a smaller toroid. I used a FT50-43. The balun was build on a piece of copper clad PCB board. I terminated the balun with a 100 Ohm resistor and measured the return loss.
The return loss was very good. On 10 MHz the return loss was still 20 dB and below 5 MHz even better than 25 dB.
See the plot below:
Next try was to make 2 baluns and test a piece of UTP cable. A length of 30M was found in the cable box. Losses were still very acceptable. The plot below shows the losses from 0-10 MHz. On 1.8MHz, my main interest, the cable and the 2 baluns had a loss of 2.5dB
The whole measurement set-up: