Interesting technical articles
40 meter Antenna Project
Members of the Central Coast Amateur Radio Club met at the club on June 21, 2025 to build a 7 MHZ vertical antenna. The impetus for this build came to get a 40 meter antenna ready for the upcoming Trans-Tasman contest which we participated in. The antenna is easily built and doesn’t cost much. It can be adapted for portable operations.
Seeing the good in Solar winds at the bottom of the sun cycle
It is normal that strong ionised particles escape the sun during a solar flare-up. The number of sunspots (bright spots visible on the sun) that indicate the flare-ups vary over a cycle which can be as short as 7 years or as long as 11. More sunspots equate to a consistent re-charging of the Earths Ionosphere and hence better DX conditions around the globe within the Ionosphere.
Testing the losses of Multi-coupler’s, Splitter & Low Pass Filter
My Stridsberg (USA) Receiver 8 port multi-couplerfailed and being unsure of where to procure the LNA replacement and unable to find information, I replaced the unit with a substantially more affordable 5 port unit from the UK manufacturer Cross Country Wireless.
SMALL “MAGNETIC” TRANSMITTING LOOP FOR 80-20 METERS
A loop antenna is generally considered “small”, if its circumference is less than 10% of the operatingwavelength. So in my case (for 80 mtrs), “small” would be a circumference of less than 8 mtrs, e.g., acircular loop with a diameter less than 2.5 mtrs (≈ 8.2 ft). To be more precise, we are talking about asmall resonant loop. Note that a multi-band loop that is “small” in the lowest band, is not necessarily”small” in the higher bands ( = higher frequency)
MX-P50M HF Amplifier Tests and findings by Peter VK2EHQ
The IC-705 will primarily be utilized for WICEN HF data activities as well as portable use. Reports I read, indicated that the MX-P50M didn’t create splatter and the signal was readable and without apparent issues. This is possibly fine for SSB on VHF/UHF but HF data is a “little” more demanding. The transceiver may meet all the criteria of frequency accuracy, stability and signal drive level, but an amp can change that ideal scenario.