VU2JO Jon

Amateur Radio HF & LEO satellites, Hobby Electronics, Space, Astronomy, Technology, Horticulture, Aquaculture.

[Johnson's Aquaculture & Horticulture @johnaquaculture]

I am very happy to document the rapid growth of my sweet corn plants in garden pots! https://t.co/sxTAHWLgtx

[VU2JO Jon @Johnsontechword]

Receiving the QO-100 narrowband downlink is a straightforward project, as you can repurpose standard satellite TV hardware. The downlink operates at 10.489 GHz, so the main objective is to downconvert that signal to an IF that RTL-SDR can tune to...https://t.co/DSUHutNA25

[VU2JO Jon @Johnsontechword]

The J-Pole antenna is a popular, practical, and highly efficient omnidirectional antenna. At its core, it is an end-fed half-wave dipole that uses a clever impedance-matching trick to connect to standard coaxial cable. https://t.co/hF8SG1A1Rg

[VU2JO Jon @Johnsontechword]

How long-distance flights communicate w ATC depends entirely on where the aircraft is. As radio waves have physical limitations, aviation industry uses a layered system of technologies that change as a plane leaves land & heads over ocean or remote areas. https://t.co/ollIU2vCc6

[VU2JO Jon @Johnsontechword]

Vivaldi antenna (tapered slot antenna) is an ultra-wideband, co-planar directional antenna. Instead of using wire or aluminium tubing, they are typically etched directly on a PCB with an exponentially flared slot that looks a bit like the bell of a trumpet https://t.co/JKbISk6QoI

[VU2JO Jon @Johnsontechword]

How long-distance flights communicate w ATC depends entirely on where the aircraft is. As radio waves have physical limitations, aviation industry uses a layered system of technologies that change as a plane leaves land & heads over ocean or remote areas. https://t.co/ollIU2vCc6

[VU2JO Jon @Johnsontechword]

@N4JAW Today morning, around 7 am local time, we had a transient drop in 40m propagation with S9+30 dB signals falling to S7. But the Planetary K index was all in green.

[VU2JO Jon @Johnsontechword]

@CMcKayFL But a bit expensive! Of course, it will not protect from a direct hit anyway.

[VU2JO Jon @Johnsontechword]

An automated lightning detection and antenna disconnection system is a critical line of defense for a radio shack, especially when dealing with the massive capture areas of 80m or 160m wire antennas. https://t.co/2OpiqOutXN

[VU2JO Jon @Johnsontechword]

The J-Pole antenna is a popular, practical, and highly efficient omnidirectional antenna. At its core, it is an end-fed half-wave dipole that uses a clever impedance-matching trick to connect to standard coaxial cable. https://t.co/hF8SG1A1Rg

[VU2JO Jon @Johnsontechword]

The random wire antenna is considered a powerhouse for portable operations—like Parks on the Air (POTA), Summits on the Air (SOTA), or general field deployments—because it perfectly balances logistical convenience with RF performance. https://t.co/NV3iPoxVuD

[VU2JO Jon @Johnsontechword]

An automated lightning detection and antenna disconnection system is a critical line of defense for a radio shack, especially when dealing with the massive capture areas of 80m or 160m wire antennas. https://t.co/2OpiqOutXN

[VU2JO Jon @Johnsontechword]

The Carolina Windom is a popular, multi-band wire antenna that takes the traditional Off-Center Fed Dipole and gives it a specific twist: it intentionally uses a section of the coaxial feedline as a vertical radiator. https://t.co/Uu1y6BccGO

[VU2JO Jon @Johnsontechword]

The random wire antenna is considered a powerhouse for portable operations—like Parks on the Air (POTA), Summits on the Air (SOTA), or general field deployments—because it perfectly balances logistical convenience with RF performance. https://t.co/NV3iPoxVuD

[VU2JO Jon @Johnsontechword]

LNA, LNB, LNC, and LND represent different configurations of the front-end RF hardware mounted directly at the focal point of a satellite dish antenna. Their primary jobs are to amplify the incredibly weak microwave signals...https://t.co/q8pucEOm6x

[VU2JO Jon @Johnsontechword]

The Carolina Windom is a popular, multi-band wire antenna that takes the traditional Off-Center Fed Dipole and gives it a specific twist: it intentionally uses a section of the coaxial feedline as a vertical radiator. https://t.co/Uu1y6BccGO

[Johnson's Aquaculture & Horticulture @johnaquaculture]

For certain types of hydrangeas, the color of their blooms acts like a living, growing pH strip for your soil. However, the pH itself isn't what directly dyes the petals; it's actually all about aluminum. https://t.co/BHFeLqWuTr

[VU2JO Jon @Johnsontechword]

LNA, LNB, LNC, and LND represent different configurations of the front-end RF hardware mounted directly at the focal point of a satellite dish antenna. Their primary jobs are to amplify the incredibly weak microwave signals...https://t.co/q8pucEOm6x

[VU2JO Jon @Johnsontechword]

Demo of cross polarization losses. Maximum loss occurs when the antennas are at right angle to each other, with about 30 dB loss.

[VU2JO Jon @Johnsontechword]

Faraday rotation as the electromagnetic wave gets refracted through the ionosphere