ChrisSmolinski

I have a different antenna on each KiwiSDR here, so perhaps they wanted to see how reception varied between antennas? Assuming they had some rational purpose in doing this, which might not be a valid assumption 😀

The diurnal changes in SNR scores are interesting to observe, below is the KiwiSDR with a 400 ft south directed Beverage antenna. Somewhat different results on the other KiwiSDRs with different antennas, as expected the 11/10m dipole is pretty dismal by comparison 😀

Earlier today I got an email from an SWL with a KiwiSDR & AirSpyHF+. He was complaining about very high noise / RFI levels, even though he lives in a rural area much like myself (he was comparing his noise levels to what he sees when using one of my online KiwiSDR receivers).

We exchanged a few emails back and forth, so I could understand his setup. He has a 80 ft T2FD and 500 ft sky loop antenna, so comparable to some of my antennas. I asked him if the coax shields were grounded, he said yes. OK, I asked how. 

"I have a very nice ground it is a 8-ft rod into the ground and it is connected with the 12 gauge copper wire to the coax cables."

I explained that the connection from the ground rod to coax shield needs to be as short as possible. Ideally a few inches. How long is it? If it is many feet long, the inductance will be high, and it will not work as a good ground connection.

"Apx 12 feet". 

Hmm... So he shortened that to 9 inches, and reported the RFI levels dropped down to as low as if no antenna was connected to the radio. Ideal background noise levels.

He was pretty happy 😀

So the moral of the story is, if you want your ground to work, you need to keep the connection to it as short and low inductance as possible.

This is a work in progress, but perhaps useful for some. It's an online real time SWBC schedule, driven by the EIBI schedule database.

You can enter in various parameters (country, target, language, bands, etc.), and see a list of stations currently on the air. More useful for KiwiSDR users, you can also enter a list of KiwiSDRs (saved via cookies for your next visit) and links to those KiwiSDRs will appear next to each entry in the SWBC schedules results. So you can just click on a link to be taken to that KiwiSDR, and tuned in to the broadcast.

In addition to SWBC transmissions there are also some utility transmissions and other broadcasts. Unfortunately the EIBI database does not have mode (AM, USB, etc) information, so the schedule makes some guesses based on the frequency, which is occasionally wrong for out of band SWBC transmissions.

https://www.hfunderground.com/on_the_air/update.php

Perfect, thank you!