[Gary Eldridge]

Rainer,

There are all sorts of things that can cause signals around 174 MHz. 174 MHz might not be the fundamental frequency but could be a 2nd or 3rd harmonic. The first thing I would do is put your meteor radar (computer and receiver) on battery power if you can. Then while you are observing the spectrum and see that signal appearing, throw the main breaker to your house and shut off all power to everything in your home. While your receiver is still running with battery power see if the signal goes away. That may indicate that something in your house is generating that harmonic. It could be a wall wart power supply, a fish tank pump and heater, a garage door opener or anything with electronics in it.

If the signal is still there while your house power is shut off then of course you will know that it is coming from outside your home.

I have found so many interfering signals from inside my own home over the past few years and I constantly have to keep tracking new ones down. My internet WiFi router is the worst offender and I'm still trying to deal with that issue. It throws signals all over the ham bands from 1.8 MHz all the way up through VHF frequencies. I had a HP Printer power supply that I had to get rid of and get a different one because of the same thing. Also my power tool battery charger for my electric drill puts out lots of signals. There is a string of remote controlled LED lights out on my deck that makes a lot of interference so I have to keep it unplugged.

On some echos, not all of them, you will see some slight doppler effect. Those large balloons you  speak of are most likely not capable of creating any noticeable doppler effect as they are too slow.

Good luck in hunting this down.

Gary

[rsf...@rsfotografia.com]

Hi Gary,

Thanks. Will see what I do. I have not added anything new in the past days in my house.

regards Rainer

[rsf...@rsfotografia.com]

Hi Gary,

Here in this video you can see the white line blocking me the meteor echo reception but only when I adjust 174 308 000 Hz. Adjusting to 174 307 500 Hz then everything is OK. At the end of the video you can see how the strength goes down and this happens randomly.

https://rainerehlert.com/000_RTLSDR/20201214_NHSA_RMO_SpLab_ScSh.mp4

Rainer

[Gary Eldridge]

Rainer,

I see two steady signals in that video. This is the audio spectrum. What does it look like in the RF spectrum. You may need to zoon in on the spectrum to see the signal well. Do you see two signals and are they always together or does one fade and not the other one?

Gary

[rsf...@rsfotografia.com]

Hi Gary,

One is steady and the other one sometimes fades.

But so far no problem with them at all. Instead of having 174 308 000 Hz I am working with 174 307 500 Hz and I have not false long echos anymore. Sometimes on of those wanders.

I will observe it how it behaves.

Rainer

[rsf...@rsfotografia.com]

Hi Gary,

Update. The strong line misteriously disappeared :-)

Everything is normal more or less.

regards Rainer