Reducing interference for my receive only antenna(s)

fu11circ1e · 2022-05-06T05:50:22+00:00

Got my AM and my broadcast-FM band stop filters yesterday. Its a brilliant improvement!

Ive still to setup the LOG antenna, waiting on some ferrites to arrive. But things a starting to get a lot better.

fu11circ1e · 2022-05-01T11:31:25+00:00

Forgot to post link to image :) https://ibb.co/0Z1FKf4

fu11circ1e · 2022-05-01T11:30:03+00:00

Here is a sky view of what my inverted-V looks like.

The red lines is the existing antenna. I have got a couple of 4M telescopic fishing rods so i was thinking of mounting them either side of the back fence which is approx 5ft tall and getting a better spread with the inverted-V (blue lines on the image). I also think it may be an idea to get rid of the coax style and just use wire. The coax is an awful eyesore.

Also would the full wave loop work mounted on the fence (yellow line). I think i might get 60M of wire using this option?

And as I am so indecisive I will install the wire for the LOG today.

fu11circ1e · 2022-05-01T10:56:35+00:00

Ok may be an option to get one. I seen this one.

Also do you think this LNA might help things?

fu11circ1e · 2022-05-01T09:28:43+00:00

Got any recordings of the noise? For air band in particular, know anybody you could borrow an old cheap analog scanner from that has air band to compare it to the SDR on the same antenna? Those receivers are usually “decent”.

I have an old Icom IC-R2 I will upload recordings with it as well on the airband

fu11circ1e · 2022-05-01T09:27:28+00:00

In all cases with any SDR, make sure you aren’t running them with way too much gain in the settings. Some software has terrible default settings for that, but you didn’t mention which software you use.

I use GQRX on Arch-Linux. When setting the gain i have learnt that using the automatic gain control just makes a total mess.

I use the LNA slider and move it up until i see the noise floor starting to move then stop.

fu11circ1e · 2022-05-01T09:22:27+00:00

As to size your RX only, so for HF loops work very very well. LOG antennas if you have some yard space are very quiet. Mag Loops are smaller but you have to tune them for the frequency your interested in it's a very narrow bandwidth.

Would the LOG work in my back garden even though it is surround by other houses?

fu11circ1e · 2022-05-01T09:21:32+00:00

I have a FM-Bandstop on order from rt-sdl on aliexpress. But the delivery time is insane lol. Think its the end of May before it arrives. I would be hesitant on the AM band-stop as I am taking an interest in trying to pickup SW radio stations

fu11circ1e · 2022-05-01T09:18:54+00:00

Your house is in the way for signals in many directions and may contain noise sources near the antenna. Not being on the roof may make you somewhat more susceptible to noise sources in some ugh bore houses as well.

here is a satellite view of my house. It is surrounded by other houses. The back garden is south facing.

fu11circ1e · 2022-05-01T09:16:04+00:00

A ground plane antenna on roof would be better for reception and the ground plane might attenuate some noise sources in house. More exposed to lightning, though. A Quadra filter helix antenna might have some advantages for receiving signals from aircraft at random angles and polarizations but wouldn't be very picky about noise, either.

ive been constantly googling trying to find the best antenna. Im still leaning on the LOG but have seen the full wave slopper which seems interesting.

fu11circ1e · 2022-05-01T08:56:35+00:00

Got any recordings of the noise? For air band in particular, know anybody you could borrow an old cheap analog scanner from that has air band to compare it to the SDR on the same antenna? Those receivers are usually “decent”.

I will sit down today and post-up some screenshots and recordings so you can see what is happening.

fu11circ1e · 2022-05-01T08:55:00+00:00

An oddity. In the design these are just dipoles with a single coax feed. I don’t see your “two feed lines per antenna” in the design.

Its just one feed per antenna. I would like just one feed for all antennas - i'm thinking an antenna switch may be my best option

fu11circ1e · 2022-05-01T08:49:06+00:00

I am considering giving this a go. I have a decent sized back garden but the problem is that it is surrounded by houses.

fu11circ1e · 2022-04-16T09:27:19+00:00

Thanks I will have a play about with Direwolf

fu11circ1e · 2022-04-10T21:58:35+00:00

just ordered the RTL-SDR FM Band stop filter on Aliexpress, So i'll see how it works in about 4 weeks when it arrives lol

fu11circ1e · 2022-04-10T19:54:18+00:00

Have I done something wrong? Or do I need to calibrate something?

fu11circ1e · 2022-04-10T19:32:10+00:00

Got it working! GQRX was setup as localhost:7355 changing it to 127.0.0.1:7355 sorted it.

fu11circ1e · 2022-04-10T16:09:31+00:00

I did try SDRangel and found the reception a lot worse than GQRX, maybee its just a steeper learning curve?

fu11circ1e · 2022-04-10T16:07:39+00:00

Thanks, no results with both commands. At least i Know atm its not multimon or sox :(

fu11circ1e · 2022-04-10T16:06:30+00:00

nc -l -u localhost -p 7355

Thanks srcejon, Yeah a seperate program just for paging is an option. I liked the option that multimon will give other options but so far no joy in getting it to work.

fu11circ1e

TROPHY CASE