unknow radio stations on 27 mc

Main forum to discuss RTL-SDR related topics.
Post Reply
radiowaz
Posts: 30
Joined: Wed Jan 03, 2018 2:09 am

unknow radio stations on 27 mc

Post by radiowaz » Mon Jan 29, 2018 2:01 am

using HDSDR and a 20 dollar sdr and 40 meter fullwave dipole...see attacted radio spectrum picture,, I still haven't found out where or why I am hearing these am radio stations on 27mc.. any ideas,, very loud and clear. and I live in the middle of the sticks,, nearest big town is Nashville, over 100 miles away.. but these am stations seem to be from all over the country (east of the Rockies ) and Cuba, S. America , French and Norwegian? Question WHY???!! freq 27.090 to 28.185
Attachments
27mc.gif
from 27.090 to 28.185
27mc.gif (347.83 KiB) Viewed 3326 times

Aussie Susan
Posts: 37
Joined: Sun Jul 31, 2016 1:55 am

Re: unknow radio stations on 27 mc

Post by Aussie Susan » Mon Jan 29, 2018 2:56 am

Isn't that Citizen Band?
Would not explain the long distance though...
Susan

rtlsdrblog
Site Admin
Posts: 2428
Joined: Mon Nov 19, 2012 11:54 pm

Re: unknow radio stations on 27 mc

Post by rtlsdrblog » Mon Jan 29, 2018 3:31 am

Are you in direct sampling mode? DSM mirrors all signals around the center point of 14.4 MHz, so this is something you need to be aware of.

radiowaz
Posts: 30
Joined: Wed Jan 03, 2018 2:09 am

Re: unknow radio stations on 27 mc

Post by radiowaz » Mon Jan 29, 2018 10:02 pm

I am in direct sampling, but in anything else, I hear nothing. when I run [email protected] I hear nothing on those freq or, and, pretty much nothing else on any other freq. (I'm still working on it). With HDSDR the bands are full and quality is excellent. but I can switch to sharp same freq and hear and see nothing. I don't know if the problem is with HDSDR or sharp or the idiot that is trying to use them..

W1ABA
Posts: 21
Joined: Fri Jul 06, 2018 5:05 pm

Re: unknow radio stations on 27 mc

Post by W1ABA » Fri Jul 06, 2018 7:31 pm

You're hearing images, these types of receivers are very dirty, due to overload (causes non linear responses) and from the upconverter used in the tuner chip, which lacks proper rf filtering for the sum of the frequencies and the original frequency. Eliminate the tuner chip and use a high level mixer with proper filtering, and it would be a stellar performer.

1ABA

Post Reply