HF Signals not being received

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LXT118
Posts: 3
Joined: Sun Mar 15, 2020 5:46 pm

HF Signals not being received

Post by LXT118 » Sun Mar 15, 2020 6:03 pm

I am using an RTL-SDR V3, with the long dipole antenna kit.

When I go into the Direct Q Sampling mode, I see AM frequencies, but no CB/hams, etc. In fact, the AM frequencies are reflected to higher frequencies, as well as other signals I am not able to identify.

I'd just like to know if there's anything I can do to fix this. I do realize that I do not have the correct HF antenna for the job, but I'd also like to know if there's anything hardware-related that is causing this reflection issue.

Thanks!

rtlsdrblog
Site Admin
Posts: 2633
Joined: Mon Nov 19, 2012 11:54 pm

Re: HF Signals not being received

Post by rtlsdrblog » Tue Mar 17, 2020 3:23 am

The reflections are just a known part of life with direct sampling mode on the RTL-SDR. To get rid of them you need to use a 14.4 MHz high pass filter.

For CB @ ~27 MHz, you should still be able to receive that in quadrature sampling mode, and that is not affected by reflections.

Ideally you would use a proper CB antnena. But to maximize the dipoles performance extend the long arms out to the max, and put it in a vertical position outdoors.

LXT118
Posts: 3
Joined: Sun Mar 15, 2020 5:46 pm

Re: HF Signals not being received

Post by LXT118 » Wed Mar 18, 2020 8:55 pm

Thank you, I'll try it!

Update: When I tune into the CB frequencies, the WFM stations are reflected down into its frequencies, so I don't see anything other than FM. Is there any way to fix this?

Thanks

Username
Posts: 593
Joined: Sun Oct 09, 2016 7:27 am

Re: HF Signals not being received

Post by Username » Mon Mar 30, 2020 3:33 pm

You can buy a FM Filter from ehre: https://www.rtl-sdr.com/buy-rtl-sdr-dvb-t-dongles/
Mine Work but beware if you want to receive a Frequency above or below the FM Band the will not work. :lol:

I recommend to use a Airspy for CB and HF for me the work the best.

LXT118
Posts: 3
Joined: Sun Mar 15, 2020 5:46 pm

Re: HF Signals not being received

Post by LXT118 » Thu Apr 02, 2020 3:06 pm

Thank you

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