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Help listening to Shortwave

Posted: Tue Apr 17, 2018 6:10 pm
by illllm
Hi All,

I have been trying to pick up MW and SW broadcasts but very unsuccessful. Not even a blip on the screen. I tried a long wire, a loop, an LNA with an antenna, nothing. Except for local FM channels and once in a while someone speaking to the local air tower, i cannot pick up anything else. I am near Washington DC.

Any suggestions and help is greatly appriciated :)

Re: Help listening to Shortwave

Posted: Tue Apr 17, 2018 8:31 pm
by illllm
I read in a few places that the RTL SDR cannot receive LW, MW and SW without an upconverter. Could someone please clarify this?

thanks,

Re: Help listening to Shortwave

Posted: Tue Apr 17, 2018 11:32 pm
by HobbyMan
What RTL-SDR do you have? With the newest one you can enable direct sampling to listen down to 100 khz without an upconverter. You can do this with the older versions, but you are going to need to mod the stick for it to work. In SDR#, you click the gear icon and look for the sampling dropdown, (if it is grayed out, you’ll need to press stop) in the dropdown menu, select direct sampling i branch or direct sampling q branch (whichever works best, that’s what I do) and then press play.

Re: Help listening to Shortwave

Posted: Wed Apr 18, 2018 1:36 pm
by illllm
The new v3. I just got it last week. I have set it to direct sampling and also tried a long wire and a dipole. It is not picking up anything

Re: Help listening to Shortwave

Posted: Wed Apr 18, 2018 2:38 pm
by HobbyMan
I’m using a ground plane monopole designed for 122.8 MHz, I can pick up plenty of shortwave broadcast stations using direct sampling Q branch. Don’t know why you would be having problems.

Re: Help listening to Shortwave

Posted: Wed Apr 18, 2018 5:19 pm
by Kenn
Yes, your version 3 will tune down to 100 kHz with no additional hardware nor internal mods. One selects Direct Sample mode, as you've already done. What I suspect is we can figure this out via software settings, most likely gain. Even with just a few arm-lengths of wire you should be able to pickup local AM stations. You'll likely be able to pickup at least one of the NIST time transmissions on 2.5, 5.0, 10.0 or 15.0 MHz. Do tell us what software you're using.


-Kenn


https://ranous.wordpress.com/rtl-sdr4linux/

Re: Help listening to Shortwave

Posted: Wed Apr 18, 2018 6:28 pm
by illllm
ok so I was making a mistake of using I channel for direct sampling. I corrected that to Q and I can now pick up some MW bands. This is my test setup
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has anyone used this LNA before ? I dont see any difference using it.

I just wound up that 9:1 for test. I dont see a difference using that too.

Need to experiment some more.

Re: Help listening to Shortwave

Posted: Wed Apr 18, 2018 6:32 pm
by illllm
I am using the software SDRSharp.

So if i understand correctly I can make a ground plane monopole using aliminium foil on some cardboard and a straight wire positioned above it?

And as always.....Than you all for your replies - Hobby Man, Ken

Re: Help listening to Shortwave

Posted: Wed Apr 18, 2018 9:50 pm
by HobbyMan
You don’t have to make a monopole. I was just saying that, even with an antenna that isn’t tuned to the right frequency range, you should still be able to pick up broadcast AM. I’m using no LNA or filters, just direct SDR to Antenna (through a lot of coax too, probably 50 feet at least. I have a crappy setup), i can pick up quite a few AM broadcasts still.

Re: Help listening to Shortwave

Posted: Thu Apr 19, 2018 1:48 am
by illllm
I figured it out finally. I am getting a few AM and SW stations but noise is a problem through the entire spectrum. Tried with LNA, with ferrite UNUN, monopole , wire antenna.....test showed no change between just a direct wire and all the other gadgets.

I wonder if the LNA is working ?

Should I enable bias T when using the LNA ? The LNA has a 6volt Power supply of its own.