HF without upconverter?

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Eric
Posts: 164
Joined: Fri Feb 21, 2014 4:52 pm

HF without upconverter?

Post by Eric » Tue Apr 15, 2014 5:54 pm

I saw some posts on RTLsdr.com lately about a mod whereby people were able to receive HF without the upconverter. Has anyone tried this? I'm a bit excited about it. Even if the results aren't perfect- this expands the power of the RTL-SDR dongles significantly!

Cheers
Eric
I make videos and content on all things electronics, 3D prining and "Maker"
http://www.mkme.org
https://www.youtube.com/mkmeorg

jcims
Posts: 7
Joined: Thu Apr 03, 2014 6:32 am

Re: HF without upconverter?

Post by jcims » Wed Apr 16, 2014 10:37 am

I've been using it recently. I've also done the direct sampling mod but I think this works better (there is at least some filtering in the front end) and of course you don't need to mod the hardware.

I've been using it in sdrsharp, but i imagine it works elsewhere just as well. Grab a recent build of sdrsharp, pull down the modified rtlsdr.dll here (https://dl.dropboxusercontent.com/u/430 ... MOD_VC.dll caveats about random binaries apply ) or build it from keenerd's fork (https://github.com/keenerd/rtl-sdr this may not include the bit to enable upon selecting AGC). Drop it in to replace the 'factory' rtlsdr.dll and tune away.

I don't have any good HF antennas, so i just use an old 100' extension cord and it picks up a good bit of stuff. I don't think it competes with an upconverter, but it's still a lot of fun.

Eric
Posts: 164
Joined: Fri Feb 21, 2014 4:52 pm

Re: HF without upconverter?

Post by Eric » Sun Apr 20, 2014 5:08 pm

That is great info! I need to make some time to play with it for sure then. This could be really handy when travelling instead of taking my upconverter. Thanks!

Eric
I make videos and content on all things electronics, 3D prining and "Maker"
http://www.mkme.org
https://www.youtube.com/mkmeorg

jcims
Posts: 7
Joined: Thu Apr 03, 2014 6:32 am

Re: HF without upconverter?

Post by jcims » Mon Apr 21, 2014 7:36 am

I think it would be cool to send a dongle up in the payload to see what it can pick up at altitude...that and a wifi adapter with a parabolic pointed straight down.

I saw you mention somewhere that you don't have a ham license yet. I think the process is a little bit different for Canada than it is in the states, but I'd definitely suggest pulling down a few practice apps for your smartphone platform of choice and just tinkering when you have a few minutes. I passed my technician and general in one go after a month practicing that way (mostly on the toilet, haha). The theory aspects are directly derived from basic high school physics and the rest is just rote memorization. My 10 year old daughter passed the practice exam for technician the first time through with a 90%. She had a hard time repeating that performance, but the hairs started raising on the back of my neck once she got halfway through it that first time...it was a little creepy lol.

kwinly
Posts: 8
Joined: Tue Mar 25, 2014 4:30 am

Re: HF without upconverter?

Post by kwinly » Sun May 18, 2014 11:47 pm

Very cool.
Be sure to rename the file to rtlsdr.dll
Wasn't picking anything up at first.
Then I attached about 50' cat6. I used 2 opposite pairs twisted together and hooked them up all caveman like to a mcx to f type female with a 2" piece of rg6 and walla.
Cant wait to make and test a proper antenna.

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