RTL.SDR HF RX Issues

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mfn002

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I recently acquired one of these. When I hooked it up to SDR#, it receives VHF and UHF fine, but the HF end is completely blank. I checked the HF antenna connection and it seems fine. What's going on here?
 

ka3jjz

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If memory serves, you need a converter to receive HF. I believe their coverage starts at about 25 Mhz or so; apart from hams and CBers, there just ain't much here to hear. There's been several articles written on the Ham it up converter, and there are no doubt more of these....

Mike
 

Token

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I recently acquired one of these. When I hooked it up to SDR#, it receives VHF and UHF fine, but the HF end is completely blank. I checked the HF antenna connection and it seems fine. What's going on here?

What specific RTL SDR did you get, by model number or source. What modifications, or upconverter, do you have to make it do HF? Without this info any answer will be a guess at best.

T!
 

Token

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If memory serves, you need a converter to receive HF. I believe their coverage starts at about 25 Mhz or so; apart from hams and CBers, there just ain't much here to hear. There's been several articles written on the Ham it up converter, and there are no doubt more of these....

Mike

Mike, there are a few RTL SDRs sold that have HF in them right out of the box. Some are modified for direct sample, some have the filter section changed, and others come prepackaged in a single encloser with an upconverter.

T!
 

mfn002

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I'm not exactly sure about the model number, but it has a separate antenna connection for HF. It's not the USB stick type, but an external box.
 

ka3jjz

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Mike, there are a few RTL SDRs sold that have HF in them right out of the box. Some are modified for direct sample, some have the filter section changed, and others come prepackaged in a single encloser with an upconverter.

T!

We could use such a list of RTLs that are like that in our wiki...the article is linked in this thread....it would be useful information....TIA Mike
 

IdleMonitor

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Make sure the power cord (usually a printer cable) is plugged in a long as everything else is setup properly. Then turn it on and try it. Thats what happened to me in the beginning. I forgot to power the hf converter.
 

Token

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I'm not exactly sure about the model number, but it has a separate antenna connection for HF. It's not the USB stick type, but an external box.

Is the box about 2" x 1.75" x 3/4", black with white ends? HF antenna jack on one ends and VHF jack on the other, with a slide switch on the end with the VHF antenna?

T!
 

mfn002

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Is the box about 2" x 1.75" x 3/4", black with white ends? HF antenna jack on one ends and VHF jack on the other, with a slide switch on the end with the VHF antenna?



T!



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Token

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That is not the one I was thinking of when I wrote that description, I was thinking of the Soft66RTL.

I have never used the model you have, but from what I see on the web (and there is not much about it) you should not have to do anything special to receive HF. It apparently has a combiner or auto switch to select HF or V/U input, so if the HF is not working and you know the antenna is good there might be something wrong with the unit. But keep in mind what I said, I have not used that specific model, although I have used similar.

T!
 

Token

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We could use such a list of RTLs that are like that in our wiki...the article is linked in this thread....it would be useful information....TIA Mike

Mike, part of the issue here is that many of these changed or modified RTLs come on the market, sell a few dozen, and then disappear. They are typically poorly documented and little is sometimes known about the maker. The SDR the OP has is pretty typical of this, it is sold as simply "RTL.SDR" with no makers name (there is an image of a Dolphin on the PC board) and it is based on the R820T/RTL2832 with a built in upconverter, the frequency range is advertised as 100 kHz to 1700 MHz, it can be purchased (only on eBay and from more than one vendor) in either kit form or completed, and there is almost no information available on it beyond that. What little information does exist is on a couple of Chinese language pages. And there appears to be at least three different versions of this radio out there, I have no idea what the performance or specifications differences between them are.

There are literally dozens of variations / production runs of the R820T/RTL2832, and they can have different frequency ranges, not even counting the modified ones or ones with an upconverter.

T!
 
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jay427

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Maybe I missed it but is there a switch on the other end for UV/HF? If so could he be missing the offset in SDR# or whatever he is using?
 

mfn002

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Maybe I missed it but is there a switch on the other end for UV/HF? If so could he be missing the offset in SDR# or whatever he is using?

No, there's no switch. I'm using SDR#, and I've also wondered if I'm missing some sort of setting in the program.
 

Fizz306

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Michael,

I'd be curious to see a few screen shots of whatever you're using on the software end (SDR#, HDSDR, SDR-Radio, etc.) and see what you're defining as blank in the waterfall. Are you getting any appreciable amount of background noise? Or are we talking completely silent?

Silly question as well, but what's your antenna setup for HF?

Rob
 

mfn002

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Michael,

I'd be curious to see a few screen shots of whatever you're using on the software end (SDR#, HDSDR, SDR-Radio, etc.) and see what you're defining as blank in the waterfall. Are you getting any appreciable amount of background noise? Or are we talking completely silent?

Silly question as well, but what's your antenna setup for HF?

Rob

I'm using SDR# and there is static, but it won't pick up anything. I attempted to see if it would pick up a local AM station, but it didn't. It seems that I don't start picking anything up until I go above 22 MHz. As for the antenna I'm using, it's an AOR SA2000 mounted outside. It worked perfectly fine with all of the shortwave radios I have.

I ordered another one yesterday (from a different seller). I'm wondering if there is some sort of problem with the upconverter because it seems to receive VHF and UHF just fine.
 

IdleMonitor

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I'm using SDR# and there is static, but it won't pick up anything. I attempted to see if it would pick up a local AM station, but it didn't. It seems that I don't start picking anything up until I go above 22 MHz. As for the antenna I'm using, it's an AOR SA2000 mounted outside. It worked perfectly fine with all of the shortwave radios I have.

I ordered another one yesterday (from a different seller). I'm wondering if there is some sort of problem with the upconverter because it seems to receive VHF and UHF just fine.
How are you powering it?
 

Fizz306

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I'm using SDR# and there is static, but it won't pick up anything. I attempted to see if it would pick up a local AM station, but it didn't. It seems that I don't start picking anything up until I go above 22 MHz. As for the antenna I'm using, it's an AOR SA2000 mounted outside. It worked perfectly fine with all of the shortwave radios I have.

I ordered another one yesterday (from a different seller). I'm wondering if there is some sort of problem with the upconverter because it seems to receive VHF and UHF just fine.

Just ruling out a few other things. Are you using the frequency shift feature in SDR sharp? Does the upconverter have a 100 MHz or 125 MHz oscillator?

If there is an upconverter in there, I would imagine there would need to be a switch that would either allow passthrough or upconvert of the signal. Because there are two inputs for separate V/UHF and HF antennas, I'm thinking there should probably either be an upconverter switch, or two separate RTL devices in the enclosure.

On a personal note, I've had great success with the folks over at NooElec. You will probably pay a premium compared to the Chinese devices, but their RTL sticks, along with the Ham It Up converter, work very well.

It's hard to tell if this is a software configuration issue or a hardware issue here. See if you can ascertain the upconverter oscillator's frequency, and post a few screen shots of your software configuration and waterfall in SDR#.

Rob
 

mfn002

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Just ruling out a few other things. Are you using the frequency shift feature in SDR sharp? Does the upconverter have a 100 MHz or 125 MHz oscillator?

If there is an upconverter in there, I would imagine there would need to be a switch that would either allow passthrough or upconvert of the signal. Because there are two inputs for separate V/UHF and HF antennas, I'm thinking there should probably either be an upconverter switch, or two separate RTL devices in the enclosure.

On a personal note, I've had great success with the folks over at NooElec. You will probably pay a premium compared to the Chinese devices, but their RTL sticks, along with the Ham It Up converter, work very well.

It's hard to tell if this is a software configuration issue or a hardware issue here. See if you can ascertain the upconverter oscillator's frequency, and post a few screen shots of your software configuration and waterfall in SDR#.

Rob

Kind of a stupid question, but how do you take a screenshot? I've never been able to quite figure it out.
 

Fizz306

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Kind of a stupid question, but how do you take a screenshot? I've never been able to quite figure it out.

Nah, not a stupid question. It's simple, hit the print-screen (PrtScn) key on your keyboard. This copies a picture of the screen into the clipboard. Open up Paint, paste the photo, save as a JPEG, and upload to RR.

This will come in handy a lot considering how much stuff needs to be tweaked in a program like SDR# depending on what you're trying to accomplish.

Take a screen shot
 
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