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  #1 (permalink)  
Old 01-05-2018, 10:44 AM
   
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Default Airspy HF+ intermod

I have massive MW overload on my brand new Airspy HF+ all the way up to 3.5

Is this normal for the HF+? My antenna is a OCFD and I live 10 miles from any MW transmitters.

None of my other radios or devices have this type of intermod.

Does anyone else see this?
Do I have a bad unit?

https://imgur.com/kvhrF38
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Old 01-08-2018, 1:39 PM
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I just posted about this. Yes, it's certainly ugly down there, though apparently "normal".

Edit: I meant to mention that I, stupidly, bought TWO of them.
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Old 01-09-2018, 1:12 AM
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It is not normal. There are many units without that issue. You need to determine the source of the noise. Email us direct for assistance.
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Old 01-11-2018, 6:10 PM
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It seems that there are plenty that have. The groups.io group seems to have amassed a few disappointed buyers. I wasn't expecting a great improvement from the HF+ (with all of its actually minuses), but I definitely wasn't expecting that the performance would be worse than using a Airspy R2 and a Spyverter - which is what's happened.
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Old 01-11-2018, 9:08 PM
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Quote:
Originally Posted by Flatliner View Post
The groups.io group seems to have amassed a few disappointed buyers.
A few?? Oh my.
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Old 01-11-2018, 9:28 PM
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I don't have an Airspy HF+ but do have a new SDRplay RSP2pro which is kind of similar. If I run it with gain maxed out and my larger antennas (133ft OCFD) it will overload on MW. Backing the gain down fixes things and it works quite well. Does the Airspy have a gain control or attenuation you can engage?

I live between a couple of 50kw stations in LA, KFI at 640KHz and KNX at 1070KHz plus a foreign speaking station just a couple of miles away and they all come in around 60dB over S9.
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Old 01-11-2018, 10:00 PM
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Quote:
Originally Posted by slicerwizard View Post
A few?? Oh my.
And I'm willing to bet that a few of the few are the usual "Youssef hurt my feelings, so his hardware sucks" trolls.

M
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Old 01-12-2018, 12:47 AM
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Quote:
Originally Posted by Flatliner View Post
I just posted about this. Yes, it's certainly ugly down there, though apparently "normal".
Definitely not normal. THe Airspy HF+ cleaned up my LW / MW reception from what I see with my SDRplay RSP2. I'd try a choke or two on the USB cable as my first step.

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Old 01-12-2018, 5:09 AM
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Quote:
Originally Posted by mtindor View Post
And I'm willing to bet that a few of the few are the usual "Youssef hurt my feelings, so his hardware sucks" trolls.

M
To attempt to delegitimise the complaints of legitimate purchasers by referring to them as "trolls", seems straight out of the book of Trump with his claims that objections are "fake news".
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Old 01-12-2018, 5:15 AM
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Quote:
Originally Posted by prcguy View Post
I don't have an Airspy HF+ but do have a new SDRplay RSP2pro which is kind of similar. If I run it with gain maxed out and my larger antennas (133ft OCFD) it will overload on MW. Backing the gain down fixes things and it works quite well. Does the Airspy have a gain control or attenuation you can engage?

I live between a couple of 50kw stations in LA, KFI at 640KHz and KNX at 1070KHz plus a foreign speaking station just a couple of miles away and they all come in around 60dB over S9.
prcguy
The RSPs and the Airspys will overload on too much signal.

What is to note though was the claim of no need for a gain control on the HF+. I thought that, as did others, that that may be a tad over-confident and a little arrogant. So, no, there is no gain control to back off, for the HF+. Now it seems that there are complaints about signals appearing in places that they shouldn't. The recommendation seems to be to use attenuation on the antenna input. It's good advice, though a ridiculous situation and completely kills the sensitivity.
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Last edited by Flatliner; 01-12-2018 at 6:19 AM..
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Old 01-12-2018, 9:05 AM
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Quote:
Originally Posted by mbott View Post
Definitely not normal. THe Airspy HF+ cleaned up my LW / MW reception from what I see with my SDRplay RSP2. I'd try a choke or two on the USB cable as my first step.

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Hi Mike,

It's already double choked. I got an ebay USB cable marketed towards the Airspy crowd. It did make a surprising improvement on many of the repeating lines and better than the single-choked cable that came in the box.

I saw quite a difference between the RSP2 and the RSP1a too with a twin-choked A/B ebay cable. Though even without chokes, the cheaper RSP1a actually looks better than the older, though more expensive, RSP2. It is damn good value that RSP1a.

It's shame also that the bandwidth on the HF+ isn't wide enough for MW in its entirety. I can't even dedicate it to weather sats as it can't get the whole band in there either. Kinda regretting buying two too as I admit that I got sweeped up on the hype. I'll move one on and see where we are in a few weeks on the other. Right now, there is infinitely more fun with an R2 and Spyvertor or with the RSP1a, than this little brick. Shame.
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Old 01-12-2018, 9:28 AM
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Flatliner,

I was pretty much set on the Airspy HF+ before the RSP1A was announced. Figured the HF+ would make a nice upgrade to the RSP1 and I'll keep the RSP2 available. So far, that is still the plan.

As for the BW of the Airspy HF+, It will take a bit of getting used to 768kHz. When I first ran the RSP1, I used the entire BW. Over time, I slowly backed the BW down to 2meg. SDR Console V3 works with both the HF+ and the RSP2 so I use it for my comparisons. However I am working with the SDR# software, too.

Hope everything gets sorted for you.

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Old 01-12-2018, 9:37 AM
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2 MHz does seem to be the best compromise maximum bandwidth, you can get very many useful bands in that. Ironically, it's what we had with the RTL dongles, and they really did love me long time for only only $5!

For reference, here's a pic of the supplied HF+ cable VS the ebay "Airspy" cable.

https://forums.radioreference.com/at...1&d=1515767802
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Old 01-12-2018, 4:24 PM
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Leif Asbrink, a well respected member of this hobby, has made a video demonstrating the problems with IMD with the HF+

https://www.youtube.com/watch?v=k6I-_LfspIs
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Old 01-12-2018, 4:29 PM
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Adam 9a4qv (LNA4ALL developer) has also posted about the HF+ over-loading issue.

https://www.youtube.com/watch?v=fQJj15uFIY0
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Old 01-14-2018, 5:53 AM
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Lief also said "The HF+ is a significant step forward as I have shown in previous videos, but it is not a step big enough to make external filters unnecessary."

That said, We are sure few will be disappointed that it will not outperform units costing 6 times as much. That still makes the HF+ an excellent value.

The great thing about SDR is that most of the magic happens in software, and the HF+ is brand new. There will be many improvements likely while other units may be many years old and all the limits are pushed as far as they will go.
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Old Yesterday, 7:03 AM
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I have a homebrewed BC Band killer filter I built years ago to keep a nearby station from trashing most of my HF radios. Only my NRD-515 seemed immune. It didn't cost much and I was amazed at how it cleaned up the background noise on the affected radios. I see there are now small SMA connector equipped filters being sold now, like the one on this page.

https://www.rtl-sdr.com/buy-rtl-sdr-dvb-t-dongles/
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