Constantly Changing Waterfall Contrast

[sunwave]

The real issue is evaded horribly. Close the thread moderators.

[KA1GJU]

If I activate automatic IF Gain, I will get pumping as well, but mine is random (lightning strikes, electric fence pops, or ???), nothing that ratchets up and down like yours.
I noticed my radio controls are slightly different, but mine are all operated via the server feature.
Top image is IF Gain OFF @ -30dB
Lower image is IF Gain Automatic @ -30dB , Note the random pattern of noise floor jumping vs your video that rises and falls in ~2 second intervals.

73 Kriss KA1GJU

[Max]

The real issue is evaded horribly. Close the thread moderators.

I suggest you read this:

https://www.sdrplay.com/wp-content/uplo ... SDRuno.pdf

For software other than SDR-Uno, all the developer (Simon in this case) can only implement the API as provided by SDR Play. One has to assume that the API controls the hardware in exactly the same way as for SDR-Uno. It may, it may not. As SDR-Uno is proprietary software we can't know this.

It does look like as far as the gain and AGC controls are concerned they mirror those offered in SDR-Uno, so no reason to assume they act any differently. Where there may be differences is in the way the software handles the IQ data thrown at it. Here I guess it's possible there could be some processing differences that change the apparent behaviour. Only the programmer will know this. But as far as the hardware is concerned, what you are seeing is how the HARDWARE of the radio is acting under the influence of a signal that's outside the focussed/tuned area. A perfect receiver won't do this. Very few of us can afford a "perfect" SDR, though any come much closer than the RSP radios, but at a much higher price. Nobody is criticising, just observing from long experience.

Nobody is evading your issue horribly. Just explaining the likely cause. Yes, RSP1A is a step up from RTL-SDR V3 for sure, and maybe from RTL-SDR blog V4 (although the latter is impressive for tiny cost) but if you are a serious HF listener then you need to read the advice being given here. At the prices we are talking, all radios have their own individual issues. If your main interest is HF listening then many on here will tell you from broad experience that the RSP1A is far from the top of the tree. Next step up for HF is most definitely the Airspy HF+. As Kriss says, it's usually offered at a big discount once a year on or near to Black Friday.

I suggest you go on the SDRC server and try out Kriss's excellent selection of SDRs and there you can readily compare the use and operation of Airspy HF+ versus SDR Play and decide for yourself. Having done that you might consider (if you like what you find) purchasing an Airspy HF+ Discovery in the Black Friday sale. It's usually a massive bargain. If you decide we are wrong you would be able to sell it again and not lose a cent of your cost. They are very sought after in the used market. My guess is you would never want to sell it once you've tried it.

HF+ has been optimised for HF work and does not cover upper VHF or UHF bands. Also the maximum bandwidth is less at 768kHz. However, wider bandwidth on the RSP is largely pointless on HF as it reveals some more serious misdemeanours. The RSP1a and other variants are more of an "all rounder". Excellent for a general tool. Not so great for specialist LF/MF/HF listeners. But does many frequencies the HF+ does not offer. Ideally you would keep both.

If you want to go the next step up consider a "direct sampling" SDR like Elad Duo etc.

Anyway, yours to take or leave as you wish. Just be aware that people on here take the time out to answer questions when they could be doing other stuff. There's no agenda. We just give advice to the best of our ability based on our own experiences and with no other agenda.

Max

[KA1GJU]

@Max,

The maximum bandwidth on the Airspy HF+ Discovery is 912kHz, if firmware is up to date. This came out a few years ago, but I still have a few that are 768kHz on my fleet of SDR's (13 onine as I type with more to follow at a new location 53 miles north up in FN43lt)

73 Kriss KA1GJU

[Max]

@Max,

The maximum bandwidth on the Airspy HF+ Discovery is 912kHz, if firmware is up to date. This came out a few years ago, but I still have a few that are 768kHz on my fleet of SDR's (13 onine as I type with more to follow at a new location 53 miles north up in FN43lt)

73 Kriss KA1GJU

Ah thanks Kriss. I must do the firmware update. TBH I only really use Hermes Lite 2 for HF these days, or when I'm being lazy I just plug in the RTL-SDR blog v4 for casual listening across all frequencies. Think it is a stellar little radio for just $30! Not perfect of course.

Note on his spec on the product page (HF+) he says:

"Up to 660 kHz alias and image free output for 768 ksps IQ"

Anyway, will do the firmware update and have a play!

73

Max

[Max]

Ah thanks Kriss. I must do the firmware update. Note on his spec on the product page (HF+) he says:

"Up to 660 kHz alias and image free output for 768 ksps IQ"

Anyway, will do the firmware update and have a play!

Max

OK did firmware update. Then spent about an hour thinking I had bricked it!

Eventually recovered it by taking it to another PC and running update on there. Worked. Not sure quite why but not really bothered as all is well. Think was a USB power issue.

Anyway, tried it out for first time in a long time and was reminded of what a truly excellent receiver it is for LF//MF/HF. Due to another post in the other group I also tested to VLF where I thought I remembered it being a bit deaf, but no, superb all the way down to 10kHz. It also dug quite a few CW signals out at 144MHz to (there's a CW contest on there).

Did not see any degradation due to max bandwidth 912kHz. Maybe I will start using it a bit more again!

73

Max