Compared an RSP1A alternately with an RSP1
Posted: Mon Dec 18, 2017 6:00 am
I've had (and loved) an RSP1 for over a year now.
I bought an RSP1A for a ham friend as a gift. Before wrapping it I decided to try it in place of my RSP1 just to see what differences there are and whether the refinements would yield a better user experience.
TL/DR summary: I still like my RSP1 and probably won't buy myself an RSP1A upgrade.
Now for the details:
The only obvious thing I noticed in SDRuno 1.21 is that with the RSP1A the change in a few buttons in the MAIN panel, including the [MW/FM] band filter button... I've wondered how well that works and whether it reduces spurious signals, etc. Also, the RF Gain Reduction doesn't quite seem to work quite the same; I guess the LNA has been integrated into it. In a way, it feels like it works a little better, though I'm completely used to the way it works for the RSP1 and how it interacts with the AGC control.
I compared performance at Long Wave, Short Wave, VHF, and UHF frequencies using a fairly narrow bandwidth (LOW IF, Signal Rate 2 MHz, DECimation 2).
Honestly, I couldn't sense much difference for Long Wave stuff. When I first tuned some of the beacon signals around 286 kHz I thought the RSP1A was doing better than I'd seen from my older unit, but when I swapped the RSP1 back in I was able to pull in the same signals at about the same strengths. The waterfall displays looked almost identical. I was surprised to see that the aliased signals down near zero were about the same.
I tuned some 160 meter stuff at 1.84 MHz and there I saw more difference, with the RSP1A showing fewer signals but at the same time some oddball background noise I don't see in the RSP1. Both units tuned FT8 ham comm signals and WSJT-X was able to do a good job of interpreting quite a few of them. It's possible the differences I saw between the units could be explained just by changes in propagation. I honestly can't say one was better than the other.
I tuned CHU Canada at 3.330 MHz and the signal strength and whole waterfall display looked virtually identical between the two.
I thought the waterfall display on the RSP1A at 10 MHz tuned to the WWV signal seemed much cleaner - until I realized I had dialed the RF Gain Reduction back a good bit. When I set them similarly both units again showed virtually identical waterfalls and signal quality.
Other spot checks at higher frequencies again netted no great surprises.
I did see a strong reduction in AM (Medium Wave) and FM signals when I invoked the [MW/FM] filter button on the RSP1A, and so I went looking for places where that might matter - e.g., tuning above several hundred MHz. Sure enough, blocking the seriously strong and numerous FM stations we have here in south Florida really made a difference in the imaging in the sub gigahertz ranges. If you're listening to UHF, the RSP1A's additional capability will matter.
I tuned some police frequencies with both units at around 851 MHz and again both units performed about the same.
I checked both units for aliased signals, and this is one area where the RSP1A really shined. At many different frequencies I stepped the frequency up 1 kHz at a time with LO LOCK off and I only saw very faint signals marching the other way on the RSP1A, where I do see more of those in my RSP1. But not a LOT more. Just a few. This alone is ALMOST enough to make me want an RSP1A of my own.
I tempted myself with a thought exercise: What if I gave my friend my old RSP1 and kept the RSP1A for myself? Surprisingly, my emotional response was actually NO - really I don't see much improved performance and somehow I feel more comfortable with the unit I already know and use. It wasn't the answer I expected, to be brutally honest.
I hope this helps others know that the RSP has been and is a fine piece of gear, and while there are small refinements in the new model, they are evolutionary, not revolutionary.
I'll have the RSP1A for a few more days, so if you can think of something I should have checked, or want specific comparisons, screenshots, etc., please ask.
-Noel
I bought an RSP1A for a ham friend as a gift. Before wrapping it I decided to try it in place of my RSP1 just to see what differences there are and whether the refinements would yield a better user experience.
TL/DR summary: I still like my RSP1 and probably won't buy myself an RSP1A upgrade.
Now for the details:
The only obvious thing I noticed in SDRuno 1.21 is that with the RSP1A the change in a few buttons in the MAIN panel, including the [MW/FM] band filter button... I've wondered how well that works and whether it reduces spurious signals, etc. Also, the RF Gain Reduction doesn't quite seem to work quite the same; I guess the LNA has been integrated into it. In a way, it feels like it works a little better, though I'm completely used to the way it works for the RSP1 and how it interacts with the AGC control.
I compared performance at Long Wave, Short Wave, VHF, and UHF frequencies using a fairly narrow bandwidth (LOW IF, Signal Rate 2 MHz, DECimation 2).
Honestly, I couldn't sense much difference for Long Wave stuff. When I first tuned some of the beacon signals around 286 kHz I thought the RSP1A was doing better than I'd seen from my older unit, but when I swapped the RSP1 back in I was able to pull in the same signals at about the same strengths. The waterfall displays looked almost identical. I was surprised to see that the aliased signals down near zero were about the same.
I tuned some 160 meter stuff at 1.84 MHz and there I saw more difference, with the RSP1A showing fewer signals but at the same time some oddball background noise I don't see in the RSP1. Both units tuned FT8 ham comm signals and WSJT-X was able to do a good job of interpreting quite a few of them. It's possible the differences I saw between the units could be explained just by changes in propagation. I honestly can't say one was better than the other.
I tuned CHU Canada at 3.330 MHz and the signal strength and whole waterfall display looked virtually identical between the two.
I thought the waterfall display on the RSP1A at 10 MHz tuned to the WWV signal seemed much cleaner - until I realized I had dialed the RF Gain Reduction back a good bit. When I set them similarly both units again showed virtually identical waterfalls and signal quality.
Other spot checks at higher frequencies again netted no great surprises.
I did see a strong reduction in AM (Medium Wave) and FM signals when I invoked the [MW/FM] filter button on the RSP1A, and so I went looking for places where that might matter - e.g., tuning above several hundred MHz. Sure enough, blocking the seriously strong and numerous FM stations we have here in south Florida really made a difference in the imaging in the sub gigahertz ranges. If you're listening to UHF, the RSP1A's additional capability will matter.
I tuned some police frequencies with both units at around 851 MHz and again both units performed about the same.
I checked both units for aliased signals, and this is one area where the RSP1A really shined. At many different frequencies I stepped the frequency up 1 kHz at a time with LO LOCK off and I only saw very faint signals marching the other way on the RSP1A, where I do see more of those in my RSP1. But not a LOT more. Just a few. This alone is ALMOST enough to make me want an RSP1A of my own.
I tempted myself with a thought exercise: What if I gave my friend my old RSP1 and kept the RSP1A for myself? Surprisingly, my emotional response was actually NO - really I don't see much improved performance and somehow I feel more comfortable with the unit I already know and use. It wasn't the answer I expected, to be brutally honest.
I hope this helps others know that the RSP has been and is a fine piece of gear, and while there are small refinements in the new model, they are evolutionary, not revolutionary.
I'll have the RSP1A for a few more days, so if you can think of something I should have checked, or want specific comparisons, screenshots, etc., please ask.
-Noel