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Re: [IRCA] Perseus Vs. RF Space SDR-IQ
At 08:45 PM 7/2/2008, Guy Atkins wrote:
>Hi Les,
>
>Walt Salmaniw can tell you about the SDR-IQ vs. Perseus, as he owns both
>receivers. I'll mention that the RFSpace receivers are more like laboratory
>test equipment in their operation, and in some ways not useful for quick and
>easy DXing as Perseus. However, Perseus definitely has its quirks and issues
>too! These advanced receivers are in their infancy, and it will be exciting
>to see what the next few years will bring as SDRs mature and become more
>polished.
Hi, Les. Guy is correct. I do own both the SDR-IQ and the Perseus SDR. I owned the IQ for about 4 months before receiving the Perseus. In a nutshell, both receivers are amazing instruments and unlike anything I've ever owned. As you might know, I've owned perhaps 20 or 30 different high end receivers, so I'm very much aware of the user end of receivers. Up to several years ago, I was pretty much exclusively into SW dxing, but since then have confined most of my listening to MW dxing, especially TA and TP. The IQ, as Guy mentions, operates very much like a lab instrument. It's dirt easy to set up and has always worked for me flawlessly, even on an older Windows 98SE machine. It's not the easiest to use...ie changing side band parameters, etc. I don't like having to go into a menu and then set it and exit. Perseus is much better this way. Of course, I quickly became spoiled and wished for wider RF recording possibilities. The Perseus group (and especially it's deve!
loper, Nico) is very dynamic. Hardly a day goes by without numerous interesting posts. The IQ group seems to have become very quiet...as if it's reached it's maximum capabilities. The feel of the Perseus group is that things are just beginning, and one can expect more and more software updates. The Perseus interface is very user friendly. It's much more like a receiver, instead of a lab instrument. It's not perfect...there are things I like better on the IQ than on the Perseus. For example, hovering the cursor over a waterfall frequency on the IQ shows the frequency down to the Hz. Not so on Perseus....a small issue, but still an irritant. We're still waiting for decent timer functions on Perseus, although the PRS works pretty well (an external application written for Perseus). The IQ is limited to a single timer, although Chuck Hutton has written a nice program for multiple recordings, TOH, etc although he insists on using Real Audio, not my preferred system....I!
'd prefer mp3 myself. The look of Perseus just looks very professiona
l (compared to the IQ)....what's expected as it's over twice the price. Now Perseus requires much more computer power, and I had a lot of trouble initially until I went over to a Intel Core 2 duo CPU. Even so, there's still occasion for hesitation and pops. One has to be very careful not to overload the computer with too many tasks. This is mostly true when recording RF, not so when just monitoring (also for playback). There has been a lot of trial and error to get things right. Things work fine at the lower sampling rates of 125 and 250 kS/s, but watch out at 500, and especially 1000 kS/s. I've found things work best for me when recording onto a external HD. I love the possibility of recording 800 kHz of spectrum. Absolutely amazing! Nico is considering a version with a full 1200 kHz of recording ability....imagine, the entire MW spectrum! I can imagine this as a hugely useful tool during hot dx sessions. I know that I'm still working on some files from months a!
go! (This in itself can be viewed as a problem, but I like to keep a positive outlook). For the last 10 or so days, I've been using my Perseus in this manner: I record 800 kHz centered on 930 kHz....ie between 530 and 1330 kHz.....almost the entire spectrum. I record between 11:45 and 12:15 UTC which requires 1.67 GB or so per 5 minutes of recording time! Better have a big HD! I then review the frequencies of interest, either systematically or I'll target specific frequencies and times, based on queries from other observers (this is quick and easy to do).
>MW Splatter Rejection is a new feature introduced in Perseus (beta version)
>that helps reduce splatter from an adjacent channel signal that is
>overlapping your desired station. Using the number-crunching power of the
>computer, this feature takes the opposite "clean" sideband of the QRMing
>station and uses it in a phase-inversion fashion to subtract the splatter
>from the DX signal. A description of how it works is found here:
>http://microtelecom.it/perseus/amrej.html After becoming familiar with the
>steps, it takes just a few seconds to activate the feature on a signal. The
>limiting factor to success, I believe, is multipath distortion that may be
>present on the QRM signal. The times I've been successful with this new
>feature, it has worked very well. Other times...nada.
I've played with this a bit. In the real world of live dxing, I don't think that it's all that useful. One still has to fiddle with things....choose a different BW (AM only), then shaping the bandwidth and double clicking the offending signal to
activate the splatter rejection. I've noted that it worked ok in some circumstances, but mostly it didn't seem to be worth the effort. In my cases, I found a combination of side band, and PBT, and occasionally notch filtering achieved
as good of a result. That's another point....there is a notch on the Perseus, but not the IQ.....it's a primitive notch. I'd rather see an automatic notch, such as that found on the Timewave 599 zx....ie multiple notch at a press of a button. I don't particularly like how the Perseus' notch is activated....better than nothing, though (it does work well, though). I kind of wish that the splatter rejection could be activated by a single "smart" button....I'd love that! .......a few comments from Walt Salmaniw, Victoria, BC.
>73,
>
>Guy Atkins
>Puyallup, WA USA
>www.perseus-sdr.blogspot.com
>
>
>-----Original Message-----
>From: Les Rayburn [mailto:les@xxxxxxxxxxxxxxxx]
>Sent: Wednesday, July 02, 2008 1:09 PM
>To: dx@xxxxxxxxxxxxx; irca@xxxxxxxxxxxxxxxx
>Subject: Re: [IRCA] Perseus Vs. RF Space SDR-IQ
>
>
>I'm an owner of the RF Space SDR-IQ, and have been very impressed with it's
>capabilities. It easily compares to any high end MW receiver that I've ever
>owned including the Drake R8B and AOR 7030.
>
>Been following the news of the Perseus, and would love to hear more about
>the "MW Splatter Rejection" feature. What is it? How well does it work?
>
>Also, I'd love to hear someone compare the SDR-IQ with the Perseus in
>regards to MW DXing...
>
>73,
>
>
>Les Rayburn, director
>High Noon Film
>100 Centerview Drive Suite 111
>Birmingham, AL 35216-3748
>205.824.8930
>205.824.8960 fax
>205.253.4867 cell
>
>
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