Perseus SDR

[John Faulkner]

Does anybody here own the Perseus SDR for MW DXing? I recently got one and am totally blown away by its performance. My AR7030 cannot dig in between the European channels like the Perseus.

Cheers!

John

[John Faulkner]

Mike suggested I write a little about the Perseus, so here are a few bits I have compiled from previous notes I have made about this remarkable receiver.

The Perseus SDR (Software Defined Radio)

There has been much hype about this little black box. The overwhelming opinions of others were such that it outperformed anything else. It sounded too good to be true. I have to say I did not believe it and so joined the Perseus Yahoo group before making a decision to buy this receiver.
http://groups.yahoo.com/group/perseus_sdr

Why bother? I already have the excellent AR7030 for my MW DXing. For me, I find it increasingly difficult to stay awake for early morning DX sessions. So, for the last couple of years, I have been recording a single channel from my AOR AR7030 so I can play it back the following daytime and hopefully hear some decent DX. Recording one channel has obvious limitations.

Since I discovered that the Perseus can record virtually the whole of the medium wave band (and will be able to record more than this soon) I realised that the Perseus was probably the only way forward for me. I could then return to having a normal daytime life – I am one of those people who require at least ten or eleven hours sleep each night.

The Perseus software currently lets you record 800kHz of bandwidth though this actually extends to more than 1MHz but with a degree of performance degredation outside the 800kHz. I can’t say I have noticed any to be honest. Recording 750 - 1550 kHz actually gives me 600 - 1700kHz and I can even go a little beyond this!

The Perseus records a huge chunk of I.F. and not traditional "audio", so you can play back the IF the next day and tune the radio exactly as if you were there the previous night. You can tune, change mode, adjust the bandwidth, insert the notch filter, adjust the level of noise reduction, etc., etc. But it’s weird if you think of it like this … people are now able to send each other their medium wave band so they can DX it too! It's true. This is some Perseus DXers are doing! I have done it myself.

So, I now record more than 100 10kHz channels! “Exactly how long does it take to play all this back?” you may ask. Well, for me, it takes a lot less time than I expected. Quite simply, it depends how much time you want or “need” to put into doing this. The conditions will play a big part in this. The beauty is that you can see the carriers on your PC display so you know if there is any DX worth going for before you start! It is up to you how many frequencies you wish to check, and for how long. If conditions are good then you would probably wish to spend more time.

The recordings Perseus makes are in chunks of 1.7GB = five minutes. Playback automatically loads and plays each 1.7GB file back-to-back, seamlessly. I have found that an overnight recording of twelve hours occupies 243GB of my USB hard drive. That’s not small amount, but as portable storage gets cheaper we will all be able to store more for less. A DXpedition would require several of these drives. You have the option of being able to tune around while you are making your recording, or you could just go to sleep and let the Perseus save the DX for you, for a later time or date. One day, we may be able to exchange these huge files to each other easily over the internet and thus attend virtual DXpeditions!

The Perseus software is free to download and successive upgrades will allow increased bandwidth recordings and all kinds of other improvements. The hardware remains the same. One of the reasons I chose Perseus against other SDRs was because designer Nico Palermo actually listens and responds to DXers needs and is keen to incorporate our suggestions. How many other companies do that?

Perseus is both very sensitive and very selective. One article I read suggested that the Perseus is not as sensitive as the AR7030. I actually found the reverse to be true. The Perseus offers superb technical specification. Not only is the sensitivity excellent, selectivity is also astounding! I don’t know how Perseus does it, but I can easily tune to a 10kHz channel which is squashed between two adjacent European signals and I can narrow the passband down to 1.5kHz or much less and still have intelligible audio. It is quite muffled of course but the AR7030 would not have coped with such narrow bandwidths, even when I fed the IF of my AR7030 into Winrad to improve the selectivity, 1.5kHz on that would have been a garbled mess. Somehow, the digital processing of Perseus seems to offer better results with such tight bandwidths. I was able to hear a clear signal from CIWW 1310 recently – a frequency which is almost impossible on the AR7030. The Perseus seems to suck the weak signal out of the noise. The Perseus noise reduction is also very good.

I plan to take the Perseus out into the wilds of the Derbyshire countryside in a few days and run out a beverage. I will let you know the results.

Good DX!

John

[tvdxrools]

i had a loan of the perseus receiver for a few days and ran it side by side with my aor and in my opinon on DX stations the perseus wins. it can dig signals out of the mush when the aor was struggling. the filters are much better in the perseus but again in my opinion for audio quality on a stronger station the aor wins that one but we are talking about dx. the only fault i have found with the perseus is antenna choice for overnight/early morning recordings ie loops or other antennas you have to tune when moving up/down frequency yes the perseus can record a huge chunk of spectrum but if using a antenna which needs tuned narrows that down a great deal but with ewe"s beverage etc you have the ultimate dx machine but with tunning antennas you have the ultimate dx radio when sitting live in front of it. so if i was are looking for a real dx radio it would be the perseus with the aor a very close second .... david h ... scotland

[mrhoover]

Hi David.

I haven't had the benefit yet of trying the Perseus(await Vhf frequency
extension version ;) ) but bear in mind what filters are in the AOR 7030 you're comparing it with.

The IF selectivity via the "Stock filters" that come with the AOR can be improved on considerably by installing better ones.I have a Collins mechanical one for 3KHz AM use and a 2 KHz for SSB use.

With the AM Collins one and tweaking of the passband tuning control picking up 917 KHz Nigeria I can more or less get rid of 918 QRM even before using
the AOR's audio notch filter.This just wouldn't be possible with the original
filters.

AM DXing here in Portugal is a real challenge on some frequencies,living next
door to Spain & their "borderblasters" plus a 720 KHz
Portuguese transmitter 5 miles down the road I look forward to trying the
Perseus & seeing how it compares in due course.

If it produces any "hash" on 1440 KHz from the 720 KHz transmitter it's going straight back as the AOR performs very well in this respect.On a car radio 1440 KHz is impossible & this is a prime Nigerian frequency for me.

One also needs a "quiet" PC which doesn't radiate a load of RF s***
to get the full benefit of the Perseus.I shall certainly have to change
mine which is dreadful in this respect.

Cheers

Hugh

[tvdxrools]

howdy hugh. there is really not that much in it but the perseus "seemed" to dig signals out the noise better than my aor with just the out of box filters but the aor wins easily with audio quality and again if i was getting a perseus i would have to dx live as the overnight recordings are no use to users who have antennas that need tuned ie loops etc or you would be left with a small bandwidth of recordings. and if i am being truthful while the perseus is a really good dx radio i still like to turn buttons with my hands ie a "real" radio ...
cheers david h