Perseus SDR Receiver Test Results

[W1VD]

Receiver: Perseus SDR

Preamp off:

Band	MDS	Blocking DR	Two-tone DR
		(20 kHz)	(20 kHz)
80 meters	-129 dBm	127 dB	99 dB
40 meters	-129 dBm	127 dB	99 dB
20 meters	-129 dBm	127 dB	100 dB

Preamp on:

Band	MDS	Blocking DR	Two-tone DR
		(20 kHz)	(20 kHz)
80 meters	-131 dBm	127 dB	99 dB
40 meters	-131 dBm	127 dB	100 dB
20 meters	-131 dBm	127 dB	100 dB

AM audio S/N: 50 dB

AM Audio Frequency Response: in dB, referenced to 1 kHz measurement   

100 Hz	200 Hz	400 Hz	600 Hz	800 Hz	1 kHz	2 kHz	3 kHz	4 kHz	5 kHz	6 kHz
0	0	0	0	0	0	0	0	0	0	-4

AM Audio Distortion:

Mod	100 Hz	200 Hz	400 Hz	600 Hz	800 Hz	1 kHz	2 kHz
30%	.71%	.71%	.79%	.79%	.63%	.63%	.63%
50%	.56%	.56%	.63%	.63%	.63%	.63%	.71%
70%	.56%	.56%	.63%	.63%	.63%	.63%	.79%
90%	.71%	.63%	.71%	.71%	.79%	.79%	.89%
100%	1.1%	1.3%	1.4%	1.4%	1.3%	1.3%	1.3%

Notes: MDS, blocking and two-tone IMD measurements made using a 500 Hz wide filter and AM audio measurements made using a 12 kHz wide filter. Description of the system: Perseus SDR > P4/2800 MHz/1G Ram > Delta 44 sound card > Hafler DH-110 preamplifier > Hafler P3000 amplifier.

Perseus SDR software version 2.1c was used for the test. Both standard AM and synchronous AM detectors were tested and little if any difference was noted in the measurements. Blocking dynamic range occured at about the ADC clipping level which is -3 dBm (preamp off) and -6 dBm (preamp on). It's possible that the audio distortion numbers are even better than shown since measurements are likely at the limit of the test equipment in use.

Final judgement on just how well the Perseus works will be withheld until I've had a chance to use it under battle mode conditions - full on cw and ssb contests. For the moment though, all other receivers have been pushed to the side in favor of the Perseus. It's that good ... especially as an AM receiver. The audio performance betters the previous hot ticket R-390A / Softrock only by a small margin but offers many features that only a direct sampling receiver can.

Info on the measurement setups and test results on other receivers can be found at:

http://www.w1vd.com   Scroll down to 'Receiving'.

Sample screen shot using version 2.1c software attached below.

[WA1GFZ]

Very Cool Jay?
Still waiting for Santa here

[flintstone mop]

There was something very new for an SDR radio in QST that digitizes the RF. I'm not sure if it was the raw RF or an I.F., and the software takes it from there. Around $2000??? 
Great for archiving, as it would be the entire band that the device was programmed to listen, that was recorded or stored in your computer. HUGE recording files.

fred

[Steve - WB3HUZ]

Wow. The K3 beats it in DR. Guess it's not the holy grail some claim it to be.

[W1VD]

The Perseus literature suggests a DR of 104 dB in a 500 Hz BW...but I haven't been able to replicate that. It's my guess that they measured this using an early software version.

I started out using an early version of software that had AGC action down to the background noise. DR measurements were at least several dB different with the AGC on or off. In a 'normal' receiver there is no agc action for the first few uV of input signal so IMD products close to the noise floor have not activated the AGC and are not AGC leveled. Obviously 'leveling' the IMD products makes the receiver seem better than it is...when making measurements with an audio voltmeter.

The newer software has an adjustable AGC threshold that is set to a default of  2 uV so the AGC can be left on for the measurements. Perhaps the folks at Perseus know now that their 104 dB was 'optimistic' but are reluctant to change their spec. Just speculation on my part...

I used the K3 during the 160 meter contest a few weeks back and the band was packed with BIG sigs. There was no sign of blocking or multi tone IMD products - everything was as it should be - this with the receiver run wide open with no front end attenuation. Wish that the Perseus had been on hand for the same test but it will have to wait for another time.

So the K3 receiver wins the MDS and DR war but looses on AM audio recovery. Obviously there's quite a bit of cool stuff that comes with the Perseus - like the spectral display and the ability to record up the 1.6 MHz of spectrum , play it back and seemingly tune the band in real time. And the K3 includes a transmitter!

A holy grail receiver? Been looking for that for 30+ years...still ain't found it but may be getting closer...

[Steve - WB3HUZ]

A holy grail receiver? Been looking for that for 30+ years...still ain't found it but may be getting closer...

Exactly. They all have their strengths and weaknesses. The Perseus has been touted on this forum as the end-all-be-all with everything else as junk. Just ain't so.

[WA1GFZ]

The designer of the K3 hangs on HPSDR and active part of the design. I'm sure the next one will be even better. It will be interesting to see what 2 more bits buys.
My RA6830 still beats out flex software when conditions are bad

[flintstone mop]

My memory banks are not that bad after all. I may not have perfect 100% recall, but this Perseus SDR was what I saw in QST.
$2K for a receiver??
Better contact Santa

Fred

[KL7OF]

Jay.  How does one set up the Perseus for use with a transmitter?  Does it have muting? The QST  Dec-08 article said  "The Perseus's $1299 price tag may seem a bit breathtaking......."      Steve

[WA1GFZ]

Just put the speaker leads through a relay contact and open it during tx.
might consider shorting the RX antenna input to ground so it doesn't ever see any high RF voltage. I know of a guy who blew the A/D giving it too much RF voltage.

[W1VD]

$1299...but I bought mine used so someone else took the major hit...

I use a 90+ dB isolation mil relay for T/R and the system is fully sequenced. Another relay disconnects audio out from audio preamplifier to power amplifier. Headphones get output from mod monitor during transmit so I'm never listening to the receiver during transmit.

[KL7OF]

Does anyone have a 90+ dB isolation relay that is surplus to their needs? .. Perhaps I could homebrew one....Any schematics or suggestions on how to do it?   Steve

[WA1GFZ]

all you need to do is get a SPDT relay and wire it so the RX is grounded during TX. SMA relay would be perfect. Or a SMA DPDT transfer relay.

[WB2YGF]

I got excited till I looked up the price at SBE. 

[Steve - WB3HUZ]

$2k and no muting? What a joke.

[Steve - WB3HUZ]

$2k and no muting? What a joke. Even the Flex has muting and it transmits.

[WA1GFZ]

Flex QSD is old stuff now.
They get their ideas from HPSDR which was the base for SDR5K
I bet the next one will have something more modern.

[Steve - WB3HUZ]

The HPSDR is recreating capabilities that have been around for at least 10 years. None of this stuff is new or modern. At least the Flex has mute and can transmit. That makes it vastly superior.

[WA1GFZ]

True Huz, but no ham product on the market is doing this configuration. It has only been a year or two since the 130 MHz. A/D hit the street. Now there is a 170 MHz part out there. BTW, Perseus is only a RX. Mute is no different than any other radio, A set of relay contacts.
Flex, Lyle of K3, Nico of Perseus, even Rohde tunes into HPSDR. A network of real sharp software guys including Alberto I2PHD who has provided ham radio some very cool free software.
HPSDR can put out 1/2 watt so far with third order IMD better than -50 dB
and sounds quite good on AM. At lower power the IMD gets even better. I can run up to 50 watts carrier so far and working my way up with a modified MRI amplifier strip. I don't know of any commerical radio that clean.
Mercury,Ozy,Penny,Atlas about $600

[Steve - WB3HUZ]

HPSDR is just copying old Agilent and Rhode Schwartz designs. Nothing new.   All the receivers I own do not required any external relay for muting. Lame.

[WA1GFZ]

It still takes a set of contacts to mute any RX as a control. No different you still need something to mute the radio.
Try and buy a fast A/D 10 years ago. A bit cheaper today.
holy grail? where.
Mercury just delivered a few minutes ago

[WA1GFZ]

Mercury lives....Listening to AM a slop bucket right next to us was not heard.
Let the testing begin

[W1VD]

Will be interested in your test results Frank when you get to it.

That may have been a first...a Perseus, Mercury (WA1GFZ) and QS1R (KF1Z) on frequency at the same time. Cool stuff...

[WA1GFZ]

With Bob K1KBW running his 2 dozen class E rig on the side.
Jay I'm missing the attenuator function so don't know what state it works in. There was some mention of it a few days ago but forgot not having the HW.
I went to 160 and nothing. Just need to run the calibration test before it would play. Very cool to monitor 1800 to 1950 all at once.
once the software gets better I'll see what it takes to break it.

[KF1Z]

I was only running 1 dozen pills here..( tabs actually )

The QS1R can monitor 50mhz of band at once...
Doesn't do you a whole lot o good, without a 50meg antenna though!

It is fun to twidle the knobs on the RX ANT tuner and watch the wave on the screen to where it's peaked.

Stu was in there as well... he may have been using his softrock implementation... I didn't ask.


I'm glad to know Flex is a far superior reciever because it transmits....