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Author Topic: RF Spectrum analyzer for computer - recommendations?  (Read 102620 times)
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K1JJ
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« on: December 28, 2010, 08:49:08 PM »

I'm looking for a self-contained piece of RF spectrum analysis hardware that will put out a USB signal to the computer.  I already have a SoftRock board, but it's fried - doesn't work. I don't want to waste any more time on it or buy another one, nor depend on an outboard receiver for the 455kc output.

Steve/HX had sent me a link six months ago (IIRC) of a tunable RF unit that put out the required audio signal for about $350?  I can't seem to find it.

Or can anyone recommend another lashup besides the SoftRock that is self contained besides the computer?

T
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KF1Z
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« Reply #1 on: December 28, 2010, 09:35:20 PM »

Confused...........

You want to take 455kc IF from your current reciever, and display the spectrum on the computer?
Is that it?

The softrock isn't capable of what you want to do? or just the board you have doesn't function?

Not sure what you mean I guess because I don't think anyone would spen $350 just to do that !   Huh

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WB2EMS
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« Reply #2 on: December 28, 2010, 09:40:25 PM »

Quote
self-contained piece of RF spectrum analysis hardware that will put out an audio signal to the computer soundcard.

Not quite sure what you are looking for based on this. Are you saying the softrock doesn't function and you're frustrated with it or that it didn't do the job you needed. Are you looking for an instrument with demod, or a receiver that can show the surrounding spectrum and signal levels?

The RFSPACE SDR-IQ receiver is about $500 and when run with Simon's sdr-radio.com software and connected to the USB port shows the spectrum pretty well and is a fair receiver. You can tune in mine, or others, by loading the console software and in the input section connect to remote receiver and use the search the web option to find an open receiver. It's not a stand alone receiver in that it needs the pc to function, but might do.

The softrock with powersdr has more software capability than Simon's software currently I believe, but everything is changing rapidly.

The Flex1500 is a little more expensive, but is a 5 watt QRP transceiver. It's limited to 48 khz of panoramic display.

I hope this is helpful.

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73 de Kevin, WB2EMS
K1JJ
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« Reply #3 on: December 28, 2010, 09:55:13 PM »

The RFSPACE SDR-IQ receiver is about $500 and when run with Simon's sdr-radio.com software and connected to the USB port shows the spectrum pretty well and is a fair receiver.  

Yes, this is what I meant. The SoftRock is fried.  I'm looking for a self contained unit with a ~0.1 to 30mhz RF antenna input and outputs a USB signal for computer analysis use.

The unit you suggested is it - an "SDR-IQ™ Software Defined Radio, Spectrum Analyzer and Panoramic Adapter:"

http://www.rfspace.com/RFSPACE/SDR-IQ.html

I think there is something even cheaper that did the same thing. I'll do some more searching now that I know what it's called...   Tnx.


* Basically, I'm looking to monitor my RF transmit signal on SSB or AM and adjust the system for best IMD figures.

T
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Use an "AM Courtesy Filter" to limit transmit audio bandwidth  +-4.5 KHz, +-6.0 KHz or +-8.0 KHz when needed.  Easily done in DSP.

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WA1GFZ
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« Reply #4 on: December 28, 2010, 10:10:00 PM »

HPSDR Hermes single board transceiver will do RX 10 KHz to 6 Meters. I think they are converting the interface with a network cable so it will pass more data. Supposed to come out in 2011. Also a 1/2 watt transmitter that should do -50 dBc IMD.
It will interface with Flex software which I find very accurate as an S.A.
QSR1 or Perseus also good. I see used Perseus deals come up from time to time.
Jay VD bought a used one.
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K1JJ
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« Reply #5 on: December 28, 2010, 10:16:50 PM »

Frank posted a few years ago:

"If you are planning to tap off the IF of your receiver, the Softrock is not needed. A far simpler NE602 based downconvertor will work just fine. Get the schematic of the one KE1GF built several years ago to demod DRM."

I did a search here and don't see KE1GF's circuit.  I still would consider using a downconverter, especially if I could use my old FT-102 8.2mhz? IF output.   Is that circuit still around?

The Hermes and Perseus receivers - how much are the basic RX boards and is this overkill if I just wanna do spec analysis on my TX signal?

T
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Use an "AM Courtesy Filter" to limit transmit audio bandwidth  +-4.5 KHz, +-6.0 KHz or +-8.0 KHz when needed.  Easily done in DSP.

Wise Words : "I'm as old as I've ever been... and I'm as young as I'll ever be."

There's nothing like an old dog.
Steve - K4HX
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« Reply #6 on: December 28, 2010, 10:25:04 PM »

http://mysite.verizon.net/sdp2/id12.html


I got's one here. It works FB.
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WA1GFZ
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« Reply #7 on: December 28, 2010, 10:27:59 PM »

I think Jay got his Perseus for around $500.
It will blow the doors off your FT1000D close in.  It does not have an RF amp so not as sensitive above 40 meters. The RF amp chip came out a bit after the Perseus and QSR1 went into production. A 4 leg broadband high dynamic range amp chip would fix that.
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K1JJ
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« Reply #8 on: December 28, 2010, 10:42:40 PM »

http://mysite.verizon.net/sdp2/id12.html
I got's one here. It works FB.

Excellent!  That link has all the info I would need to put one together. I like the idea of building it myself for better control of crapouts.  The software looks pretty sharp, like it cud give some very detailed IMD readings.

Maybe I will use my SP-600 for the 455 I.F. in this case. That RX has a good front end and is well shielded..

Should I use the free "Spectrum Laboratory" software as shown or something else?  

T



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Use an "AM Courtesy Filter" to limit transmit audio bandwidth  +-4.5 KHz, +-6.0 KHz or +-8.0 KHz when needed.  Easily done in DSP.

Wise Words : "I'm as old as I've ever been... and I'm as young as I'll ever be."

There's nothing like an old dog.
Steve - K4HX
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« Reply #9 on: December 28, 2010, 11:04:24 PM »

Or PowerSDR or maybe some others.
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K1JJ
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« Reply #10 on: December 28, 2010, 11:12:10 PM »

OK, then I'll do it.

I just checked the 455 kc output of the SP-600 and it's clean and strong. I normally use it into the o'scope.

I'll order the parts tmw and go from there.  This shud be a cheap way to get a quality spec analyzer going here.

TNX!

T
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Use an "AM Courtesy Filter" to limit transmit audio bandwidth  +-4.5 KHz, +-6.0 KHz or +-8.0 KHz when needed.  Easily done in DSP.

Wise Words : "I'm as old as I've ever been... and I'm as young as I'll ever be."

There's nothing like an old dog.
KF1Z
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Are FETs supposed to glow like that?


« Reply #11 on: December 28, 2010, 11:43:29 PM »

Ok that's what I thought......

you aren't looking for an 'actual' SDR !

just a simple mixer out of any handbook!


If you are tapping an IF off an existing reciever.... buying a whole SDR RX is a waste of money.



------------

Today I'm finishing up building my 45th SDR transciever....
I lost count on the softrock recievers... last I remember the count was 29...
Only 7 different models overall....
Man it's time for more variety!
 Grin
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Steve - K4HX
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« Reply #12 on: December 28, 2010, 11:46:41 PM »

Wow. You must have some incredible eyes - and patience!
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Pete, WA2CWA
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« Reply #13 on: December 28, 2010, 11:47:43 PM »

I think Jay got his Perseus for around $500.
It will blow the doors off your FT1000D close in.  It does not have an RF amp so not as sensitive above 40 meters. The RF amp chip came out a bit after the Perseus and QSR1 went into production. A 4 leg broadband high dynamic range amp chip would fix that.

He must have bought a used one. New, they sell for around $1200. http://www.universal-radio.com/catalog/commrxvr/0122.html
Then, there's the SDR-14 for about $1K. http://www.universal-radio.com/catalog/commrxvr/0014.html
The SDR-1Q sells for about $499. http://www.universal-radio.com/catalog/commrxvr/0106.html
The Flex 1500 QRP software defined rig (rcvr section tunes from 10 KHz to 60 MHz) is on sale for $619 http://www.flex-radio.com/Products.aspx?topic=F1.5k_features
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« Reply #14 on: December 29, 2010, 12:41:03 AM »



Softrock Lite 6.2 was $12! How can that be a waste of money for what it does!

Tom Vu........... I have one setup for 455KHz..... you want it?
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KF1Z
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Are FETs supposed to glow like that?


« Reply #15 on: December 29, 2010, 09:16:49 AM »



Softrock Lite 6.2 was $12! How can that be a waste of money for what it does!



Well, when I said a "whole" SDR rx, I meant an all-band rig... not a mono-band rx...
I should have clarified...   Cheesy

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KF1Z
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Are FETs supposed to glow like that?


« Reply #16 on: December 29, 2010, 09:22:57 AM »

I think Jay got his Perseus for around $500.
It will blow the doors off your FT1000D close in.  It does not have an RF amp so not as sensitive above 40 meters. The RF amp chip came out a bit after the Perseus and QSR1 went into production. A 4 leg broadband high dynamic range amp chip would fix that.

He must have bought a used one. New, they sell for around $1200. http://www.universal-radio.com/catalog/commrxvr/0122.html
Then, there's the SDR-14 for about $1K. http://www.universal-radio.com/catalog/commrxvr/0014.html
The SDR-1Q sells for about $499. http://www.universal-radio.com/catalog/commrxvr/0106.html
The Flex 1500 QRP software defined rig (rcvr section tunes from 10 KHz to 60 MHz) is on sale for $619 http://www.flex-radio.com/Products.aspx?topic=F1.5k_features


Then the QS1R RX,  http://srl-llc.com/    $999.

Then a KIT  transciever..160m - 6m ...the Genesis G59  for $349 and 10 watt amp kit $129
http://www.genesisradio.com.au/

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WA1GFZ
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« Reply #17 on: December 29, 2010, 10:22:32 AM »

Bruce,
What do you use for a crystal frequency in the 455 KHz IF softrock. I used a color burst crystal. You really want to use a tayloe type mixer so the software takes care of images. The spectrum display will be cleaner that hanging a mixer off a wideband 455 kHz. I.F. It will work though. A few of my Racals have 6.4 KHz baseband outputs so just dumped them into a sound card.
Power SDR (Flex) is very accurate. It tracks the output of my HP8640B within a dB.
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KF1Z
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« Reply #18 on: December 29, 2010, 10:53:49 AM »

The color burst is easy to get , works fine...
Also 3.7mhz
As far as easy to get, readily available.... they are the best choice for 455kc IF.
Leaves about 8khz from 455kc to center F.


Can use 1800khz xtal as well, connect the "4x" jumper, instead of "8x" but leaves only 5khz to center F

3640kc is a readily available too... but that lands 455khz as the center freq, which you need to avoid.

3.6864mhz  another standard xtal works , but only leaves 5khz to the Center F.

Doesn't really matter, as long as your soundcard has enough bandwidth to land 455kz in one half or the other of the display. ( above or below center F).

If your soundcard is 96 or 192khz,  then 3.859mhz is good.

Puts 455khz   27kc from center




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KF1Z
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« Reply #19 on: December 29, 2010, 10:59:12 AM »

Of course...
If you want to get REALLY fancy,
You do away with the crystal, by a "QRP2000" ...

Get rid of all the frequency selective bits at the input of SR ( make it cap input?)
And you can use whatever frequency you want for the LO ( center freq).

AND
use the same SR IF setup for up to about 10mhz
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K1JJ
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« Reply #20 on: December 29, 2010, 11:45:13 AM »

Looks like a lot of options. Tnx for the ideas.

Yes, Buddly, I would like to give the SoftRock another go if you have a working 455 kc board.  That would be great - and the easiest path of least resistance right now.  Let me know what $ to PayPal you or maybe you can use some parts in swap?

I'll jump in the water with this simple lashup and it might wet my whistle to enter the wild whirl of SDR in a bigger way later.

It would be kinda cool to try a Perseus SDR or similar high end RX that could work even better than the FT-1000D when working very weak DX on 75/40M.  Though, I don't know how I could possibly hear any better into Eur, Steve... cough cough...  Wink

T
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Use an "AM Courtesy Filter" to limit transmit audio bandwidth  +-4.5 KHz, +-6.0 KHz or +-8.0 KHz when needed.  Easily done in DSP.

Wise Words : "I'm as old as I've ever been... and I'm as young as I'll ever be."

There's nothing like an old dog.
WA1GFZ
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« Reply #21 on: December 29, 2010, 12:02:14 PM »

Even the best synthesizer is a slop generator compared to a crystal oscillator.
Perseus, QSR1 and HPSDR direct sample receivers eliminate the neeed for a synthesizer.
ONTOH you take an R390A and hot rod it with better mixers and that would be a cool shootout with all those tracking filters. The R390A still had one of the cleanest local oscillators known to man.
Then take a direct sample RX and add a high performance tracking preselector ahead of it and try again.
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K1JJ
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« Reply #22 on: December 29, 2010, 12:16:00 PM »

Frank,

The thing is I rarely have problems with adjacent strong signals taking out my receiver from overload. It is usually caused by IMD SPLATTER on frequency - and no receiver, no matter how selective will eliminate on-channel crud.

In addition, the next biggest problem is atmospheric noise generated by propagated T-storms, rain static, power lines, etc. I understand no DSP system will help this problem either. (well, maybe power line pulse-type problems can be reduced)

So what's left is back to adjacent channel overload, and usually the f-b and high angle suppression of the antennas keep this problem at bay most of the time on 75/40M.

As for synthesizer noise, the band noise is MUCH louder and covers up any residual syn noise by at least 10db. esp on 160-40M. I just checked and even on 20M when I connect the antenna the noise comes up about 6db higher than the syn noise.  At night on 75/40M the band  noise can be 20db louder.

So my expectations would be low regarding an SDR being a BIG improvement over the FT-1000D in the real whirl of band action.  What do you think?  [caw mawn]

T
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Use an "AM Courtesy Filter" to limit transmit audio bandwidth  +-4.5 KHz, +-6.0 KHz or +-8.0 KHz when needed.  Easily done in DSP.

Wise Words : "I'm as old as I've ever been... and I'm as young as I'll ever be."

There's nothing like an old dog.
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« Reply #23 on: December 29, 2010, 12:23:33 PM »

IMD splatter sounds worse when you have close in synthesizer phase noise
Then you have those nice vertical filter skirts that don't ring

I'm being as anal as "you can work DX with a low dipole"
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KF1Z
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Are FETs supposed to glow like that?


« Reply #24 on: December 29, 2010, 01:28:46 PM »


So my expectations would be low regarding an SDR being a BIG improvement over the FT-1000D in the real whirl of band action.  What do you think?  [caw mawn]

T

you should join some SDR groups, and read about it..

Lot's of people disagree with that statement.

I don't own an ft-1000d, so I can't comment.

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