The AM Forum

Over the last few weeks I have been building and playing around with a Soft Rock Lite version 6.2.

The objective was to have the best of both worlds. A great boat anchor radio that performed like the best of todays radios being produced at less than the thousands one must spend to get the signals off the airwaves. So I purchased a Softrock 6.2 lite for the 455 IF of the r390a.

I had some reservations because I have never worked with surface mount components (SMT). There are 4 chips and a dozen .1 caps that are SMT. The rest of the components are standard stuff and there are two toroids that need to be wound up.

I must admit that with a good magnifying lamp and a good grounded soldering iron the assembly was very easy.

 There are few tricks that Bill KA8WTK gave me that made the smt part of the project easy and in less than 1 hour I had mounted all the smt components. The rest of the components were placed and soldered in place and I had a populated circuit board in less than 2 hours.

All that was left was two coil I needed to wind and frankly that took more time than the rest of the project only because I wanted the coils to be perfect and  I took my time. I will say after winding the first one which took about 40 minutes the second one was done in about half the time.

I downloaded the Flex SDR software which has a selection for the Softrock and fired up the circuit and  bingo we had a working device.

I now have a very nice R390a that has all the capabilities of todays radios and it cost me $12.00. I now have Synchronous AM, LSB, USB, DRM , Digital L and Digital U.  All coming from a radio that didn't even know this stuff existed when it was built. Good stuff.

I spoke with Tony Parks (Softrock) and he can make a Softrock lite for any IF. I know a few people that have ordered a few for various radios and if's they have.

So if you want to play around with the SDR stuff this is a cheap and easy way to do it while enhancing your boat anchors performance and capabilities.

The attached image is a shot of the SDR software using the new Softrock lite . I am listening to Nick KG2IR as you can see on the pan adapter.

If you decide to do this or need any help send me an email and I will try to help you on this cool little project.

G

Gary thanks for the user/builder report.

When I first heard people talking about this unit, it struck me the same way as the magic of external synchronous detector boxes like the Sherwood, below.

My friend dating back to high school, Chuck Rippel, WA4HHG, showed me the extraordinary performance the Sherwood brought to his R390A. Chuck,  many here will know, is the unchallenged leader in the repair and restoration of the R390A, so his testimonial carried great weight.

But, while quite innovative when I saw it a dozen years ago, the Sherwood offered primarily just that one function, synch detection, and then at about $400^a the benefit was not that powerful for me.

This latest external unit, if only I had the time to build one, sure sounds like a winner.

---

^aManufacturer's price now $569.

(http://www.sherweng.com/images/se301-2003.gif)

http://www.sherweng.com/interfac.html (http://www.sherweng.com/interfac.html)

Gary,

You have us at an advantage...

No idea what the hardware is that you're talkin' about!
The kit?
The software?
How about a link to it?
Google has not been terribly helpful so far...

Sounds exciting.

                 _-_-bear

http://www.amqrp.org/kits/softrock40/

http://groups.yahoo.com/group/softrock40


or google   softrock40

http://ewjt.com/kd5tfd/sdr1k-notebook/sr40/v6-pics/index.html (http://ewjt.com/kd5tfd/sdr1k-notebook/sr40/v6-pics/index.html)

http://www.elektor.com/magazines/2007/may/software-defined-radio.91527.lynkx?gclid=CIHeqYSIyZECFQGzGgodJ3Zj3A
 (http://www.elektor.com/magazines/2007/may/software-defined-radio.91527.lynkx?gclid=CIHeqYSIyZECFQGzGgodJ3Zj3A)

http://www.cliftonlaboratories.com/softrock_lite_6_2.htm (http://www.cliftonlaboratories.com/softrock_lite_6_2.htm)

Sorry Bear

The links Bruce and Paul  posted were for the TX/RX . The kits are single band boards.

The Lite is a single board receiver only

When using the lite from an IF you get all bands /any frequency you can tune from the receiver front end!! One Boards all bands  - - - -- $12.00  Nice

 All you need to do is email Tony and let him know the IF you need to us. Paypal 12 and in three days build it.

The photos below are the Softrock Lite.

Here is a link that may help.

G
http://groups.yahoo.com/group/softrock40/message/7846 (http://groups.yahoo.com/group/softrock40/message/7846)

Hi Gary,

Did you order it from this site?  

http://amqrp.org/kits/softrock40/version5.html 

This is for the latest version of the receiver.

I'm looking for a source for the RXTXv6.1 SoftRock QRP transceiver.

73,
Ellen - AF9J

Ellen I have the 6.2 version which is the latest SoftRock Lite version . Just email Tony and he will give you the ordering info. I did not order from that site.

==raparks@ctcisp.com==    (remove = signs)

Here's a link to the most recent ordering information, with product info for all models.

http://groups.yahoo.com/group/softrock40/message/17011

- JT

The "main site" for the softrock kits is the yahoo groups....


http://groups.yahoo.com/group/softrock40

BUT, it can be difficult to sort out what is what....

The best place I found for current info is:

http://www.softrockradio.org/node/1



Purchasing Information

The SoftRocks kits may now be ordered via PayPal to raparks @ ctcisp.com (remove spaces around the "@").

Or by mailing a check or money order to:

Tony Parks
1344 E 750
N Springport, IN 47386





I've built about a dozen of these kits so far... most of them the "IF" kits...
And several  transciever kits.....

A lot of people want them... but don't want to try to solder them together themselves!

They are a FINE entry level SDR kit..... and fun, once you get your mind around how, and WHY they work!

KF1Z or Gary

What would be a good way to get coverage on the Lite units up to the AM portion of the bands if one doesn't already have an IF source.  Out of the box, the 80M versions are down around 3.504 to 3.552 MHz.
 
- JT

You are right Bruce, perfect entry level stuff for SMT.

I can say that after I soldered my first cap in place I knew that I could do it and it wasn't all that hard.

Again for the price and the performance it really is a no brainer

G

JT ,


You have a radio and it has IF's. You could just find a pick off point run a wire out of the radio and hookup. You would just need to determine the IF frequency.

JT,

I used a NorCal DDS  to replace the oscillator that comes on the unit...
(On my RX/TX)

That gave me full coverage of 75/80 meters....

You can do the same with crystals..... but you are limited to 24 and 48khz depending on your soundcard....

Also, a little tweak of the input xformer could be done to improve things at the 3.885 area...
But not necessary .


If you get one, email or PM me and I'll give you more details.

Right for the kit we're talking about.....

But JT doesn't HAVE a receiver yet!

Yes good point Bruce.

I can see this getting confusing.

I just want to be clear to all that I built the Lite which is a receiver only(single band stand alone) but by using the IF they will go anywhere your receiver goes.


If I can help anyone please PM or email me

Ok,

let me try to understand this thing... probably this ought to be in the Technical Section...


the receiver is usually a direct conversion receiver. A xtal or some other rather high freq synthesizer source determines the receive frequency. In your case Gary, you've got the receive frequency set for "455kc".

Do I have this right?

Now, my question is don't you have to take the 455kc right after the mixer, and before the IF cans, if you want to have the spectrum analyzer feature work in a useful fashion? Otherwise, I'd think that taking the output after all or most of the IF cans & filters would yield the highest performance if you want the thing to listen through?? Once you run through the IF, you've got the selectivity of the IF section and that will be shown on the spectrum display.

Do I have any of this correct?

And, the other question is just how much computer does this thing take to run, and what OS's?? Seems to me that if you have to buy a $300+ computer to run it, it starts to look less attractive cash-wise?

Oh on the site: http://www.cliftonlaboratories.com/softrock_lite_6_2.htm
he talks about problems with the 0.1ufd blocking cap on the audio output. Scratching my head as to why he doesn't make the cap larger, or strap a an opamp follower on the ouput and get rid of the problem and all that transformer testing...??  ::)


          _-_-bear

Yeah, sorry for the confusion Gary.
 
Bruce, yeah.. please PM me any additional details.  This may be a good way for me to get a RX on the air while I save for a really nice AM receiver instead of settling for something mediocre at best for now.
 
- JT

That is correct Bear. You can buy as an direct conversion receiver but your limited unless you get the DDS Bruce mentioned or you can have Tony design you a IF model for whatever IF you may have and then be multi band.

In my situation I  had an 455 IF off the back of the r390a so I just wrote to Tony and asked for a 455 IFmodel. He just has a different tuned  circuit for whatever IF you may need.  Mine is 455 so you can see the 455 in the frequency box on the software. I just turn the dial on the R390 and the rest is done through DSP in the software.

As far as the .1 blocking cap ? I have no clue . This little board I have worked perfectly and I have no problems with the audio -- it sounds great.

In reality I am sure all the "experts " could punch holes in this little board but for the cost and the improved performance I could care less. It is just a fun little project .

I just loaded the SDR software on my existing computer Bear. It works fine and there are several different software programs for this board so i am sure you could find one that will work with your existing computer. Bill KA8WTK is really a better expert on this stuff and I am sure he will chime in hear when he gets back form the hamfest he went to this morning.

For me I just bought, built, and used this great little board. I leaned how to solder SMT and wind toroids.  Good schtuff sonny!!

I don't see a thing wrong with this...Adapt improvise and make do...Sounds like Amateur Radio to me...Good Job... :)

Bear...

Yup....  direct conversion RX with the osc freq running at 4X the receive freq, through a quadrature detector...


You need to determine where to pick of the IF for best performance...
Sometimes mods to the receiver are needed....


You don't need a super-computer to run it...
And just about ANY stock soundcard is sufficient.


As for the site you mentioned....
Looks to me like a case of someone taking what is meant to be a simple, ENTRYLEVEL kit......
And OVERANALYZING  the bejeezus out of it.


As Tony stated.... it is NOT going to give you the performance of a commercially built SDR, like the Flexradio.
It is meant to give you a little taste of software defined radio, with a useable, homebuilt kit.

Gary - W2INR & Bruce KF1Z,

Thanks for the order info on the RxTX V6.2. :)

73,
Ellen - AF9J

What Bruce said -- -

All I can add is that it works great and the SAM is worth the adventure.  Wth e filter and DSP I can hear stations I can't hear on the r390a alone!

Hmm, a simple DC receiver for 75M shouldn't be too hard to build for use with the Softrock Lite.

- JT

Although changing the crystals to 15.36 MHz crystals should, when divided by 4, give a center frequency of about 3.84 MHz. 

- JT

The softrock lite IS a DC RX!

Just order the 80 meter version, and change the crystal to where you want to receive.

Yeah, call me stupid (as usual lately).  I don't know what I was trying to say there.
 
Ordering a couple softrocks today.

- JT

You can use x4, or x8... there is a jumper on the board to use either....

Remember, the exact center frequency is unusable ... you want to shoot for about 5kc or so higher, or lower....

If you have a soundcard that samples at 96khz,  you have an available tuning range of just under 48khz.... if a 48khz soundcard... only 24khz of tuning range...

So if you're shooting for the 'ghetto',  you want a center freq of say...3.870.

Good point about the center frequency not being usable.  I have some 30 MHz crystals which would give me a center of around 3.875.  On the 40M kit, I assume I'd want a center frequency to be around 7.265 - 7.270?

Thanks

- JT

Something like that.......

A 30mhz xtal would give you 3.750 though
A 31mhz would give a center freq of 3.875

You could just order the RX/TX kit for 40 and 80...
Even if you don't plan to use the TX section.... you'd have 2 bands in one board...

Though I thinks it's actually cheaper to build the separate receivers...

Yeah, the 40/80 RX/TX kit is only $30.  I was thinking of getting a 40/30 RX/TX in addition to the 80 RX but maybe I'll just get an 80/40 RX/TX to play with for now.

- JT

Ok, well I am a bit slow on the uptake here.

In the case of using it for ONLY a 455kc or in my case 500kc IF - you'd want a crystal that is 4x that freq, or for the 500kc.; that would be a 2khz xtal??

But what is this about it not working on the center freq??

Guess this is my main interest, using it  coming off the IF of my BC-388.
Am I correct, it does do "sync" detection and USB/LSB then??

Now, what is the purpose of the soundcard in all of this??

That's unclear to me so far (would be nice if there was a concise rundown on it)?

            _-_-bear

WOW, now that SDR is cool you guys will find out the softrock has all the receiver performance of the SDR1k.
Gary your signal into the softrock board is pretty high, it will limit your dynamic range. Every receiver IF level is different so Tony has no way of knowing how to set up the board. He sets it up for use as a receiver hanging off an antenna. Your noise floor should sit around -120 dBM to get the full dynamic range of the board.
Your floor is 40 dB above that so you are losing that much dynamic range. There are a couple ways to set this properly. 1. Reduce the op amp gain. 2. reduce the signal level into the board. 3. Set your sound card inputs lower. I'm not sure if the 390 has enough dynamic range to just reduce the RF gain but that would be the easiest way. The Flex software has a very accurate S meter so if you can run in manual gain mode and calibrate the s meter you will have quite a nice tool. This will also serve as a great spectrum monitor with the very clean R390 LO.
I built a fixed gain front end with Racal RA6830 and RA6840 DF modules into the QSD. Then I calibrated the system to track the output of a HP8640B within 1 dB.  
You know when you are in overload when all of a sudden you have a spurs across the spectrum.
I2PHD software is also very cool. Alberto has a cool phase meter for sync detect AM that shows phase modulation and slow drift very well.
Stepping into 2008 HPSDR (TAPR) is now taking orders on the exciter module. 1/2 watt output with third order crud down over 50 dB.

Thanks Frank ,

I am in the beginning of the learning curve with this stuff. All of my help came from Bill KA8WTK with the SR and Jay N3WWL with the SDR software to get me started.

I installed a 5:1 pad and it knocked down the IF input signal to about -120dbm noise floor going into the SR board.

Bear,
It might be easier to get all the info you're looking for on the sites listed above.

There's a few reasons that the center frequency is unuseable....too many to discuss here...

In most cases, it isn't even a problem, and can be eliminated ....


The soundcard is used to get the I/Q signals into the computer for processing... and, obviously a way for the audio to get out to speakers....

For the xtal... yes... choose a crystal that is either 4x or 8x your IF... plus or minus about 10kc... to avoid any possibly "center frequency problems"
(shoot for 490khz center).

Tony supplies a 3.56mhz rock with his 455khz IF kits

Well, I've looked at the sites... I'd rather not spend the time to read through the blogs and all the posts to get at the essence of the set up to decide if it is something that I'm interested in spending any time working with...

Guess I'll try the yahoo site and hope they've put up some basic info off to the side...

               _-_-WobblyBear2GCR

Bear

I wish I understood this stuff better to help you out but I don't .

In fact all I did was order one, build it, plug the audio cable into my sound card . plug the IF from the r390a into the SR and apply 9 volts power. Then I downloaded the SDR software, set it up and bang it worked. That is all I know. I have no clue as to how it works and I could care less.

Buy it, Build it, play with it, and then you will know, its only $12.00 bucks Bear.

Heh, gotta love INR's style..

- JT

Yeah, no matter what your IQ is!  :o
 
- JT

VGB: Or just learn how to setup filtering in your existing email client.  I use one email client for all my emailing and probably receive close to 500 emails/day.  When, for example, an email comes in from the AM Reflector it automatically gets moved from the inbox and into its own folder.  I then scan the subject headings and read those I want to read.  When I am done reading, I click all off them and say "mark as read".  I can then archive all emails this way if I ever need to go back and look something up.  I may get 500 or more emails a day but it is actually very quick and easy to read and manage.
 
- JT

KF1Z - YahooGroups is the same thing as an email reflector.. it just allows you the choice of reading it online or having it sent by email.  I prefer email lists myself.
 
- JT

Yup, to each his own exactly.  Email is second nature to me as I've had to administer large email systems, and reflectors, in the past as a career and I've also been subscribing to reflectors long before there was the ability to read them via a web browser.  But I guess we are now really getting off-topic.
 
- JT

The BEAR has come out of the woods and just posted to the softrock40 group. :D 


(Yes, I am easily amused tonight)

- JT

Hey

Hijack someone else's thread.

Thank you

G

Not many Mack, just those that people allow to go off topic.

I just felt talking about yahoo groups was far from the original topic.

G

The reality of softrock is the performance is very good. It has a crystal oscillator as a source which is cleaner than any synthesizer or DDS source. I have done a number of tests on the stand alone QSD. It's performance is better than anything in my shack. It is a cleaner spectrum analyzer than my hP141. The only problem is that it is only a small part of the spectrum.
I got real interested in SDR just after Tony sold his last softrock  4. a friend who bought a Racal from me in Ca. offered to do the drafting and artwork if I designed a QSD.  I did a converter very similar to the SDr1K RX and the oscillator divider similar to softrock. We made it a plug in module for the RA6830. It cost us over $200 and plenty of labor to duplicate 2 softrock 6s.
The performance limit of this stuff is overload. Any signal that gets into the QSD  is processed. If the level saturates the sound card you are all done. This is why hanging off the IF of a good RX with limited bandwidth is the best of both worlds until the dynamic range of A/Ds gets better.
The third generation stuff is just hitting the ham market. The QSD and local oscillator is completely eliminated by sampling the spectrum with a very fast A/D. Again the wide bandwidth of the system makes it susceptable to overload but great hanging off a good RX IF.
Steve HUZ  posted a link to a great SDR article a few weeks ago. This is great reading. A bit dated with older parts but source of understanding. I suggest reading it cover to cover about 10 times.
Pete WA1SOV got me interested in this stuff almost 8 years ago before the days of doing this with a computer sound card...Later some creative software guy figured out how to make the stereo input handle I/Q decode.
Gary, Now that you have your level right how about a picture of a real strong crystal oscillator. I would like to see the effects of the very clean LO in the R390.
I bet the performance could be impressive if the 390 has enough dynamic range.

I just finished  building a SoftRock 80/40 transceiver which does not work and  browsed this thread missing the whole point of it.  A QSO this evening with KAQ set off the light bulb in my brain.  My only reason for building this thing was to get a panaramic spectrum analyzer to study incoming signals.  I couldn't care less about transmitting.

I sent mine off to a friend who built one that works to see if he can fix it but now it is obvious that it's the wrong tool for the job.  Being xtal controlled, it's use is really limited to a learning experience.

The idea of setting it up to the IF freq of a receiver for complete coverage really gets me excited.

Is there any reason why this would not work on my S40B?  Or the S38 for that matter?

Where would be the best place to pick up the signal on the S40B?

For the record, the problem with the one I built is excessive current drain on the 5V side of the regulator.  My thinking is one of the IC's  is bad but I lost interest when it came to proving this.

js

HAY, GEE...

NOW YOU GOTSA REEL RESEEVA, THAT MEEN YOO AINTS GUNNA CALL MI QWARTER KILAWHAT PISWEEEK?

UH.... OVA!

BIFF

Jack.

No you didn't miss the point and I started this thread yesterday morning.

The answer to your question is yes. All you need to do is figure our what the IF frequency is where you want to pull off the receiver and then email Tony.

G

Did I here Thom in here?

Frank

I installed a 20db pad in the IF line and I have the noise floor knocked down  pretty good.

Below is a screen capture of the SR with the calibrator on in the R390a.

WOW...way cool...

The reason I missed the point was that I stopped reading when it didn't seem to relate to my needs.

I just ordered the IF version from Tony.

I am looking forward to this as I already brought out the IF node to feed to a scope but lost interest in just looking at the RF envelope.

This is really what I want to do.  As $12 Flex.

js

There seems to be somthing amiss with the suggestion to just buy the thing and plug it in - doesn't that reduce us to the dreaded appliance operator status?

Other than spending the time to read endless (and reasonably large) files on the Yahoo site, or having got started with the whole thing early on, is there no overview or FAQ for this board/kit??

Some kind soul from the Yahoo group sent me a block diagram... that's a start, but still doesn't tell me very much at all.

Ah well...

              _-_-bear

Just what is it you haven't found yet Bear?

What part of the system do you want to know about?

The unit itself is very simple.....

It contains an oscillator, mixer, quadrature sampling ic.... that's it...

The rundown is:
RF in... (from antenna, or IF stage)...mixes with the LO...(down to audio frequencies) and the quadrature sampling IC , the I/Q signals generated   (2 sigs, 90 degrees out of phase)  go into the soundcard which on the input is used as the A/D converter...

From there, it's all in the software, and I can't explain what exactly is happening there.......

Hope that helps a tad....

Bear,

You have to build it. Not appliance operation if that is your concern, other than that I can't figure out what your looking for. Magic Bullet? Holy Grail? Maybe you could just get one and figure it out for yourself!!

Get it -- build it and learn

Bear, I'm squarely with you on this one.  I looked at some of those frigging yahoo group messages and they all presuppose that you know all this stuff to begin with, and it's bogged down with all kinds of minutiae which isn't useful to an outside who just wants a quick overview.  All I wanted was a pic, a schematic, and soundcard requirements.

This link is by far the best, but it appears the item described is NOT the same thing that everyone is discussing here.
http://www.amqrp.org/kits/softrock40/

That's the problem with projects like this.... the people involved all kinda know what was happening from the git-go but it's very difficult for someone who's just diving in to *quickly* make heads or tails of what the hell is going on. 

This isn't difficult stuff... it's just a LO, a quadrature divider, and a I/Q detector with a bit of amplification and filtering.  I see it connects to the audio input of the sound card; it was my impression from the first that it used the USB bus somehow (it does, but ONLY for power).

Reminds my of my college nuclear physics instructor, who, when skipping over some intermediate process too complex to describe, would say "...and a magic wand is waved, and we have..."  ;D

""..
Reminds my of my college nuclear physics instructor, who, when skipping over some intermediate process too complex to describe, would say "...and a magic wand is waved, and we have..."  "



Exacly as explained here.....

http://www.greenmountainradio.com/files/science.jpg (http://www.greenmountainradio.com/files/science.jpg)

Gary,
What is your crystal frequency. I run a color burst crystal that allows me to do a 15 KHz bandwidth. Your carrier looks to be only about 5 KHz away which will limit your bandwidth.
The height of the carrier tells me the audio level into the sound card is kind of high so it might be better to set the level controls lower and change the input attenuator to less attenuation. My carrier comes up about 30 dB out of the noise floor. Yours is almost saturating the sound card. You may have to reduce the op amp gain of the softrock card by changing 2 resistor values. I think Tony runs gain of 50 if I remember. I find in IF monitor applications gain of 10 is plenty.
Also, I wonder if you could get a stronger signal into the radio. It has to be a crystal oscillator though. I would like to see the phase noise performance of the 390 when the signal gets up to the point of just about saturating the sound card. I would like to see the strongest signal you can pump through without raising the noise floor. Maybe you could get the reference out of another radio or piece of test equipment. I think the 390 could serve as a bench mark for low phase noise and it would be a cool hunk of information for me.
After a while you will be able to tell the clean signals from the dirty ones by the width of the Christmas tree.
TNX gfz

Great segue to another topic.... is the guy who buys a restored or working Valliant any more buzzardly than the guy who buys a rice box?  I don't think so.

>Other than spending the time to read endless (and reasonably large) files on the Yahoo site, or having got started with the whole thing early on, is there no overview or FAQ for this board/kit??

I think the answer is yes but no one knows where to find it. 

>Some kind soul from the Yahoo group sent me a block diagram... that's a start, but still doesn't tell me very much at all.

I have schematics but they don't help much either.

My credentials consist of having built one of the transeivers which doesn't work but I will still suggest that you send Tony $12 and have a go at it.  I just did and presume it will be like falling off a log compared to the tranceiver.

I have no idea how he can even break even at the prices he charges nor where he finds time to answer all the questions but if you have a Paypal account, your project will be in the mail tomorrow.

Tony Parks.....  raparks@ctcisp.com

In case it's not obvious by this time, you don't just plug it, you have to convert a bag full of parts and a circuit board into a useful device.  Tips on doing this are included in the info you can download.  Just don't ask me where I downloaded them from but I think there are links in the kit.

Have at it!

js

Frank

The crystal supplied is 1.843 and I use the / x 4  jumper producing a 0.46000 center frequency.

Which resistors and what values to reduce the gain? Better yet could a pot be added to replace one of the resistors to have a variable gain control?

G

Gary,
The two feedback resistors go between the negative input and output of each op amp. I think they are R10 and R11 and presently 4.99K. These values need to be very close to each other or image rejection will suffer. Try hanging 1 K in parallel with each one. You can tack them in on the back of the board. The long leads of a pot would blow the noise floor. Then you will have to adjust the attenuator so more signal in coming into the module. If you are using a 2 resistor divider make sure the one going to ground is around 50 ohms. I noticed the carrier only 5 KHz away. This will limit your usable bandwidth to about 9.75 KHz.

For those trying to grasp the concept....
This explanation is more eloquent (and correct) than my feeble attempt...

http://www.greenmountainradio.com/SOFTROCK.pdf (http://www.greenmountainradio.com/SOFTROCK.pdf)

Frank I do not have 4.99k resistors in this circuit.

The schematic is below.

G

The resistors in this schematic are R11 and R13. They are now 1 k. Looks like Tony reduced the gain from SR6 the units I bought. You could reduce the gain by putting another 1 K in parallel with each R11 and R13 but first I would reduce the levels going into the sound card on the computer mixer panel to reduce the LO carrier level.
Then bring the RF level back up. I look at the noise floor with nothing connected to the input. Then I connect the radio and adjust things to raise the noise floor about 10 dB. My HPSDR module will do better than -140 dbM noise floor but my crappy RS audio cables pick up hum so run everything a bit higher and set the HPSDR input level higher with internal jumpers.
Any imbalance in the input transformer will jack the carrier up. fc

BTW, I just checked my notes. My setup goes into spur mode when the signal gets above -17 dBM. I think your LO is close to that level.

Startin to get some focus now...

Well, no one has addressed my question about where to pull off the IF freq in the reciever? Before the IF cans/filters (after the mixa) or somewhere down the line...

...or does this thing have "magic" selectivity using some magic of DSP??

(inquiring mindz want to know)

Seems to me I need two of these thingies for what I am thinkin of?
One for SSB & sync detector. The other for spectrum analyzer.

Btw for those not following the libretto, it seems you really do need a 96kHz soundcard in order to get 96kHz of band into the spectrum display! (thanks for the link Bruce).

              _-_-bear

Bear

I am running mine at 48000 and it works great which is plenty for an IF version. You would want 96 if you were using it as an stand alone receiver and tuning it. Remember you use the radio to tune and the software for the DSP in the IF version.

You would want to tap the IF after the filters to reduce the possibility of overload to the QSD. It will process EVERYTHING that gets to it so using the filters in the widest position will limit what is going into the SR to only the widest filter position.

I have one unit and it works as my detector,SSB and pan adapter all at the same time.

Bear,

I'm not totally sure about the best place to pick off your IF....

BUT... I do think the "magic" is there in the DSP.....
I believe the real worry there, is to pick off at a point where you won't load down that stage in your RX....

Frank should chime in here......

..............
space left for Frank
..............



No, I don't think you need 2 units?
Unless they are to go to different RX's ?  
Not real sure what you getting at there....

If only one RX ...
Then you have your spectrum display, and your RX demodulation capability all in one...

And if you use software like WinRad (cool..) or Power SDR (flexradio)
They both have SSB, AM, SyncAM, CW, FM, and a couple others...  oh yes, I think one of them does DRM as well.....

Plate of the last IF toob, via a 10 pf or so capacitor would do it Bear.  Re-peak the last IF xformer and yer good to go.  Same drill for a solid state receiver.  You want as much filtering and AGC action BEFORE the IF tapoff.

Or, in the case of your 51J-4 or R-388, there's already a convenient IF output jack that's isolated via a cathode follower.

I have tried a number of configurations interfacing to the IF. Presently I right after the second mixer post amplifier. I am using some high performance hardware though. I'm hitting almost 110 db of dynamic range wideband. The set up has the typical Racal  2 6 pole crystal roofing filters in the first IF. I used a pair of 20 kHz filters and the response falls off quickly outside 20 kHz. This set up has the lowest possible gain ahead of the QSD.
As Gary said interfacing after the filters allows more selective positions. I guess it is up to the user. The tighter the bandwidth ahead of the qsd the lower the noise and also the reduced chance of overload. The downside is smaller width of the spectrum display. I also sample at 48 kHz but my lo is further away from Garys allowing up to 15.5 KHz bandwidth. I used a color burst crystal giving me low side conversion with the lo 7.625 kHz. away from 455.
My friend who did our artwork and made the boards interfaced his QSD after the IF filter and left it that way. The R390 has a 16 kHz position so there is plenty to look  at. BTW it is fun to watch the display when the slop buckets park themselves next to us.
Just remember the QSD wants to have a 50 ohm source so a resistive divider of a source follower is required if you are hanging off a high Z interface.
Don't be afraid of using a low end computer sound card it will still work. I'm running a 1 gHz Dell with 500 meg of ram. I'm running about 65% horse power sucking in USB data off the hPSDR. It does not work well sampling at 96 Ksamples and locks up at 192.
I hear the Italians think the world is round.....

John,
Any AGC ahead of the QSD screws up the s meter that is why I'm using Racal DF
hardware with no AGC, But it is very wide dynamic range. Close in I am only limited by synthesizer phase noise and find 110 dB of dynamic range is plenty enough at this QTH.  I have a number of pre/post selector options if it becomes a problem.
A way around the AGC problem is to run manual gain so the S meter will give accurate relative results. It is very accurate. 

I just ordered an 80M  SoftRock Lite.  Tony is also throwing in a 30 MHz crystal so I can try and play with it around 75M.  A 30.96 crystal would be much better for full "ghetto" coverage but beggars can't be choosers.

- JT

Would the IF version help to improve the performance and usability of a cheap BA receiver such as an HQ-100 or -110?

- JT

yes JT

A friend sent me this link which is a gold mine....

http://www.cliftonlaboratories.com/softrock_lite_6_2.htm#Introduction

js

That is a great article Jack. My home brew QSD will do 25 volts output with 2.5 volts going in but no sound card including HPSDR can handle that kind of dynamic range. Even the SR6 pushes the limit of a sound card signal handling. The 5 volt supply on the op amps is more than enough to make the sound card the limit of performance. 600 ohm isolation transformers is a great idea I have not tried yet. I can't open up the HPSDR because of hum. The best 600 ohm transformer I have ever seen is a MIL-T-27 made by Pico rated for 5 watts. I used one in a design once at 1 volt and the frequency response was impressive.
Bear you only need one SR6 to do both functions unless you want one broadband input and the other tight. You could just switch the input.

It is interesting to listen to normal RX audio compared to sound card output. It takes a while to get used to the processing delay. I have not seen a case when Flex software outperformed the RA6830 under poor conditions BUT I have seen Alberto's software outperform the Racal under high noise conditions.
The HPSDR guys are talking about PDM and EER SSB with the new module coming in May. This is to drive a class e final.

OK Frank

Here's the latest.

I installed a pad on the IF input. I am using a 1k pot across the IF feed and the wiper feeds the SR input. This allows me about a 50db adjustment to dial in the input voltage.

I set the noise floor by unhooking the ant and setting the noise floor at -140dbm. Then I hooked up the ant. You are looking at the crystal calibrator in the R390a.

This could be a great tool for anyone using an BA to use the SR to set the level going into the SR since all radios will have different IF levels. Thanks to Bill KA8WTK and Buddly WD8BIL for their help with this.

Thoughts?

Looks good Gary. I think you can raise the RF input a bit. Now it would be cool if you could look at a crystal oscillator about 20 to 30 dB stronger so I could see the
oscillator sidebands. Looks like it is about 400 hz wide at 70 dB down. I would like to see the width at 100 dB down so it will take a stronger signal. It needs to be a crystal oscillator that is clean like a reference out of a radio of piece of test equipment. I would like to bounce it off the data I collected on my set up. I'll be glad to compare data but the 390 should be cleaner. I would put the variable resistor in series with a 47 or 51 ohm resistor to ground and feed the SR across the 50 ohms. The SR needs to see a good input Z for best performance.. 

Frank GFZ

Think this might be the pix you were looking for...


The above was taken using one of my receiver crystal test oscillators into the R390A. Receiver was operated in MGC mode, i-f output through a step attenuator to the SoftRock and into an M Delta 44 sound card. 

In going through my receiver data apparently I've never measured R-390A phase noise (hard to believe!) so decided to do so while it was set up. The following was measured using crystal oscillators, a pair of HP8640Bs, step attenuators and true RMS voltmeter in standard receiver testing fashion.   

MDS (.1 kHz BW): -141 dBm

Blocking dynamic range (20 kHz): 115 dB

IMD dynamic range (20 kHz): 82 dB

Phase noise - receiver bandwidth 1 kHz

Freq.		dbc/Hz
1 kHz		-100*
2 kHz		-115*
5 kHz		-134
10 kHz		-138
20 kHz		-146
30 kHz		-152
50 kHz		-152
100 kHz		-152

* phase noise measurement compromised due to beat note - poor opposite sideband rejection with 1 kHz filter - performance would be much better than shown if not for the beat note. Makes me want to try a good 500 Hz wide mechanical filter in place of the relatively useless 2 kHz.

Also made interesting measurements of R-390A i-f output linearity for various MGC settings as well as SoftRock and Delta 44 overload levels in order to optimize the R390A / SoftRock setup. Will see if I can get it together in a usable form and post here or in a new thread...if there's any interest...

Jay

TNX Jay I'll study this, but man that 390 is clean. I'll add it to my EXCEL record of RX phase noise. Jay can you give me 200 Hz and 500 Hz.
Did you do 20 dB correction for 100 Hz. BW?

Jay, How about doing your RF 590 while you are at it. I looked at my EXCEL and the 390 blows away the best synthesizer. Maybe I should have kept my 390 and done a hot rod job on the dynamic range and add 20 more dB.

we can now compare this the HPSDR and QSR1

The phase noise measurements were made in the 1 kHz BW position - therefore a 30 dB correction was used.

No point in trying to measure the phase noise at 200 and 500 Hz offset because of the large opposite sideband tone leaking through the 0.1 and 1 kHz filters. The measurements at 1 and 2 kHz were also compromised as noted. Without a better i-f filter the measurement isn't possible... unless one were to notch the tone.

Sent measurements on the RF-590 about 6 months ago  - here they are in case they've been misplaced. 

MDS (.3 kHz BW): -130 dBm

Blocking dynamic range (20 kHz): 104 dB

IMD dynamic range (20 kHz): 82 dB

Phase noise - receiver bandwidth .3 kHz

Freq.		dbc/Hz
0.5 kHz		-69*
1 kHz		-94
2 kHz		-93
3 kHz		-93
5 kHz		-93
10 kHz		-98
20 kHz		-108
30 kHz		-130
50 kHz		-137
100 kHz		-150

* phase noise measurement compromised due to coherent tone from synthesizer

Please send a copy of your phase noise spreadsheet - had one but can't find it. The clean display you see for the R-390A is after a some attention to reducing ground loops, hum and other sources of noise in the SoftRock setup. Agree the R-390A would be the hot ticket with another 20 dB IMD dynamic range. Data on the i-f linearity to follow...

Jay,
I'll add both and send it again.

Well hands down the R390A wins cleanest LO but suffers in the dynamic range dept. It will be interesting to see how the latest SDR configurations compare.
That is the real reason I wanted to see the R390A phase noise. Even looking at Jays spectrum display you don't see the blob of phase noise between 1 and 10 KHz dBC.
now Jay hang your soft rock off the 590 and you will see the difference. As you see from my EXCEL the 590 is one of the cleaner sources. I bet your R599 is also pretty clean.   

Makes you wonder what a 390 with a 7360 front end would do?

I think the 7360 in place of the 6C4 mixers would be quite the RX.

First a typo correction...the IMD dynamic range on the RF-590 is 88 dB not 82 dB.

Here's a shot of the RF-590 into the SoftRock. The elevated 'noise floor' is the phase noise. With step attenuators between the crystal oscillator and receiver and between the RF 590 and SoftRock it's easy to verify that everything is operating linearly. With an input signal above about -40 dBm (S9+33) the phase noise rises out of the receiver noise floor...   


Roger the 7360s! Recall the article by W2QWS? ... he used 7360s in the 75A4 1st and 2nd mixers. Don't think there were any hard numbers on improvement though. Guess it's time to pick up a spare 390A rf deck and have at it.

Got the latest QEX yesterday. Step aside Clapton ... 'Drentea is God'... ;)

   

thanks Jay,
I need to study this some more. I still think your dynamic range should be higher at 20 KHz unless the roofing filters are very wide.
I would think it should be well into the 90s. my hotrod Racal is around 100 dB and a stock one is around 95 dB. I like the 590 first IF better than the stock 6830.
Yes, Drentea's radio is something else. The only thing that caught my eye was the attenuator ahead of the LO input to the SD5000.
Maybe it is an error but why a 15 dB pad??? I have a jar of these amps ant considered using them at one point but stuck with MMICs and 2n5109s. That FET Norton amp is very cool. I have a copy of his book around the house somewhere. Notice his references to Hendrix
(Rohde) Imagine the man hours he put into that work of art?

Now here is a question. Notice the measured numbers match the display for the R390 but they do not match the numbers for the 590.
I don't know why but I think it has something to do with the BW correction and the way the FFT works. some smart guy wanna set me straight here.

Here's some info on R-390A i-f linearity and PowerSDR S meter/display calibration using manual gain control MGC mode.

The SoftRock will output 4 volts p-p before the onset of clipping...so make sure the Softrock's output will not overpower your sound card. I'm using a Delta 44 card and it will accept up to 10 volts p-p before bad things happen - other sound cards are likely different. The 455 kHz level into a stock Softrock (1000 ohm op amp feedback resistors) that's just shy of pushing the output into clipping is -6 dBm. Under all circumstances one will want to keep the level into the SoftRock below this level.

With that in mind here is what the i-f output of my R-390A looks like with different signal generator levels. Other receivers will likely be somewhat different. S meter readings are shown just to give some meaning to the -dBm numbers. The i-f output levels are shown for the receiver in AGC mode with the rf gain control at the full up 10 position. Also shown are the i-f output levels in manual gain control MGC at several different setting of the rf gain control 7, 8 , 8-1/2, 9 and 10.

Generator

AGC 10

MGC 7

MGC 8

MGC 8-1/2

MGC 9

MGC 10

-113 dBm

-43 dBm

-85 dBm

-71 dBm

-62 dBm

-37 dBm

-103 dBm

-38 dBm

-75 dBm

-61 dBm

-52 dBm

-27 dBm

-93 dBm

-35 dBm

-65 dBm

-51 dBm

-42 dBm

-18 dBm

-83 dBm

-31 dBm

-56 dBm

-41 dBm

-32 dBm

-8 dBm

S9

-73 dBm

-29 dBm

-45 dBm

-31 dBm

-22 dBm

+3 dBm

S9 +10

-63 dBm

-27 dBm

-34 dBm

-21 dBm

-11 dBm

+10 dBm*

S9 +20

-53 dBm

-26 dBm

-78 dBm

-24 dBm

-11 dBm

-1 dBm

+15 dBm*

S9 +30

-43 dBm

-26 dBm

-68 dBm

-14 dBm

-1 dBm

+8 dBm

S9 +40

-33 dBm

-25 dBm

-58 dBm

-4 dBm

+9 dBm

+12 dBm*

S9 +50

-23 dBm

-24 dBm

-48 dBm

+7 dBm

+12 dBm*

+16 dBm*

S9 +60

-13 dBm

-22 dBm

-32 dBm

+12 dBm*

+16 dBm*

S9 +70

-3 dBm

-22 dBm

-2 dBm

+16 dBm*

* = gain compression

In case the chart above isn't readable http://www.w1vd.com/R-390A IF output.PDF (http://www.w1vd.com/R-390A IF output.PDF)
   
In terms of dynamic range the MGC 10 setting is not a good choice because gain compression starts at only S9+10 dB. Similarly the MGC 7 is a poor setting due to the wild nonlinearity. I've been using MGC 8-1/2. Since the receiver will go into gain compression just north of +9 dBm i-f output, I use 15 dB of attenuation between the  R-390A and the Softrock. This reduces the i-f output level to -6 dBm... the maximum SoftRock input. The sound card input level and/or PowerSDR 'preamplifier' low, med or high position can be used to accurately calibrate the s meter and display.

What does one do with signals bigger than S9+40? This is a good application for a step attenuator ahead of the receiver...or one can go 'uncal' and reduce the MGC setting.  One note: MGC settings below 9 negatively impact the minimum discernible signal at around -130 dBm at the far other extreme.   

I guess I can afford $12 bucks. It would be something to check out. I'll print these many pages coz some replies refer to I.F. levels and audio levels for clean response and calibration of the card/software.
The synch detector is of interest to me for listening to music on Short Wave. I'm getting tired of switching between a vertical, a 600 foot long wire, and dipole to find the least distorted signal.
It's time to play a little.
Fred

I assembled an 8.83 IF kit for Ralph, W3GL.  This was my first attempt with SMT's, and small components.  It went together quite easily.  For those timid of surface mount technology, don't fret.  You need a good grounded soldering station, thin solder, a magnifying lamp, and a means of holding the 1 inch square board in place.  I used a toothpick to maneuver the parts in place after dropping a dab of solder on a pad.  The biggest hassle was winding the toroids.  It was a fun little project.  If I can do it, almost anyone can.

At the least $12 buys you one nice spectrum display.

I would suggest getting ahold of a small syringe of paste solder...

If you have more than one smt project in mind....

The stuff works like magic!

It is sticky enough to hold the part in place, and solders in a heart-beat with a 10-15 watt iron....


I soldered a 48 pin TQFP Ic last night... (<3/8" square)... and wow.. it was indeed painless!

Along with dozens of 0805 size caps/resistors.

A little dab of solder paste....drop the part on with tweezers... hold the top of the part with the tweezers.....touch the pad with the iron, for about 1 second...

Getting a little more practice with the SMDs ... it's becoming fun!


I have some very small wire solder (0.012")  if anyone needs enough for a kit, I'd be happy to send you a chunk....

I could offer some paste solder as well... because it is expensive, but I don't have any extra syringes to pack it into....

Here is a link to a small amount of paste solder....actually enough for quite a large kit....

http://www.zianet.com/erg/ShopSolderPaste.html

Attempted repair R-390A i-f output chart...

S meter

Generator

AGC 10

MGC 7

MGC 8

MGC 8-1/2

MGC 9

MGC 10

-113 dBm

-43 dBm

-85 dBm

-71 dBm

-62 dBm

-37 dBm

-103 dBm

-38 dBm

-75 dBm

-61 dBm

-52 dBm

-27 dBm

-93 dBm

-35 dBm

-65 dBm

-51 dBm

-42 dBm

-18 dBm

-83 dBm

-31 dBm

-56 dBm

-41 dBm

-32 dBm

-8 dBm

S9

-73 dBm

-29 dBm

-45 dBm

-31 dBm

-22 dBm

+3 dBm

S9 +10

-63 dBm

-27 dBm

-34 dBm

-21 dBm

-11 dBm

+10 dBm*

S9 +20

-53 dBm

-26 dBm

-78 dBm

-24 dBm

-11 dBm

-1 dBm

+15 dBm*

S9 +30

-43 dBm

-26 dBm

-68 dBm

-14 dBm

-1 dBm

+8 dBm

S9 +40

-33 dBm

-25 dBm

-58 dBm

-4 dBm

+9 dBm

+12 dBm*

S9 +50

-23 dBm

-24 dBm

-48 dBm

+7 dBm

+12 dBm*

+16 dBm*

S9 +60

-13 dBm

-22 dBm

-32 dBm

+12 dBm*

+16 dBm*

S9 +70

-3 dBm

-22 dBm

-2 dBm

+16 dBm*

* = gain compression

I kinda have to go with BEAR and W3JN, John, on the prolific amount of info and responses on the Yahoo about the Soft Rock stuff, but let's cut to the chase.
I noticed that the 40M receiver and Soft Rock Lite I.F.only uses the USB plug for power. How in the world does the info from the board concerning I.F. bandpass and spectral display, for either product, get into the computer through the sound card connection?? The software loaded into the computer has to talk to something to give you control over the RX board or I.F. board.
Am I coming from outer space with my question??
I'm ordering anyway.
Fred

DISREGARD my last O.F. post. I have seen the light........Amen brother!!! Can I get a witness.
It is a magical thing done through the I and Q output of the Soft rock board into the sound card and that info is fed to the software for an audio output to the outside world of human ears.
OK FINE

Fred

Key word there Mack...

CURRENT version...

6 is out 7 is in....


(By the way... if someone just wants the surface mount parts soldered on the boards, and do the through-hole stuff yourself....... PM or email me... )

I have a couple SR7s but not crazy about the design because it uses an RC to make the I/Q phase. He did that so it would work up to 10 meters. Flip Flops may not work at 120 MHz with the present oscillator design.
It won't be long until he has a new one. Actually SR6 was one of the longest runs.

Frank

I heard somewhere that you came up with another configuration for the input xfmer on the soft rock ( T1)?

G

Gary,
For 455 kHz I used a two hole type 73 core with three turns trifilar #30. I think it will have better balance that the low perm core with so many turns on it. I think Jay W1VD did the stock transformer. If we get some dynamic range numbers on the softrock at 455 KHz. We might be able to compare performance. My guess is it won't matter all that much at 455 KHz. but my design takes all of about two minutes to wind. I would use type 43 for use above a couple MHz. My fair-Rite book is at work so can post part numbers Monday.
I'm thinking Tony might come out with a board with a DDS on it. This would eliminate a ton of work on his part. I see a lot of posts on his site talking about different options.
I would love to see him take $50 worth of parts and sell the kit for $100 to get the same performance as a SDR1K. Then sell a few thousand of them. He is a good guy and it would be cool to see him do well. Imagine all the time and effort that goes into his kits to maks a couple bucks each. After that build a transmitter board. 

Is there some way to get the info on the SoftRock radio without joining the Yahoo newsgroup? I don't need another email address. I just want to skip to the chase and get the building instructions for the Lite I.F. board then download the software, which apparently can be anything for SDR.
Is the SoftRock product a take off from the FlexRadio folks? Like an affordable version of the $2700 FlexRadio? Minus many whistles and bells??
With the proper software loaded can I demodulate the usual modes plus synchronous detector and DRM???
Thanks
Fred

"Is there some way to get the info on the SoftRock radio without joining the Yahoo newsgroup? I don't need another email address. I just want to skip to the chase and get the building instructions for the Lite I.F. board then download the software, which apparently can be anything for SDR."

I'll send them to you.

"Is the SoftRock product a take off from the FlexRadio folks? Like an affordable version of the $2700 FlexRadio?"

Nope.

"With the proper software loaded can I demodulate the usual modes plus synchronous detector and DRM???"

Yes!

Bill KA8WTK

No.


The Softrock costs $12. It is nothing more than a converter - a quadrature converter - but just a converter. It takes some higher frequency RF and converts it to two (2) lower frequencies in quadrature-phase. These lower freqs can then be fed into your computer sound card. From there, you can use several different software packages to tune, demodulate, etc. The PowerSDR software is one of the software packages you can use. It is the SAME software used on the Flex software. With a SoftRock and the PowerSDR, you can do anything on receive (minus the tuning range limitation of the particular SoftRock you are use) you could do with a Flex Radio.




Almost none on receive. See above.

Thank You
Steve and Bill

Fred

Steve
looking at your VU meter, I can see that there is not enough processing in your audio. The Munky isn't schwangin' steady near the red......................hi
Fred

Here's the info on the input coil / transformer setup I switched to on the 455 kHz i-f SoftRock. Since I have two units I was able to A-B stock to new looking at 'gain', center frequency and bandwidth. Gain and bandwidth were virtually identical and the center frequency was corrected to 455 kHz - not that this was an issue in the stock setup. Haven't had a chance to look at improved balance with the trifilar wound transformer. 

L1 - 39 turns FT-37-61 ferrite core

This new coil measures 81 uH with a Q of 200. The original coil measured 94 uH (too much inductance causing the center frequency to be low) and a Q of 55. The new 81 uH coil resonates with C21 right at 455 kHz.

T1 - 4 turns trifilar on a BN-61-2402 (2861002402) binocular core

The new transformer measures 4.7 uH with a Q of 75. The original coil measured 4.6 uH with a Q of 145. The new transformer resonates with C22 right at 455 kHz.

Looked at the 1 and 3 dB bandwidth of the modified SoftRock and found the following:

1 dB BW: 415 - 495 kHz

3 dB BW: 395 - 515 kHz

Is it worth swapping to these components? The new L1 is a much better fit on the board and is significantly easier to wind. T1 will provide better balance (perhaps improved performance) and is likewise much easier to wind. If anyone is interested, I have a stash of these cores and can drop a set in the mail.

 

Jay, I used the same size core for the transformer but used 3 turns trifilar on type 77. Type 61 should be good up to 6 meters. Sounds like 61 is the winner. 77 gets lossy above 10 mHz but may be better for lowfer applications.
fc

Jay

 I would be interested in changing out the original inductor and matching transformer with the cores you suggested.

If you could I would like a couple cores.

G

G

More than happy to help out. QRZ.com address okay?

Yes

Thanks Jay

G

Mistake I used type 73 cores not 77.  They are very similar though.
Jay you might send him some trifilar wire what 3 or 4 inches should do it.

Jay,

If you would, I am also interested in the "new" cores, as you state...

Only because of the winding problems with the original L1 coil; winding all that wire in that little space...

Ralph, W3GL...  QRZ is OKfine... Thank you...

PS,  of course the improved Q etc should help my old SX-28, don'tyaknow.

Yes...I'll include some #32 trifilar for T1 - anything larger won't fit and some plain #32 for for L1 - although you can fit larger wire on that core. Ralph...you're on the list.

Hello Jay,

I have ordered two 455khz softrocks.  I would like to try your cores on one, if available.  I will put one on the HRO, and one on the RME 69.  The winding is getting a bit hard for these old eyes.  Thanks!

Address is ok on QRZ.

73,
Rick

Received the package, Jay...

The inductor is wound and ready to install on the board.

Thanks again...

Ralph, W3GL.

Hi Jay,

I received your package today, also received the SR kits from Tony today!  Now I can fire up the new soldering station I picked up at the Marietta hamfest on Saturday. 

Thanks again,
Rick

Received some questions re the 'cleanliness' of the R-390A 'big signal' display a number of posts back...

Any ground loop induced hum or noise will compromise the cleanliness of the display - this is particularly noticeable on a clean unmodulated test carrier as used for that test. Any hum or noise will appear as unwanted products close in on each side of the displayed carrier - how far down they are depends on the severity of the problem. It may be far enough down to be inaudible (or nearly so) but still be readily apparent on screen. 100 dB down is a long way!

In my situation (with the R-390A on one bench and softrock / computer a distance away on another bench) the hum and noise problems were pretty bad looking when first installed. Several things helped the situation. The 455 kHz input to the SoftRock (ANT INPUT/ANT RETURN) connections are floating above ground and keeping the ANT RETURN above ground made a significant improvement. Initially I started with a standard BNC connector on the housing and grounded the ANT RETURN. Switching to an isolated ground BNC made a big improvement. 

Since there's up to 4 volts p-p at the AUDIO I and Q output it's prudent to feed the sound card with separate shielded cables - not a pair of wires inside a single shield. I used good quality RG-174 coaxial cable. One might be tempted to install a stereo jack on the housing (as I did in the initial setup) but this can be a mistake. Unless the jack is isolated from ground this can be another path for ground loop hum and noise. Running the cables out through a grommet solved that problem.

For power I used a standard coaxial power connector attached to the enclosure, however, the power supply is a regulated wall wart that is isolated from ground. The board draws about 18 mA so long term battery powered operation may not be practical.

So the only ground connection for the board occurs at the computer sound card input via the AUDIO OUT I and Q cables. This has provided the cleanest display. No problems with rf pickup from other high powered transmitters running in the shack have been noted. As always, your mileage may vary.

After using the R-390A/SoftRock/PowerSDR setup for a couple weeks now I can attest that this is one nice setup. The R-390A is an impressively clean front end (albeit a bit weak in the IMD dynamic range department) and the SoftRock/PowerSDR setup is nothing short of impressive.

Probably the best "12 bucks" I've ever spent on radio...     

Jay,
great information. My friend in Ca. who did the artwork on my board found stereo isolation transformers also reduce hum. I think he bought them at Radio Shack. My set up is also a long run between the radio and audio input. fc

Jay,

Thanks ever so much for sending me the toroids and wire!!
Very generous of you.

Wonderful!

Now, if the bag o' tiny parts ever arrives with that little board...  ;D

                     _-_-bear