The AM Forum

I'm starting this new thread to focus on one aspect of a much longer thread.

I've often heard people comment that an important advantage of a software defined radio... such as the Flex 5000/3000/1500 series and the Flex SDR-1000 (which I have, and use primarily for reception on AM)... is:

"... although the hardware stays the same, the software is constantly being improved to add additional features and functionality".

But, those of us who have designed/worked with software defined systems know that adding features to deployed software defined systems is much easier said than done... particularly if the platforms (hardware and operating system software, drivers for interfaces, data-defined feautres that are activated) are not identical.

Looking back at the versions of the Flex software I've used with my SDR-1000... including the latest beta release 2.16... I'm wondering what new, useful features I have in release 2.16 (other than bug fixes and colorful new user interface choices) that I didn't have in release 1.14.

As was pointed out, near the beginning of the earlier thread, with two antennas, two independent receivers and two associated indpendent displays, I could do some interesting things with noise and interference cancellation (adaptive nulling) that are much more difficult to do with something like a Timewave ANC-4. But I need to upgrade to a Flex 5000 to do those things.

Stu

After spending many hours watching the various SDR videos, reviews and studying the specs, I've come to the same conclusions, Stu.

If it were a simple matter of having a universal transmitter and receiver that stayed the same (no evolution) then new software would be all that's needed over time. But alas, hardware is ever-changing too along with creative ways to interface to it - and adding new hardware bells and whistles never ends.

There is a certain hardware longevity that is governed by how well the manufacturer predicts the future trend of innovation and likes and dislikes of users. The Flex 5000 people appear to have done a good job at this as the stable price and desireability of a 3-year old rig shows.  

I think most hams fear this: They plunk down $3500 for a high-end SDR and within a year a new piece of hardware comes out that is a MUST-have, but cannot be added to their existing rig.  They feel left in the dust and watch the value of their rig drop. That will happen, given enuff time.

Other than that, we can bite the bullet and just live with older technology. There's still guys on with ssb rigs from the 70's who do well. But can they do PSK31, split, RF processing, bandscope, digital readout, etc? Maybe, maybe not.

I think a modular approach, building/selecting  your own discreet hardware, is the best protection against this. The easy way out is to buy a 5000, but then the risk is higher.

T

Yeah...What you said Tom

The ever changing nature of the hardware and the software plus the fact that the operator becomes a beta tester are the reasons I haven't spent any time or money on SDR...I'm still very interested, but don't have the time to devote to SDR right now....

after the June 30, 1948, press conference that announced the transistor there was
a technical demonstration for relevant specialists on July 20 of that year. Lee de Forest
was invited but he declined to attend with the following (paraphrase): I cannot attend
the wake of my 42 year old infant, the Audion, and I suspect that the internment
of the remains will prove to be a long, time-consuming process.

In reference to the other thread that Tom started,  I would like to have a software defined spec analyzer ONLY....No TX , No software to keep updating.Just a spec analyzer to monitor the transmitters with...

I have been an SDR fan from early on. W9AD and W8ER got me hooked and I'm happy with the plain vanilla SDR 1000. I am still running version 1.10.4 software. I don't care to change software just to see a different GUI. I hold out for actual software changes to the radio.

One problem I have run into is a bit of prejudice on the part of the Flex software side of the house towards making newer digital modes work and paying no attention to suggestions regarding fixes to the software for AM.

I wish we had an AM oriented software genius here that could pry the lid off PowerSDR (open source software) and invent a few lines of code that gives us a noise blanker or two that work for AM. Simple truth is the noise blankers have no effect in the AM mode because they didn't think it needed to be addressed and other newer and more interesting modes take the higher ground.

At the end of the day The flex 1000 is a fun receiver to use every day. I have been running it for years and I can still say it's fun. It just needs a few AM tweaks.

Mike

I'll send them an email and tell them I am thinking of buying a Flex 5000, (which I am) but need to know why the noise reduction does not work on AM...   I can be very persuative if need be... ;D

T




Initial msg sent to the Flex sales dept:


"Hi,

I am interested in buying a Flex 5000 with the ATU and the 2nd receiver.

What is the delivery time for these?


Also, someone on an AM forum warned me that the PowerSDR software noise reduction features do NOT work in the AM mode. Can this be possible???  AM is my main activity and I am expecting your wonderful noise reduction system to be fully functional on AM....?

Thank you.

73,

Thomas Cathey, K1JJ

CT"

The noise blanker in powersdr works well for me in AM....
Modulation relative to the carrier is easily adjusted too.
I think it started as version 1.0.8 ?  something like that... maybe 1.8.0 ?
I don't remember...

Kicker is... it won't worke with flex-radio now!   ;D

I've never been much interested in SDR because it seems like you usually have to have a Windows PC to run one and I don't want to blow hundreds of dollars on a Windows PC only to run a ham rig.  I also don't like depending on a PC to run a rig.  There are enough things to go wrong with the rig, even without a PC.   When the SDR 1000 had been out around a year a good friend got one and spent the following 24 months messing around with it fixing an unending stream of little issues.  When he was done he had spent around $2K on a fancy soundcard, a zillion ferrite cores, an after market TCXO, a newer dedicated PC just to run the rig, then there was the infamous flex radio 11 KHz spur on AM, and then it started blowing the IPA (I think or maybe the PA) repeatedly.   He doesn't have the Flex rig any more and I am extremely glad I never got one.    If I'm gg to fool with a computer I'll do it in my job where I'm getting paid to fool with it, and focus on boat anchors at home (mac user here at home).

Rob

Tom,

Thanks for the effort..... However.... Noise "reduction" (as far as PowerSDR is concerned) is for eliminating the carrier squeal when listening to sideband close to an AM broadcast frequency or an AM amateur station. The WORST invention ever made! You probably have them scratching they're heads.  ;D

PowerSDR dose have (I think) two other noise blanker switches for slopbucket that don't work for us. Good luck!!!

Mike

OK, Mike I understand.

I was playing with their demo PowerSDR software and also saw the video demonstration of how the noise blankers work. I'll send a modified email to stop the NL confusion. 

Yeah, Rob, there is always a risk of the computer giving troubles. I've read about it on some of the forums. I worry about QRO and computers too.

But, before I jump in with two feet, I will use the 455kc  down converter as a spec analyzer and receiver first to see how I feel about the whole thing. I may even wait another year or two and use what I have if it looks like better stuff is coming out soon.

T

Bruce,

 I gave up trying to get my point heard when Flex was accepting suggestions for new widgets for upcoming releases of software. I followed my submissions for a year at least with no action taken. I gave up because I had nothing to offer except a want. Maybe I'm not holding my mouth right? I have never experienced any noise blanking while using the software. By the way what do you mean when you say


I had some problems at first with the Flex. I made a decision early on to make the Flex computer (Windows based) a stand alone system for the TX and audio with limited network access and that part has freed up processor time that might be taken up by other jobs. I had audio problems at first that LOOKED like RF problems but turned out to be some really strange products of overdriving the audio input of the rig. A scope and mod monitor are recommended and learning how to set tilt and overshoot is a must.  I think all of us have heard Dave/W9AD a time or two with his Flex 5000. He sounds awesome to me and he is having fun with the Flex stuff just like I am. Take that fun and amplify it by 3 DB and you might see why I like the receiver so much.

I know Frank/GFZ will chime in with other suggestions for better SDR receivers and he is always right! I guess I prefer an easier path.

Mike

Mike,

I was wondering if I cud put TWO SoftRock Lites (or equiv) in dual diversity using the PowerSDR software or does PowerSDR require two Flex 5000 receivers only? They said something about firmware in the Flex 5000 that communicated with the software on some things.    Maybe a simple plug-in left and right stereo sound card is all that's needed for two boards to activate the many features involving dual diversity, I dunno.

Anyone know?

T

I see the direction your heading Tom. Anyone that has tasted the Dual Diversity fruit is doomed my friend to dissatisfaction with anything less.

I am not qualified to answer your question regarding the use of PSDR in dual diversity mode with anything other than a 5000. I hope you find some reliable positive answers here. I am curious as well.

Tom,

A lot of it has to do with an individual's tolerance for surprises.  Things that torque me off and result in my saying bye bye to something and getting a refund may not bother other people.  If I pay a lot of money for something I expect it to work.  If it doesn't I'll put up with a few minor glitches or imperfections but if I sense that the technology is way beyond my troubleshooting ability or a fix is going to be a big time sink, then I send it back.   This is partly what moved me to get into vintage gear.  I think I have a chance at dealing with a broken vintage rig.  I have a shot at understanding the technology.  Something new with a black square inside it that has 100 pins in a 10 x 10 matrix, not much chance here.  If it's a $50 DVD player no big deal.  If it's a $5000 ham rig then I don't like being in that situation with a mystery black box.  I may have distorted or exagerated the situation but I guess basically I like to have ham gear I can get into and make even worse  ;D   I admire people who understand and can actually fix the new stuff but I doubt if I'll ever get there since surface mount etc. isn't what I'm really interested in. 

rob

The power sdr software I have was re-written for the Genesis SDR kits that I have...

The fellow doing the software had left out AM, axcept for recieve..
When I gave him my list of wants, he went right to it....

He told me he didn't waste any time with it before, because he didn't think it was even LEGAL to transmit AM in most countries.! ( He's in Serbia )

I set him straight on that one, and he restored AM functionality...

I am able to block out a lot of noise, lightning static, electric fences... etc...
At least mostly....
But I never use that stuf anyway, because no matter what you do... if you take away noise... you take way part of the signal (fidelity) ...

Bruce,

That's a cool S-meter. Is that a stock option or did you add it in?

I was just reading about the Genesis. I didn't realize it was a QRP transceiver. How are the receiver specs compared to say the 5000 or a Perseus?  Transmitter IMD?

I have an MRI SS linear that might be a good interface for one. The price at $350 is pretty good - plus it's standard lead in hole construction.

I'm wondering if two could be put together and used with the same software in dual diversity RX too...

T

I used this S-meter on my Flex 5000.

(http://www.woodboxradio.com/uk/image/BobSmeter_Flex_specchio.jpg)

Flex has zero interest in AM. I sent them some suggestions on how to make sync AM detector better by changing the loop constant after lock to get better fidelity, back in 1000 days. I got the idea it could be done in software after seeing Chuck's modified SE3 in action. Alberto's SDR has the best sync detector for am with a phase meter so you can see FM and drift on the signal.
Alberto is behind a lot of the Perseus software, very sharp guy.
I just read a post on HPSDR on the diversity using 2 Mercury receivers. The user was quite happy with and posted some audio. Once the new inferace module hits the street in Feb. the USB bottleknect will go away.
Flex one upped HPSDR in the 5000 going to fire wire. HPSDR will fix this in a few weeks. 
The new interface module will be the second module replacing the first configuration. The Janus was the I/Q audio interface for SDR1000, Softrock or homebrew. It may come back as an Audio generator / spectrum analyzer once test equipment modules happen.
I wouldn't waste my time with anything Flex unless you can get it cheap.
A used Perseus is the best value out there for most modern configuration.
QSR1 is a Mercury without an RF amp, same hardware.
I'm very happy with HPSDR and  the ability to upgrade modules.

Frank and Mike had the same experience I have had regarding staffers at FlexRadio Systems, and whether they're receptive to the development and use of their products on AM.

I spent a half hour with one of their people at the Dayton Hamvention a few years ago, at the company's display in the exhibit hall.  While standing there, the guy seemed interested in my assessment of how well the Flex 1K was doing among users in the AM Community, and he asked a few questions that indicated he wanted to know more.

So with that response from him, we kept talking.  I suggested that the marketing people at FlexRadio Systems ought to consider a tailored push toward the AM Community, even to the point of re-branding one of their models to include some features of specific interest to our part of the hobby.  He actually took notes.

I followed up with a few phone calls to their home office at Austin, Texas, and never got called back.

With what I now hear from you guys, it sounds like they couldn't be bothered.

It's their loss.  We outnumber some of the groups they do market toward, both in raw numbers and in weekly hours of airtime.  Both would have been a strong marketing advantage now that competitors are off the starting blocks and catching up with products that may do the job better and be more satisfying to use on AM.

S-meter is stock...
$350 kit gets you 10mW output.. add $129 for a 10 watt amp.
Some SMD , but not many.

I heard a year or two ago from a very reliable source (otherwise I would not be posting this) who had conversations with the Flex guys, and was told that they, or one of them who partly calls the shots, didn't like what was going on with the SDR-1000 and the super wide ESSB users so they started making a conscious effort to limit their product focus to the standard SSB/CW crowd--average bandwidth down to space shuttle audio.  Could be that they lumped AM in with ESSB.  I think their newer rigs, or two of them, have tx frequency response limits whereas the earlier rig was limited only by what your soundcard could do.

Considering the number of AM stations I've heard using Flex rigs on AM, and how great they sound (even by your own admission on several posts in the past), I'm sure their "loss" is minimal.

My Flex 5000 can go out to 20K bandwidth on transmit and receive. The Flex 3000 can go out (with PowerSDR 2.xx software) to around 7K. Don't remember what the Flex 1500 does and too lazy to pull up the specs/manual.

If I remember correctly, back in the "good of days of SDR-1000" W3DUQ and several others passed along some AM related issues in the early software that was incorporated in later versions.

To address the noise blanker "does not work" statements, last night I tried the following test.

Last night I fired up the Flex rig on HF but found very little in the way of any perceived impulse noise. So, I switched the rig to 6 meters, the AM mode,  and set the receiver on a beacon frequency, 50.068 MHz, located up in North Jersey.  With the beam directed at them, it was well received and well over any noise. Then, rotated the beam about 90 degrees and pointed it at some 10KV overhead lines that were about 1/8 mile away. Impulse noise from the lines rose to about S6 and the beacon was lost in the noise. Engaging the noise blanker on the Flex removed the impulse noise down to a very small barely perceptible rush and the beacon was now fully heard even though its signal strength was down to near zero or S1.  It could very well be that the existing hardware of the SDR-1000, even in combination with the current or past software, was just not that effective in making the noise blanker do its job. I had a SDR-1000 for about two years, but don't remember how effective or non effective the noise blanker function was since I very rarely ever used it.

One has to also remember, the purpose of the noise blankers (there are two of them) is to reduce or eliminate impulse noise. It does not eliminate atmospheric static or other types of noise that you might be hearing. And like most noise blankers, depending on how high or where you have the various levels set, engaging it sometimes degrades the quality of the receive signal. Why you would want to use it on AM, or be an issue for AM reception, is a mystery in itself.

I sat down with my pencil to make a list Stu, but then realized your observation seems to be on target. Other than bug fixes and the ability to customize the interface, there's nothing to write! That being said, I can only say that I am having more fun with my Flex 5K than any other piece of equipment in the station. I guess that counts for something!

The enhancement list at the Flex feature request site is interesting to browse, with over 500 suggestions being made by owners. Many of them seem to be reasonable and possible, but time will tell how many come to life. Flex seems to be consumed at the moment with efforts to get the Flex 1500 and its balky USB driver to behave.

On a brighter note, some of the peripheral devices that are being adapted to the PowerSDR interface (independently by owners) are pure genius. This one involving the insertion of code to PowerSDR to allow mapping the PowerSDR Flex functions to the controls of a DJ mixing console has amused me to no end:

http://www.youtube.com/watch?v=NR-ZwUaffI8

I'm puzzled by the comments regarding perceived flaws with reception on AM using synchronous detection. It comes very close to my SP600 in the fidelity department, and with the ability to vary each sideband independently to eliminate "other mode" noise, it excels. I don't have a lot of RF noise here, but when my wife is using the paper shredder or other such domestic RF generators, NB1 or NB2 or both of them combined clean up the noise very nicely. The NR function appears to have the same effect that noise limiter diode circuits had with older receivers, so I don't bother with it. Flex does acknowledge that at some point in the revisions of PowerSDR its performance took at least one step backward.

At any rate, since the fun factor is high, I am pleased with what it does and if new functionality comes along, that's frosting on the cake.

Rob W1AEX

Rob,

I saw a post on the Flex? forum where you were involved with trying to iron out IMD or audio problems on a friend's Flex 5000.  The audio .mpg you posted did sound rough.  You also mentioned that opposite sideband suppression was poor. Was that ever resolved and what was causing it?

Yes, you have more fun with that rig than you should.. ;D  There's no doubt that the Flex 5K revitalizes interest in ham radio. There's something about that pan adapter and being able to ambush and jump on people with a click of the mouse, no?

T

Hi Tom,

My suspicion is that the RF driver stage or the PA stage were not properly biased. Unfortunately, he sold the rig before any attempt was made to correct it, so I can't say if it was ever resolved. There is diagnostic, calibration, and alignment functionality built into the PowerSDR software which would have made fixing that as easy as a few mouse clicks.

When I first used my Flex 5K I got reports that the alternate sideband suppression was horrendous. In my case, it turned out that several things were fouled up (by me). I was using a sampling rate that was too high for my computer to handle well, and buffers that were too small in the TX portion of the DSP. Fixing both took less than 30 seconds. I also never bothered to check to see how hard I was pounding the TX ALC (it was pegged all the way to the end of the meter) and after making a few adjustments, it was clean as a whistle.

I have found that its best to never mention that I have a real-time spectrum scope because the assumption could be that I might be a bandwidth Nazi! The truth is, I just like to talk (and listen)!

:O)

heheheh -  There are certain thangs we learn - to evade the land mines of ham radio... ;D

OK on the bias.  Also the computer set up causing the other problems.   The state of SDR technology reminds me of the first transistor with leads hanging out everywhere.  Eventually they put thousands on the head of a pin.

I saw a tiny SDR transceiver on the web called "The Cube" IIRC.  It used no extenal computer and could be held in your hand. Digital readout and a mini spec display.   It would be nice to see a big version of that someday.  I have decided against getting a Flex 5K.  I'll use my FT-1000D and SoftRock spec/rx for now.

T

There are lots of interesting SDR solutions. I like the hardware and software that Bruce KF1Z is using. It sounds great and looks very slick. A few days ago, while chatting with Nigel VE3ELQ, he told me about his RF Space SDR-IQ receiver, available from HRO for around 500 bucks:

http://www.hamradio.com/detail.cfm?pid=H0-009533

He is using SDR software written by Simon HB9DRV (the guy who has written much of the Ham Radio Deluxe software) and it's very slick. He took a screenshot of my signal as I altered my bandwidth and it picked it right up very neatly. It does mp3 recordings on the fly and will work with Virtual Audio Cable to decode DRM broadcasts using the Dream software. Not bad for a free piece of software!

http://sdr-radio.com/

Simon's software will also function with the SoftRock boards, so you might want to give it a shot just for the fun of it. I have not used it myself, but it would be interesting to see how well it functions on AM. Incidentally, for those who want to try SDR without purchasing any hardware, Simon's page has a java plug-in that allows you to connect by IP to about a dozen different receivers that users have made available around the world.

http://www.sdr-radio.com/OnAirServersFree/tabid/186/language/en-US/Default.aspx

Rob

I've been using the flex software for a while now, and I am also a software developer.  There are definitely some implementation bugs, but on the whole, it does a very good job.

The AGC has major problems on AM.  The AGC, when receiving AM, responds to the modulation - a BIG no-no for any AGC system for AM.

The filters ring to some extent.  You can somewhat mitigate this by reducing the receive buffer size, but it's not a perfect solution - it is tollerable, particularly if there is not a lot of atmospheric noise present.

That being said, I use the SDR all the time  - there is NO receiver I have EVER used that is as good at getting rid of interference, and making an otherwise uncopyable signal copyable as the SDR (Flex software with a softrock).

I have looked at the source code with an eye to make changes - it is COMPLICATED code.  I've written a lot of very complex code in my days, and it is a time consuming process.  If you're a software developer by day, you are probably dis-inclined to do more complex software development at night, particularly when you're not getting paid to do it.  But, I would like to solve the AGC problem with respect to AM, so at some point, I might take a shot at it!  8)

Note to Rob - on some of what you said, I could not agree more.  There was NO WAY I was going to shell out big bucks for a high performance sound card or for the flex hardware for that matter.

But, you can get into SDR and the advantages of using it for almost 0 money, and still keep the BA receivers.  That's what I do here - usually use the BC-1004 for receiving, and the computer is off.  But, for those times when the 1004 can't cut it, it's sure nice to flip on the computer and the softrock, and abra-cadabra, a high performance receiver is at my fingertips!.

I'm using a 1.8gHz Pentium 4 that they were throwing out at my son's job (these machines are generally free or available for tiny money) and it does the job.  The secret is to run NO other software - a bare bones operating system (XP recommended even though Windows 2000 is more efficient).  The keyboard is on a slide, under the workbench so it doesn't take up any valuable bench space, and the computer is in a rack, behind the rack-mounted 19 inch monitor (19 inch flat screen monitors fit just about perfectly into 19 inch racks, and look pretty good too)!

Anyway, that's one way to go about it.  I *never never* have any trouble whatsoever with the computer because there's nothing on it to cause screw ups!

Regards,

Steve

Steve, interesting on the AGC AM problem using the SoftRock and PowerSDR software. I'm surprised the guys on AM have not brought it up, at least that I've heard. I will look for it when I fire mine up this week.

Cool idea on putting the video monitor in the 19" rack.

I just did an indepth reading on the Elecraft K3. Lots of reviews from users.  From what I read, it's not a perfect radio either. The cost is prohibative to me... $4700 new and maybe  $3500 used.   I'll continue to look into the SoftRock and later the high end receiver boards like Perseus, WinRadio, etc.   Man, this stuff will make your head spin.

All in all, it almost makes me happy with what I have now...  ;D

T

Steve, I suspect the guys who share this cool software do it as a day job so it isn't a lot of effort.
I bet a lot of the processing software is cookbook making the real work the GUI.

When the going gets rough, I turn off the tubes and use the Flex for receive.
Steve, if you're serious about working on the Flex software, you might want to contact my buddy Jeff, K6JCA.   He's worked on it a lot.   Many of his changes have been incorporated in the standard software.  Early users might remember when his console was more popular than the standard software. He might have been WA6AHL back then.  Anyway, he's very picky about AGC and may have actually already taken a run at the AGC system, not to mention the sync detector and half a dozen other things.  Heck, Steve.  You probably met Jeff when you were out here all those years ago.  He's good in QRZ.

By the way, your comment about "software developer by day" sure hit a chord.  That's what I did for a living for a couple of decades before I went into manglement -- write system software, operating systems, compilers, file systems, networking code.  I just can't work up any enthusiasm for doing it as a hobby.

Jeff is a good guy. I owe him one.

I don't see Jeff's email address in QRZ but it is in his blog which is a fun read.  Flex stuff is way back, click "older posts" a bunch of times.

http://k6jca.blogspot.com/

Jon 'JEK' just notified me of this thread regarding SDR AGC and AM...

First, yes, I met Steve at Jon's place a couple of years ago (hi, Steve).  And hi, Frank!

I've actually dug into the PowerSDR AGC code, but it was some time ago and I no longer recall much about it.  I just know that it was a pain to understand, but if you put in the effort, you can do it (and I'm speaking as a hardware guy, not someone who spends his days writing software).  Four or five years ago, when I first purchased my SDR-1000, the AGC had major problems -- turns out the code was truly broken.  I made some mods myself to fix it.  But since that time it's been rewritten and improved upon by the Flex team (and if I recall, even commented?), and seems to do the job now.

I did want to add, in my opinion, the Flex software really shines in synchronous AM (SAM) mode, and my Flex-5000 is my receiver of choice (of the many I have) when I operate AM.  I haven't experienced any noticeable AGC issues in SAM mode, but I usually keep my AGC set to a long decay (couldn't tell you which setting, as I'm not in the shack at the moment), so perhaps that's the reason why.  Steve, if you could give more detail regarding what you're experiencing, I could do some listening tests myself.

By the way, I know at least one ham who has used the Softrock and the PowerSDR code for reception when he's operating AM, and that's Mike, W6THW.  It's worked well for him, and I've purchased a Softrock myself to do the same thing one of these days.

Oh, and by the way, my email address is on my blog.  If you have any questions regarding the Flex AGC code, I can look it over and see if I can answer them.

- Jeff, k6jca

Steve, tnx for the information.  Very useful and glad it is here where I can get it in the future.

Jeff,  what is the language of the powerSDR code?  I assume it is OO instead of top down but is it an interpreted language like Python or is it lower level like assembly?  What do they use for version control?  I've been learning to work with Git and am finding it is pretty cool.

tnx
rob

Most guys on AM wouldn't notice it since it would be no different from receivers they've used in the past. The AGC in many boatanchor RXs responds to lower frequency audio.

Hi Rob,

The PowerSDR GUI (e.g. for the controls & panadapter) is written in C#  (c sharp) and requires a compiler.  All processing, such as the AGC, is in either C or C++ (I've forgotten which).

I'd done a few small things in C before for work, but I'd never seen C# (and I'd had zero experience with GUI code like this).  However, the syntax wasn't that difficult to understand once I got into the code and starting mucking around with it.

Revision control had been done using Tortoise SVN, but I think Flex might now keep their development efforts off-line.  Not sure about that, though, so for those interested it would be worthwhile doing more research.

- Jeff, k6jca
http://k6jca.blogspot.com/

Hi Jeff,
I agree long decay helps with distortion of pumping AGC. Alberto's AM sync mode used a longer loop time constant but was slower to lock and cleaner.
I suggested years ago wondering if the loop time constant cound be changed after lock. This would be a way to get the best of both worlds.
On another note. Nice 813 rig. About a year ago you came on here looking for some panel meters. I sent you a PM asking which ranges do you need? You never responded so figured you were all set. Anyway, if those are the same meters in the rig picture I have a few like that. If you still need any let me know what ranges and I will see if I can provide them.

I have been running that combination for over a year and am very pleased with it. I have it set up on an old laptop in the corner with the server software on it  connected to my house network via wireless and dozens of people a day log into it and use it. I have to log in to the laptop to boot them off to use it myself!  ;D I've been very pleased with Simon's software, although I prefer the faster panadapter of the Spectravue software that came with the radio. But I never use it directly anymore, just over the net, even in the house.

You can use my radio via the net by downloading the software from Simon's site, look for the beta kits, and in the input source drop down menu there's a choice to use remote via web. When that window pops up, in the upper left corner is a browse the web option. It shows all the receivers currently online and registered with the site. Once you've connected to a receiver, it's IP address is stored in the menu of the pop up box and you can just go directly to that IP in the future. There were at least a half a dozen SDR-IQ units available last time I looked. Plus a bunch of softrocks.

The Flex 3000 now has 4.5 Khz audio bandwidth available in the 2.0.x versions of the software, or 9 khz total occupied bandwidth with both sidebands. I don't know why they restrict it.

I have greatly enjoyed the Flex for AM. After getting my feet wet with the SDR-IQ, I decided to get an SDR transceiver and found a used SDR-1000. I operated it for a year and enjoyed it so much I started looking for a used Flex 3000. Found a good deal on a F5K instead and took the plunge. I have to say that between the SDR-IQ and the Flex it's really invigorated my interest in ham radio. Operating without the panadapter makes me feel blind these days.  ;D

For a more modest investment, a used Flex 3000 seems like it gives you most of the flex experience in a compact package. You give up some transmit bandwidth (I rarely run more than 4khz I find) and some of the front end receiver specs and the ability to do diversity receive, but for most use I think it would be fine. The SDR 1000 worked well, but the F3K and F5K get rid of all the extra wiring with the external audio box.

There may be higher performance hardware out there, I have some local friends who are into the Gnu radio development and were pushing me towards various kits, but they were complicated and in flux and just were hard to get good info on. In the end I decided that a semi turn key solution from Flex fit my needs at this time better. YMMV. Certainly a softrock on the IF of a good receiver run with PowerSDR will give you most of the receive advantages we are enjoying.
 

Steve, when listening in the AM mode how does this issue manifest itself? I have definitely noticed some kind of peak distortion in AM mode on heavily modulated signals with every version of PSDR I have used, both with the Flex 5K and my 455kc down converter and wonder if that is what you are referring to.

It has never been a serious issue for me since I always use the synchronous detector when operating AM, and SAM seems to receive everything very cleanly.

Rob

Thanks, Frank.  I didn't see your PM until last night when I logged onto AMFone after a very long absence.  Many thanks for your offer, but nothing needed at the moment.

The SAM demodulator in early versions of the PowerSDR code took a noticeably long time to lockup if the carrier frequency changed by a significant amount, and I found this to be a big problem when operating a boatanchor net in which no one was on the same frequency (figure +/- 3 KHz from the designated frequency).  I got around this problem by adding what I called my "SAM Lock" code to my version of PowerSDR.  Essentially, it'd look for a the strongest signal within a user-defined frequency window, and if that signal was there long enough, it would zero-beat the VFO to that frequency.  And because of the long lock (and, more importantly, unlock) time of the SAM demodulator, the phase-lock loop would regain lock quite quickly because, essentially, every new signal was zero-beated, and the phase-lock loop didn't have time to drift too far away.  Kind of an inelegant, brute-force method, but it actually worked pretty well.

I believe Flex has improved their SAM demodulator phase-lock loop.  Or I should say I haven't really had a need to add my "SAM Lock" code to the later consoles.

- Jeff, k6jca
http://k6jca.blogspot.com/

I see this too, on most AM signals when in AM mode, on the voice peaks. I've wondered about it too, as it seems to be too sensitive to the peaks compared to other receivers on the same signals.



Agreed. Although it doesn't seem to like Tim's SBE very much.  ;D Had to revert to straight AM when listening to that yesterday.

Yes indeed, Tim's SBE signal seems to defy the SAM's ability to lock onto it. Of course this is what happens whenever an unstoppable force meets an immovable object!

Incidentally, I did see your call in the list of available IP receivers while browsing Simon's site. I'll be trying to login shortly! Thanks for making your resources available!

:O)

I just received an email back from Greg at Flex answering some of the issues we are talking about here.  I sent him an email axing for his permission to post it here. More later.

T

jeff tnx.  i have no experience with C#; vy little with the other C flavors.   too bad they still use SVN.  Git has some advantages for example everyone has the complete repository so it is possible to work without a network connection.  more here:  http://progit.org/book/ch1-1.html  and finished work commits can be put here: http://github.com  I figured that since the code has to execute in close to real time it would probably be compiled.  There was some sort of panic when MS started moving beyond XP to 7 or Vista--I think it was Vista that came next because the Flex seemed tied to XP.  That has probably been resolved along with some driver issues but it made me leery of it.   There are no OS or  driver issues with your 813 rig I bet   ;D

rob

Received from Greg Jurrens at Flex, posted below (with his permission) is the response to a few of my questions… I am happy with the careful attention he paid to everything asked.

BTW, current Flex owners – notice the way to connect your own spec-monitored transmitted signal to the FINAL outboard linear amplifier. They are now connected to the 100w Flex output itself and show nothing what the final linear amp is doing, if used. This is an important feature to have if you want to know the real story. The other way is to use a separate, outboard softrock monitor on the final stage linear, etc.

T
-------------------------------------------------------


Tom:

Sorry for the delayed response.  Just catching up from the holidays....

I will have more stock on the FLEX-5000A with RX2 later this week.  I completely sold out during the Holidays.  We will be shipping again by weeks end.

Your data is partially correct regarding some inconsistencies with the Noise Blanker and Noise Reduction code: During the development of our Version 2.0 software, we managed to disturb the DSP code that supports NR, NB1/NB2, and ANF functionality.  We are actively working a solution now and will hold final release of V2.0 until we fix this.  Our current STABLE release 1.18.6 is fine. 

For the FLEX-5000, our Monitor function is a direct TAP from our 100w PA chain.  I agree it would be useful to be able to monitor the amplified signal to ensure signal purity etc.  One method to do this would be to use the RX2 second receiver and enable reception on RX2 while transmitting.  You would feed RX2 the HPA's tapped signal using a directional coupler with at least 80db but preferably 100db of attenuation.  For example:  2KW = +63db - 100db attenuation = -37db Full scale.  This would give you an S9+36 signal on the input to RX2.  BIG... but not damaging and well inside the linear region of the receiver.   Please note we have not done this specifically at this power level but routinely do this with a 100w signal and don't expect you would have any issues.

For me to answer your "Diversity" question with softrocks, I have to define the term:  In the purest sense, receiver diversity means any 2 receivers on the same frequency with separate audio outputs.  Using 2 FLEX-5000s or 2 anything receivers would accomplish that.  What FlexRadio has done is go "Beyond Diversity(tm)" by creating 2 completely phase synchronous receivers.  This allows us to do both magnitude and phase correlation on the received signal.  The resultant signal can then be null-formed or beam-steered to the operator's advantage.  To our knowledge, the FLEX-5000 with the RX2 is the only amateur product that can accomplish the Beyond Diversity function.


PowerSDR will not currently handle 2 sound cards for RX1 and RX2.  In our FLEX-5000, the sound subsystem is integrated so we do it by a different method.  Your softrock solution would require someone to program that functionality in.  If you you are interested, most of PowerSDR is released under the GNU Public License.  You can request a "tarball" of the source by sending an email to gpl@flex-radio.com . 


Tom, I hope that answers your questions.  Please let me know if I can support you further in your evaluation. Let me know what else I can answer for you.  It's clear you are a very active ham.  I'd love to make you a FlexRadio convert.



73,
Greg - K5GJ

Greg Jurrens - K5GJ
VP, Sales and Marketing
FlexRadio Systems Inc.
T: 512-535-5266 x203
E: greg@flexradio.com
SKYPE: WD0ACD
“Tune in Excitement” ™

I came in  a little late on this thread. I'm not certain what version of Flex software I have for my old Flex 1000 BUT The NB works FB on my radio in AM. I had a nasty street light almost blank out AM QSO's on 160M and cliking it would clean it up almost entirely and the signals were good again.
I always thought the NB was good at pulsed noises, not steady buzz interference.

FRED

I think I started the poor reports regarding the noise blankers and noise reduction as it applies to my SDR-1000 running PowerSDR version 1.10.4 and I maintain they don't work at all for me. It has been a few years since I made my requests for noise blankers that worked for AM and after watching my request on the sidelines for a long time, I just gave it up.

I downloaded the newest software (version 1.18.6) today and while I can use it only in DEMO mode (no receiver) it dose seem that one of the filters seems to work. I also looked up the manual and I have a few corrections to my earlier post.

You have basically four noise blanking and noise reduction buttons with PowerSDR. NR (Noise Reduction), ANF (automatic notch filter), NB (noise blanker) and NB2 (second noise blanker). Noise reduction seems to have some effect in 1.18.6. I won't know how well it works until I try it with a receiver connected. ANF is the carrier squeal eliminator for SSB. NB and NB2 are for impulse noise (I'll have to try them as well). After reading Greg's email I don't expect much until version 2.X is finally released in it's official version since I don't like fussing with the beta versions.

I saw some chat from N4HY on the mail reflectors a while back that seemed to indicate that he was making good progress on fixing the problem with the noise blanking system. From what I recall he seemed to indicate that it would be even better than it was before 2.x broke it. That would be good. I have found it does work pretty well on impulse noise even as it is, and watched a video (one of Burts?) that showed it really knocking down the general background noise and making signals at the noise level pretty usable. I presume that was a version of the software before 2.x broke it.

The automatic notch filter seems to work reasonably well, in SSB modes, but doesn't seem to function in AM mode, which is a shame. There are times when two QSO's are spaced such that it could be handy (of course you can tuck in the filter edge to remove it), as would some sort of manual notch filter that could be clicked into place.
 

Muddy bass mostly, since this is where the largest IMD occurs. Also, most receivers exhibit a huge increase in THD at the lower frequencies too. Take a look at the measurements done by Jay, W1VD.

http://www.w1vd.com/BAreceivertest.html

The test I ran on the noise blanking the other evening (earlier post) was running PowerSDR 1.18.6 which is the current "blessed" release.

Very interesting measurements.  Unless I'm misreading the data, it appears that using a Softrock SDR receiver and PowerSDR software as a demodulator off of a receiver's IF (e.g. R-390A) gives stellar audio performance compared to the other boatanchors.

Of course, it makes one wonder...why not just use the Softrock as a straight receiver and remove the boatanchor from the chain?

- Jeff, k6jca

That's probably because most people don't understand the Softraock is INTENDED to be a stand-alone receiver!

It's " too small to be a good receiver...".
 ;D

It's a great little ONE BAND receiver. And without an adjustable oscillator it only covers a portion of one band.

With the Rock Lite 6.2 on an I.F. of an existing receiver you have SDR with bandswitching covering the whole band.
I have a 6.2 on my Drake R4A's first I.F. and it works great. It covers the entire band and I have instant bandswitching. It's the best $12 I've spent in ham radio in a loooooonnnnggg time!

That's what is done with the Sherwood SE-# sync. detectors.   I think Don does that with his 75A4, and the sync detector drives a tube audio amp.  His 75A4 is pretty much used as an IF strip.  If he sees this he may add some corrections/details.

those THD spec's for the boatanchors are pretty interesting for I assume the rx were all stock, so they reveal some distortion at fairly low modulation levels by modern standards.  I recall some were over 10% THD on sigs. that were 80% modulated.  I interpreted that as the limitation of envelope detectors and wondered why old rx such as the SX28 got high marks for audio.   Maybe it had a product detector?    My 75A3 was unuseable for good audio without a product detector mod and a detector tap out to an extermal p.p. amp.

Rob

Just a comment on the evolution of the NB within PowerSDR Beta versions. I use Beta 2.08 and would have to say that the combination of NB-1 and NB-2 are very effective at removing impulse noise. I am blessed with a location that is generally quiet on HF, but if I point my 6 meter beam to the SW during the day, I can find a noisy pole out there that kicks up to about S-5 on the meter. I placed a 30 second MP3 file at this link if you would like to hear the NB for yourself:

http://members.cox.net/ender/6meter.mp3

The little attached picture is a screenshot of the 6 meter mp3 as it looks in Adobe Audition. The mp3 starts out with the impulse noise present, then you can hear NB-1 drop it down significantly, and then NB-2 removes it completely. I cycled the cascaded noise blankers three times during the clip. The receiver was on 50.4 MHz in the AM mode with a bandwidth of 8 kc. When the NB is adjusted carefully, you can minimize signal degradation on wide signals somewhat, but as Pete said earlier, why would you want to use a NB on AM? it's always best to have the problem fixed at the source.

As far as the Synchronous Detector goes, I would have to say that PowerSDR does an outstanding job with the AM mode. In fact, it sounds at least as good, if not better, than my SP-600 with the tapped detector. I made a recording of (WA1QIX) Steve's exceptional Class-E signal several months ago and placed the 30 second MP3 file at the link below. How's it sound to you?

http://members.cox.net/ender/QIX.SAM.mp3

Rob W1AEX

The notch filer is working in my FLEX 1000 AM mode with the old 1.14 whatever software. When those strange carries appear during  a QSO I see them pop up but do not hear them. I wondeyt if some here having issues might be from a computer with not tenbough horsepower or not using  5the supported sound card. I have the DELTA M-Box. The best is theEdirol FA66.....another $500.00 oh well

Fred

Sorry for the last post and all of the errors.
The AMFONE BB still has some gross defect: IF I quote a long reply MY reply jumps up and down as I type and I cannot see my typing errors.,.........I know SM remark will come...........do not make any errors

Any way I use the supported sound card M-Delta and the best being Edirol FA66.
I think the secret for all the whistles and bells and for the hardware and software to be at its peak is the FA66 sound card for the older generation of FLEX. The newer stuff has it's own hardware.
The FA66 needs a fire wire card in the 'puter....another $20.

Are yous guys with issues using supported sound cards in your flex software? And even IQ I.F. cards (softrock)??

Fred

It's only an issue when using I. E., hence the notation on the left Sidebar: "Best Viewed with FireFox."

I definitely agree. I can run various PowerSDR versions here including the latest beta release V2.0.16 and the synchronous detector works great. However, the software and computer made large grunting sounds when trying to lock on to Tim's modulated oscillator the other evening. It's even fascinating to watch his signal bounce around on the panadapter screen.

Call it an SB-Eliminator (SideBand)   or a SD-Eliminator (Sync Detector)    - take your pick... ;D


I heard a new SBE modulated oscillator on the air the other night.   A W2? had an 833 modulated by a pair of 813's running.

T

"Supported"... means NOTHING.
Many cards work very well, in unsupported mode.

All that is, is a list of cards from YEARS ago, that they tried, worked ok, and wrote a database of the settings that worked well ...

The list is old, there are many cards that are MUCH better than any on the supported list now.

I use the EMU1212.
Blows the doors off the m-audio d44, and the edirol FA66.
Specified SNR of the 1212 is 120db...
The d44 is 99db, the Edirol 105db.
And yes, I had both here to compare...
Edirol FA66 used to be my favorite as well. Does have the handy feature of phantom power for condenser mics though...
As far as SNR and other noise... the FA66 WAS the best.... about 8 or 10 years ago..

Even the lowly E-MU0202 performed better in RX than the Edirol...

The only thing to look out for is 2 channel cards, (such as the emu1212...) that will not allow you to use phone-modes...
The software will not switch between LINE-IN and MIC-IN.
So you must use a second card for microphone input... but this can be almost any cheap input device ( on-board audio... $10 usb devices...etc.)


I've played with dozens of fairly expensive "cards" over the past couple years...
Hands down, the E-MU1212 is the best RX soundcard I've found...
Seconded only be the new Zonar.

Theses cards are current production, and cost less than $200.

Also to note...

There are some very interesting "audio devices" coming out, that will be THE thing to use with SDRs that don't already have them built in.

They will breath new life into the old sound-card dependant radios...

I will hopefully have the priveledge of testing one such a device before it hits the market in the near future.

http://w9oy-sdr.blogspot.com:80/2009/08/diversity-update.html

Here's an SDR Flex 5K article I received from a vely famous AMer who now owns a Flex 5K with the 2nd RX.  I'm cornvinced this technique will become the receiving edge of the future - noise notching and null steering using two diversity antennas with software.

Listen to the .mpg of the LU station with normal diversity and null steering added.

"With steering off, you get the normal advantage of diversity, but with steering on you get help against fading as well as noise notching. You have to adjust the bulls-eye to give you best readability but once you get used to playing with this it doesn't take long to make signals other wise unreadable quite Q5. "


T

Hey Tom
Where do you see and hear all of this?? There is an LV call sign I clik on and it's some CW with extreme narrow bandwidth, but nothing giving ability to move the diversity bulls eye around.
Thanks
Fred

Hello
I 'won' a FA66 from ebay for $200 from a guy in Australia.
I'll try to report on any improvement between the M-delta and the FA66.
Flex engineer told me that the better 'cards' show more bandwidth in the panadaptor.

Not many show up used and they still command a high price. NEW FA66 are still near $400. For such 'old technology' they still are in high demand. I'm looking forward to the ability to plug my condenser mic directly into the FA66 and let the computer do all audio processing.

My old M-Delta audio  card and Symmetrix 528 might show up "For Sale"

I'm sure FLex radio folks were trying to optimize their product for plug n play folks. Seems like other sound cards can lead to more headaches. 2 channels 4 channels software switching between mic/line,,,etc

Fred,

Here's some actual null steering diversity that was just posted by a guy experimenting with a pair of Mercury SDR boards.   

There are THREE .wmv videos there showing impressive results for noise, BC and 40M.

T


http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/2011-January/013970.html

Really nice job on taking out the impulsive noise.

Yep, and the guy was using just a couple of simple wires for ants IIRC.


Lucky day.

Posted a message on the HPSDR reflector looking for questions/help and axed if anyone had HPSDR boards for sale. Great help response.  Was offered and bought a complete set of new HPSDR boards to build a transceiver for $550 shipped.  Includes the Mercury/RX, Penny/Exciter,  Atlas/socket frame,  Pandora/cabinet,  Ozy/USB comm interface board,  Janus/ high end soundcard, LHU/power supply for boards - including shipping.  

I still need a second Mercury RX for diversity and a ref clock.  But I gots what I need to get something cooking now.  Heck, just one Mercury board from Germany alone normally costs $437.

One of the guys on the board (K5SO) is making big advances with the diversity null steering. He now has three RX boards working together in null steering diversity.  I told him I'd like to be a beta tester soon. He gladly accetped since no one has tried it on larger gain ants yet, at least anyone who has posted the results. Some big talent there and a very friendly group willing to help. (Just like AMfone - but I'm the brand new newbie there  ...  HA!)

Jump in - the water's fine.

T

Don't sell the delta until after you find out how much noise your firewire interface causes.

Hopefully you'll get lucky.

Like I said before... FA66 IS a pretty good "card"...
Way back when , it was THE card to have for SDR..
If the noise it may generate, and/or the firewire isn't too bad, you'll like it.

( It does say right in the user's manual, that it isn't intended to be used near radios, among other things, becasue it may cause interference!)

I've had three of them over the past 5 years or so... only the one I had recently was unuseable with either of my newer computers.

Good score! Did you get the Gemini and Saturn boards?

They were out of stock. But I'm in good company - they name their boards and I name my rigs.  I might approach them about developing an SDR Plexiglas enclosure named "Fabio". What ya think?

T

Just make sure you get the one with the Taylor hybrid option. Otherwise, they don't work worth crap.

BTW, the Saturn board will melt four feet of snow in two minutes.

Glad you joined the gang Tom.
It has been very interesting lurking with really smart guys.
You quickly learn why we have two ears but one mouth

I keep getting private emails from these guys offering more ideas and help just from those two posts I made.  They know how to treat a Newbie, I'll say that.

BTW, a VK said he has 100w SS amps available -  "We use a local amplifier here which is from a Codan Flying Doctor Radio.  0.5 watt in for 100 watts out.  I can source one for you very cheaply if you want."   He says they are -50db 3rd and remotely controlled by the HPSDR for bandchanging.


Another German mentioned that if two linears of the same IMD are put in cascade, they will be 6db IMD worse at the output. I always thought it would be more like ~one db worse???    6db seems a bit much considering the multi-stage chains of SS amps used today.

T


T

I still prefer the erb on a big heatsink. You can't beat medical equipment for good design. The amps had digitally controlled bias so it was switched on just before a pulse is sent through to control heat. That is the reason they get away with a small heatsink. I bypassed all the digital stuff in your amp.
I sawed it off my amp and duplicated the bias circuit on that little piggy back board in my set up.