How do I view an envelop with Flex 5000?

[w1vtp]

OK

Here's the Tx scope mode but I can't get the same display in Rx mode.  Just the AF output of the detector which is useless

Al

[N2DTS]

You cant.
They may correct that in the future, a number of people have told them about it.
The auto notch filter does not work in AM also...

Brett

[AB2EZ]

Al

As a work-around (until these capabilities are built into the Flex products), here is what I do:

I purchased ($179.00) a USB oscilloscope from these folks: http://www.syscompdesign.com/CGR101.html

It is essentially a full capability, 2 channel real time digital scope that works with signals having frequency content up to 2 MHz. It does some very useful things... such as continuing to display the last sweep until the next trigger event. It works in conjunction with your computer... and displays in its own window.

To do what I think you want to do, I run a separate receiver... with a 455 kHz i.f. output... in parallel with my Flex 1000. [Of course, you need an antenna switch, so that you don't transmit into the separate receiver]

I run the 455 kHz output of the separate receiver into one of the two USB scope channels.

I run also run the 455 kHz i.f. output of the separate receiver into a simple envelope detector (DC coupled AM demodulator].

I use the output of the AM demodulator as the other input of the USB scope, and also as the triggering source for the scope.

The AGC in the separate receiver keeps the level of the i.f. signal presented to the scope (and the envelope detector) at a constant level.

Attached is an example of what I see. The envelope of received signal (channel B) is superimposed on the i.f. output signal (channel A) [In this particular example, I was triggering with the i.f. signal... but normally, I trigger with the output of the envelope detector]

Stu

[w1vtp]

Thanks guys.  At least it's  sanity check.  Yeah, Stu --I gott check out that scope.  No problems running it on the same puter?

I have tried monitoring myself using the second receiver and think that'll work to check any grunge outside the BW of the Flex

Al

[flintstone mop]

Good info here.
I was realizing the same thing for an enveolpe display. Would be nice. Any techies out there willing to get into the hardware of a FLEX and get a 455 I.F. or any 'scope viewable freq before it's changed to digital?

I have a FLEX 1000 and the auto notch works on A.M.. I would think that was a software thing.
It has saved a lot of QSO's from going down the toilet with the key-uppers and testers on the air.

Fred

[w1vtp]

You cant.
They may correct that in the future, a number of people have told them about it.
The auto notch filter does not work in AM also...

Brett

My auto notch works on AM but the audio sounds like crap when it's on.  I'd rather drag the filter away from the offending carrier.  No answer from Flex-Radio about this (send the question yesterday).

Al

[K9ACT]

Interesting question primarily because I asked the very same question on the Noon Time Four a few days ago.

It just seems intuitive that with all the computer power, we should not have to resort to a stone age receiver and oscilloscope to produce an envelop display.

I just built a cathode follower circuit into my Hamerlund to display the IF on a scope but there just has to be a better way.

As a question to Stu, it looks like you have done it but it's not clear if your view shows the carrier level with no modulation.  This of course, is key to the reason to want the waveform in the first place, i.e. checking mod percentage.

The scope option on the display sort of looks like yours but with no mod, we only get a base line.

js

[N2DTS]

On my 5000, running 1.18.3, the auto notch seems to want to notch out the strongest carrier which is usually the one I want to hear.

Brett

My auto notch works on AM but the audio sounds like crap when it's on.  I'd rather drag the filter away from the offending carrier.  No answer from Flex-Radio about this (send the question yesterday).

Al

[WA1GFZ]

Gee, I wonder how much computer power it would take to grab the FFT data inside the bandpass and turn it into a scope trace. Then who decides the horizontal sweep rate?

[AB2EZ]

Since the separate receiver's AGC is doing an excellent job of removing the level changes when receiving... and since the separate receiver picks up a constant signal level when you are transmitting... there is no problem picking out the carrier level. Just transmit without talking, and wait for the auto trigger function to paint a trace. That level is the carrier level. You can add an adjustable attenuator (or gain, if needed) between the if output of the separate receiver and the scope (and also the envelope detector) to make the carrier level equal to one of the marks on the scope. There are many alternative ways to mark the carrier level. A key point is that I am using a digital real time scope that stores the waveforms and keeps them on the display until the next trigger event. A traditional analog scope (like we all used when we were in school) won't do that.

Also, instead of using the second input to display the detected envelope: on transmit, you can use it to display the audio input to the transmitter. That way you can see how well your transmitter's rf output envelope is tracking its audio input. I normally do that, because I have more than one real time digital scope... so I use another scope to monitor the output of my rf sniffer on one channel, and the audio input to the transmitter on the other channel. [As an aside... this other digital scope has plenty of bandwidth... so I don't have to look at the if output of a separate receiver... I just look at the output of my rf sniffer. Of course, that scope costs somewhat more than the 2MHz bandwidth scope that works with the separate receiver's if output. The prices of these things are falling very rapidly... and I expect that $179.00 will buy a 10 MHz bandwidth, 2 channel, real-time digital scope in the near future].

The problem with trying to get an analog i.f. signal out of the Flex is that its (internal) analog I and Q outputs are at a very low i.f. frequency. Using digital filtering, you (or Flex) could extract the modulated envelope from the digitized I and Q signals... but it is not easy to build an analog envelope monitor that can extract the envelope of an AM signal centered at 11 kHz. If Flex builds an envelope extraction and display feature into the software that performs the digital signal processing... that will be nice. I tried looking at the analog 11 kHz output of my SoftRock-like mixer with my various analog envelope detectors. Again, with only an 11kHz i.f. I didn't get very far. I am able to extract the envelope of the 50kHz i.f output of my Drake 1A... but in that case, at least there is a reasonable difference between the i.f. frequency (50 kHz) and the modulation frequencies (<7.5 kHz).

Stu

[N2DTS]

I suspect it would be easy to do the correct display on the flex, it was just an oversight as they show what cw and ssb guys want to see, and just forgot about the difference in AM.
I think the TX display does show the carrier? so it can and is done.

I think they are adding a manual notch, and might improve the auto notch in AM, which also seems to have been setup for ssb, notching the strongest steady signal in the bandpass, which is usually the carrier on AM....

The 756 pro series rig I had in the past had a great auto notch, it worked in all modes, and would even follow a vfo swisher all over the place and notch it out with little effect on the audio quality.

There sure is a lot they could do in software if they ever got off their butts.
I got the flex about 4 months ago and there have been NO released upgrades.
You can download experimental software, but I will wait for the finished product.
That way I can count on the radio working.....

They really could expand a lot if they wanted to, come out with a small receiver only unit with better than flex 5000 spec's that takes less computer to run.

I am waiting for a plug in card (like a wireless card) for the computer that is a great receiver.
The sdr-iq is close to that....

Brett
 

[AB2EZ]

Anyone who has been involved in commercial software development will recognize the serious problems that Flex will have to overcome with this product line (and I very much hope they do). One can get a feeling for the scope of the problems reading the issues and questions that are being raised (every day) and dealt with (with considerable effort) on the Flex reflectors.

At this time, just including Flex's ham radio products, Flex is trying to support the Flex 5000, the Flex 3000, and (soon, if it is released) the Flex 1500... as well as their legacy products. Each of these is a complex blend of hardware and software, with many diverse applications (AM, SSB, CW, Digital modes,... involving various peripheral devices). The hardware/software platforms include: Windows XP, Windows Vista, and Windows 7... and a wide variety of evolving hardware interfaces (e.g. Firewire interfaces). Complex interactions within the computing platforms appear (so far) to be causing subtle problems that different users are reporting... and that is to be expected. Flex is being very customer focused... and is addressing these problems... but the number of problems and the number of users requiring support is growing fast.

I believe the Flex is trying to simplify its software/hardware architecture... to make it less platform dependent... and to make changes easier to implement (without introducing bugs)... but that is always more easily said than done.

It will be interesting to see if Flex can "pull this off"... given the relatively low volume and the relatively high complexity of the product... and the high diversity of users (their platforms, their applications, their expertise, ...).

Stu

[w1vtp]

<snip>... it was just an oversight as they show what cw and ssb guys want to see, and just forgot about the difference in AM.
I think the TX display does show the carrier? so it can and is done.

<snip>

There sure is a lot they could do in software if they ever got off their butts.
<snip>

Brett
 

Well, the ssb'ers would find the carrier mode useful too should they care about the quality of each other's signal.  A lot of AMers get the benefit of the other person reporting "yer out of phase" (hi Dirk)  I've been told that I was flat topping and was able to make on the fly adjustments.

That is a carrier display on TX -- no talkie = an envelope display

I'm betting they are working their arses off but do need our input in order to prioritize things

Al

PS:  Yes, Stu, I agree wholeheartedly with your observations.  It may be a box but it's not a rice box -- it's made in the good old USA - I hope they pull it off

[w1vtp]

One more thought. Isn't the SW open?  Might it not be that one of our programmers could add these type of AMer preferred features?  Also, at one time Flex was working on a Linux version and then suddenly it dropped off the radar screen.  They were touting Version 2 series.  No more word on that

Al

[AB2EZ]

Al

You asked/suggested

One more thought. Isn't the SW open?  Might it not be that one of our programmers could add these type of AMer preferred features?

Yes, but that person would likely be buried (for years) in requests for support in helping people get the changes to work, updating the changes to accommodate ongoing changes in other parts of the program ("feature interactions" etc.) and addressing problems that emerge when the underlying platforms change.

As just an illustrative example:

I had been running one of the Flex "alpha" versions of PowerSDR with my SDR-1000 for the last month or so. Suddenly it stopped working (I tried to open the application... but, instead, received an error message). I haven't attempted to update the application. I haven't changed anything about my computer or the set of other applications I am running (certainly not between the last day it worked, and the next day when it didn't work). I have a back-up copy of the entire Flex alpha application (the SVN file)... on a USB drive. So... I deleted the non-working application from my computer, and then reloaded the backup copy. No luck. So I'm now back to running 18.4 (also not a fully supported release)... and that is working.

So what happened. My guess (just speculation) is that Microsoft downloaded and installed a Windows XP update on to my machine (which is what I want them to do)... and whatever security problem Microsoft was trying to fix changed something that alpha version of the Flex software could not accommodate.

What ever the cause of this problem... I'm sure it will be diagnosed and worked around... but the question is how much customer support can Flex afford to provide... and how much care and feeding will customers be willing to expend to keep any end-user and/or third-party customized features working?

Stu

 

[w1vtp]

Excellent points Stu -- guess I can keep on hoping. . . . .  Still a great machine

[N2DTS]

Yes, I bet both guys at flex are working hard on the new software....

Stu, that is why I run the flex on a dedicated computer with no web access, no other programs running, no virus scan, etc...

I do everything else on the laptop, and if I need to upgrade the psdr software, load in on a usb flash.

As complex as the new flex stuff is, and since its so critical to keep the firewire speed up, I think its a bad idea to expect the average computer to run it flawlessly...
Its not that you need a really fast computer, but you do need a stable one with a fast firewire port that is not sharing an IRQ with the ethernet port!

I wonder if the sound card based systems are better in that respect, as they do not use the firewire interface, do they?

Brett