The AM Forum

Check this out  www.radioassociates.com.
They make a unit that uses a pc to monitor your modulation.
Any good?

Don W9BHI

It's beyond good! It's deluxe! I will have to admit that I do not have Steve's hardware yet, but I have run the software in demo mode and played back a couple of files that were emailed to me featuring my own signal. Quite a few guys here in the northeast are using the REA Amplitude Modulation Monitor and love it. I'm sure they will give you more substantial information about how it's working for them. If you don't have a scope this would be a must-have item. If you do have a scope, it might be time to move it to make room for this.

Rob W1AEX

I have serial #3, the first consumer purchased unit and it's indispensible for proper operation of my AM station.

Al

Hi Don,

There are approximately 50 units in the field as of this writing.  So far, everyone really, really likes the monitor :D  I have received a fair amount of unsolicited email from customers telling me how pleased they are with the product (I really appreciate the feedback, by the way!).

There is a full money back satisfaction guarantee.

I prefer this monitor to any I have used so far, and currently I have 3 modulation monitors running in the shack.

About half of the monitors in the field have gone to broadcast stations with the remainder to hams.  There is a low power AM interface under development which will allow the monitor to be used with 100mW part 15 equipment and without any direct connection to the transmitter.

The nice thing about a software display unit such as this, is that one can add all kinds of features without having to change hardware, re-layout boards, etc.

Regards,

Steve

Hi Don,
           I have one of these modulation monitors, serial 47 and it is really a great unit. I do have a Heathkit SB-614 station monitor scope here too, but the REA Modulation Monitor is SO much more when it comes to giving very useful information.

At a glance you see the percentage of positive to negative peaks, the negative peak flasher lights up at what set point you desire, I run at the default 99 percent and the positive peak flasher I run at thew default 125 percent.

My current rig is a DX-100 with a self powered external modulator running 811A triodes. If I had better Mic, and driver for the line level modulator it would easily drive more positive.

After using it, I consider it as a must have for the station.
Interesting also is that I tied in my very old second computer, a P3 running at 550 Mhz and only 394 megs of ram with Windows XP Pro and it still ran fine.
This is below the required spec the device spec sheet comes with but the monitor works nicely on the old computer so I set that old desktop at the operating position and leave this machine for the internet activity.

Before I had purchased my unit, I also had downloaded the software and played back recorded files containing my off the air audio together with the monitor data.
So when I played these back, I saw and heard it as if I had one actually live here.
The demo was as true as the actual one I have operating now.

In past broadcast jobs, I have had to work with the commercial mod monitors both AM and FM..setting the carrier input level was a critical factor.

With this REA unit, the working range of sample carrier level is quite wide and automatic. If you wish, you can mouse select the meter showing average ratio of positive to negative peaks or you can select the working carrier reference level / sample level.

If ever you have had to work with existing commercial mod monitors you get to think that I wish it would do this or not that.
It would seem that the REA designer must have been thinking the same thing when designing the REA modulation monitor.

This monitor is clearly well thought out, taking input from all needing one and those features were added. At a glance I see what I need to and the display has worked out the real numbers, saving study time otherwise spent at the scope for peak ratios.

The fact that large VU meters, Bar graphs and average positive to negative ratio meters are all there gives you the choice of what display type you like best. I use all of these in one easy view. It is feels very natural to watch my modulation status with this unit.

Once you operate with one, I do not think you will be happy without having this mod monitor as part of the system.
I also wish I had this unit available the last time I purchased a commercial unit for a commercial AM broadcast station.
This unit does so much more, it should set the standard for the AM broadcast monitor industry.

Regards,
Mike
WA1MNQ
 

I gots one too. Serial 29?
It is not a CPU hog or software bloated.
I use it my WIN 7 computer with Power SDR on my Flex 1000. When I stomp on the PTT the monitor display pops up on screen. There is no lag in what I see, with the meters moving like the real hardware, and bar graphs showing pos and neg peaks. When I UN-key, the mod monitor minimizes in the system tray. I did not know with my wave form monitor O'scope, with RF pickup, that I was severely over modulating in the negative.
If you want to monitor the real audio from your TX just plug an amp and speakers into the audio out jack on the USB interface box.
Fred

I love mine!

I don't know what serial number it is, but it only took a few moments with it to realize that my settings on the Flex 5000 were not optimal and start making improvements I could measure.

I love the scope function, and the positive and negative meters. I run it under XP on an old dual opteron machine that also hosts PowerSDR and both run fine. A great piece of kit.

I don't have the actual AMM-SD1 Monitor hardware and pick-off yet, but Steve sent me a special file of my recorded AM signal using his own new AM monitor off the air. I was transmitting on my old class E rig. (RIP)   I watched it on his software (in video) as if it were a real-time transmission.

It was very obvious what the proper audio polarity was when viewing his monitor.  When using my scope and power meter, it was much more difficult to tell which was correct. It depended on what voice frequencies I used.  But at times the monitor showed 140% positive and -95% negative. It was VERY obvious which was correct on the monitor.

I plan to add one here when the new rig is finished.  It will make a great addition to the HPSDR rig that already resides on the station laptop.

The pop-up window during transmission is a nice feature enabling one to focus on the SDR receiver window until the TX PTT is hit.

I also look forward to interfacing it directly into the SDR receiver to be able to give out on-air reports to others - much like what Steve did for me.  This will require a custom interface to the correct receiver I.F.    Steve says he is working on this option.  

What's not to like for $199.950000 plus future accessories?   Plus upgrades are done in software.

It will be interesting to see how this product eventually turns out in the marketplace. Maybe we see Steve soon with big yacht and pletty girls?

T

Big yacht maybe, pletty girls, not so sure.  His wife will have something to say about that. ;D

Where can you download the software from??? I don't see any link on the home page......but I have been known not to be able to find a shirt in the closet....AL/W8FAX

No yacht or pretty girls here ... but.... I did just order one of Steve's super whiz-bang do-it-all AM modulation monitors! Now maybe I can finally get my audio out set properly.

Thanks for making it all available, Steve.

73
Jack
WA2OLZ


PS: DITTO:"Where can you download the software from??? I don't see any link on the home page......but I have been known not to be able to find a shirt in the closet....AL/W8FAX"
Good to know it's not just me, Al. My Google-fu is always lacking though  ;D

I do not think there is software involved. There may be firmware imbedded in a chip in the USB interface. The AM-monitor shows up in the Device manager as an audio device. All I had to do was to turn the virtual level control to MAX and it played. I needed some help on that from Steve. Some WIN 7 computers interpret devices differently and my 'puter turned that level control to MIN. Seems that XP machines do not screw with that adjustment.
Fred

There is software involved - at least for the computer version.  Steve has the link.  Dunno about any hardware version - I have the software version that shows up on my Power SDR screen when I xmit

Al

Hi Fred,

I think Fred meant the display software itself.  I will create a section for demos  ;)  I have the transcript of K1JJ and W1EAX and I think W2PHL was in there also -  I could use this as a demonstration.

The AM Modulation Meter arrived yesterday, was installed today on the Valiant and connected to the laptop with the provided USB connector. Yes, there is software required and it is downloaded from Steve's website.

I don't yet understand all of the nuances but ..... WOW! It is fantastic to finally have a visual representation of what my audio is all about. I'm at least sure now that my audio was set waaaaay to low. More to follow.
73
Jack
WA2OLZ

PS: Steve - nice job!

I'd be standing in line to acquire this thing.  And I might even pay a premium as a penalty for being a luddite who has no MS products in my house.  If there were software compatible with OSX ... Well, you'd already have made a unit of gross margin on my purchase ..

As someone who abandoned anything from MS a long time ago, it's the usual story.  Just a friendly plea -- a set of cross platform libraries makes it pretty simple to take into account that not everyone has or even wants to have even a cheap and otherwise useless Windows something-or-other machine from 10 years ago running their ham shack ... and wouldn't waste their money on one.

But it sure looks like a nice product ....

Steve K1MV is running the monitor on his Mac using VMWare and Windows 7.  I can't tell you a lot more about it than that, but Steve says it works really well.

Howdy Y'all,
Well, you could say I have a severe case of "Digititus".
I don't like all the digital intrusion into the world of Analog, even though it's supposed to be "better" and "more efficient". The Analog way of things suits me just fine.  :)

That being said, for all Y'all that are upgrading to Steve's new Modulation Monitor, I would sure be in the market for the original Analog REA AMM-HF1. I have been looking for one of those for a long time.

Take Care,

Wouldn't that be digi-phobia  ;D   In this case, digital really is better.  The nice thing about the new monitor, is that the audio path within the monitor hardware is 100% analog - the audio output from the monitor hardware interface is analog.  The display path is digital, and with that you get a whole lot of features that would otherwise be unavailable, and of course the price is a lot less too.

Some kind of digi-somethin!  ;D

That's great news on the Audio Path Steve.  :)

The problem I have is I like Stand Alone units and don't like having to have to tie anything into a computer for it to function. I like the idea of the older Rack Mounted unit that has everything self contained.

This exchange caused me to wonder or should it be wander ? Can an interface be built to allow connection to a panel mounted meter? Perhaps an optional LED dual bar graph rack mounted display meter sold at an additional cost would work. This would bring the best of both worlds together. The mod monitor in a digital world and the analog for those that are digitally resistive. One could choose to use one or the other or both if they like.


73
Btian
KB3WFV

Btian,

Please, please, don't let your mind wander, it might not come back............


klc

You know, when mine wandered off, it used to come back when I called it...

now it just laughs at me and does what it wants...

...... I have two kids and a Wife my mind was lost some time ago
if you don't believe me .... ask them  ;D

KB3WFV

I don't have one of these, but do I need to hook up an oscilloscope again, primarily to monitor the AM and CW output from my new 833 linear amp. Maybe someone can give me some advice.

I used to have a scope tuner directly connected to the vertical deflection plates on a cheap Heathkit IO-18 scope. It used a simple balanced link-coupled parallel tuned circuit and covered 80-10. Adjusting the variable capacitor to get the right amount of voltage across the tuned circuit (and the deflection plates) worked beautifully. I could do it that way again, but I am thinking of another design, something more broadband, that will also cover 160 with no adjustment. Has anyone ever used a broadband ferrite-core transformer to couple their KW output signal to their vertical deflection plates?

Not watt you asked for, but it is interesting.

http://amfone.net/ECSound/K1JJ8.htm


klc

I use a similar tuned circuit set-up to feed the vertical plates directly, works perfect.

Using broadband xfmr would work but you'll need a high step-up ratio.  The plates need about 50-80 volts.  You'll still need some way to adjust the amplitude.

Fred

Just use a modern scope with real vertical amps and almost any RF sample will work.

Really -- "old," but modern laboratory grade analog scopes are $25-$100 on the surplus markets these days, and typically reach up to 250 or 500Mc.

Just use whatever antenna you aren't on the air with as an RF pickup, put the sensitivity in the right zone, and adjust the sweep rate to get a waveform. Most of them have a triggered sweep, so you can prolong the life of the CRT besides.

I wouldn't want to waste my eyesight on those little Heathkit scopes, plus, you have a decent scope for bench work.

This works for aging eyes:

  (http://ecx.images-amazon.com/images/I/51iXPz-AHJL.jpg)

That's the way to go, yes. But I don't want to move my Tektronix 465B from my lab test bench to my radio operating position. Not only is there not room for it there, but the Heath scope fits on the shelf, and the Heath scope's CRT is larger and easier to see. :-)

Yup.  Pretty much.  All I was saying that the scope needs to be pre-calibrated if one is concerned about the 1500 watt PEP measurement. Otherwise go for no flattopping.  Some improvised samplers have the potential of variation of coupling depending on shack variables which negates calibrating for 1500 watts PEP.

W0BTU: One needs only to be concerned if the possibility of exceeding 1500 watts PEP is there. Otherwise, just don't flattop. A scope works for that.

Those miniature scopes really don't make it only to show that things are kinda OK. The "string of pearls" sortof show up on those scopes.

I just use this old Gates monitor

(http://i670.photobucket.com/albums/vv62/mikeinkcmo/testgear/Gates%206659%20Mod%20Mtr/GatesMtr1.jpg)

I  THINK I WILL BE CALLING STEVE ABOUT ONE. ???

I think some ham is getting a nice Father's Day present!  A woman with no associated ham call (that I could tell) ordered a  Modulation Monitor, which we shipped out on Tuesday - plenty of time for a Father's Day delivery!

Will the software ask the video card to wait for vertical interval (vertical sync) before updating the video output array to the VGA DAC?

It is beneficial when the internal monitor refresh timing or rate is not the same as the video card's DAC writes. If the graphics card is high performance, the result can be what looks like a tear across the screen, with the current data on the top section and the previous frame's data across the lower section. If the tear is where there is movement (the scope) then it is visible. It was also an issue on older cards and analog monitors but for slightly different reasons.

It can be set in the graphics card user menu, usually, but then it is ON or OFF for all applications unless the menu provides a choice to have it controlled by the application, which is how mine is set.

The software providing this control (flip a bit on) is what I am asking about.

I realize this is a weird question, but I built the new PCs here somewhat better than the previous ones so it comes up.

Thank you.

I know the effect you are talking about.  I have seen this with full motion video on certain monitor/system combinations, but this is _NOT_ an issue with the Mod Monitor on the same equipment.  The graphics engine in the Mod Monitor does small and very selective updates to the screen and uses the lowest level system calls to do the job (where you can actually write to a small portion of the screen and that's what is updated - and, more importantly, the update is not done unless the video subsystem is ready).  I am very sensitive to tearing effects and other video artifacts, and such effects are definitely not there in the Monitor.

We have, at this point, and with the installed base of Mod Monitors, run on a very large number of systems and combinations.

In my own shack, the Mod Monitor is running on a 10 year old Pentium 4, 1 gHz with a very garden variety graphics adapter and an OLD LCD monitor.  The system is so bad that Internet Explorer will actually NOT run correctly, (I.E. is painfully slow due to the poor machine/graphics performance), but the Mod Monitor runs perfectly and looks great!  It is a very efficiently written piece of software.

That's great. I'm glad you care enough to do low level calls.

Has anyone tried to use the AMM-SD1 with a transmitter using controlled-carrier modulation such as the Heathkit DX-60?  Is the monitor able to establish a reference carrier level when the carrier varies at a syllabic rate?  Is there some minimum time required for the monitor to set itself up before displaying an accurate reading?

And what about this downloadable software that runs the indicators on the host computer?  Where is that on the REA site?  I don't think anyone answered W8FAX's question about that.

Jim, K7JEB

 

Monitoring controlled carrier accurately would be very challenging  :D  The change in carrier level will be picked up as modulation.  Controlled carrier also causes problems with the AGC of many receivers.  If the AGC at the receive end is sufficiently slow to remove all low audio frequencies from the AGC control voltage, it will also have difficulty following the controlled carrier.

I've modified a number of DX-60s and DX-40s.  Always best to go straight screen modulation.  Properly done, screen modulation is capable of incredible audio fidelity.

As far as a software demo for the AMM-SD1, we haven't put up an "official" demo download yet, but if you send an email to support@radioassociates.com, we can send you a link to a demo  8)  I think it's probably time to get a demo download out on the R.E.A. website anyway.

Regards,

Steve

A rack-decor compatible application could be a self contained fanless PC fitted to the front of a rack, or, a panel display and a remote self contained PC mounted wherever. These solutions are rather common nowadays and used ones are fairly cheap.

Some have solid state disk for the o/s and some have touch screens. all kinds. The only task is to pick one with a width that fits the rack or cut a panel for a small one.

If the unit is mounted so that it's flush, there is no ugly display panel sticking out from the rack. An alternate function is with camera inputs to view the various tubes which may not easily be seen in some equipment.

Received mine a few weeks ago.  One of the most impressive pieces of hardware I've used.  as other have noted, the software runs efficiently and does not drag down other running applications.  I'm using WIN XP on a crippled Dell w/ Intel Core 2 Duo CPU, 2G RAM.

The only change I would make is to replace the two 1/8" TRS jacks with a BNC for sampling and RCA female for audio.   I really detest 1/8" hardware as good connectivity depends on a single-point contact.  I took apart the processing unit and discovered that Steve is using PCB-mounted connectors.  It's a very efficient PCB layout.  A connector change *can* be done, but with some effort.   I would gladly pay a bit extra just to have some higher quality connectors.

Paul, W9AC       

Glad you like the Monitor  :D  There's one guy running the software on an old Pentium III, which is definitely unsupported - and it works just great.  We figured a Pentium IV was about the lowest configuration that would be valid because there is a lot of math going on, etc.  The software is very efficiently written and every possible optimization was used to minimize CPU and other resource usage while keeping the real time performance.  The oscilloscope display is the most mathematically complex portion of the Monitor's display.


We went back and forth quite a bit about connectors, and finally decided on the 1/8 inch jacks because they are just so common.  We did choose very good quality connectors, and have not had any trouble whatsoever in the field.  The AMM-HF1 hardware monitor (from a few years back) also used 1/8 inch jacks.  Only audio frequencies are sent over the 1/8 inch connectors.  All RF stays at the SO-239/PL-259s connectors at the input side of the pickup unit.

We've just about sold out of the first production run of Monitors, so it's been pretty popular so far.  Even a few CBers have purchased a Monitor.  Some of the email communication with these guys has been very interesting  ;)

Steve, perhaps for the next production run, you may want to consider a high-quality RCA jack option for both the sample and audio jacks.  They're just as common and inexpensive as 1/8" TRS jacks -- but the inner conductor contact point mates with significantly more surface area that also resists twisting and slippage.  Unlike the TRS, the inner and outer RCA plug conductors form a grip on the jack. 

Another benefit, is that there's essentially nothing but generic 1/8" TRS hardware/cable on the market, and most cables today use a foil rather than a braided shield.   By contrast, someone who wants to upgrade to a better RCA connector or cable with braid can look to vendors like Neutrik and Switchcraft.


It's one of the best performing devices I've ever used, Steve.  Thanks for making it available to us.

Paul, W9AC