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Author Topic: Station monitoring......your opinions please  (Read 7649 times)
KB8BAB
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Posts: 100




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« on: August 16, 2012, 01:21:13 PM »

Well, I've been building my station now for a while (as "play funds" allow) and think I have a decent set-up.

My transceiver is a TS-940S, Al-80B linear, AT-2500 Tuner (in repair process). Backup is my TS-530S and MFJ-993B.

In consideration for other operators, I want to set-up a station monitor so that I can see what I'm putting out and not contaminate the band with needless splatter, noise etc.
I have a Tektronix 2336 100Mhz scope from the days when I was playing with CB and TV repairs, I believe this should do ok.
I'm also toying with the idea of a spectrum analyzer....

All probably complete overkill? but I want to make sure I'm "true and clean".....

I've found two companies that offer interfaces: CleanRF (www.cleanrf.com) and PreciseRf (www.preciserf.com) both offering similar products.

The other alternative was to software/pc based by Virtins Technology (www.virtins.com), this would be scope/analyzer in one package.


What else is out there...what are you using and works effectively...?

Any comments and or suggestions are greatly appreciated.

73
Bart
« Last Edit: August 16, 2012, 02:15:35 PM by KB3HGR » Logged
WA4NJY
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Posts: 108




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« Reply #1 on: August 16, 2012, 05:17:00 PM »


  Just keep the rig within ALC range and you will be ok.  I only use a scope with the AM rigs.

Ed
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AA4PB
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Posts: 12689




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« Reply #2 on: August 17, 2012, 05:29:58 AM »

If you are running SSB, a spectrum analyzer is the only way to really tell how clean your signal is. It takes a lot of distortion to see it on an oscilloscope. Very few stations monitor their signal on a spectrum analyzer. If things are properly tuned and you keep the ALC within limits you shouldn't have any problem.
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K1CJS
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Posts: 5885




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« Reply #3 on: August 19, 2012, 06:35:28 AM »

Agreed with the last two posters.  Station monitoring is OK--once in a while.  If you keep your rig properly adjusted, you don't have to worry about it.

Although this isn't exactly 'monitoring,' it is a cute story.  One of our friends continually wanted to 'check the input' of a two meter repeater we use to see how the signal was using a scanner.  We cured him of that by going simplex on the output of the repeater so he was listening to dead air on the input.  Took him a couple of days to catch on, but now he doesn't always go to check the input constantly anymore.   Grin
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KB8BAB
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Posts: 100




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« Reply #4 on: August 19, 2012, 03:34:14 PM »

Always great to hear other opinions!

Thanks guys! I'll leave it be for now.

Bart
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W8GP
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Posts: 190




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« Reply #5 on: August 23, 2012, 11:01:05 AM »

I'll have to disagree with the others, I have used scopes for years and I find them very useful.For one thing, they just look cool! I can still remember seeing an oscilloscope in school for the first time and I thought it was the neatest thing.When I became licensed, I knew I had to have one, and I've been using one ever since. On a practical note, they make tuning an amplifier much quicker and allow for instant feedback on tuning issues, improper loading, wrong antenna, etc. I always use a trapezoid pattern which is much more useful that just watching the waveform. With this set-up, you can tune your amp to full power in a couple of seconds just by speaking an "aaaah" into the mike and watching the pattern, and it's much easier on the amp than using a steady carrier. So do you NEED one? No,and I wouldn't spend a lot of money on one, but to me it's a fun gadget that's useful as well.
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ND6P
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« Reply #6 on: August 24, 2012, 04:25:45 AM »

I have a TS-590 and an AL-80B.  I bought the CleanRF devices to check for linearity.  It was fine.  I've put the CleanRF devices in storage in case I need them in the future.  Nice to have them and glad I checked out my station with them.
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K1CJS
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« Reply #7 on: August 25, 2012, 06:47:37 AM »

....I have used scopes for years and I find them very useful.  For one thing, they just look cool! ...

Well, I guess if you like to have the toys to show...  But I will maintain that checking the rigs occasionally with the monitor and keeping the adjustments where they should be (once you've found out where they should be) is all you have to do.  Of course, I'm of the opinion that my ham station should be useful, not flashy, and your opinion may differ!   Grin  73!
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AA4PB
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« Reply #8 on: August 25, 2012, 07:02:37 AM »

Those big "on the air" signs are really cool too  Grin
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W8GP
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Posts: 190




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« Reply #9 on: August 25, 2012, 03:11:11 PM »

 Of course, I'm of the opinion that my ham station should be useful, not flashy


  Those big "on the air" signs are really cool too


  Thanks for your comments , kids, and I'm proud of you for being able to keep your stations clean with a minimum of equipment. If a monitor scope is "flash" then bring it on! The appearance of a well equipped station is one of the things that attracted me to the hobby in the first place. If you would spend a little more time tuning the bands then you might notice the horrible signals from the people who obviously don't have a clue how to operate their equipment. And it's often the same stations with their wide signals night after night thinking that their set-it-and-forget-it adjustments are good enough.  I commend the original poster for having the interest in keeping his signal clean and I'm a little suprised (or not) that he was discouraged from using an obviously helpful piece of gear.
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AA4PB
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« Reply #10 on: August 25, 2012, 04:25:23 PM »

I'm just questioning how useful an oscilloscope is as a continuous station monitor for a SSB station. He said he was also considering a spectrum analyzer. I think that would provide a far better indication that he was outputting a clean signal.

I think you first indicated that you liked oscilloscopes because they look "cool".  Wink
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ZENKI
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Posts: 906




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« Reply #11 on: August 26, 2012, 03:43:24 AM »

The best station monitor you can buy or own is a SDR receiver. 

A SDR receiver especially a direct sampling receiver captures every piece of trash that comes out of your transmitter. Most of the good SDR receivers have better dynamic range and speed that exceeds  the performance of the
mega buck name brands spectrum analyzers. They excel in station monitoring  applications.  You wont go wrong adding a SDR receiver to your station as a monitor.

Oscilloscopes work OK on AM however for SSB and CW use they just about useless unless your signal is badly over driven. Oscilloscopes do not work in the RF domain!
It always amuses me hearing comments  from stations like " i am looking at my oscilloscope and I cant see any splatter"   
You really need some kind of FFT storage analyzer if you going to see flat topping however you wont see any splatter unless you have a faulty spectrum analyzer!

Most of the splatter that you hear on the air comes from radios with poor ALC designs  that causes excessive IMD and buckshotting. A  SDR receiver gives you a perfect picture of what damage your radio is doing.
Its also a great tool for monitoring your transmitter audio quality. SDR receivers are to as close to perfect as you can get for  assessing audio frequency response and transmitter audio quality.
A SDR receiver can also tell   you if you have holes in your audio frequency response or whether you are concentrating your voice energy  and power in the wrong end of the  audio spectrum(excess bass)

If you moderate ALC and dont use selfish inconsiderate modes like  ESSB  audio you will be ok 99% of the time  when using a stock factory radio and mic.

The worst station monitor you can have is a ham buddy. Most dont know what splatter is, most dont know how to do a proper splatter assessment, and most good ham buddies dont want to hurt your feelings. They will tell  you deliberate lies. I hear this kind of behavior all the time when some other ham gives a station a report that he or she is splattering. The buddy will say " i hear no splatter here, you S9 and and I hear nothing. Most people who live in the city  have noise floors that are too high or  the signal strength from the offending  hams is  not strong enough to give an indication of signal quality. The worst station to ask for a splatter report  is a DX station, yet we hear many stations asking DX stations if they can hear any splatter. Most splatter products are below legal QRP power levels. If you have confidence in  a DX stations  ability to   give you a honest splatter report, just reduce your power down to 1 watt and see if he can hear you. If cant hear a  1 or even a 5 watts signal how  is he  ever going to able to hear your splatter products from the other side of the world.

If someone gives you a report  that you are splattering you should always ask for the signal S-meter  level  rather than screaming its your stinkin receiver. Then you simply get of the air, plug in the SDR into a  dummy load or attenuator and transmit into the SDR receiver at the  signal level  that the reporting station gave you. You will instantly know if you splattering if you are using a good SDR receiver. You can see the splatter signal signature there on the screen.
When you look at the waterfall display you will see a nice brick wall signal. Signals with excessive splatter will have the distinct buckshotting lines being emitted from the waterfall pattern. In the spectrum domain if you narrow the span and scale you can see the 45 degree IMD shoulder as it falls away from the signal. Many stations have that really broad 45 degree shoulder indicating IMD problems. Good radios like the FT5000  even when the signal is 50 over S9 dont have this characteristic IMD 45 degree shoulder. The signal is essentially clean. Anyway you will learn all these signal traits as you monitor many stations.

My view is these days, is that the louder and more a station protests about receiving a splatter report  the more technically incompetent that  station is. You never hear the big mouths say look OM  I have a second receiver monitoring here and I cant hear anything. Its always your crappy receiver or  that you have the noise blanker on.   Most stations are aware of the receiver issues and noise blankers etc etc   these days. Its really hard to cause any modern receiver real problems from simple overload from a single single. Even a basic radio like a IC706MK2 is a good enough receiver to use as a station monitoring receiver. Its a bad receiver if you have the noise blanker on!

Anyway every ham station should use a SDR as a station monitor rather than a close to useless oscilloscope. Its even more important to  use  a SDR receiver if you using one of the Russian tetrode amplifiers with a modern radio. This combination is the biggest cause of splatter we see on the ham bands!  Even a simple Softrock receiver is better than any oscilloscope as a station monitor. Its a real pity that the available pan adapters on most radios cant even monitor the TX signal. Rather than adding useless features on transceivers the manufacturers should add things like TX monitoring from the bandscope, a  -40db tap  or a simple 40 Db attenuator dummy load for these tests.  These features would be easy to add to radios these days.

With  a SDR receiver in the shack any ham can have a true professional signal quality monitoring system in place that rivals the best commercial spectrum analyzers, what  more can you want?
The next best thing would be to have IMD laws like commercial SSB radios so that you know that you can never splatter or over drive. You certainly would not need SDR monitor receiver if the ham services  had
proper transmitter IMD laws.  It always amazes me when  I take my old Icom Marine radio and put it on the air, perfect audio and no splatter regardless of what I do, this is how ham radios should be designed!



Well, I've been building my station now for a while (as "play funds" allow) and think I have a decent set-up.

My transceiver is a TS-940S, Al-80B linear, AT-2500 Tuner (in repair process). Backup is my TS-530S and MFJ-993B.

In consideration for other operators, I want to set-up a station monitor so that I can see what I'm putting out and not contaminate the band with needless splatter, noise etc.
I have a Tektronix 2336 100Mhz scope from the days when I was playing with CB and TV repairs, I believe this should do ok.
I'm also toying with the idea of a spectrum analyzer....

All probably complete overkill? but I want to make sure I'm "true and clean".....

I've found two companies that offer interfaces: CleanRF (www.cleanrf.com) and PreciseRf (www.preciserf.com) both offering similar products.

The other alternative was to software/pc based by Virtins Technology (www.virtins.com), this would be scope/analyzer in one package.


What else is out there...what are you using and works effectively...?

Any comments and or suggestions are greatly appreciated.

73
Bart
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K1CJS
Member

Posts: 5885




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« Reply #12 on: August 26, 2012, 07:16:55 AM »

Of course, I'm of the opinion that my ham station should be useful, not flashy

Those big "on the air" signs are really cool too

Thanks for your comments , kids, and I'm proud of you for being able to keep your stations clean with a minimum of equipment. If a monitor scope is "flash" then bring it on!

Yep.  You have the nerve to call us kids, but then you begin by practically saying "He who has the most toys wins!"

Quote
The appearance of a well equipped station is one of the things that attracted me to the hobby in the first place.

Granted that point, but there is a basic difference between 'well equipped' and 'flashy'.

Quote
If you would spend a little more time tuning the bands then you might notice the horrible signals from the people who obviously don't have a clue how to operate their equipment. And it's often the same stations with their wide signals night after night thinking that their set-it-and-forget-it adjustments are good enough.  I commend the original poster for having the interest in keeping his signal clean and I'm a little suprised (or not) that he was discouraged from using an obviously helpful piece of gear.

Talk about bouncing from one side to the other!  Some of those 'well equipped' stations are the ones who have those horrible signals, simply because they're always tweaking their equipment to try to get the most out of it.  On the other hand, some operators who take the care to know and adjust their equipment but do not always have all matters of test gear always hooked up and running are some of the best sounding stations on the bands.

There is a basic difference between having a well equipped, well run station, and having a station that is not much more than a showpiece of a person who wants to display their toys and always makes sure every piece of equipment can't be helped but be noticed.  73.

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W5DQ
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Posts: 1209


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« Reply #13 on: August 26, 2012, 07:34:52 PM »

Your scope should be fine providing you can find a way to couple it to the RF. I use the Kenwood SM-220 and on QRO (600W) it helps me ensure that I am not doing a NO-NO on SSB and RTTY.  It is great on TX but severly lacking for any decent observations on RX as it is sold to to. I bought it used a few years ago.

Gene W5DQ
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Gene W5DQ
Ridgecrest, CA - DM15dp
www.radioroom.org
W8GP
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Posts: 190




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« Reply #14 on: August 27, 2012, 07:16:52 AM »

Some days I go in my shack and I don't even get on the air, I just sit there and admire all my stuff!
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