Real On-Air Spectrum Analyzer Test Videos - Put 'em on the table mate!

[K1JJ]

OK, thanks, Frank.  Now that I understand what it's measuring, I think it's a great waveform to test with.

Bruce, that SBE picture looks like a worm wiggling it's way across the band... :-)

The other night when talking with Tron on his SBE rig, I came up with an analogy:  Ever see a biker club rolling down the highway?  They usually have at least one guy on a trike in the back. He takes up a full lane and protects the motorcycles in front of him from cars cutting in too close...  Tron is riding the trike on frequency...


Another analogy:  Tron using his SBE is the drunken miscreant who gets on the bus and sits down next to you. He belches in your face and then pukes down your collar. He then gets up and sits next to an old lady....

I find the SBE rig a scream when it occasionally shows up.


BTW, speaking of triangle tests - Don/ K4KYV - I'd really like to see your clean sounding transmitter doing the 600/400 and 200HZ triangle test.  With several transformers in line, I'd be real curious how it handles it.  Put those BA's up on the table mate!
 

[K1JJ]

Here's new triangle pics with the digital audio low pass filter out of the circuit.  Notice how much sharper the peaks are than before - shows wider high-end frequency response.

#1 = 600hz
#2 = 400hz
#3 = 200hz

[K1JJ]

Just to show how tough the triangle test is at low frequencies, here's a 35 hz sinewave thru Fabio running moderate power at 2KV.  You would normally think it looked pretty good, but the triangle test disagrees somewhat.

T

[WA1GFZ]

I bet you are saturating the mod transformer. Good thing we don't speak in triangle waves. Where is the 600 pounder

[K1JJ]

I bet you are saturating the mod transformer. Good thing we don't speak in triangle waves. Where is the 600 pounder

No, I don't think it's a power saturation issue with the mod transformer. If I put 3KV on the rig, I can modulate a carrier even bigger than the one at 2KV, cleanly. I think 4X1 modulators at 2KV are dying for more voltage. The Eimac specs start at 4KV and go up to 6KV.  I would really like to have 2KV on the final and 3KV on the modulators, but I have only one supply.   So the compromise is to have 3KV on both and load the final lightly so there is plenty of modulation headroom for the given carrier.  The problem then is the mod xfmr is at it's voltage breakdown limit and scares me to run it that way.

Another problem is I have 400 volts reg screen voltage on the modulators, so that effectively reduces the plate voltage 400 volts. The 4X1's are screaming, "MORE PLATE VOLTAGE!"

Yes, the [1300] pounder mod iron wud be nice for voltage breakdown reasons, but it's gone to somewhere in Maine.... .

T

[W2VW]

Come and get it's brother. U move it.

[N2DTS]

Pix of my rig at 100% modulation, 20 Hz, triangle wave, received off the homebrew RX IF output...

Brett

[K1JJ]

Damn, that's a nice waveform, Brett. It's 20hz or 200hz?  Is this an H series modulated E rig?

What does it look like when you run a 1khz or 2khz freq thru?  

Does the point of the triangle sharpen up when you increase the triangle freq?

T

[W1DAN]

Brett;

Great waveform!

Modulate Proudly!

Dan

[K5UJ]

I've been getting caught up here.  Jack, sorry you didn't know about the RTA feature.  I use it a lot.  I can look at my high end rolloff for one thing.  If I had known you had one of those 2496 "ultra-curve pro" swiss army knives I would have told you about it a long time ago.  

Tom, are you using a mod. reactor?  Separate p.s. for the modulator sounds great but pricey of course.  There's that 5 KW mod. trans. on ebay (but it is in Utah  ).  

I have a 1000MP Mk V that is fixed to handle low frequencies but I have no idea how to generate one of these triangle sigs.  I have an AF sig. generator that puts out sine waves and square waves.   I have the station setup now on 1880.  Going to be on 160 for a while since the 160 season is starting to wind down.

Rob  

[WA1GFZ]

Brett,
I bet the peaks would be sharper if you looked directly at the TX output with a scope pick up.

[N2DTS]

20 Hz, not 200.
Going up in frequency looks the same.

Flex 5000, into the homebrew amp, about 1000 watts pep.

Below is the homebrew pair of 813's, 4cx250b mod deck, 90% power output, 200 Hz triangle, DC through the mod transformer.
All waveforms off the homebrew RX if output, I never looked at the waveforms directly off the RF...

Its very risky running high power tests, I once blew out the mod transformer in the 30K1 doing full power tests at low frequencies, it went VERY quickly!
I am not going to try 20 Hz 100% modulation through the 813 rig...

Sweeping it at 50% modulation shows 40 to 18,000 +- 1 db.

I don't think you would ever pass a clean 20 Hz triangle through any sort of transformer...

Also, I found a free tone generator program on the web that does saw tooth, triangle, impulse, sine, etc.
Its called NCH tone generator.


Brett

[K1JJ]

The 813 rig looks decent, especially the sharp peaks for high freq response.

A good MOSFET audio driver might help your 813 rig too. I'll let ya know when we get a working unit soon. Design is going on now in the background by a famous board member here.

Dave/ VW:  Hang on to it. Maybe I will make the trip down there if I get just a little more more desperate....

T

[DMOD]

It is a shame others don't have your diligence.

And Tom, your audio sounds great, even with a lot of bandnoise and adjacent stations.

In fact, your bandwith was much better than the SSBer's running on 3.870-75 Sunday night. They were running about 14 kHz RF bandwidth.

Phil - AC0OB

[ke7trp]

Yes.. They are jamming the AMI net right now on 3870.  They wont even move for a NET.  People are real frusterated. What a bunch of A-holes.  The one with the deep voice in particular. He is about 12 WIDE easy.. Says he has a Right to run ESSB for us to get off his Freq..LOL

Tom makes his own conditions.. I can always hear him.


C

[N2DTS]

There are plenty of guys on AM that are 20+ KHz wide, so 12 KHz is not bad.

Just use the other sideband with the ecss detector, its like they are not there.

I once was on 3870, since I have a strong plazma TV noise on 3880, and those guys were on 3868.
After the qso I went down and thanked the guys for leaving room, which they thought I meant they did not leave room (since they were there on purpose to cause trouble).

They said something like the AM window was 3870 to 3890 and they had an agreement that AM would stay within that window, and if my sidebands were outside, they could get as close as they wanted since I was outside the window.

I told them, as a phone operator, I was allowed anyplace in the phone band, and I never made any agreement to stay within the window. They went off on that saying the treaty was void and war would break out.

I think its nice to stay within the window during prime time, I don't have a problem with that, and its more aimed at not bothering them.
But the idea they were not bothering me being 2 KHz away went over their heads.

I find it amusing that so many guys have nothing better to do in life but play games on radio, both ssb and AM operators.

I think its best to get a GOOD receiver and operate as best you can, ignoring anyone who gets close.
With modern sdr receivers, you have brick wall filters, can pick bandwidths and the sideband you listen to, and can eliminate 95% of ssb interference.
I also notice that lots of interference does not exist on a good receiver, a clean signal CAN be VERY close and not be heard.
Looking at the sdr displays, many ssb signals are VERY close to each other, I have seen three ssb qso's in 10 KHz without causing each other any problems!


What you cant eliminate is the bozo on AM that is over 20 KHz wide who takes up the entire window plus...

I have been running the sdr-iq on the laptop while I am on the air, and with the EQ chopped 24 DB above 6 KHz,  I seen to be about 6 to 8 KHz wide, with very slight artifacts out to about 15 KHz, not sure if that is the sdr-iq being so close, its not a great receiver in that respect, but its likely because the highs are only 24 DB down.....

I will just stick to uncrowded daytime operation....

Brett

[ke7trp]

Let them run wide.. I dont really care. I am not a band cop.  THe issue is that when we have a scheduled net with a couple dozen operators, They tell you to F off and refuse to move, We have a problem.. 

To me, It does not matter, I can talk right over them and I have good recievers.  Its a real shame though when you see all these guys on low power rigs that waited all week to use the station they worked on, And cant.

C

[K1JJ]

Yes, nets and large groups with some weak stations involved can be a problem and vunerable to QRM, no doubt.

When someone comes in to intentionally QRM a QSO I'm in, I consider it a challenge to continue the communication without skipping a beat. This does two things: First, it will often bore the QRMer cuz he doesn't get a rise and sees he is having little effect - and usually goes away. Two, I get some great practice working the weak ones in tough cornditions. Having "good ears" is an acquired skill needing constant practice, so they are actually doing me a favor...

Oh, one last thing - once in a great while QRM is generated simply cuz a frustrated ham wants a signal report - he wants to see what kind of effect he has on the QSO.  Occasionally, I've said to the QRMer, " To the QRMer - your signal is S9+20 - a good signal, though most in the group are a little louder." (I give a true report) Sometimes they continue on. Sometimes they go away after being acknowledged. One even keyed his carrier twice as a thank-you and then split...

T

[ke7trp]

LOL..   Good story tom.

It sucks to have to run high power all the time.  Before the SSBers landed on 70, I used to sit there with a Damn Ranger, SX100 and a D104.  I talked 4 or 5 nights a week to all my Friends. We never had a problem. Life was so simple. Turn on ranger, Turn on receiver, Talk and enjoy yourself.

C