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Author Topic: Splattermaster  (Read 94587 times)
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KZ5A
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« Reply #125 on: January 17, 2012, 09:04:31 AM »

Well, this thread seems to have devolved into a semi interesting airing of everyone's opinions about monitor scopes.  Mine is that any monitor scope is better than no monitor scope. Huh

At the risk of getting back to the original subject.... I live in Tyler, TX about half way between WW9W and the rest of the 3890 crew in north Dallas.   I normally listen to AM on a 75A4 but split the RX path and feed the other half back to my Elecraft K3.  The K3 supports a "LP-PAN" panadapter that runs full screen on a 22 inch monitor.  If it's out there, I can see it.

I usually monitor the 75M AM window till around 10AM when I move to 7160.   You do see the occasional over-driven audio type signal and most of the heavy iron rigs appear a bit wider than  the typical ham TX.   What I don't see is the 10's of KCs wide signals reported by the lid with the cheezy ricebox pan-adapter.

When I first started using the LP-PAN  setup my impression was that most of the SSB TX's in the world had poor unwanted SB suppression, because I could see the "other" SB on the pan-adapter.  A little further down the learning curve I figured out that a normal SSB signal that is 40 db above the noise is going to show the other SB at around 10 db.  30 db being fairly typical SB suppression.

Some of the really strong AM stations, like say Robert's, hit me 60 db above the noise floor and I can see artifacts outside the "normal" passband but they are 50 db or so down from the CXR and do not constitute a problem, just the normal reception of an extremely strong signal. 

When I TX, the panadapter goes into gross overload and shows my CXR appearing again about every 10kcs over the entire 190kc's it monitors.  Near as I can tell there is only one actual signal there. 

I think this is whats happening to the lid that did the u-tube postings, the difference being that he is too uneducated and/or un-intelligent to understand that what he is seeing is created by his overloaded POS ricebox.

73 Jack KZ5A

QOD - Does "the minimum power necessary for reliable communication" cover running enough power to keep the SSB operators at bay? Grin Grin Grin

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73 Jack KZ5A
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« Reply #126 on: January 17, 2012, 01:31:29 PM »

30 dB is piss poor opposite sideband suppression for a modern rig. Even my CE 100V beats that and it's 55 years old.   But that's an SSB topic for another time and place.


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KM1H
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« Reply #127 on: January 17, 2012, 02:04:51 PM »

Many seem to be confused how to hook up a modern broadband SS scope to an AM rig as the ARRL lost interest long before anything like that arrived.

Perhaps a tech article in the proper forum section is due. Or even in ER or horrors....QST!

Carl
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WD8BIL
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« Reply #128 on: January 17, 2012, 03:21:17 PM »

Quote
That third video tells it all.   The transmitter appears to have high frequency audio parasitics OR has some arcing going on somewhere between the modulator/final and the antenna.  To cover +- 100kc with that raspy side splatter is indicative of one or both of these problems. (Or caused by severe receiver overload if the receiver is located down the block and using a full antenna without attenuator - as mentioned later in this thread)

This may well be the case,Tom. But it may also be showing the point at which the receiver can no longer handle strong signals and whatever stage is crashing starts to generate massive IMD.

The only way to straighten that out is to have the receive op crank in enough attenuation to be definitive.

If we're gonna start throwing eggs at each other we better be abasolutely sure of our fact. These videos are in no way conclusive.
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K1JJ
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« Reply #129 on: January 17, 2012, 04:17:30 PM »

Quote
That third video tells it all.   The transmitter appears to have high frequency audio parasitics OR has some arcing going on somewhere between the modulator/final and the antenna.  To cover +- 100kc with that raspy side splatter is indicative of one or both of these problems. (Or caused by severe receiver overload if the receiver is located down the block and using a full antenna without attenuator - as mentioned later in this thread)

This may well be the case,Tom. But it may also be showing the point at which the receiver can no longer handle strong signals and whatever stage is crashing starts to generate massive IMD.

The only way to straighten that out is to have the receive op crank in enough attenuation to be definitive.

If we're gonna start throwing eggs at each other we better be abasolutely sure of our fact. These videos are in no way conclusive.


Yep, it could be the receiver being heavily overloaded. That's why I mentioned it in my comments above.

I certainly have no axe to grind. Never met or heard him on. Just going by a video that may be accurate or invalid.   Maybe he does have a problem with the rig or maybe not.  It's better to have some proper tests run than for us to speculate and sweep it away. I've had problems pointed out with my rigs and was always grateful - and jumped on it right away.  Some were real and some were not.  It's hurts all AMers if there are real problems with our rig and nothing is done to correct it.   Has anyone contacted him and offered to help? How far is Lorraine, Ohio from him, Bud?  Grin

T

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Use an "AM Courtesy Filter" to limit transmit audio bandwidth  +-4.5 KHz, +-6.0 KHz or +-8.0 KHz when needed.  Easily done in DSP.

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« Reply #130 on: January 17, 2012, 05:11:44 PM »

Quote
That third video tells it all.  ...

... These videos are in no way conclusive.

Did anyone notice that those videos are dated July 2010?

But the very wide splatter I mentioned from Maine in an earlier post in this thread was in the past month or so. (But I haven't heard it since.)
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73 Mike 
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ke7trp
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« Reply #131 on: January 17, 2012, 06:24:33 PM »

Its the Icom that cant deal with the big AM signal.  Its full scale to that front end. 
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WD8BIL
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« Reply #132 on: January 17, 2012, 09:29:34 PM »

As the crow flies I'm 981 miles from Robert. I have heard and qsoed with him many times and didn't notice what is shown in the video. I've been in qsos 5kHz from him and not had a problem. FWIW!
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K5IIA
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« Reply #133 on: January 17, 2012, 09:41:38 PM »

old stuff that has been fixed long ago. but still some good reading in the thread for sure.  i'd like to find out who is making all these lighting crash sounds in my rx in the middle of january? haha
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K1JJ
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« Reply #134 on: January 17, 2012, 09:51:38 PM »

"Did anyone notice that those videos are dated July 2010? "

"old stuff that has been fixed long ago."



Cheezz... That's over 18 months ago.  Another 10 minutes of my life wasted...  Roll Eyes   Wink


T
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Use an "AM Courtesy Filter" to limit transmit audio bandwidth  +-4.5 KHz, +-6.0 KHz or +-8.0 KHz when needed.  Easily done in DSP.

Wise Words : "I'm as old as I've ever been... and I'm as young as I'll ever be."

There's nothing like an old dog.
Pete, WA2CWA
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« Reply #135 on: January 17, 2012, 10:13:36 PM »

I saw that right when Don posted the links at the start of the thread. You guys aren't very observant.
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K5UJ
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« Reply #136 on: January 17, 2012, 10:16:08 PM »

  i'd like to find out who is making all these lighting crash sounds in my rx in the middle of january? haha

There was LIGHTNING just south of me this morning when I got up and looked on the Vaisala thing.   Huh 

It's frigging JANUARY and I guess I can't even relax and leave everything hooked up in the dead of winter anymore.
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k4kyv
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Don
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« Reply #137 on: January 18, 2012, 02:37:43 AM »

"Did anyone notice that those videos are dated July 2010? "

"old stuff that has been fixed long ago."

Yes, I was aware of the date on the videos.  But if the problem was "fixed long ago", why haven't the videos been taken down?

Besides, some here don't seem to agree that the issue has been resolved.  Re-read replies #2 and #3. OTOH, the thread on QRZ.com just appeared less than a month ago.

The issue is not how long ago something was posted, but the fact that complaints about "bandwidth" and "splatter" aren't just limited to slopbucketeers griping about AM; AMers are complaining about other AMers on non-AM forums, drawing previously disinterested members of the amateur community at large into the fray.

If this isn't going out of one's way to instigate more "bandwidth" controversy (and possible petitions), I don't know what is.

Most importantly, it behoves all of us running AM to take measures to assure that our signals really are clean, and that the inevitable complaints we do get are without merit.
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Don, K4KYV                                       AMI#5
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flintstone mop
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« Reply #138 on: January 18, 2012, 06:48:16 AM »

"Did anyone notice that those videos are dated July 2010? "

"old stuff that has been fixed long ago."



Cheezz... That's over 18 months ago.  Another 10 minutes of my life wasted...  Roll Eyes   Wink


T


It's My Wirl..................It's My Whirl...............
From the Prudential commercial......I wish I could find the clip and send it to JJ....I cannot figure out if Tom wants to AXE us something or he is grinding a new AXE.
geday
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Fred KC4MOP
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« Reply #139 on: January 22, 2012, 02:27:46 PM »

A good example of a splattermaster, the SW broadcast station on 21.630 MHz is severely overmodulated and is splattering all over the 15M band.  Discovered it today while listening to some 15M AM ham stations.   I sent an email to the stations website.
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K3ZS
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« Reply #140 on: January 22, 2012, 02:33:56 PM »

They just switched transmitters or dropped power and it went away 14:30 EST.
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Steve - K4HX
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« Reply #141 on: January 22, 2012, 02:40:59 PM »

It's still there. I can hear it right now. Incredible splatter!
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wb1ead
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« Reply #142 on: January 22, 2012, 05:17:07 PM »

The SW broadcaster is not really the topic here but well could be..that's downright nasty!..this station a religious oriented station on 21.630 has been "splattering" for over 3 months..at times reaching as far as 600khz left and right of the main signal..I left word with W0TDH to contact Chuck Skolaut to look into this..this is the 2nd time I do this..for awile they seemed to heed the concern as they were very "clean" signal wise..methinks it's time for a new engineering crew there or if no crew then hire one..I guess the lesson is if ya want to really experience splatter..head to 21.630 and tune up or down..FWIW there's my rant on this subject although it is off topic a bit....by the way Steve I hoid ya today on 15mtrs just b/4 I yakked it up with Bill..nice signal!  73 de DAVE
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« Reply #143 on: January 22, 2012, 11:12:49 PM »

Call the station again and tell them you are going to complain. They might not even know it if it does not always happen. Maybe some poor engineer can make a buck if the station fears the FCC. It could be an arcing issue or something, they think its fixed but the root cause was not found?  I can't pick up the station.
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Steve - K4HX
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« Reply #144 on: January 23, 2012, 12:28:50 AM »

That station is putting some of the CBers to shame with the wide signal. It almost sounds like FM!
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KX5JT
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« Reply #145 on: January 23, 2012, 01:31:56 AM »

That station is putting some of the CBers to shame with the wide signal. It almost sounds like FM!

Steve, are you talking about the SW Holyroller broadcaster or the Ham station originally talked about?

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Steve - K4HX
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« Reply #146 on: January 23, 2012, 07:27:53 PM »

The shortwave station I heard yesterday.
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