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Author Topic: Way too much power OM BS  (Read 3776 times)
K5USF
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« on: June 09, 2011, 08:23:02 PM »

What is the deal with some of these PSK operators...Twice in the last month some dope cuts in and prints ""way too much power OM" without identifying themselves.  That's an unauthorized transmission.  I run 30 watts psk into a 31 foot vertical with 40 radials and a auto tuner at the base of the vert.  Radio is ICOM 746pro with signalink USB and dm780...ALC is ZERO.  They need to identify themselves and give me a S/N and IMD reading.  But no, they are just out to piss people off. I'm telling ya, some of these guys are going to be the demise of ham radio.
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N3OX
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« Reply #1 on: June 09, 2011, 09:56:52 PM »

What is the deal with some of these PSK operators...Twice in the last month some dope cuts in and prints ""way too much power OM" without identifying themselves.  That's an unauthorized transmission.  I run 30 watts psk into a 31 foot vertical with 40 radials and a auto tuner at the base of the vert.  Radio is ICOM 746pro with signalink USB and dm780...ALC is ZERO.

This is what happens when people don't understand the possible dynamic range of propagation variations and furthermore insist on using a reception system with negligible selectivity.

People with good big signals, no matter how they got them, wipe out the PSK waterfall.  Instead of kicking filters in, people bitch and whine, apparently even go around yelling at people.  All the while, they're failing to understand the huge range of signals on HF even from identical stations.  If I look at the range of SSB signals coming in on 20m at certain times, and I "read the mail" a bit to find out what pepole are running, I find something which is kind of an obvious thing to me after being on the bands for a while.    100W and a dipole from somewhere with marginal propagation might have a signal right near the S5-ish noise floor, while the same station from somewhere else (always seems to be Texas or Colorado) might be S9+30dB.  This, on my radio, is probably between 50 and 60dB difference.

If I try to explain this with power variations between the two stations, they have to be different by a factor of ONE HUNDRED THOUSAND to ONE MILLION.  If the weaker station is running one watt, the bigger station has to be running a literal megawatt.  And yet, over and over and over again I hear people trying to claim "oh, that guy is running illegal power" or, in the case of PSK31, "that guy is running more than the pitiful amount of power that it's socially acceptable to run on PSK31."

These people (not just confined to PSK ops, at all) are just lacking in understanding of HF path loss and how two stations, both running 100W, might have a MILLION times different signal level. They blame it on transmitter output power even though that's absurd.  Since many people are just running a stock 100W, the loud guys must be running 100,000,000W.  Yikes!  People also don't really seem to understand that the little crystal filter in a rig fairly easily knocks down signals far outside of its passband by a factor of a million or more.

Anyway, next time you get on the air, please use a thousand to one voltage divider between your rig and antenna otherwise I'm going to yell at you.  I won't identify so consider this your warning Grin
« Last Edit: June 09, 2011, 10:01:15 PM by N3OX » Logged

73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
KC2UGV
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« Reply #2 on: June 10, 2011, 06:00:00 AM »

What is the deal with some of these PSK operators...Twice in the last month some dope cuts in and prints ""way too much power OM" without identifying themselves.  That's an unauthorized transmission.  I run 30 watts psk into a 31 foot vertical with 40 radials and a auto tuner at the base of the vert.  Radio is ICOM 746pro with signalink USB and dm780...ALC is ZERO.  They need to identify themselves and give me a S/N and IMD reading.  But no, they are just out to piss people off. I'm telling ya, some of these guys are going to be the demise of ham radio.

Because they have sub-standard gear, with sub-standard filters...  And kvetch when someone happens into their bandpass.

I, at first thought the same thing, that people wiping out my waterfall were running too much power.  Then I discovered the "IF Shift" knob, and remembered I had a VFO Smiley

I never did rage on a station without ID though.  I figured (Rightly so), "maybe I'm doing something wrong".
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AA4PB
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« Reply #3 on: June 10, 2011, 06:54:21 AM »

Using a wide SSB filter while trying to receive a narrow PSK31 signal is like using a filter wide enough to let in the whole 20M band while trying to receive a SSB signal.

On one occassion when I informed a complainer that I was only running 30W (on 20M) he informed me that my antenna was "too good". According to him, PSK31 was designed to be used with a low dipole, not a tower and Yagi.  Grin

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W8JX
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« Reply #4 on: June 10, 2011, 07:10:03 AM »

It is not so much your signal strength as it is the receiver in radio of those complaining. If their radio lacks IF selectivity a strong signal will swamp their radio AGC and make weaker signal tuff to copy. Your sound card waterfall cannot fix this. When I used a narrow digital mode I use a narrow CW xtal filter in IF.  It makes such potential problems far more manageable.
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K5USF
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« Reply #5 on: June 10, 2011, 09:03:33 AM »

RR for all the comments.  When I get hit by a big psk signal (one that has good IMD and no sidebands present), I start playing with the twin PBT on my ICOM and null it out...Real simple..The only signals I have seen that wipe out the band are nasty with crappy IMD.
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N3OX
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« Reply #6 on: June 10, 2011, 10:43:15 AM »

Some people view multiple-signal reception over a 2.4kHz+ waterfall to be their inalienable fundamental right, rather than something nice you can do for casual scanning when the dynamic range of the signals you can hear is small enough Grin
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73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
K5USF
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« Reply #7 on: June 10, 2011, 10:51:19 AM »

Thanks guy!  73s Jim
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W8JX
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« Reply #8 on: June 10, 2011, 11:58:48 AM »

Some people view multiple-signal reception over a 2.4kHz+ waterfall to be their inalienable fundamental right, rather than something nice you can do for casual scanning when the dynamic range of the signals you can hear is small enough Grin

Well put!  Smiley
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G0GQK
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« Reply #9 on: June 10, 2011, 02:04:39 PM »

When PSK31 was invented the originator of the software designed a narrow communication method which would allow more people to operate on a frequency with low power and have worldwide communication with poor antennas. He decided that after many months testing, that all that was required was 10-15 watts and often if more power was used the transmitted signal became distorted and consequently caused problems to stations adjacent to the signal.

G0GQK
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W8JX
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« Reply #10 on: June 10, 2011, 02:44:33 PM »

When PSK31 was invented the originator of the software designed a narrow communication method which would allow more people to operate on a frequency with low power and have worldwide communication with poor antennas. He decided that after many months testing, that all that was required was 10-15 watts and often if more power was used the transmitted signal became distorted and consequently caused problems to stations adjacent to the signal.

G0GQK

I doubt this. Distortion is not a product of power of transmitter (product of receiver not being able to handle signal level differential in its bandpass) nor is 10 to 15 watts all that is needed at all times and with poor antennas. Also from 15 watts to even 50 watts is less than one S unit and not a cause of major problem. If there is a problem it is with those that think they can do this all the time with a wide bandwidth waterfall and never run into AGC or strong vs weak signal issues. If you run PSK with a wide bandpass you are going to have these problems. Solution is a better receiver and tighter bandpass,  not in expecting others to check with you as to how much power they need to run to keep your wide band pass and waterfall happy.   
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M0HCN
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« Reply #11 on: June 10, 2011, 03:29:51 PM »

The point at which the transmitter IMD and phase noise becomes problematic for other stations is clearly highly rig dependent, but the fundamental issue of blocking dynamic range is only peripherally related to the power being run by any one station given worldwide usage.

80+ dB range is not, can not, be because one guy is running 1000W and another is running 10W (Thats only 20dB difference), it is down to propagation pure and simple, and as has been said, the cure is narrow IF filters, high first mixer IP3 figures, careful tuning and (Particularly on the longer wavelength bands) using the input attenuator sensibly.
If the in band background noise is say S6 in a 250Hz BW (Not that uncommon around here on top band, and I have seen much worse) then there is no harm in padding down to put the in band noise just above the receivers noise floor and the resulting 20+dB of attenuation will cost you NOTHING in being able to copy stations and will improve your strong signal handling by the same amount.  

Someone is crying because their operating skills don't cut it when the conditions get tough or their rig has poor BDR, the fix is at the receiving station. A 250Hz crystal filter between the first mixer and the IF amp will solve many problems, as will appropriate use of the tuning knob and any available PBT or IF shift controls.  

On the transmitting side, there may be something to be said for going to a cartesian loop design to improve the linearity, it is actually nowhere near as hard to do as it once was.

Regards, Dan.
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KB4MB
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« Reply #12 on: June 14, 2011, 08:50:44 AM »

Let's look at this another way - if you are getting this complaint often, try to see if you can dial the power back to 5-10 watts and make the same contacts.  If you struggle at all, go back to operating the way you did, but if you don't, be happy that you can do QRP and be 100% effective, and in the process not swamp those with low end receivers.

Yeah, its most PSK operators fault that they don't have good IF filters, and not giving a call is wrong, and it is a little jerky to just assume anything, and, and you shouldn't have to change - but just trying to see if you can do QRP PSK without any difference might add to your enjoyment, and then those without the filters can carry on with their conversations.  
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KG6AF
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« Reply #13 on: June 14, 2011, 09:28:28 AM »

Let's look at this another way - if you are getting this complaint often, try to see if you can dial the power back to 5-10 watts and make the same contacts.  If you struggle at all, go back to operating the way you did, but if you don't, be happy that you can do QRP and be 100% effective, and in the process not swamp those with low end receivers.

Yeah, its most PSK operators fault that they don't have good IF filters, and not giving a call is wrong, and it is a little jerky to just assume anything, and, and you shouldn't have to change - but just trying to see if you can do QRP PSK without any difference might add to your enjoyment, and then those without the filters can carry on with their conversations.  

If I cut back from 30 watts to 10, that makes my signal ~4.8dB lower, less than a standard S-unit.  How does that help the guy who's complaining?  In all but a very few cases, it doesn't.
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KB4MB
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« Reply #14 on: June 14, 2011, 10:16:37 AM »

Yup, I agree... almost no cases.  But then again, it might just be enough to not swamp an agc circuit.  And it should make zero difference to you and your station in making contacts.  And then you can tell the ham who can't bother to identify himself that you are running 5-10 watts, and to suck it up.

I don't do PSK very often - I find it boring because almost all qso's are canned - at least with other modes if it is a quick qso it ends quickly - psk ones can last a minute and I know how fast of a processor the other guy has or when the operator was "created"; I have tried to engage in a qso and questions won't get answered because there isn't an F key for that...  It is also the only mode where stations get upset when you aren't as bad as them (not as good) in equipment/power/station/antennas. 

I have had my agc swamp as well - but I have never thought to gripe to that operator - I always assumed it was because they had a superior antenna and I an inferior receiver - I just made it a point to work them and see what they are running.  Once the op said it was a 100 watts, and I explained why that should be avoided - every other time it wasn't a power issue - just good antennas or propagation.
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