How much rejection should I expect?
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How much rejection should I expect?
 
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I have a neighbor on the next street...our antennas are only about 800 feet apart (according to Google maps). I know he doesn't run 1500 watts (luckily) but I think he does run 300 - 400 or so. My question is, how much receiver rejection and/or overload should I expect? He pretty much tears up the entire band on my K3 if my antenna is pointed his way, but not quite so bad on the side. On my P3, the entire noise floor is raised many S units (I'll have to switch to dB and see what it looks like.
Should I expect better, or is this to be expected. I know I haven't provided any real details, but I think many will get the idea. Unfortunately, we're both primarily CW ops! Allen N5XZ K3 #2324 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: How much rejection should I expect?
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His signal level into your receiver is pretty close to 0 dBm. Considering
that an S9 signal is -73 dBm, you really have a huge amount of signal messing things up. Phil - AD5X ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: How much rejection should I expect?
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In reply to this post by Allen Brier N5XZ
Hi,
I live only 300 metres from VP8LP. He works mainly SSB with about 400W. Rig FT-1000Mk5 + 1K solid state amp, ant 3el SteppIR. I use whatever mode gets the job done. K3 + Acom 1000, ant Optibeam OB9-5. Usually 400W. We can usually work the same band 20/15/10 if I'm on CW and Bob is SSB as long as I'm not pointing at him and the required signal is at least S3. I do hear the band noise rise and fall when Bob transmits and when I point at him the K3 shows 9+60dB. On 17/12 metres it's more of a problem. If we are both beaming EU/NA or AF then we have some help from the beams and Bob is only 9+30dB. If there is something juicy on we cooperate instead of killing each other. The first one to work it alerts the other and leaves the playing field clear. Regards, Mike VP8NO On 20/02/2012 15:01, Allen Brier N5XZ wrote: > I have a neighbor on the next street...our antennas are only about 800 feet apart (according to Google maps). I know he doesn't run 1500 watts (luckily) but I think he does run 300 - 400 or so. My question is, how much receiver rejection and/or overload should I expect? He pretty much tears up the entire band on my K3 if my antenna is pointed his way, but not quite so bad on the side. On my P3, the entire noise floor is raised many S units (I'll have to switch to dB and see what it looks like. > > Should I expect better, or is this to be expected. I know I haven't provided any real details, but I think many will get the idea. > > Unfortunately, we're both primarily CW ops! > > Allen N5XZ K3 #2324 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: How much rejection should I expect?
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In reply to this post by Allen Brier N5XZ
On 2/20/2012 10:01 AM, Allen Brier N5XZ wrote:
> My question is, how much receiver rejection and/or overload should I expect? He pretty much tears up the entire band on my K3 if my antenna is pointed his way, but not quite so bad on the side. On my P3, the entire noise floor is raised many S units (I'll have to switch to dB and see what it looks like. It will depend a LOT on what rig and amp he is using, and how he tunes (or mis-tunes) his amp. A K3 is REALLY good at rejecting off-frequency signals, but there are a lot of rigs and amps that fill up the band(s) with trash AWAY from their frequency. In contests, I run two K3s, each feeding a Titan 425 amp at about 1.2kW, into mono-band antennas that are about 150 ft apart. On 20M and above, they are 3 and 4-element Yagis. Depending on how those antennas are pointed, I can have them as close as 60 kHz ON THE SAME BAND and one K3 does not know the other one is there! On the other hand, if I point either of those antennas at the other, I'll hear a lot of my own phase noise, and the K3 will automatically turn off the preamp and kick in the attenuator. Now, the smallest coax in my station is very good RG8/213 and RG11, some of it is CATV hard line and Heliax, all the connections are carefully hand soldered to Amphenol connectors, I'm careful about how I tune the amp, and I don't use AGC between the amp and the K3. We also use three K3s for our county-expedition during the California QSO Party, and on 20, 15, and10, have two tri-banders set up about 150 ft apart, carefully located so that when pointed east, they are at 90 degrees to each other. We run 500W amps, and this past year one of them was a KPA500. We also used an ACOM and a Yaesu amp. With that setup, we could have both CW and SSB stations on the same band and one would hear phase noise from the other at about S6-S7. Coax is typically a grab bag of what's everyone's spares, and a lot of it is crimped from a popular ham vendor. I've got an 80-year old neighbor about two miles south of me who works SSB contests by calling CQ non-stop as long as he's awake. I have no idea what he's using for a rig or amp, but he wipes out all of whatever band he's on with phase noise and intermod. My neighbor, K6XX, is 3 miles away, and runs K3s to several different f ancient amps. We can work 500 Hz from each other on any band. Another neighbor 10 miles away runs an Icom 7600 into a big amp and sometimes wipes out 20 kHz with his phase noise and clicks. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: How much rejection should I expect?
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In reply to this post by Allen Brier N5XZ
Your situation is essentially two stations in the same location. It's like
a multi-transmitter contest station. A set of bandpass filters should let you operate on a different band than your neighbor, needing only to avoid the immediate vicinity of his harmonics. But operating on the same band would require very sophisticated filtering and probably staying on opposite ends of the band and therefore on different modes. I don't recommend it. /Rick N6XI On Mon, Feb 20, 2012 at 10:01 AM, Allen Brier N5XZ <[hidden email]>wrote: > I have a neighbor on the next street...our antennas are only about 800 > feet apart (according to Google maps). I know he doesn't run 1500 watts > (luckily) but I think he does run 300 - 400 or so. My question is, how much > receiver rejection and/or overload should I expect? He pretty much tears up > the entire band on my K3 if my antenna is pointed his way, but not quite so > bad on the side. On my P3, the entire noise floor is raised many S units > (I'll have to switch to dB and see what it looks like. > > Should I expect better, or is this to be expected. I know I haven't > provided any real details, but I think many will get the idea. > > Unfortunately, we're both primarily CW ops! > > Allen N5XZ K3 #2324 > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > -- Rick Tavan N6XI Truckee, CA ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: How much rejection should I expect?
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In reply to this post by Jim Brown-10
Jim, did you mean ALC?
73, Mike NF4L On 2/20/2012 1:42 PM, Jim Brown wrote: and I don't use AGC between the amp and the K3. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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In reply to this post by Allen Brier N5XZ
As Jim pointed out, there are two factors to consider - your receiver and
his transmitter. I operate SO2R with a pair of K3/P3/amp set ups. I live reasonably close to other contesters who are usually operating the same mode/same band as I am. Before, when I had a pair of FT-1000Ds, I could hear 'em when they were within 25 KHz of me. Now, I often don't know they are even on the air until I pass their operating frequences. So, the K3 is excellent. But, I "dirty" transmitter that is producing close in spurs will cause problems no matter what kind of RX you are using. Rob K6RB > I have a neighbor on the next street...our antennas are only about 800 > feet apart (according to Google maps). I know he doesn't run 1500 watts > (luckily) but I think he does run 300 - 400 or so. My question is, how > much receiver rejection and/or overload should I expect? He pretty much > tears up the entire band on my K3 if my antenna is pointed his way, but > not quite so bad on the side. On my P3, the entire noise floor is raised > many S units (I'll have to switch to dB and see what it looks like. > > Should I expect better, or is this to be expected. I know I haven't > provided any real details, but I think many will get the idea. > > Unfortunately, we're both primarily CW ops! > > Allen N5XZ K3 #2324 > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: How much rejection should I expect?
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In reply to this post by Mike Reublin
On 2/20/2012 11:36 AM, Mike wrote:
> Jim, did you mean ALC? Yes. Thjanks. Jim ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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