Re: Topband: B7P
On 4/3/2024 8:13 AM, w3...@roadrunner.com wrote: This thread implies that Life in China comes with huge QRM-powerline noise, which makes a lot of sense. Since the introduction of switch-mode power supplies, the fact that they are cheaper than traditional linear supplies, and the mandate for their use about 20 years ago, they, and other electronic noise sources like power control electronics for motors and solar systems, have become the the dominant noise in most of the world. While power line noise is still there, it is a total mistake to assume that noise we hear comes from arcing in defective equipment and hardware on power lines. I commend this applications note I prepared about eight years ago on the topic. It begins by showing how we can determine whether it's the impulse noise generated by arcing (mostly) on power lines, and the electronic noise. Their RF spectrums are very different, and there are differences in the ways we need to chase them. http://k9yc.com/KillingReceiveNoise.pdf and this slide deck for a talk at Visalia in 2017. http://k9yc.com/KillingRXNoiseVisalia.pdf NK7Z has developed excellent techniques using a very inexpensive (under $150, last I looked) SDR RX to identify multiple electronic sources and reveal the times of day they are active. Topbander WD8DSB has done excellent work on methods of chasing to the source(s). NK7Z's work can help us avoid chasing our tails when multiple sources are present (and they often are), and can tell us what times of day to chase them. Bottom line -- it's still critical to use DFing to get to the source, but electronic noise sources have both drastically increased noise levels around the world, and made finding the source more complicated. 73, Jim K9YC _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: B7P
That sure seems to be the case, Bob. Heck even on 40 meters I have found myself calling loud Chinese stations in vein. My dipole at 45ft just doesn't cut it. It must be that there aren't very many BY hams that live in rural areas with low noise floors. Hopefully portable operations with verticals on the beach will catch on there. Somewhere I have a recording of WA6TQT running stations during the CQ WW 160 SSB contest from the old W6BH mountaintop super-station near Anza, CA. I was surprised to hear a couple of Europeans call him that I could actually hear Q5. It was quite a thrill. Conditions must have been very good that evening. 73, Mike W4EF... On 4/3/2024 8:13 AM, w3...@roadrunner.com wrote: Great to hear ur recording of B7P on 160m popping thru the noise, even if I am 2500 miles further east Hi Hi. This thread implies that Life in China comes with huge QRM-powerline noise, which makes a lot of sense. So the Chinese ops flock to 10m. Most of the ones I worked with my home brew Moxon at 22 ft were peaking 59 and in some cases even stronger during a 15-30 minute window post- Ohio sunset. _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Any Chinese stations with Big Sigs operating on 160?
On 4/3/2024 7:57 AM, Michael Tope wrote: In the case of that 160 meter dipole it was almost always better as a receive antenna for 80 meters. It was better at rejecting ferocious local QRN than the 80 meter inverted-V. Absolute signal level always dropped owing to the mismatch, but the noise level dropped even more improving SNR (from really deaf to pretty deaf). I am sure there were cases where the 80 meter inverted-V was better, but that was the exception not the rule. Signal to noise in the direction of the desired signal is always the issue with RX antennas, just as radiation efficiency in the desired direction is the issue for TX. 73, Jim K9YC _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: B7P
Great to hear ur recording of B7P on 160m popping thru the noise, even if I am 2500 miles further east Hi Hi. This thread implies that Life in China comes with huge QRM-powerline noise, which makes a lot of sense. So the Chinese ops flock to 10m. Most of the ones I worked with my home brew Moxon at 22 ft were peaking 59 and in some cases even stronger during a 15-30 minute window post- Ohio sunset. -From: topband-requ...@contesting.com To: topband@contesting.com Cc: Sent: Wednesday April 3 2024 10:59:11AM Subject: Topband Digest, Vol 256, Issue 2 Send Topband mailing list submissions to topband@contesting.com To subscribe or unsubscribe via the World Wide Web, visit http://lists.contesting.com/mailman/listinfo/topband /> or, via email, send a message with subject or body 'help' to topband-requ...@contesting.com You can reach the person managing the list at topband-ow...@contesting.com When replying, please edit your Subject line so it is more specific than "Re: Contents of Topband digest..." Today's Topics: 1. Re: Any Chinese stations with Big Sigs operating on 160? (w3...@roadrunner.com) 2. Re: Any Chinese stations with Big Sigs operating on 160? (w5znj...@gmail.com) 3. Re: Any Chinese stations with Big Sigs operating on 160? (w3...@roadrunner.com) 4. Re: Any Chinese stations with Big Sigs operating on 160? (Wes Stewart) 5. Re: Any Chinese stations with Big Sigs operating on 160? (Jeff) 6. Re: Any Chinese stations with Big Sigs operating on 160? (David Raymond) 7. Re: Any Chinese stations with Big Sigs operating on 160? (w3...@roadrunner.com) 8. Re: Any Chinese stations with Big Sigs operating on 160? (Jim Brown) 9. Re: Any Chinese stations with Big Sigs operating on 160? (Steve Harrison) 10. Re: Any Chinese stations with Big Sigs operating on 160? (Michael Tope) 11. Re: Any Chinese stations with Big Sigs operating on 160? (Michael Tope) 12. Re: Any Chinese stations with Big Sigs operating on 160? (Jim Brown) 13. Re: Any Chinese stations with Big Sigs operating on 160? (Michael Tope) -- Message: 1 Date: Tue, 02 Apr 2024 17:25:02 + From: w3...@roadrunner.com To: "'topband@contesting.com'" Subject: Re: Topband: Any Chinese stations with Big Sigs operating on 160? Message-ID: Content-Type: text/plain; charset=UTF-8 Just dabbled in the WPX contest looking for Asian stations on 10m, and worked a phenominal ( for me) 13 of them! The big question is: Are there any being heard on Top Band these days? -From: topband-requ...@contesting.com To: topband@contesting.com Cc: Sent: Tuesday April 2 2024 12:00:44PM Subject: Topband Digest, Vol 256, Issue 1 Send Topband mailing list submissions to topband@contesting.com To subscribe or unsubscribe via the World Wide Web, visit http://lists.contesting.com/mailman/listinfo/topband /> /> or, via email, send a message with subject or body 'help' to topband-requ...@contesting.com You can reach the person managing the list at topband-ow...@contesting.com When replying, please edit your Subject line so it is more specific than "Re: Contents of Topband digest..." Today's Topics: 1. Test (Jean-Paul Albert) -- Message: 1 Date: Tue, 2 Apr 2024 08:42:21 +0200 From: Jean-Paul Albert To: topband Subject: Topband: Test Message-ID: Content-Type: text/plain; charset=utf-8 Do not answer, this is a simple test as the list is quiet. 73? F6FYA depuis son iPhone -- Subject: Digest Footer ___ Topband mailing list Topband@contesting.com http://lists.contesting.com/mailman/listinfo/topband /> /> -- End of Topband Digest, Vol 256, Issue 1 *** -- Message: 2 Date: Tue, 2 Apr 2024 12:46:00 -0500 From: To: , Subject: Re: Topband: Any Chinese stations with Big Sigs operating on 160? Message-ID: Content-Type: text/plain; charset="us-ascii" The last, in fact the ONLY, BY station I have ever heard (and worked) on 160 meters was BD4WN in December 2017. 73 Joel W5ZN -Original Message- From: Topband On Behalf Of w3...@roadrunner.com Sent: Tuesday, April 2, 2024 12:25 PM To: 'topband@contesting.com' Subject: Re: Topband: Any Chinese stations with Big Sigs operating on 160? Just dabbled in the WPX contest looking for Asian stations on 10m, and worked a phenominal ( for me) 13 of them! The big question is: Are there any being heard on Top Band these days? -From: topband-requ...@contesting.com To: topband@contesting.com Cc: Sent: Tuesday April 2 2024 12:00:44PM Subject: Topband Digest, Vol 256, Issue 1 Send Topband mailing li
Re: Topband: Any Chinese stations with Big Sigs operating on 160?
In the case of that 160 meter dipole it was almost always better as a receive antenna for 80 meters. It was better at rejecting ferocious local QRN than the 80 meter inverted-V. Absolute signal level always dropped owing to the mismatch, but the noise level dropped even more improving SNR (from really deaf to pretty deaf). I am sure there were cases where the 80 meter inverted-V was better, but that was the exception not the rule. I agree that Ken has the nice problem of having lots of antennas to chose from for RX :-) 73, Mike W4EF On 4/3/2024 2:20 AM, Jim Brown wrote: At N6RO's superstation (among other things, it was the antenna labo of ARRL Antenna Book Editor N6BV, who lives 100 miles away in the city of San Francisco), Ken patches lots of antennas to his operating position for 160M contests for use as RX antennas. The reason is simple -- the elevation, and even the horizontal direction at which signals arrive can vary widely with time, based on propagation. Ken is a very smart engineer, and a bunch of very smart engineers and operators are on his team. 73, Jim K9YC _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Any Chinese stations with Big Sigs operating on 160?
At N6RO's superstation (among other things, it was the antenna labo of ARRL Antenna Book Editor N6BV, who lives 100 miles away in the city of San Francisco), Ken patches lots of antennas to his operating position for 160M contests for use as RX antennas. The reason is simple -- the elevation, and even the horizontal direction at which signals arrive can vary widely with time, based on propagation. Ken is a very smart engineer, and a bunch of very smart engineers and operators are on his team. 73, Jim K9YC On 4/3/2024 12:25 AM, Michael Tope wrote: I just occurred to me that my description of the receive situation at W6UE is backwards. The 160 meter flat top dipole improved the 80 meter receive noise floor from really deaf to pretty deaf. On 160 meters we were just really deaf whether we listened on the 160 meter dipole or the 80 meter inverted-vee _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Any Chinese stations with Big Sigs operating on 160?
I just occurred to me that my description of the receive situation at W6UE is backwards. The 160 meter flat top dipole improved the 80 meter receive noise floor from really deaf to pretty deaf. On 160 meters we were just really deaf whether we listened on the 160 meter dipole or the 80 meter inverted-vee :-) 73, Mike W4EF.. On 4/2/2024 6:03 PM, Michael Tope wrote: When we tried operating in 160 meter contests from W6UE in Pasadena, it was amusing to see the packet spots complaining about how deaf we were. We were running a full size flat-top dipole at 90 feet. It apparently worked pretty well as a transmit antenna. Using the 80 meter inverted-vee for receive that was off the same 90 foot apex at more or less a right angle to the dipole actually improved things significantly (e.g. from really deaf to pretty deaf). Here is an iPhone video of a Q5 "speaker copy" B7P calling CQ on 160 meters during the 2022 CQ WW SSB contest. I tried calling them (off the video) with no luck whatsoever. I don't think they worked any North Americans. By contrast, during the 2024 ARRL SSB contest, JA3YBK who was also Q5 speaker copy came right back to me on the first call (I don't think I have a recording of that QSO): https://www.dropbox.com/scl/fi/kd2euhx7x5a5dd5iatm7c/B7P-2022-CQ-WW-SSB-160M.mp4?rlkey=xd6qpj5d3ikg2u39fvotheqhz&dl=0 73, Mike W4EF... On 4/2/2024 3:12 PM, Jim Brown wrote: On 4/2/2024 2:45 PM, David Raymond wrote: Yes, the Chinese have really discovered ham radio in the last decade. And beginning 6-8 years ago, they figured out that they had to set up stations where the noise was low enough that they could hear stations calling them. When they first appeared, the noise made them deaf. No different from here in NA. 73, Jim K9YC _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
