I did get thru this morning at 1104 utc, after calling for quite a while. Good thing the weather is cool this time of year or maybe the 4sq would have melted. Signals went from -20 to as high as -4 and I squeaked out a reply on the peak. He worked a few JA;s but I never saw any other NA in the log then. No shortage of stations calling.
On Wed, Oct 23, 2024 at 4:42 PM Michael Tope <[email protected]> wrote: > This is an excerpt from the news report from C21MM website dated Oct 18, > 2024 (https://c21mm.mydx.de/?News): > > "We erected two 22m Spiderbeam fiberglass poles for 160 and 80m > verticals with one elevated radial. For 40m and 30m we use (rhombic) > loops with 50 Ω impedance and on 60m we use another vertical with > one elevated radial. DL8LAS and DL6KAC installed a DHDL receiving > antenna. This helps against the very high atmospheric noise (up to > S9). Fortunately, we do not have a lot of manmade noise at both > QTHs. Regarding the lowbands, we are very satisfied with the antenna > performance from 80m to 30m. On 160m we didn’t hear any station > until now." > > > This feels like a long shot, but how sensitive is FT8 decoding to > receiver settings in a high tropical QRN environment? I don't operate > FT8 too much and I live in Southern California, so I really don't have > any experience using FT8 in the presence of strong random bursts of > noise. Does AGC pumping from static bursts clobber FT8? Is reducing RF > gain and increasing AF gain the right approach? > > 73, Mike W4EF........................ > > > > On 10/21/2024 1:34 PM, GEORGE WALLNER wrote: > > Low band noise on DXpeditions: > > It is easy tothink that going to a small island you will escape the > > noise of modern "civilization". Far from it! > > > > If the islandhas some population, they will be using generators, solar > > panels, inverters and electronics of the cheapest kind, with zero or > > verylittle filtering. In one place, the TX vertical was picking up the > > noise of the solar plant of a village (pop.300) from 1.5 miles! > > Elsewhere, the DXpedition brings its own noise sources: generators > > (especially invertergenerators), computers, switch node wall-warts, > > inverters and so on. > > Unless they the station is very close to the water, grounding will be > > difficult asmany islands have very poor ground (coral rubble and > > sand). And unlike with a home station, there isn't enough time tohunt > > down, filter and eliminate all the noise sources. If it is a tropical > > island south of the equator, the TS noise fromthe Inter Tropical > > Convergence Zone (ITCZ) and then after about 10:00 Z, the TS noise > > emanating from Papua NewGuinea/Indonesia will add to the local noise. > > At all our recent DXpeditions (VP6A, E51D, K8R, T32JV, FW7JV and N5J) > > noise was the biggestissue on TB. We spent precious hours and days, > > hunting down sources and filtering them. There are many things that > > can be done,including placing the generators at a distance, grounding > > them and filtering the power cables, etc. Grounding all thestation > > equipment also helps. Installing clamp-on ferrites or pre-made common > > chokes can reduce the noise radiated bycables and the noise carried to > > the antenna on the outside of the coax shields. You can go on like > > that ... until you find that theDXpedition is over and it is time go > > pull it all apart... without the noise being completely eliminated. > > What I've learned is that, apart from good basic noise reduction > > practices at the station, a good RX antennaplaced at a substantial > > distance is the best and the most "time-effective" way to improve > > reception on TB. TheDXpedition that seriously wants to work CW on TB > > (and most promise) should prepare in advance and carry all the > > material needed toinstall an RX antenna on the second day. (On the > > first day you are working the big guns... buteven then.) A flag at 500 > > to 1000 feet from the nearest antenna and the station, fed via a well > > choked coax(check Jim, K9YC's excellent write up on chokes at > > http://k9yc.com/2018Cookbook.pdf ) will be often sufficient. It will > > be much better with a remote low-noise pre-amp. A DHDL will be even > > better but it is a verylow gain antenna and a low noise remote pre-amp > > at the antenna is a MUST! All that should be prepared in advance, not > > jerry-rigged on site > > from available bits and pieces. > > If you do it right, you will get emails like this: > > "...incredible ears on E5-N, this morning, at 1107 UTC, just before > > local SR, I worked E51D QRP, using a "nothing special" Inv-L. " > > It wasn't the ears, which are not what they used to be. It was a 50 > > foot long DHDL pointing NE with a low-noise pre-amp, at the end of > > 1000 feet of quad-shield coax with three chokes, grounded at two > > points, feeding a Flex 6700 via the RX ANT port. That's all. > > 73, > > George > > > > > > > > > > > > > > > > On Mon, 21 Oct 2024 01:47:59-0700 Michael Tope wrote: > >> C21MM has been in solid for well over 1.5 hours on FT8 tonight and > >> it's stillearly. They were loud enough at times (at least on my end) > >> for a CW QSO, but they didn't decode my signal on FT8 untiltheir > >> signal peaked up to R=0, whereas on this end I was decoding solidly > >> down to R=-20. Clearly they have some receivechallenges. The DHDL > >> antenna that C21MM plans to use for receive has been employed by > >> AA7JV on some of his expeditions,so it's got a proven track record. > >> Perhaps there is a storm that is very close to them causing unusually > >> high QRN. > >> > >> I need to go to bed, today is a work day 🙁 > >> > >> 73, Mike W4EF................. > >> > >> On 10/20/2024 6:13 PM, Wes Stewart via Topband wrote: > >> > >>> The realities aboutsome of these DXpedtions is that they are > >>> organized by Europeans and favor working EU. Take the just concluded > >>> (if theykept to schedule) PX0FF expedition. The ops were all > >>> Europeans and >60% of their Qs were with EU and only 21%were with > >>> NA. They didn't even operate 160 CW. They made 1046 FT8 QSOs on > >>> 160 out of >150,000 total. > >>> > >>> 8R7X was another one with EU 54% and NA 31%. Of course propagation > >>> favored EU, but they were activelong enough that I worked them on > >>> both 160 CW and FT8 as well as 22 other band/modes.Ditto A8OK that I > >>> worked on 33 band/modes, none on topband. EU 64%, NA 19%.I'm not > >>> trying to disparage our EU friends, I'm just pointing out the numbers. > >>> C21MM will be QRV for at leastanother week. So far they haven't > >>> made any topband CW contacts and only 6 with NA presumably on FT8. > >>> Theyclaim to have installed an RX antenna, but have high noise. So > >>> we shall see, but I'm not holding my breath. To their credit they > >>> have worked about the same number of CW and FT8 Qs and a few on > >>> RTTY, three of them mine. > >>> AA7JV is a dedicated 160 man, who will put in the hours needed. > >>> These other guys are not so motivated and want torun up their Q > >>> count by working the most productive bands, or by turning on the FT8 > >>> robots.Wes N7WS > >>> > >>> > >>> > >>> On Sunday, October 20, 2024 at 12:11:54 PMMST, Jim Brown > >>> <[email protected]> wrote: On 10/20/2024 11:14 AM, Steve > >>> Harrison wrote: > >>>> If possible, please spend some timeattempting to work some North > >>>> American stations on *160 and/or 80m **CW*. A few minutes here and > >>>> there > >>>> is NOT enough; HOURS on the low bands are needed in order to catch the > >>>> propagation peaks all across the NA and SA continents. > >>>> > >>> YES! Veteran expeditionerAA7JV recognized that topband openings > >>> tendedto happen on one or two nights of a multi-week activation, and > >>> developednetworks to allow simultaneous operation on CW and FT8 > >>> during every hourthere's a possibility of propagation. One of the > >>> most glaring failuresis abandoning the band at the first hint of > >>> daylight, when propagationPEAKS over the next 45 minutes to an hour! > >>> 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 > >> > > > > _________________ > > 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
