Re: Topband: Dipole/remote tuner
On 11/17/2022 7:22 PM, j...@kk9a.com wrote: You can significantly widen the SWR bandwidth that your radio sees on 80m by using a coax match. Connect your dipole to a 1/2 WL multiple of 50 ohm coax and then add a 1/4 WL section of 75 ohm coax. Of course this does not change the actual antenna's SWR but neither would a remote tuner. Yes. There's a development of this concept on my website, where the matching method is used as an example in a tutorial on using SimSmith to design antenna matching networks. http://k9yc.com/PacificonSmithChart.pdf When I was introduced to the concept by local contesters, they credited it to Dave Leeson, W6NL. When asked about it, he said the idea was much older than he was. 73, Jim K9YC _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Dipole/remote tuner
You can significantly widen the SWR bandwidth that your radio sees on 80m by using a coax match. Connect your dipole to a 1/2 WL multiple of 50 ohm coax and then add a 1/4 WL section of 75 ohm coax. Of course this does not change the actual antenna's SWR but neither would a remote tuner. John KK9A Jake K9WN wrote: Looking for input from the collective knowledge of the reflector. You have a wire dipole for 75 meters fed with a 1:1/5K rated balun. You want to transition to a remote tuner so you can move around 75/80 meters. The question is: Do you leave the balun in place, or remove it and feed the dipole directly from the remote tuner? We have mixed answers from the local "Population". That's why I'm coming to the reflector. Please, don't be critical and ask questions like: what gauge wire, bare of covered wire, How high, yada yada yada, That's all. Thanks in advance. 73 K9WN Jake _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: loop on ground vs beverage
Hi Andy, One thing I noticed listening, was an apparent lack of gain or noise equalization between the two antennas. Either that or the LOG is WAY quieter than the beverage. Adding an amplifier to an RX antenna, preferably out at the antenna IS a bit of a pain, and needs careful work with a signal source to get right, providing the only way to see exactly is going on. Sometimes gain equalization shows one antenna as significantly better in a given direction, or can reveal that an amplifier out at the antenna was what was needed, not a new antenna. LOGs and BOGs are lossy RX antennas and generally could use an amp. One thing about LOGs is that they need to be modeled to account for the severe velocity factor (VF) changes possible when laying on the ground. The actual pattern can vary considerably depending on VF, and LOG patterns are not at all intuitive. To figure out the modeling, you have to measure DOGs to "tunej" the model., that is set the model's ground constants and wire height above ground to match what you are getting with the DOG. There is no cookie cutter size that fits all. A while back, here in North Carolina, a brave band of locals went on a VF study around the region to try and help explain the widely varying behavior and effectiveness of BOG's. Measured VF's of DOG (dipole on ground) wires laid on the ground varied from 45% to 85%, R at X=0 between 80 and 200. We sometimes measured wild variations between various spots on the same single piece of property, even after verifying no buried conductors. In a few cases, we observed wide variation between N-S and E-W DOGs that had a common center point. Wide variation over time was seen with dry periods vs. wet, covered by snow in winter, with and without accumulated seasons of falling leaf cover, laid on grass vs. notched through the grass down to the dirt, laid on unmowed grass during the growing season, vs. same during late fall and winter, laid upon old leaf cover vs notched down to earth. In the end the only way to size a 160 BOG was to lay down a DOG in the same exact place and placement method as the intended BOG. Trim the DOG to get a resonance (X = 0 ohms, not minimum SWR) at 1.140 MHz, and without moving the dog wire, connect the wires at center and add the stuff at the ends to turn it into a BOG. Those worked very well until the variations above set in. Particularly falling leaves then becoming wet. I had phased LOGS on Europe here, with all the issues above paid attention to, including all the tuning falderal to get them to correctly phase. At the start they were wonderful, but started to drift toward mediocre and worse. Experience was that they had to be retuned several times a year for rearward null, and being under leaves basically shut them off. This necessitated blowing leaves off the wires. A serious accumulation of snow degraded performance. The best thing was to retune them before a contest. AT some point other household issues controlled and the loops were retired in place. And then the FCP thing started, soaking up all available time. Those who live in the desert would be able to put LOGs down, tune them up and keep them, unless it rained. Otherwise, especially if one's property is heavily wooded, one has a cranky set of problems that go along with LOGs. Good luck with it and 73, Guy K2AV On Thu, Nov 17, 2022 at 6:38 PM Andree DL8LAS via Topband < topband@contesting.com> wrote: > Hey, > today a very nice receiving test and result.I compared my 80m long LOG > direct on ground in a circle with my858 ft long beverage to JA.Dietmar > HS0ZFV on 160m CW... > > https://www.youtube.com/watch?v=AnPnXuV0XmA > 73, Andy DL8LAS > > www.dl8las.com > www.swing-company-bigband.de/ > www.uni-big-band-kiel.de/ > _ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: loop on ground vs beverage
Hey, today a very nice receiving test and result.I compared my 80m long LOG direct on ground in a circle with my858 ft long beverage to JA.Dietmar HS0ZFV on 160m CW... https://www.youtube.com/watch?v=AnPnXuV0XmA 73, Andy DL8LAS www.dl8las.com www.swing-company-bigband.de/ www.uni-big-band-kiel.de/ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: TL8AA-ZZ
Thank you Alfeo. Ive been looking for you on 160/80m cw. Will listen for you beginning tonight Nov 17/18 on 1826 and 3527! Good luck with your low band propagation. Mille grazie! Bob W3HKK Ex: F7AL-ON8UD-5A3TG-9G1GS-W3HKK/PY8, W3HKK/PS7 - Date: Wed, 16 Nov 2022 13:59:03 +0100 (CET) From: "alfeo...@tin.it" To: topband@contesting.com Subject: Topband: RDC TL8AA Hi Guys, the propagation is very good on the high bands therefore the low bands are almost dead. We made some test last night on 160m FT8 and just few qso with very weak signal. We would like to make some test on 75 - 160m CW as per the following schedule (GMT time, depending on conditions) - Our sunset today at 04:30 - 05:30 PM (at our latitude the switch time light to dark and vice versa is very short) - Tonight at 09:00, 10:00, 11:00 PM - Tomorrow morning at our sunrise 04:00 - 04:45 AM We might test FT8 as well. Based on the result we will plan actions for the next days. Hoping to have you all in log. Alfeo I1HJT I.D.T. member TL8AA - TL8ZZ crew _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Topband 160 Today ( Nov 15th)
Woke up just before SR, staggered into the shack, and heard HL5IVL peaking 569 but with deep QSB. Fired up the amp and called Kim four times - all with no replies. Disappointed, wondering what was wrong, I happened to notice the rig was connected to the dummy load. But by that time, the sun was rising and Kim had faded out. :< PS But it would have been a memorable QSO! Message: 1 Date: Tue, 15 Nov 2022 12:30:09 -0700 From: Ron Spencer To: "topband" Subject: Topband: 160 today (11/15/22) Last night pretty good prop to EU. Worked several stations. But, not much activity. This morning, K3ZM was waking the band up. Heard several JA and HL5IVL call and work him. I tried CQing but got no answers (guess I need to improve my signal!).? But, couple JA's did call CQ as did Kim (HL5IVL) and I was able to work them. Nice to (finally) have prop in that direction. Hoping it continues and gets better.? Adrian, VK2WF, was reported on but I never heard anything from him.? Would have been interesting to hear what the far east signals sounded like from the place I have in NM (grid DM64). Bet they were LOUD! Even on my short beverage to the NE.? 73 Ron N4XD _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: R: Re: RDC TL8AA
Thanks Jim for the suggestion. The signal was very weak and heavy static during the last night, just few qso in log. We just finish to install a DHDL beaming NW, hoping it will help. We will try FT8 first to check and if the signals are strong enough we will switch to CW. Our transmitting frequency is 1826 and I will listen up to 1832. Please be aware that in the range 1829.5 to 1830.5 we have noise and it is worthless to transmit there. Best 73, Alfeo I1HJT -- Messaggio Originale -- Da: j...@audiosystemsgroup.com A: topband@contesting.com; alfeo...@tin.it Inviato: mercoledì 16 novembre 2022 20:35 Oggetto: Re: Topband: RDC TL8AA Hello Alfredo, The MOST IMPORTANT things to know about propagation on 160M are: 1) Propagation on 160M has a strong peak for 30-45 minutes on the DAYLIGHT side of sunrise and sunset. The peak lasts about one hour on 80M and 2 hours on 40M. I suspect that it is also present on 30M. 2) Propagation on 160M often acts very much like the sun peeking through clouds drifting overhead. 3) Experienced DXpeditioners have learned that very strong propagation on 160M usually happens on only one or two nights of a 2-week expedition, so it is critical to be on the air through the hours of darkness and for that 30-45 minutes of daylight on both sides. AA7JV thought this was so important that he developed a transmitting diplexer and RX antenna filters so that his trips could be simultaneously active on both CW and FT8 during these hours every day. 73, Jim K9YC On 11/16/2022 4:59 AM, alfeo...@tin.it wrote: > > Hi Guys, the propagation is very good on the high bands therefore the > low bands are almost dead. > > We made some test last night on 160m FT8 and just few qso with very weak > signal. > > We would like to make some test on 75 - 160m CW as per the following > schedule (GMT time, depending on conditions) > - Our sunset today at 04:30 - 05:30 PM (at our latitude the switch time > light to dark and vice versa is very short) > - Tonight at 09:00, 10:00, 11:00 PM > - Tomorrow morning at our sunrise 04:00 - 04:45 AM > We might test FT8 as well. > > Based on the result we will plan actions for the next days. > Hoping to have you all in log. > > Alfeo I1HJT > > I.D.T. member TL8AA - TL8ZZ crew > _ > 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
