开云体育

QRP sub-bands for FT8

John AE5X All Messages By This Member #74384 In the week or so I've been using the QDX it's become apparent to me that many/most ops are using power levels significantly higher than my 5 watts. I have too, in the past, with other rigs and will continue from time to time... I no longer call stations with my QDX who are weaker than -05 on my end. So I was glad to read this today from Joe Taylor K1JT: "We are also thinking about suggesting a "QRP FT8 sub-band" in which power should be limited to 10 W (say). "-- 73, Joe, K1JT" -- John AE5X
Hans Summers All Messages By This Member #74386 Hi John I agree, you are a lot more likely to work stations who have a higher SNR. But "many/most" is not "all"... so not exclusively so. If the other station is also running 5W too then it is perfectly viable running down at -15 or less.? This morning I was eating breakfast quietly by myself (the two big lab rats having departed for school, and the tiniest one still sleeping), just playing FT8 on 40m, remoting into my QDX station on my mobile phone. I sent some CQs and was pleased to make contact with W7DO. First time I have worked US on QRP. So I think my new antenna installation at the new office QTH cannot be doing too badly though doubtless there are?many dB room for improvement.? 73 Hans G0UPL toggle quoted message Show quoted text On Thu, Nov 11, 2021 at 5:18 PM John AE5X <ae5x@...> wrote: In the week or so I've been using the QDX it's become apparent to me that many/most ops are using power levels significantly higher than my 5 watts. I have too, in the past, with other rigs and will continue from time to time... I no longer call stations with my QDX who are weaker than -05 on my end. So I was glad to read this today from Joe Taylor K1JT: "We are also thinking about suggesting a "QRP FT8 sub-band" in which power should be limited to 10 W (say). "-- 73, Joe, K1JT" -- John AE5X
John AE5X All Messages By This Member #74387 No many/most is not all. As I'm here having my brekkie I just worked my best QDX to date: -- John AE5X
Gregg Myers All Messages By This Member #74389 I worked W0QU yesterday and I was -23 not even all the way across the US, ha, ha! There are at least three factors: you have to be able to be heard on the receiver end, the receiver has to choose to respond to the weaker station, and someone?else can't be stomping on your signal. :) But I don't see very many people on JS8 the short time I have been listening to it. It seems wide open and would therefore be a good choice for QRP (and IMO more fun than FT8) until this FT8 sub-band get's going, which I would fully support. Cheers, Gregg W7GRM toggle quoted message Show quoted text On Thu, Nov 11, 2021 at 8:25 AM Hans Summers <hans.summers@...> wrote: Hi John I agree, you are a lot more likely to work stations who have a higher SNR. But "many/most" is not "all"... so not exclusively so. If the other station is also running 5W too then it is perfectly viable running down at -15 or less.? This morning I was eating breakfast quietly by myself (the two big lab rats having departed for school, and the tiniest one still sleeping), just playing FT8 on 40m, remoting into my QDX station on my mobile phone. I sent some CQs and was pleased to make contact with W7DO. First time I have worked US on QRP. So I think my new antenna installation at the new office QTH cannot be doing too badly though doubtless there are?many dB room for improvement.? 73 Hans G0UPL On Thu, Nov 11, 2021 at 5:18 PM John AE5X <ae5x@...> wrote: In the week or so I've been using the QDX it's become apparent to me that many/most ops are using power levels significantly higher than my 5 watts. I have too, in the past, with other rigs and will continue from time to time... I no longer call stations with my QDX who are weaker than -05 on my end. So I was glad to read this today from Joe Taylor K1JT: "We are also thinking about suggesting a "QRP FT8 sub-band" in which power should be limited to 10 W (say). "-- 73, Joe, K1JT" -- John AE5X
[email protected] #74391 you shouldn't limit yourself to that. ?I have been running qrp all year, and most of my contacts are easily in the -20 to -15 range. Anthony - N1IG
Shirley Dulcey KE1L All Messages By This Member #74393 Philippines; that's a fine bit of DX from Texas! The signal reports on that QSO suggest that DU6/PE1NSQ was running somewhere between 100 and 200 watts. (I don't know the actual power level used by AE5X.) All else being equal, if you are running 5W and the other station is running 100W your signal will be -13dB compared to theirs. The difference here is 15-16 dB, depending on which report of their signal you look at: the -2 or the -3 compared to the -18 they sent you. All else isn't always equal because the S/N is also affected by the signals from other stations and by noise on the band, and the levels of those may not be the same at both locations. If your location is quieter than the other station's location the difference in levels will be higher; if you have the noisier location the difference will be lower. I'm also assuming that neither station is using a separate receive antenna. Also that the receivers at both ends are sufficiently sensitive to hear down to the band's noise floor; that will usually be true, especially on the bands that the QDX covers. When you contact another QRP station on FT8 the reports should be similar on both ends, again if all else is equal. WSJX-X can decode FT8 pretty reliably down to about -20dB and sometimes as far down as -24dB; FT4 is about 3dB worse but twice as fast. When you're getting started on FT8, stick to calling stations that you receive at -5dB or better. They're the ones you are most likely to be able to contact, and you'll be busy working them for a bit as you get experience. Later you can try calling some weaker stations; you won't always get through to them but sometimes you will. toggle quoted message Show quoted text On Thu, Nov 11, 2021 at 10:29 AM John AE5X <ae5x@...> wrote: No many/most is not all. As I'm here having my brekkie I just worked my best QDX to date: -- John AE5X
ajparent1/kb1gmx All Messages By This Member #74399 I'm very active on FT-8.? I can run 100W but very often it s more like 10-25W as that seems more than enough.? Exceptions are DX where the pileup on them will bury even 100W stations. FYI station here runs on a 150AH battery and solar so running 100W FT-8 is not a heating problem but it eats battery.? Economy of power is the game and the mode helps weak signal operators. I have found strong station running low power that cannot hear, alligators all mouth no ears.? Most common reason for that is their local noise is terrible. The other reason is their antenna is poor so they try to make it with power. A good station can easily hear to -23db, most can't due to antenna or noise. Also some receivers are very poor and suffer AGC pumping and desensitizing due to other very strong signals. In the end its funny I'll hear a station that is -12 and go back with 5W and get a -5 received signal report.? Says a lot about their antenna or maybe mine. FYI my best is JAs running 25W from Eastern Massachusettes on 20, 17, and 15M.? Key to that was not power but time of day!? We were both grey line (about 5pm EDST) here. Antenna for that was 160M inverted V (center at 10M) and the ends more than 4M high.? Seems to work well on the mid bands with lobes that aim to Europe. Slways try but observe thewaterfall as the station seems to be in a dense clump of signal likely not hearing well (their agc may be pumping). I try to stay in the clear and that makes for better results. As to QRP subband? it too late for that.? However 30M is ideal as it is power limited (least here in the USA). Allison ------------------------------- Please reply on list so we can share. No private email, it goes to a bit bucket due to address harvesting
Curt wb8yyy All Messages By This Member #74404 Since FT8 is often operated using split frequencies within the customary spectrum, a designated QRP frequency does little, and it would grab even more scarce spectrum away. I can’t figure the dB reporting or -9 and higher dB that don’t come back to my 100w. Just call regardless of the level you are sensing.? curt
Gadget Lust #74423 No hope they will put the next FT-8 sub-band in the voice bands I suppose?
Shirley Dulcey KE1L All Messages By This Member #74479 Currently digital modes are only allowed in the CW band segment. And I think that's the correct home for narrowband digital modes, ones that use 500 Hz or less for an individual transmission. FT8 is such a mode; each signal only uses about 50 Hz. It uses an entire voice channel worth of bandwidth because it's popular, with many stations sharing that 2.8 kHz piece of the band; it's more closely packed than CW operation is. An FCC proposal would allow digital modes with unlimited data rates and no bandwidth limitation, still in the CW band segment. In theory you could create a mode that used the ENTIRE CW segment to achieve data rates in the?hundreds of kb/second, perhaps using OFDM and adapting to interference. The ARRL countered with a proposal that would limit bandwidth to 2.8 kHz, but again with unlimited data rates. I think that would be a horrible mistake because wide and narrow modes don't mix well. If we're going to widely authorize modes with SSB or wider bandwidth, those belong in the voice segment. toggle quoted message Show quoted text On Fri, Nov 12, 2021 at 7:30 AM Gadget Lust <gadgetlust@...> wrote: No hope they will put the next FT-8 sub-band in the voice bands I suppose?

Previous Topic Next Topic