Re: Topband: Topband Digest, Vol 136, Issue 1
Hello Mike I have found that JT65 provides a bit better than 10 dB more than a good cw weak signal (read that as a real weak cw ) contact. I can copy signals by ear that are listed as about -18 dB or more below the noise in JT-65, and the rock bottom detection level for JT65 is about -28 or maybe a little more with a few tricks. On HF, with all sorts of pops and squawks and keyclicks/splatter, that 10 dB may not be a correct number. It could be greater..I'm not sure. There is no way I could copy extremely weak CW with QRM competing with the signal. The 10 dB number is only for listening to a signal buried in galactic noise. In my opinion, copying CW in noise is much more fun than reading callsigns on a monitor screen. There is no doubt though that JT65 is a huge improvement for detecting weak signals. 10 dB is a lot! JT65 cannot make up for a lack of propagation though!! (but what do I know?) Does that help any? Dave K1WHS That's interesting, and brings to mind a question I've been wondering about for low-data-rate weak signal modes such as JT65, JT9 (which take 60 seconds to send a CQ), and QRSS (24 hours?!). In the real world on 160, what would any of these modes really gain for an operator already skilled in CW? From reading posts about JT9 and JT65 on 160, the distance gain over ordinary CW is really nothing to write home about. Does anyone have any real-word experiences that say otherwise? 73, Mike www.w0btu.com _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: QRSS mode
On 04/01/2014 09:06 PM, Radio KH6O wrote: I know that the 600 Meter Research Group is utilizing QRSS for their experiments; that was the first I'd ever heard of the mode. Note that the 600 meter band was the former MF maritime CW band, with 500 kHz being the international CW calling and distress freq'y for about 80 years. 500 would be jammed at night when the band opened up after sunset. With the elimination of maritime CW, the 600 MRG obtained an experimental license from the FCC. You can view their research at: w5jgv.com/600_mrg.htmand500kc.com 73, Jeff KH6O / 6 Hi, The experimenters there are using plain CW, QRSS in various flavors, WSPR, and some other digi modes. One of the goals is exploring "propagation". We are hoping for an amateur allocation there and that information would be useful. The new allocation would likely be only 7 kc wide! There probably won't be any YaeComWood radios on the band any time soon so there won't be a mass influx. It looks like voice modes are right *out*. But it seems like the 'neighbors' there are easy enough to live with. I have tried to contribute to their studies with my reports but I have only been able to report a few of the CW transmissions on that band. My radios are puny and not stable enough for the weaker modes. Most of the time the resources that are shared on that band are in use elsewhere - antenna, computer, operator. I'm assembling a crystal controlled (temp compensated) SDR receiver to help with that. And a loop antenna. I have no plans to spank my oscillators with gps so one or two modes might be off the table here. Operator time is still going to be a problem. I'll be seeing some of you on the new band. 73, Bill KU8H _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: QRSS mode
I know that the 600 Meter Research Group is utilizing QRSS for their experiments; that was the first I'd ever heard of the mode. Note that the 600 meter band was the former MF maritime CW band, with 500 kHz being the international CW calling and distress freq'y for about 80 years. 500 would be jammed at night when the band opened up after sunset. With the elimination of maritime CW, the 600 MRG obtained an experimental license from the FCC. You can view their research at: w5jgv.com/600_mrg.htmand500kc.com 73, Jeff KH6O / 6 On 3/31/14, W2PM wrote: > I would just opine this is a colossal waste of spectrum - not in terms of > bandwidth per se but the inefficiency and low information transfer rate. > Moreover propagation testing is really not an issue on 160 as it would be on > the "lowfer" frequencies and one could say this mode really isn't about that > anyway. Id be interested in that hams views on band use for this since 160 > is a well used band. > > Sent from my iPhone > >> On Mar 31, 2014, at 12:35 PM, Mike Waters wrote: >> >> That's interesting, and brings to mind a question I've been wondering >> about >> for low-data-rate weak signal modes such as JT65, JT9 (which take 60 >> seconds to send a CQ), and QRSS (24 hours?!). >> >> In the real world on 160, what would any of these modes really gain for >> an >> operator already skilled in CW? >> >> From reading posts about JT9 and JT65 on 160, the distance gain over >> ordinary CW is really nothing to write home about. Does anyone have any >> real-word experiences that say otherwise? >> >> 73, Mike >> www.w0btu.com >> >>> On Mon, Mar 31, 2014 at 10:52 AM, Lee K7TJR wrote: >>> >>> ... the carrier on 1810.8 KHz has been found. ... a ham running QRSS >>> where it takes 24 hours to send a CQ. HuH? >>> >> _ >> Topband Reflector Archives - http://www.contesting.com/_topband > _ > Topband Reflector Archives - http://www.contesting.com/_topband > _ Topband Reflector Archives - http://www.contesting.com/_topband