Re: [digitalradio] Best line of the day
>I agree. Static crashes are a powerful QRN source here too. >Guess Olivia would be better, even 8/250 would stand a better chance of >good copy. >In spite of strong signals, if there is no "second chance", it does not >matter much how clever Varicode is. It is certainly a big step ahead on >quiet bands, but when QRM dominates, it is simply not enough. >73, >Jose, CO2JA Hi Jose, We are using PSK63 to PSK250 on 2 meters for NBEMS with excellent success and fast data transfers, as there is essentially no problem with static crashes on 2 meters. Wether we use PSK63, PSK125, or PSK250 is simply a function of the path loss on 2 meters we have to overcome to get a usable S/N, and there is no QSB to contend with either (up to about 100 miles). However, as you note, static crashes are a big problem for PSK31, and a huge problem for PSK250, so those testing NBEMS on HF have had to resort to MFSK16 (already included in the NBEMS software), which is much less disturbed by static crashes. However, data transfer is very slow using MFSK16, especially after adding ARQ, so we are seriously considering using DominoEx, which is faster, easier to tune, within 1.5 dB of the weak signal performance of MFSK16, and that we hope is more like MFSK16 in tolerance to static crashes, but we do not have enough experience to know if it is or not. The problem is that DominoEx is not used a lot, so if you, and others reading this post, can compare DominoEx11, or DominoEx16, to MFSK16 during times of many static crashes and let us know the result, I would greatly appreciate it. Multipsk supports both DominoEx, and MFSK16 under Windows, as does fldigi, under Linux. 73, Skip KH6TY NBEMS Development Team
RE: [digitalradio] Best line of the day
Olivia would be a much better choice for critical information. Next would be Contestia, then MT-63. MFSK-16 should also be a consideration Within all 3 of these are variations in number of tones and bandwidth that will give you choices based on propagation. PSK-31 is a narrowband "one-shot" digital mode. It is the "least common denominator" as it requires zero learning curve. FEC, and finally ARQ will both yield more accurate results. I don't waste my time on the amateur bands with Pactor III due to the bandwidth arguments, but use it on NTIA freqqencies and it would be my first choice to save life and property. PSK would fall somewhere around the Campbell Soup can and twine category... Just tools in the toolbox. David KD4NUE -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Jose A. Amador Sent: Sunday, April 13, 2008 11:13 AM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] Best line of the day I agree. Static crashes are a powerful QRN source here too. Guess Olivia would be better, even 8/250 would stand a better chance of good copy. In spite of strong signals, if there is no "second chance", it does not matter much how clever Varicode is. It is certainly a big step ahead on quiet bands, but when QRM dominates, it is simply not enough. 73, Jose, CO2JA David Little wrote: > That's what happens when there are static crashes, like those from the > string of cells (or super-cells) moving across the Eastern US. > > Got FEC?? > > The station could improve the odds against him by using faster (or no > AGC) for quicker recovery time to lessen the lost data (again, no FEC - > no redundancy- no second chances)... > > Of course, the ease of using PSK as opposed to a mode with error > correction attracts the masses, and is is narrow bandwidth... > > The station probably was actually decoding everything, including the > static crashes and resulting lost data > > David > KD4NUE > > > -Original Message- > *From:* digitalradio@ <mailto:digitalradio%40yahoogroups.com> yahoogroups.com > [mailto:digitalradio@ <mailto:digitalradio%40yahoogroups.com> yahoogroups.com] *On Behalf Of *Andrew O'Brien > *Sent:* Sunday, April 13, 2008 8:17 AM > *To:* digitalradio@ <mailto:digitalradio%40yahoogroups.com> yahoogroups.com > *Subject:* [digitalradio] Best line of the day > > Copied on 40M PSK today > > " I am having a hard time copying even though your signal is 599 , not > decoding everything". > > Andy K3UK >
Re: [digitalradio] Best line of the day
I agree. Static crashes are a powerful QRN source here too. Guess Olivia would be better, even 8/250 would stand a better chance of good copy. In spite of strong signals, if there is no "second chance", it does not matter much how clever Varicode is. It is certainly a big step ahead on quiet bands, but when QRM dominates, it is simply not enough. 73, Jose, CO2JA David Little wrote: > That's what happens when there are static crashes, like those from the > string of cells (or super-cells) moving across the Eastern US. > > Got FEC?? > > The station could improve the odds against him by using faster (or no > AGC) for quicker recovery time to lessen the lost data (again, no FEC - > no redundancy- no second chances)... > > Of course, the ease of using PSK as opposed to a mode with error > correction attracts the masses, and is is narrow bandwidth... > > The station probably was actually decoding everything, including the > static crashes and resulting lost data > > David > KD4NUE > > > -Original Message- > *From:* digitalradio@yahoogroups.com > [mailto:[EMAIL PROTECTED] *On Behalf Of *Andrew O'Brien > *Sent:* Sunday, April 13, 2008 8:17 AM > *To:* digitalradio@yahoogroups.com > *Subject:* [digitalradio] Best line of the day > > Copied on 40M PSK today > > " I am having a hard time copying even though your signal is 599 , not > decoding everything". > > Andy K3UK >
RE: [digitalradio] Best line of the day
That's what happens when there are static crashes, like those from the string of cells (or super-cells) moving across the Eastern US. Got FEC?? The station could improve the odds against him by using faster (or no AGC) for quicker recovery time to lessen the lost data (again, no FEC - no redundancy- no second chances)... Of course, the ease of using PSK as opposed to a mode with error correction attracts the masses, and is is narrow bandwidth... The station probably was actually decoding everything, including the static crashes and resulting lost data David KD4NUE -Original Message- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Andrew O'Brien Sent: Sunday, April 13, 2008 8:17 AM To: digitalradio@yahoogroups.com Subject: [digitalradio] Best line of the day Copied on 40M PSK today " I am having a hard time copying even though your signal is 599 , not decoding every thing". Andy K3UK
Re: [digitalradio] Best line of the day
"Any fool can know, the point is to understand." (Albert Einstein) Tim, N9PUZ Andrew O'Brien wrote: > Copied on 40M PSK today > > " I am having a hard time copying even though your signal is 599 , not > decoding every thing". > > Andy K3UK
Re: [digitalradio] Best line of the day
Right up there with "ur 599 599 pse rpt name es qth" 73 Dave KB3MOW Andrew O'Brien wrote: > > Copied on 40M PSK today > > " I am having a hard time copying even though your signal is 599 , not > decoding every thing". > > Andy K3UK > > > > > No virus found in this incoming message. > Checked by AVG. > Version: 7.5.519 / Virus Database: 269.22.13/1375 - Release Date: 4/12/2008 > 11:32 AM >
