[digitalradio] Alinco DX70 on 5MHz?
I want to modify my Alinco DX70 for experimental digital transmissions on 5MHz. I have already discovered this: http://www.hampedia.net/alinco/dx-70th-tx-and-rx-mod.php It says that to TX/RX everywhere remove both jumpers c and e, which seems straightforward. However, in my radio, jumper e is already missing, whereas in the black-and-white photo on the above site the jumper e is in place. So I want to be sure that jumpers c and e are indeed the right ones to remove -- the so-called jumpers are actually tiny SMD resistors, so I don't want to make a mistake. Has anyone here successfully done this modification, I wonder? -- 73 Ian, G3NRW
Re: [digitalradio] Alinco DX70 on 5MHz?
Ian, Perhaps G3YCC might know... http://www.zerobeat.net/g3ycc/dx70.htm Andy K3UK On Mon, Apr 5, 2010 at 5:18 AM, Ian Wade G3NRW g3...@yahoo.co.uk wrote: I want to modify my Alinco DX70 for experimental digital transmissions on 5MHz. I have already discovered this: http://www.hampedia.net/alinco/dx-70th-tx-and-rx-mod.php It says that to TX/RX everywhere remove both jumpers c and e, which seems straightforward. However, in my radio, jumper e is already missing, whereas in the black-and-white photo on the above site the jumper e is in place. So I want to be sure that jumpers c and e are indeed the right ones to remove -- the so-called jumpers are actually tiny SMD resistors, so I don't want to make a mistake. Has anyone here successfully done this modification, I wonder? -- 73 Ian, G3NRW
[digitalradio] WANTED: ALE-400 Chat Mode QSO's
All, Looking fro ALE-400 chat-mode skeds. I'll be QRV on 20 meters this evening. QRG 14073 +/- QRM Skeds welcome.. Tony -K2MO
Re: [digitalradio] WANTED: ALE-400 Chat Mode QSO's
I'm game too. On Mon, Apr 5, 2010 at 5:42 PM, Tony d...@optonline.net wrote: All, Looking fro ALE-400 chat-mode skeds. I'll be QRV on 20 meters this evening. QRG 14073 +/- QRM Skeds welcome.. Tony -K2MO
[digitalradio] Re: PSKMail -- Path Tests Revisited
Tony, Thank you for taking the time to perform the tests. My anecdotal evidence is at odd with these results. So the only way I add value to this discussion is to perform the field test in a more controlled way. Thanks again and best 73s, John --- In digitalradio@yahoogroups.com, Tony d...@... wrote: John, See attached. Tony -K2MO *Minimum SNR (white noise)* PSK250 -2db MFSK32 -8db PSK250R -7db *Simulation: NVIS SNR +3db* ModeCopy PSK250 62% MFSK32 100% PSK250R 61% *Simulation: Selective Fading* *SNR -3db* PSK250 67% MFSK16 95% PSK250R76% *Simulation: CCIR POOR * *SNR +3db* PSK25089% MFSK32 99% PSK250R 82% *SNR -3db* PSK25065% MFSK32 97% PSK250R 61% *SNR -10db* PSK25033% MFSK32 46% PSK250R 27%
[digitalradio] Re: PSK-ROBUST - Path Simulation Results vs field tests
Gary, Thank you for the feedback. Using ARQ systems like you did we have also noticed that faster PSK modes show better performance as in less repeat request than slower ones. Your first theory is the one we believe is the most likely contributor for the ARQ links in general benefiting from faster psk speed (up to a certain point of course). But like you we are a bit puzzled by the apparent robustness of these modes in NVIS conditions. If you are so inclined, could you please perform a comparison between psk250 and psk250R as available in the beta version 3.20 of Fldigi? The FEC of course reduces the speed by almost half but the error rare (ARQ repeats) appears to be lower than even the half psk speed (i.e. psk250r seems more robust than psk125) as Rein reported in his post on this subject. Another perspective would be appreciated. 73s, John --- In digitalradio@yahoogroups.com, Gary grwes...@... wrote: Your question is one that I have also. In our recent NVIS testing with fldigi/flarq we found BPSK250 provided better throughput than other modes we tested, and most notably MFSK32 which we thought would be our safe, robust mode. This was with a variety of band conditions including strong signal, weak signal, selective fading, lightning QRN, grungy power line noise, and all the normal stuff we experience here in the Midwest. Path distances varied from 40 miles to 150 miles which were the distances we were interested in. There were a couple ideas we kicked around as possible reasons why BPSK250 worked so much better than we expected. One was that when the signal took a hit from something like a lightning burst, BPSK250 recovered and resynchronized very fast. The second was even more speculative in that maybe the higher phase modulation rate (250 times per second) was faster than Doppler path modulation allowing the BPSK decoder to ride through. Anyway, we expected BPSK250 to be useless on NVIS but every time we have tried it, it has worked. (and better than most modes.) Maybe there is something that the path simulators are missing. Dunno... Just throwing some ideas out. Gary - N0GW
