++++++++++++++++ Date: Sun, 10 Mar 2002 11:08:01 -0600 From: "George, W5YR" To: ku4yp at earthlink.net Cc: Low Power Amateur Radio Discussion Subject: [121779] Re: PSK31 is not all it's cracked up to be Mike makes a good point about the effect of stronger signals washing the weaker ones down the drain, as it were. Unfortunately, much of the popularity of PSK31 has come from the comparative simplicity of getting a station working on the mode and the near zero cost. I say unfortunately because the lack of receiving equipment adequate to handle adjacent strong signals has made the experience Mike reports the norm rather than the exception. The plus side is that almost any SSB radio "can" be used for PSK31, though with varying degrees of success. The "engineering" answer to this problem is like that for any other interference problem: remove the effects of the interfering signal as early in the receiver chain as possible by (a) employing appropriate filter(s) and (b) using a receiver in which the AGC is not impacted by signals outside the final IF bandwidth. On some radios, this goal is obtained when CW bandwidth filters can be used in SSB mode and when the receiver AGC does not affect signals outside the CW filter passband. On most radios, however, expecially the older sets, operation is possible only with wide SSB filters and an AGC system that is controlled by the strongest signal within the passband. The newer receivers, such as the Kachina 505 DSP and the Icom 756PRO and PRO II are relatively immune to these effects because (a) very narrow filter passbands can be used in SSB mode and (b) the combination of analog AGC and digital AGC is such that effective AGC action takes place only within the final IF passband. These receivers put PSK31 in an entirely different environment, especially when used with programs like MixW which provide almost total remote control of the radio. For example, I use a macro that retunes the PRO to place the desired signal in the center of the SSB DSP filter passband (1500 Hz) and then selects a 50-Hz bandwidth. Since AGC is effective only within that bandwidth, the selected signal essentially is all that is seen and copied. As receiver designs progress to this architecture and the older equipment fades out in time, we can expect PSK31 and other digital modes to become even more attractive and interesting to operate. True, keyboarding or "finger-talking" is not for everyone, but it is another dimension to amateur radio that many have found to be a fun activity that has renewed their interest in the hobby. Adequate receiving gear and the requisite clean transmitted signal are mandatory, however, for maximum benfit. 73/72/oo, George W5YR - the Yellow Rose of Texas Fairview, TX 30 mi NE of Dallas in Collin county EM13qe Amateur Radio W5YR, in the 56th year and it just keeps getting better! QRP-L 1373 NETXQRP 6 SOC 262 COG 8 FPQRP 404 TEN-X 11771 I-LINK 11735 Icom IC-756PRO #02121 Kachina 505 DSP #91900556 Icom IC-765 #02437 All outgoing email virus-checked by Norton Anti-Virus 2002 KU4YP wrote: > > the only "problem" i have found with psk31 is the fact that a strong > adjacent signals will make all other signals low or un-readable. i guess > kind of like a "capture effect," although that may be the wrong term for > this. > ++++++++++++++++++ Date: Mon, 11 Mar 2002 09:31:09 -0500 From: trandall at idsi.net To: QRP List Subject: [121828] Re: PSK31 is not all it's cracked up to be Jeff wrote: ".... So I am sticking with CW and scrapping PSK31 for the near future. That mode is not all it's cracked up to be. Sorry not to jump on the bandwagon and talk about what a great mode it is." Apparently PSK31 isn't for you. That's O.K. I find the mode amazing and LOTS of fun myself, talking to people in Europe with 5-10 watts through my G5RV blows my mind. Even though that antenna isn't the greatest it works very well for me and I work 10m and 20m PSK31 with 10 watts or less and have no problem making and keeping contacts. Sure, prop can change but all in all PSK31 is a blast as far as I'm concerned. 73, Tom - KB2SMS ++++++++++++++++ Date: Mon, 11 Mar 2002 21:15:24 -0700 From: "Rod N0RC" To: "Low Power Amateur Radio Discussion" Cc: Subject: [121879] Re: PSK31 is not all it's cracked up to be Folks, After following the thread for a while I just have to jump in with a few belated points. 73, Rod N0RC Fort Collins, CO ----- Original Text ----- Subject: PSK31 is not all it's cracked up to be From: Jeff (fantbb at yahoo.com) Date: Sat Mar 09 2002 - 15:42:40 EST > > 1. It takes much longer to get a QSO with PSK31 than > with CW. I must confess I don't under stand the proposition: Compared to CW: A) Does it take longer to make initial contact after one starts calling CQ? --or-- B) It takes longer to call CQ, make contact, chat and complete the CQ. [...get a QSO...] Not sure I understand what "get a QSO" really means in this context. If "A" I can't understand why that should be. Possibilities included, time of day, band selection, equipment malfunction/misadjustment. I had trouble making contacts once. I discovered an audio glitch induced by a disconnected LAN card. Other stations could not lock on to me because of it. With the glitch cleared up making contacts was fairly easy. If "B"; The QSO cycle for a PSK-31 contact in theory is as fast or faster than CW. PSK-31 is capable of about 50wpm, not many CW ops work that fast. I will grant that PSK-31 seems slower but that, I believe, is a cognitive effect. While doing CW the mind is engaged in the process of forming/sending code elements into letters and words. You "seem busier" and time seems to fly more quickly. WHile doing PSK-31 the computer assembles the "code elements" and characters are sent with one press of a key, or comprehended with a quick visual glance of a "glyph" we call letters. So there is a lot of "idle time" for the brain. Consider this: Most people read a few hundred words per minute; characters coming across a PSK-31 display are probably in the 30-40 wpm range. No wonder it seems slow. > 2. Mulitple signals will be there and suddenly > disapear off the band. Chances are this is happening on the CW as well. Again I think cognition is at play. In PSK-31 a wide bandwidth is typically monitored 2, 3 or more kHz, and it is easy to see when stations appear/disappear. In CW we typically use bandwidth of 1kHz or less and the brain is concentrating on one audio frequency. It would be easy to miss a weaker station fade in/out on the edge of the passband, while concentrating on a strong sound in the center of the passband. > 3. You will call CQ and someone will come back to you > and then after your next go around will be gone. Have to say this has happened to me a time or two on CW and PSK. Sometimes I wonder is it the bands, or did the OP just decide they didn't want to chat with me? Technical reasons as cited in point one (above) may also be at play. > 4. Running low power and coming back to CQs will most > often not result in the other station responding to > you. > Again I differ to points made above, I have seldom had this problem. I am absolutely convinced that PSK is a good to excellent weak signal mode. The DSP features of software like Digipan in-fact enhance the abilities to detect and decode weak signals. Heck, it's how deep space satellite communication is made possible! DSP is black magic that I am only getting to understand and truly appreciate. My interest started with an understanding of PSK. Recently I was lucky to acquire an Icom 746pro with true IF 32 bit DSP, wow! The IF filtering and noise reduction is amazing! Jeff, your feelings are clear and It's not my intention to sway you. My thoughts are for others on the fence trying to decide: Try PSK, don't try PSK. My feeling, nothing ventured nothing gained. For me, I think PSK is what it's cracked up to be, and I am sticking with it. I find PSK fun and relaxing for times when the old gray matter is to fatigued to enjoy CW. -rc- ++++++++++++++++++ Date: Tue, 12 Mar 2002 06:01:52 -0500 From: "Pastor-KC1DI" To: , "Low Power Amateur Radio Discussion" Subject: [121887] Re: PSK31 is not all it's cracked up to be ----- Original Message ----- From: "Rod N0RC" To: "Low Power Amateur Radio Discussion" Sent: Monday, March 11, 2002 11:15 PM Subject: Re: PSK31 is not all it's cracked up to be > Folks, > > After following the thread for a while I just have to jump in > with a few belated points. > -- snip -- Thanks Rod very well reasoned response.. On other thing I think is important to state May be you did and I missed in my hurry to read on.. Most Older SSB equipment IE Drake, Heath, Yeasu and Kenwood of the early to mid 70's era is not stable enough to be used efficently on PSK-31. at signal bandwidths of on 31 Hertz . it does not take much drift to loose a lock and thus loose copy. This may be the problem for some. Also I did PSK 31 for about 1 year with a Ten Ten Scout. it suffers from the VFO Design.(Huff & Puff, locked by a coputer chip, but jump frequency especially on 80 Meters.) Though I was able to make many Qso on Psk with that rig. It was not easy and it may have been quite agrivating to the op on the other end. Though I Love CW , Been CW op for over 35 years including 10 years in the military. PSK is a great weak signal digital mode and should be tried before you give up on it. One thing that I believe will make PSK -31 or other schemes fly is that the bandwidth is very comparable to CW. Which SSB is not.. try putting 20 or thirty SSB signals in the space that CW or PSK signals will fit. . 72/73 DAVE KC1DI ++++++++++++++++ Date: Tue, 12 Mar 2002 05:48:36 -0600 From: Chuck Carpenter To: rod at n0rc.com, "Low Power Amateur Radio Discussion" Subject: [121889] Re: PSK31 [IS] not [ALL] it's cracked up to be Rod and All, Excellent post. Digital modes don't appeal too much to me now. I spend a large part of my day behind a keyboard. Don't feel like doing the same for the hobby. Maybe later on... 8^)... I have tried PSK-31 just to see what it is all about. A good receiver helps a lot and making sure you have your modulation levels correctly adjusted is important too. Those who haven't tried it should feel more confident after reading your post. BTW, if you only want to use it in receive only mode, all you need for an interface is a connection to your receiver audio out and computer audio input. I use the earphone output and a Y connector to the mic input on my laptop. Adjust volume as needed. Chuck Carpenter, W5USJ, Point, Rains Co., TX - EM22cv, NETXQRP #1 QRP-ARCI #5422, QRP-L #1306, SOC #57, 6 Club #201, SMIRK #6275 Zombie #759, QRPp-I #115, COG #11, NETXQRP http://www.netxqrp.org +++++++++++++++ From: Graeme F Harris To: psk31 at yahoogroups.com Sent: Thursday, March 13, 2003 7:32 AM Subject: [psk31] Start of PSB reporting for PSK31 Hello all, Just to let you know that the new PSB reporting format for PSK31 has started and that you are welcome to use it and refer other operators to the website. Suggested text for a 579 PSB report at this early stage is: "Your signal, reported in the PSB format (Print, Strength, Bandwidth) is 579 579. See WWW.PSB-INFO.NET for further info." PSB reporting can improve the value of PSK31 signal reports and help reduce excessive signal bandwidth and distortion. We appreciate your support in making PSB reporting seen on the bands. If you operate your own website, we would be pleased if you would provide a link to the PSB site. Best 73, Graeme VK3BGH (for the PSB team) +++++++++++++++++ Date: Fri, 14 Mar 2003 12:42:36 -0800 From: "John, KI6WX" Subject: Re: [Elecraft] K2 input level in data modes To: "Julian (G4ILO)" , Elecraft List Julian; Have you installed the PSK31 mod to the KSB2. The original ALC circuit could not handle PSK31, so I generated a set of changes to increase the decay time constant. The effect you are seeing is the normal gain increase that occurs when bipolar transistors warm-up. The mod is posted on the Elecraft sight and is now standard for the KSB2. -John KI6WX > I'm wondering whether anyone who uses their K2 for data modes has noticed > the following behaviour, and even better, can offer an explanation. > > I haven't changed the audio level output using the computer mixer, nor the > K2 menu SSB settings, for a very long time, and everything was adjusted to > give 5W output with 1 bar of ALC showing. Recently I turned on, listened > around for a while and then called a station, and noticed the output was > very low. But after checking everything and doing a Tune, all seemed OK. > > Today the same thing happened, so I decided to investigate further. I hit > the software Tune button to generate an idling PSK31 signal, and initially > no bars of output RF were showing, then the power output climbed over a > period of 10 secods or so to the usual steady 5 watt level. After that, I > immediately get 5 watts output whenever I go to transmit. I can't think > that it is the gain increasing as the K2 warms up as the time is too short, > and the output remains correct even if there is a long interval between > transmit times. If I turn off the K2 for 10 minutes or so and then turn on > again the level has dropped again, although it only took a couple of > seconds to get back up to 5 watts this time. > > Audio frequency is always the same, so it's nothing to do with being on the > wrong part of the SSB filter passband. RTTY mode is selected, to the > compressor is automatically disabled. > > I can't think what is causing this unless the firmware has a feature, > unknown to me, of detecting a low audio input and automatically increasing > the gain until the power hits the level selected. > > 73, > -- > Julian, G4ILO. (RSGB, ARRL, G-QRP, K2 #392) > G4ILO's Shack: http://www.qsl.net/g4ilo > ++++++++++++++++++++ Date: Mon, 14 Apr 2003 19:29:19 -0700 (PDT) From: "Martin AC6RM" To: Reply-To: elecraft at ac6rm.net Subject: [Elecraft] PSK31 "Ghost" Image -- Followup: To follow-up on an earlier thread I started where I was curious about these "ghost" images (see earlier thread at: http://www.ac6rm.net/mailarchive/html/elecraft-list/2003-02/msg00463.html) I have recently transferred PSK operations [digipan1.6/rigblaster nomic] from my NEC Versa SX laptop to my K6/500 desktop. My desktop has a very nice sound card in it -- Creative Labs' Soundblaster Audigy. Interestingly enough, I have yet to see any ghost images appear above the bandpass of the K2 on the waterfall (appearing above the bandpass was one of the characteristics of these ghost images). I'm still watching, but I am tending to suspect that the quality of the sound card has a lot to do with this. 73, Martin AC6RM (k2#3021) ++++++++++++++++++