Re: Topband: how to hear through static crashes?
For me - Receiver AGC doesn't matter - typically on fast. However, I will back the RF gain back so that most of the static crashes do not activate the AGC. I will advance the AF gain to compensate. I find that setting things up this way allows my brain to focus on the signal without the signal changing amplitude due to the AGC being triggered by a static crash. I am not sure IF bandwidth matter that much at this point - but typically use 400 Hz. I also find a CW tone down around 400 Hz works well for me. Not sure any digital processing really helps with this - I haven't ever found something that I would say really works. Diversity seems to help - but only after you are using directive antennas to minimize the static if possible. I have done this for a very long time - from using an S line on 80 meters at K6RR, to a C line on 160 meters at P40V, a TS850 and K3 here at my station. Tree N6TR On Mon, Mar 26, 2012 at 7:57 PM, Robin wb6...@socal.rr.com wrote: Maybe this is a good time to share the techniques we individually find successful for hearing through the giant sparks. Directional receive antennas, obviously, Receiver AGC? IF bandwidth? IF and RF gain distribution? (includes antenna preamps) what classes of digital processing do better? what's the best way to keep the receiver processing from ringing and increasing the effective duration of the crash? noise blanker performance? post receiver audio processing? can you let the IF strip clip in a modern receiver and be an effective peak limiter without serious ringing? What do YOU do? and with which receiver? some shared experience might remind all of us of things to try to hear when the big sparks are flying Robin, WA6CDR ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: how to hear through static crashes?
I have found that the cascaded 800Hz mechanical filters in my 75A4 to have less ringing and IMD induced noise than a TS-940 or 950SD with any of the 250, 400, or 500Hz selections. Rather than reducing the RF gain pot I use the front end attenuator and have an external one for the A4. None of the above are even close to ideal and each has its better nights. Id also suspect the 50-80KHz LC filtering of the vintage boatanchors to be superior but reducing the front end IMD might be a chore without the extensive mods similar to the A4. While my R-4C's had extensive filter, AGC, product detector and audio mods, nothing was done to the front ends and it was never a pleasant radio to use for extended times.with all its own faults the TS-930 that replaced it was less tiring. For about 6 months I had one of each. The NC-300/303 and HQ-170/180 come to mind Carl KM1H - Original Message - From: Tree t...@kkn.net To: Robin wb6...@socal.rr.com Cc: 160 Topband@contesting.com Sent: Tuesday, March 27, 2012 10:15 AM Subject: Re: Topband: how to hear through static crashes? For me - Receiver AGC doesn't matter - typically on fast. However, I will back the RF gain back so that most of the static crashes do not activate the AGC. I will advance the AF gain to compensate. I find that setting things up this way allows my brain to focus on the signal without the signal changing amplitude due to the AGC being triggered by a static crash. I am not sure IF bandwidth matter that much at this point - but typically use 400 Hz. I also find a CW tone down around 400 Hz works well for me. Not sure any digital processing really helps with this - I haven't ever found something that I would say really works. Diversity seems to help - but only after you are using directive antennas to minimize the static if possible. I have done this for a very long time - from using an S line on 80 meters at K6RR, to a C line on 160 meters at P40V, a TS850 and K3 here at my station. Tree N6TR On Mon, Mar 26, 2012 at 7:57 PM, Robin wb6...@socal.rr.com wrote: Maybe this is a good time to share the techniques we individually find successful for hearing through the giant sparks. Directional receive antennas, obviously, Receiver AGC? IF bandwidth? IF and RF gain distribution? (includes antenna preamps) what classes of digital processing do better? what's the best way to keep the receiver processing from ringing and increasing the effective duration of the crash? noise blanker performance? post receiver audio processing? can you let the IF strip clip in a modern receiver and be an effective peak limiter without serious ringing? What do YOU do? and with which receiver? some shared experience might remind all of us of things to try to hear when the big sparks are flying Robin, WA6CDR ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1424 / Virus Database: 2113/4897 - Release Date: 03/27/12 ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Topband: K3 specific 'how to hear through static crashes?'
On 3/27/2012 11:50 AM, Guy Olinger K2AV wrote: Clues to what to do with a K3? I'm also interested in what other K3 owners are doing to combat our summer time static crash receive problems? My situation is such that my TX and RX antenna are the same, so, I am NOT asking about various Low Noise antennas used with their K3s just interested in the AGC and AF/RF gain and ATT settings Specifically with their K3 configuration settings for AGC DCY HLD PLS SLP THR -S and -F are something I can try here TIA -- GB 73 K5OAI Sam Morgan ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Topband: Hydrocarbon Pipelines and Beverages
Topbanders: A pipeline company seeks a permanent easement to place about 450 feet of 24 inch ethane pipeline 3 feet underground under my 160 meter Beverage field. Since I live in a free country, I am not permitted to decline; I must attempt to negotiate the best possible compensation to preserve my ability to pursue happiness. Therefore I am trying to craft words to go into the easement agreement (via my attorney) that requires the pipeline company to mitigate any interference to 160 meter (and other) ham radio operation. There seem to be two possible sources of interference: 1) electromagnetic interference (however unlikely), and 2) physical interference, in the sense that the pipeline is only 3 feet deep and my Beverage post holes typically go down 4 feet. For reason 2 I am asking the pipeline company to put their pipeline more than 4 feet deep. For reason 1 I want to ask the pipeline company to remedy any cause of RFI, EMI, impulse noise, buzzing, static, etc. caused by the construction, operation, maintenance, commissioning, etc, of the pipeline. In other words, I seek words that cover any possible circumstance so that the pipeline company finds it cheaper to use engineers rather than lawyers to fix their problem. Anyone have any experience mixing permanent easements for underground utilities and ham radio operation? I intended to ask the ARRL to ask their lawyer to expand the list of legal terms that describe external interference to ham radio operations. From the collection of DXers and contest operators that frequent this forum, I hope someone can provide anecdotes to help me with my research. Thanks in advance! Victor, K1LT ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: how to hear through static crashes?
On Mon, 26 Mar 2012 19:57:32 -0700 Robin wb6...@socal.rr.com wrote: Maybe this is a good time to share the techniques we individually find successful for hearing through the giant sparks. Here are my experiences from TX3A (and other low-band DXpeditions). On TX3A, for 30 nights in a row, 8 hours each, I had the challenge of copying weak signals through strong, incessant lightning crashes (especially from sunset until about 10:30 local time). With the following set up, this is what I found to work best: Local Set-Up and Conditions: Receiver K3, ANT DHDL (-36 dBi Gain), No local RF noise, Bose noise cancelling headphones (strong local acoustic noise from birds): I set the AGC to Fast, mostly used the RF gain to control levels, and set the IF Filter to 600 Hz. This last one may sound counterintuitive, but I have found that: a) setting the filter too narrow results in ringing which stretches out the effects of a lightening crash, masking more of the signal, b) setting the K3's DSP filter narrower changes the shape of the CW pulses and makes them stand-out less, and, c) somehow the narrower filter settings degrade the understandability of weak signals. (This last one was also confirmed by my DXpedition partner, Tomi, HA7RY, who has better ears and can copy CW great.) One more thing, with the above settings and with weak signals, it was absolutely essential to be able to totally concentrate during the crucial seconds when copying a call. I found that allowing any thoughts to intrude would wipe a call. Usually, with strong signals, you don't need total concentration to work without errors. You can think of other things, such as: should I change the RX settings?, should I try the other antenna?, shift in the chair as my butt is getting sore, etc. But with really weak signals, any intruding thought would create internal noise that could cause me to miss a call. I believe that learning to concentrate, and to be able to switch off all thoughts for a few crucial moments, is as important as any DSP filter or or other signal processing hardware. I hope this helps, George, AA7JV ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Topband: how to hear through static crashes?
With a home brew receiver you can select design features that can mitigate static crashes however there are also ways to help even with a commercial ham receiver such as. 1. In my receiver I can adjust the AGC threshold so that loud crashes do not activate the AGC until they become unbearable to listen to. 2. You can do the same with most commercial receiver by simply turning the RF gain down to a lower level. Turn the RF gain control down to the point where the S meter no longer (or just barely) moves when listening to your regular back ground noise. (If the weak station that you are hoping to hear is below the receiver noise level at your QTH then you won't likely hear it will you) 3. I have found an audio limiter to be very helpful. With the AGC turn off and/or RF gain turned down, I set the audio limiter so that it limited (clips) any audio output above the level of the weak signal I am listening too. This protects my ears from excessively loud crashes etc. I am not aware of any modern receiver that include a AF limiter but the older ARRL Handbooks have circuits for building a simple outboard audio diode limiter. Just look in the index for audio limiter/circuit and you should find a sample.For the technically minded you can find the limiter I built into my receiver at: www.ve7ca.net/Hbr200.htm#AudMod 4. If interference from other stations is not a issue then try the widest IF filter Bandwideth (BW). When pulse like RF signals (which is basically what lightning crashes are, a series of large RF pules bunched together), go through the filters in your receiver they are in affect stretched out (see note 1 below) so lightning crashes that you hear will last long going through a very narrow IF CW filters than through the SSB wider filters. 5. I have done a considerable amount of experimenting with noise blanking circuits and found that they are not effective with lightning crashes. Noise Blankers are designed to limit short noise pulses like ignition circuits in the old Volkswagen Bug, lawn mower and in some cases power line leakage that have short duration periods. 6. By setting the clipping level just above the level of the signal that I am trying to copy, using a wide receiver bandwidth then sometimes I find that Digital Noise Reduction systems help. I emphasize the word sometimes. There my friends are my humble observations. I sure others will share their experiences to help us all understand and know how to deal with situations like lighting crashes during the summer season. elay is the average delay time of the energy, the time-domain representation changes and it is not just delayed. Note 1. Not really stretched out, but what is called group delayed. Group delay is the average delay time of the energy, the time-domain representation changes and it is not just delayed.e Click on the following URL and you will a visual picture of what happens to a pulse when it goes through a filter: www.ve7ca.net/Hbr200.htm#FEMixBlnof the energy, the time-domain representation changes and it is not just delayed Markus Hansen VE7CA North Vancouver, BC CANADA WEB: ve7ca.net Markus Hansen VE7CA North Vancouver, BC CANADA WEB: ve7ca.net On 2012-03-27, at 8:32 AM, ZR wrote: I have found that the cascaded 800Hz mechanical filters in my 75A4 to have less ringing and IMD induced noise than a TS-940 or 950SD with any of the 250, 400, or 500Hz selections. Rather than reducing the RF gain pot I use the front end attenuator and have an external one for the A4. None of the above are even close to ideal and each has its better nights. Id also suspect the 50-80KHz LC filtering of the vintage boatanchors to be superior but reducing the front end IMD might be a chore without the extensive mods similar to the A4. While my R-4C's had extensive filter, AGC, product detector and audio mods, nothing was done to the front ends and it was never a pleasant radio to use for extended times.with all its own faults the TS-930 that replaced it was less tiring. For about 6 months I had one of each. The NC-300/303 and HQ-170/180 come to mind Carl KM1H - Original Message - From: Tree t...@kkn.net To: Robin wb6...@socal.rr.com Cc: 160 Topband@contesting.com Sent: Tuesday, March 27, 2012 10:15 AM Subject: Re: Topband: how to hear through static crashes? For me - Receiver AGC doesn't matter - typically on fast. However, I will back the RF gain back so that most of the static crashes do not activate the AGC. I will advance the AF gain to compensate. I find that setting things up this way allows my brain to focus on the signal without the signal changing amplitude due to the AGC being triggered by a static crash. I am not sure IF bandwidth matter that much at this point - but typically use 400 Hz. I also find a CW tone down around 400 Hz works well for me. Not sure any digital
Topband: ELIMINATING STATIC CRASHES IN THE K3
I employ the marvellous control designed into the K3 to deal with such problems: the ON/OFF switch! Seriously, I use a full-wave loop working against a Beverage in diversity mode which knocks the crashes down considerably. RF cranked back a bit, CW filter set around 400 hz, DSP off. The QRN doesn't disappear but it becomes more tolerable. Bill, VE3NH ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
