December 2008 - AMSAT-BB - mailman.amsat.org

AO-51 qrp debate
by andy thomas 20 Dec '08

20 Dec '08

It's hard when you're in the field to uplink on the main channel with a 5w handheld, an arrow and a following wind - see my website www.andythomas.eu (and follow the links) for the evidence in trying. I would have opened up more eastern countries but due to the fm effect was stamped on by siberian stations, etc. Would love to uplink in a qrp channel and downlink onto the main channel so that qro ops could uplink on the main (qro) uplink and down link onto the same channel as me. I don't think qro ops listen to the qrp downlink channel? Maybe we would need some device on the qrp uplink to sit on abusers. all comments gratefully received; and my thanks to the ao-051 command team who have helped me worldwide!! andy G0SFJ: as EA6/G0SFJ/P EW/G0SFJ/P F/G0SFJ/P G0SFJ/P LZ/G0SFJ/P SV8/G0SFJ/P TA/G0SFJ/P TK/G0SFJ/P YO/G0SFJ/P

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AO-51 QRP...or does anyone actually read the real schedule?
by Andrew Glasbrenner 20 Dec '08

20 Dec '08

>From http://www.amsat.org/amsat-new/echo/CTNews.php: QRP user FM Repeater, V/U (All users restricted to 10 watts or less, omni or handheld antennas) Uplink: 145.880 MHz FM Downlink: 435.150 MHz FM I think the removal of the "graphic" schedule will force people to spend an extra 10 seconds to read what restrictions or intentions are in effect, and this problem will be solved. I'm sorry it's come to this, again, but we cannot sacrifice civility and order on the air for convenience. 73, Drew KO4MA AMSAT-NA VP Operations

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ERP is not QRP apples and oranges
by Jim Danehy 20 Dec '08

20 Dec '08

ERP is not QRP . . . . . . I never saw anything in FCC exams about QRP or ERP but it has been a long time for me since I was last examined . . . folks are confusing ERP and QRP . . . 5 watts out QRP driving an amp . . . get real . . . it is 5 watts out of the final stage feeding the antenna . . . the gain of the antenna does not have anything to do with QRP it has to do with ERP . . . one is apples and the other is oranges . . . the original issue arose out of someone feeling that folks using the AO 51 QRP channel were not using QRP . . . well I use 5 watts on the QRP channel but I only have fairly big yagis for satellites . . . If the goal is to have HT users with compromised antennas use the "QRP" channel then drop the QRP designation and ask the users to keep the power to 5 watts out from the final stage of the transmitter and then WHAT ? ? ? 5 watts many can compute but that is it . . . ERP is guess work by most . . . that is my point . . . seems senseless to me but surprising the responses . . . ERP is not QRP different concepts . . . apples and oranges . . . . Jim W9VNE

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QRP re deux
by Jim Danehy 20 Dec '08

20 Dec '08

Jack KD1PE et al A ham radio antenna installation is not very static (no pun intended) it is rather dynamic ; to wit : improper assembly of a antenna (variation from the instruction), age and mounting losses of the coax from ultra violet rays, water intrusion, the angle of the antenna wave vs. where the satellite is at the moment, use of improper coax connectors, i will keep the list brief . . . to repeat it is a dynamic (constantly changing ) situation not a static (stay put) system . . . when a TV or FM station states its ERP it can do so with more certainty since it uses very sophisticated instrumentation and hardware that is relatively static ( coax with helium etc) . . . commercial antennas that have rigorous specifications installed by professionals etc . . . so for a ham radio QRP set up you can make a SWAG (simple wild a_ _ guess) . . . a db loss from ultra violet, another for water intrusion and still more for bad connectors and you have 2 or 3 db (loss of half your imagined ERP) then find out like I did that M Square sent me elements that did not pass QC (quality control) and I got a simple ; " ah shucks" from my telephone call and confirmation by others on this BB (bulletin board) that indeed they too had received elements that did not conform to spec . . . a hack saw fixed that goof Add to that the db or two loss from the guy in New York State (some university) that told me that he just assembled his M Square antenna by starting with the longest element and progressively assembling the shorter ones to the boom DESPITE admonishment from M Square that there would be 1 or 2 sequences when the progression would require a longer element ( probably to reduce side lobes ) . . OK : so many feet of LMR 400 or RG 213 and what did the manufacture say about db gain ? do the math calculating the feed line loss and multiply that by the gain = simple QRP power . . . OK well what is the mfg's gain . . . advertised , isotropic, vs a dipole . . . read the fine print . . . not many do or even know the difference. . .what if any gain to you give a 1/4 wave ground plane ? ? ? where is its major lobe when the satellite is at 70 degrees of elevation . . . OK let me change my QRP calculation after checking the printout of the ground plane's loss . . . the premise that I follow is that QRP in the ham fraternity for decades prior to AMSAT was 5 watts output from the final stage of the transmitter . . . any other attempt which hopes to replicate that simplistic approach is speculation based upon a dynamic that is flawed from lack of accurate measurements . . . and constantly changing parameters . . HAPPY HOLIDAYS Jim W9VNE

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Re: ERP is not QRP apples and oranges
by Jim Danehy 20 Dec '08

20 Dec '08

AMSAT started using the term QRP when they probably should have used ERP or more accurately "estimated" ERP . . . after all the goal is to allow those with lesser powered rigs (HT) to have a channel on AO 51 where they could be more competitive with restricted power . . . maybe a better interpretation of ERP should be ESTIMATED RESTRICTIVE POWER rather than EFFECTIVE RADIATED POWER which in amateur radio is more speculative than accurate as I have attempted to point out in prior posts . . . unfortunately when I run 5 watts output on AO51 "QRP" channel I only have one set of satellite antennas to use . . .I could . . .( might be interesting ) use my Bird 25 watt 2 meter slug . . . on the other side of the attenuator (which I built years ago 10 db) so I could use 1/2 watt Uplink to my 10 db antenna or 50 watts estimated ERP . . .before I do that I think I will attempt my last ham goal, EME . . . Jim W9VNE ----- Original Message ----- From: Jim Danehy To: n3tl(a)bellsouth.net Sent: Friday, December 19, 2008 9:40 PM Subject: Re: [amsat-bb] ERP is not QRP apples and oranges AMSAT started using the term QRP when they probably should have used ERP or more accurately "estimated" ERP . . . after all the goal is to allow those with lesser powered rigs (HT) to have a channel on AO 51 where they could be more competitive with restricted power . . . maybe a better interpretation of ERP should be ESTIMATED RESTRICTIVE POWER rather than EFFECTIVE RADIATED POWER which in amateur radio is more speculative than accurate as I have attempted to point out in prior posts . . . unfortunately when I run 5 watts output on AO51 "QRP" channel I only have one set of satellite antennas to use . . .I could . . .( might be interesting ) use my Bird 25 watt 2 meter slug . . . on the other side of the attenuator (which I built years ago 10 db) so I could use 1/2 watt Uplink to my 10 db antenna or 50 watts estimated ERP . . .before I do that I think I will attempt my last ham goal, EME . . . Jim W9VNE ----- Original Message ----- From: n3tl(a)bellsouth.net To: Jim Danehy ; amsat-bb(a)amsat.org Sent: Friday, December 19, 2008 8:17 PM Subject: Re: [amsat-bb] ERP is not QRP apples and oranges Amen, brother. Something occurred to me earlier today in thinking about this ongoing discussion that includes a few different threads. Given all the information I can find about the nominal transmitter powers of the satellites I have worked [AO-7, AO-16, AO-27 (currently inactive), AO-51, FO-29, SO-50 and VO-52], at least half of every satellite contact I've made has been QRP - the half coming this way from space. Most of mine - but not all - have been 2-way QRP. 73, Merry Christmas and Happy New Year to all, Tim - N3TL -------------- Original message from "Jim Danehy" <jdanehy(a)cinci.rr.com>: -------------- ERP is not QRP . . . . . . I never saw anything in FCC exams about QRP or > ERP but it has been a long time for me since I was last examined . . . > folks are confusing ERP and QRP . . . 5 watts out QRP driving an amp . . . get real . . . it is 5 watts out of the final stage feeding the antenna . . . the gain of the antenna does not have anything to do with QRP it has to do with ERP . . . one is apples and the other is oranges . . . the original issue arose out of someone feeling that folks using the AO 51 QRP channel were not using QRP . . . well I use 5 watts on the QRP channel but I only have fairly big yagis for satellites . . . If the goal is to have HT users with compromised antennas use the "QRP" channel then drop the QRP designation and ask the users to keep the power to 5 watts out from the final stage of the transmitter and then WHAT ? ? ? 5 watts many can compute but that is it . . . ERP is guess work by most . . > . that is my point . . . seems senseless to me but surprising the responses . . > . ERP is not QRP different concepts . . . apples and oranges . . . . > > Jim W9VNE > _______________________________________________ > Sent via AMSAT-BB(a)amsat.org. Opinions expressed are those of the author. > Not an AMSAT-NA member? Join now to support the amateur satellite program! > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb

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Looking for TNC
by D. Mynatt 20 Dec '08

20 Dec '08

Hi all- I'm looking for TNC and have heard that an MFJ unit is very good. If someone has a TNC for sale, I'd like to see if we could work something out for after the 1st of JAN 2009. Please contact me off-line if you wish. Thanks you, Dave Mynatt Program Director ======================== http://sciencecenter.no-ip.org SID ID: S-0258 APRS Tier II Server @ pueblo.aprs2.net:14501 LAT: 38'16.278" N LON: -104'40.537" W Alt: 1460m DM78qd // KA0SWT

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QRP ????
by Jack K. 20 Dec '08

20 Dec '08

I have been Reading the various comments regarding what is or is not QRP... The various contests have all taken the easy way out - that is with a transmitter output power level - but to my way of thinking it is only the easy way out as the antenna, the coax, and the ability to direct or condense the signal are equally - if not more so - of importance. since the FCC has no problem with specifying ERP (Effective Radiated Power as compared to a specified antenna) for some modes/bands, I see no reason why that would not be the criteria for determining what is and what is not QRP... After all the real goal as I understand it is to level the playing field and the ERP rule would certainly do that. So if you want to QRP (using the 5 watts criteria), then do so, but don't brag to me when your ERP is really 125 watts because of your antennas gain and your ability to place your signal on target and keep it there... It would seem to me that is not in the spirit of the game either... DE Jack - KD1PE

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S band feed on ebay
by w7lrd＠comcast.net 19 Dec '08

19 Dec '08

I have a "S" band feed on ebay for those interested http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=110328207714&ssPage… 73 Bob W7LRD Seattle -- "if this were easy, everyone would be doing it"

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SatPC32 track error help
by Leonard Revelle 19 Dec '08

19 Dec '08

I have had this happen before and cannot remember how I fixed it. Tried to track ISS today and the track is off. Both the computer and SatPC32 show the correct time and date. Latest Keps have been downloaded. I am hearing ISS packets but the computer says it is over the southern-Indian Ocean. Any sugggestions (I'll write 'em in bold letters on the wall for next senior moment!)? Len Revelle N9IJ n9ij(a)comcast.net

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what is QRP
by Jim Danehy 19 Dec '08

19 Dec '08

QRP is a measure of the transmitter output . . . on a practical basis how would an operator accurately measure the ERP if you were using ERP (effective radiated power) as a QRP benchmark . . . you would need instrumentation to measure the feedline losses and sophisticated instrumentation to measure the gain of an antenna . . . most of that type of instrumentation is beyond the average amateur radio operator . . . . but most do have access or use of a watt meter . . . . thus the simple way of calculating QRP . . . ERP is used primarily in satellite operations because it affects the transponders (not FM repeaters) I have had several private emails in response to my comments about QRP . . . I have seen folks operate the CQ WW CW contest in the QRP category with stacked beams or monoband beams . . . . I have never seen a definition of QRP that went into ERP . . . . they just use the transmitter output with all of the ambiguities that brings . . . have fun Jim W9VNE

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