[amsat-bb] Re: what is QRP
n3tl at bellsouth.net
Thu Dec 18 09:27:15 PST 2008
During my longest period of on-air activity (i.e., spring 1983 to early 1992), I really enjoyed CW QRP work. During that time - and since getting back on the air pretty much full time - I have used the 5-watt CW/10-watt PEP benchmark that Nigel mentions here.
Without access to the kind of sophisticated instrumentation Jim refers to in his original post, I take the compromise step of getting fairly close by using the utilities on these sites:
The former provides an estimate of the line loss I experience given any setup I try, and the latter then provides me with an estimate of ERP/EIRP with that setup.
All of that being said, and accepting the results of the calculators on the sites listed above, it appearws I can achieve unambiguous QRP (i.e., less than 5 watts CW/10watts PEP rf out AND less than 5 watts CW/10watts PEP ERP/EIRP) here. I haven't made a contact yet on any of the CW/SSB satellites at that power level - but only because nobody answered my CW CQs on VO-52 the other day - the only time and satellite I've tried so far using very low power. I have plenty of contacts on AO-51, AO-27, SO-50 and a couple via the ISS repeater at inarguably QRP power levels.
73 to all,
Tim - N3TL
-------------- Original message from Nigel Gunn G8IFF/W8IFF <nigel at ngunn.net>: --------------
> QRP is not generally based on ERP.
> It's usually taken to be 10W PEP SSB or 5W carrier power max for other modes.
> I think QRP on sats used to be considered to be less than 10W ERP.
> It's not difficult to estimate feeder loss and antenna gain.
> Jim Danehy wrote: > 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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> Nigel A. Gunn. G8IFF W8IFF (have also held KC8NHF, M0NHF, 9H3GN)
> 1865 El Camino Drive, Xenia, OH 45385-1115, USA 937 825 5032
> e-mail nigel at ngunn.net www http://www.ngunn.net
> Member of ARRL, GQRP #11396, QRPARCI #11644, SOC #548, Flying Pig #385,
> Dayton ARA #2128, AMSAT-NA LM-1691, AMSAT-UK, MKARS, ALC
> Sent via AMSAT-BB at amsat.org. Opinions expressed are those of the author.
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