KPA500 troubles
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Like I said, never ever operated on 60M, I mean never without the amp. When discussed with Craig at Elecraft he could not explain the failure, just referred to a component failure. Jack W4GRJ
Same in the UK, Jim. Operation on 60m does not require the use of a
KPA500 unless one wants to contravene the terms of one's license. 73 de David G4DMP In a recent message, Jim Brown <[hidden email]> writes >On Wed,11/11/2015 12:10 PM, W4GRJ wrote: >> Got the KPA500 back from Elecraft. >> Repair $650 later: Replaced low pass filter module and installed QSK mod. >> Problem found: L22 and other components in the 60M low pass filter circuit >> burnt through the LPF PCB. > >60M LPF??? Last I looked, the US power limit on 60M is 100W relative to >a half wave dipole. > -- + - - - - - - - - - - - - - - - - + | David M Pratt, Kippax, Leeds. | | Website: http://www.g4dmp.co.uk | + - - - - - - - - - - - - - - - - + ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] If you reply to this email, your message will be added to the discussion below:
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In reply to this post by W4GRJ
Kpa500 on 60 is illegal unless you have a *measured and
documented* VERY lossy antenna that would reduce the effective radiated power to the same as 100 watts on a dipole. The simple 99 percent answer is that on 60m SHUT OFF the Kpa500 and run 100 watts barefoot. 73, Guy K2AV On Thursday, November 12, 2015, W4GRJ <[hidden email]> wrote: > Since I have never operated on 60m ever... You figure it out > Jack > W4GRJ > > On Nov 11, 2015, at 3:33 PM, Jim Brown-10 [via Elecraft] < > [hidden email] <javascript:;>> wrote: > > On Wed,11/11/2015 12:10 PM, W4GRJ wrote: > > Got the KPA500 back from Elecraft. > > Problem found: L22 and other components in the 60M low pass filter > circuit > > burnt through the LPF PCB. > > 60M LPF??? Last I looked, the US power limit on 60M is 100W relative to > a half wave dipole. > > > > > Repair $650 later: Replaced low pass filter module and installed QSK mod. > > > > On the phone I asked what caused the failure, answer was no idea other > than > > component failure. I understand stuff fails but I thought I would get > more than 2 years before a major expensive failure. > > The LPF is on the output of the amplifier. One possible cause of failure > could be lightning. > > > Previously had a Ameritron ALS-600 for 5+ years never a problem, sold it > to > > purchase the KPA500. > > > > Sometimes the grass is not greener. > > My only experience with an ALS-600 was at a contest station in PJ4 > several years ago. I found it to be a really inferior amp - most of the > time, I was lucky to get 300W out if it. No comparison to a KPA500. > > 73, Jim K9YC > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > > > If you reply to this email, your message will be added to the discussion > below: > http://elecraft.365791.n2.nabble.com/KPA500-troubles-tp7609284p7610243.html > To unsubscribe from KPA500 troubles, click here. > NAML > > > > -- > View this message in context: > http://elecraft.365791.n2.nabble.com/KPA500-troubles-tp7609284p7610259.html > Sent from the Elecraft mailing list archive at Nabble.com. > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] <javascript:;> > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] <javascript:;> > -- Sent via Gmail Mobile on my iPhone ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Don’t need any more responses on the legalities of 60M since the amp was never used on 60M
as stated in several other replies. Jack W4GRJ From: [hidden email] [mailto:[hidden email]] On Behalf Of Guy Olinger K2AV Sent: Thursday, November 12, 2015 3:05 AM To: W4GRJ Cc: [hidden email] Subject: Re: [Elecraft] KPA500 troubles Kpa500 on 60 is illegal unless you have a *measured and documented* VERY lossy antenna that would reduce the effective radiated power to the same as 100 watts on a dipole. The simple 99 percent answer is that on 60m SHUT OFF the Kpa500 and run 100 watts barefoot. 73, Guy K2AV On Thursday, November 12, 2015, W4GRJ <[hidden email]> wrote: Since I have never operated on 60m ever... You figure it out Jack W4GRJ On Nov 11, 2015, at 3:33 PM, Jim Brown-10 [via Elecraft] <[hidden email] <javascript:;> > wrote: On Wed,11/11/2015 12:10 PM, W4GRJ wrote: > Got the KPA500 back from Elecraft. > Problem found: L22 and other components in the 60M low pass filter circuit > burnt through the LPF PCB. 60M LPF??? Last I looked, the US power limit on 60M is 100W relative to a half wave dipole. > Repair $650 later: Replaced low pass filter module and installed QSK mod. > > On the phone I asked what caused the failure, answer was no idea other than > component failure. I understand stuff fails but I thought I would get more than 2 years before a major expensive failure. The LPF is on the output of the amplifier. One possible cause of failure could be lightning. > Previously had a Ameritron ALS-600 for 5+ years never a problem, sold it to > purchase the KPA500. > > Sometimes the grass is not greener. My only experience with an ALS-600 was at a contest station in PJ4 several years ago. I found it to be a really inferior amp - most of the time, I was lucky to get 300W out if it. No comparison to a KPA500. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] If you reply to this email, your message will be added to the discussion below: http://elecraft.365791.n2.nabble.com/KPA500-troubles-tp7609284p7610243.html To unsubscribe from KPA500 troubles, click here. NAML -- View this message in context: http://elecraft.365791.n2.nabble.com/KPA500-troubles-tp7609284p7610259.html Sent from the Elecraft mailing list archive at Nabble.com. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] <javascript:;> This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] <javascript:;> -- Sent via Gmail Mobile on my iPhone ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Guy Olinger K2AV
I need to correct the information on the repair cost
It was $615 with shipping not $650 as I previously reported. Jack W4GRJ On Thursday, November 12, 2015, W4GRJ <[hidden email]> wrote: Since I have never operated on 60m ever... You figure it out Jack W4GRJ On Nov 11, 2015, at 3:33 PM, Jim Brown-10 [via Elecraft] <[hidden email] <javascript:;> > wrote: On Wed,11/11/2015 12:10 PM, W4GRJ wrote: > Got the KPA500 back from Elecraft. > Problem found: L22 and other components in the 60M low pass filter circuit > burnt through the LPF PCB. 60M LPF??? Last I looked, the US power limit on 60M is 100W relative to a half wave dipole. > Repair $650 later: Replaced low pass filter module and installed QSK mod. > > On the phone I asked what caused the failure, answer was no idea other than > component failure. I understand stuff fails but I thought I would get more than 2 years before a major expensive failure. The LPF is on the output of the amplifier. One possible cause of failure could be lightning. > Previously had a Ameritron ALS-600 for 5+ years never a problem, sold it to > purchase the KPA500. > > Sometimes the grass is not greener. My only experience with an ALS-600 was at a contest station in PJ4 several years ago. I found it to be a really inferior amp - most of the time, I was lucky to get 300W out if it. No comparison to a KPA500. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] If you reply to this email, your message will be added to the discussion below: http://elecraft.365791.n2.nabble.com/KPA500-troubles-tp7609284p7610243.html To unsubscribe from KPA500 troubles, click here. NAML -- View this message in context: http://elecraft.365791.n2.nabble.com/KPA500-troubles-tp7609284p7610259.html Sent from the Elecraft mailing list archive at Nabble.com. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] <javascript:;> This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] <javascript:;> -- Sent via Gmail Mobile on my iPhone ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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That seems like a helluva lot to fix the bandpass
filter for a band that you never used. Very UN-Elecraft sounding to me. 73, Charlie k3ICH -----Original Message----- From: Elecraft [mailto:[hidden email]] On Behalf Of w4grj Sent: Thursday, November 12, 2015 7:14 AM To: [hidden email] Subject: Re: [Elecraft] KPA500 troubles I need to correct the information on the repair cost It was $615 with shipping not $650 as I previously reported. Jack W4GRJ On Thursday, November 12, 2015, W4GRJ <[hidden email]> wrote: Since I have never operated on 60m ever... You figure it out Jack W4GRJ On Nov 11, 2015, at 3:33 PM, Jim Brown-10 [via Elecraft] <[hidden email] <javascript:;> > wrote: On Wed,11/11/2015 12:10 PM, W4GRJ wrote: > Got the KPA500 back from Elecraft. > Problem found: L22 and other components in the 60M low pass filter > circuit burnt through the LPF PCB. 60M LPF??? Last I looked, the US power limit on 60M is 100W relative to a half wave dipole. > Repair $650 later: Replaced low pass filter module and installed QSK mod. > > On the phone I asked what caused the failure, answer was no idea other > than component failure. I understand stuff fails but I thought I would get more than 2 years before a major expensive failure. The LPF is on the output of the amplifier. One possible cause of failure could be lightning. > Previously had a Ameritron ALS-600 for 5+ years never a problem, sold > it to purchase the KPA500. > > Sometimes the grass is not greener. My only experience with an ALS-600 was at a contest station in PJ4 several years ago. I found it to be a really inferior amp - most of the time, I was lucky to get 300W out if it. No comparison to a KPA500. 73, Jim K9YC __________________________________________________ ____________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] If you reply to this email, your message will be added to the discussion below: http://elecraft.365791.n2.nabble.com/KPA500-troubl es-tp7609284p7610243.html To unsubscribe from KPA500 troubles, click here. NAML -- View this message in context: http://elecraft.365791.n2.nabble.com/KPA500-troubl es-tp7609284p7610259.html Sent from the Elecraft mailing list archive at Nabble.com. __________________________________________________ ____________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] <javascript:;> This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] <javascript:;> -- Sent via Gmail Mobile on my iPhone __________________________________________________ ____________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Yes, I agree and complained, they said the repair was discounted by $200. The amp is 2 years old. I am seriously thinking about selling while there is a bit of a warranty and buying the SPE 1.2KA amp. Jack W4GRJ From: Charlie T, K3ICH [via Elecraft] [mailto:[hidden email]] That seems like a helluva lot to fix the bandpass If you reply to this email, your message will be added to the discussion below: http://elecraft.365791.n2.nabble.com/KPA500-troubles-tp7609284p7610272.html To unsubscribe from KPA500 troubles, click here. |
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In reply to this post by Charlie T, K3ICH
Hi Jack,
I apologize for any consternation this has caused you. Since multiple components burned through the LPF PC board, that is major damage and would require replacement of the whole LPF board, which is a major cost component of the amp. (Taking out this board and replacing it requires disassembly and reassembly of a major portion off the amp.) The repair cost also includes the tech time to diagnose, disassemble, repair, reassemble, retest and do full production TX burn-in of the amp on all bands. Component failure like this can occur in any manufacturer's radio or amplifier for many reasons, such as power line surges, nearby lightning strikes, operating with excessive SWR, transmitting into a wrong antenna etc. You do not need to be operating on a particular band, or even have the amp or radio on to incur lightning damage. This can also cause partial damage to components that then shows up as a failure later after additional operation. As a side note, every year during lightning season we see a significant increase in all sorts of 'interesting' repairs sent in to us on all of our products. Many times the user is not even aware that a strike occurred somewhere nearby while they still had their antennas connected. I'll review your repair report with our techs to make sure we didn't over charge for anything. I'll also check to see if they mis-identified which band the destroyed LPF components were from. 73, Eric elecraft.com _..._ > -----Original Message----- > From: Elecraft > [mailto:[hidden email]] On > Behalf Of w4grj > Sent: Thursday, November 12, 2015 7:14 AM > To: [hidden email] > Subject: Re: [Elecraft] KPA500 troubles > > I need to correct the information on the repair > cost > > It was $615 with shipping not $650 as I previously > reported. > > Jack W4GRJ > >> On Wed,11/11/2015 12:10 PM, W4GRJ wrote: >> Got the KPA500 back from Elecraft. >> Problem found: L22 and other components in the > 60M low pass filter >> circuit burnt through the LPF PCB. > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Eric, Thank you for your response. I did send a message to Wayne for his review, so I don’t want to cause double efforts on this….I appreciate the review. Since I do live in a active lightning area, I have a well grounded station and polyphaser surge protection. Coax is grounded when not in use…. possible but I don’t think it was lightning related. In 15 years at this QTH I have never had a lightning issue with my station or anything in the house. Thanks Again, Jack From: Eric Swartz - WA6HHQ, Elecraft [via Elecraft] [mailto:[hidden email]] Hi Jack, > -----Original Message----- > From: Elecraft > [mailto:[hidden email]] On > Behalf Of w4grj > Sent: Thursday, November 12, 2015 7:14 AM > To: [hidden email] > Subject: Re: [Elecraft] KPA500 troubles > > I need to correct the information on the repair > cost > > It was $615 with shipping not $650 as I previously > reported. > > Jack W4GRJ > >> On Wed,11/11/2015 12:10 PM, W4GRJ wrote: >> Got the KPA500 back from Elecraft. >> Problem found: L22 and other components in the > 60M low pass filter >> circuit burnt through the LPF PCB. > ______________________________________________________________ Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] If you reply to this email, your message will be added to the discussion below: http://elecraft.365791.n2.nabble.com/KPA500-troubles-tp7609284p7610277.html To unsubscribe from KPA500 troubles, click here. |
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In reply to this post by Guy Olinger K2AV
I guess I'll have to repeat myself.
There is no requirement to have a "measured" antenna; calculated gain (loss) is permitted. It's kind of like high school algebra, you just have to show your work. With modern analysis tools such as Eznec, it is almost trivial to do so, if you know what you are doing. Soapbox mode on: When I was first licensed, we were relegated to using the DC input (Vp x Ip) as our power limit because it was assumed that we did not have the ability to measure RF power accurately. As technology improved and this was no longer the case, the power limit(s) was changed to transmitter output power. Now we have been given a band, where like every other service, we get to use ERP, since the FCC, giving us the measure of the doubt, assumes that we know how to determine it.* We should, it's a requirement of *§97.13*: "(c) Before causing or allowing an amateur station to transmit from any place where the operation of the station could cause human exposure to RF electromagnetic field levels in excess of those allowed under §1.1310 of this chapter, the licensee is required to take certain actions. (1) The licensee must perform the routine RF environmental evaluation prescribed by §1.1307(b) of this chapter, if the power of the licensee's station exceeds the limits given in the following table:" * Also see https://www.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet65/oet65.pdf where on page 16 it says: "Many antenna-modeling programs are based on NEC or MININEC analysis. These programs often yield very accurate results. An amateur enters his or her antenna dimensions and ground characteristics into the antenna model, and the program is then executed to calculate electric and magnetic field strengths near the antenna. These programs do require some amount of user skill, but the average amateur should not experience too much difficulty in using them. The ARRL Web page maintains a list of software vendors who sell antenna modeling software (http://www.arrl.org/news/rfsafety)" Soapbox mode off. N7WS On 11/12/2015 1:05 AM, Guy Olinger K2AV wrote: > Kpa500 on 60 is illegal unless you have a *measured and > documented* VERY lossy antenna that would reduce the effective radiated > power to the same as 100 watts on a dipole. The simple 99 percent answer is > that on 60m SHUT OFF the Kpa500 and run 100 watts barefoot. > > 73, Guy K2AV > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Wes (N7WS)
On Wed,11/11/2015 1:30 PM, Wes (N7WS) wrote:
> If I use an inductively-loaded vertical monopole with a minimal ground > screen over Arizona ground my "dBd gain" might well be several dB > negative. In which case, I'm allowed to compensate for that, and line > loss, in determining amplifier output power. In that, and many other > events, a 100W transceiver is inadequate, ergo, a KPA500 is not out of > the question. Your point is, of course, well taken, Wes. BUT -- there's a certain vagueness to the FCC definition, in that it does not specify mounting height of the reference dipole, making comparisons to a vertical antenna, which relates to mounting height quite differently, at least a bit squishy. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Then I guess I could just "vaguely" follow the rules, sort of like the
President, his cabinet, the heads of the alphabet soup agencies, IRS, EPA, FBI, NSA, VA, ICE, DHS,... do. That said, I think you're making this too complicated. The rule states: "For the purpose of computing ERP, the transmitter PEP will be multiplied by the antenna gain relative to a half-wave dipole antenna. A half-wave dipole antenna will be presumed to have a gain of 1 (0 dBd). Licensees using other antennas must maintain in their station records either the antenna manufacturer's data on the antenna gain or calculations of the antenna gain." Note, there is no mention of any directivity, or lack thereof, so I would take it that this is a theoretical free-space value. Zero dBd is equal to 2.15 dBi so modelling another antenna and calculating its gain in dBi, which is the normal modelling outcome, then subtracting 2.15 from that number yields the gain relative to an ideal dipole, i.e the FCC reference. Right away this gives a significant advantage to an actual horizontal dipole that has ground gain, assuming that the dipole is rotatable and the elevation angle is favorable for the path. Absent that, and considering the physical size one would probably use a vertical and bump up the power to account for the inevitable losses. Wes N7WS On 11/12/2015 3:12 PM, Jim Brown wrote: > Your point is, of course, well taken, Wes. BUT -- there's a certain vagueness > to the FCC definition, in that it does not specify mounting height of the > reference dipole, making comparisons to a vertical antenna, which relates to > mounting height quite differently, at least a bit squishy. > > 73, Jim K9YC > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Jim Brown-10
Why would one filter, that like just like all of the others is switched into the
circuit by a relay on each end, fail while none of the others do not? On 11/11/2015 1:32 PM, Jim Brown wrote: > > The LPF is on the output of the amplifier. One possible cause of failure could > be lightning. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Wes (N7WS)
On Fri,11/13/2015 1:30 PM, Wes (N7WS) wrote:
> Note, there is no mention of any directivity, or lack thereof, so I > would take it that this is a theoretical free-space value. One could do that, of course, but your original post brought ground conductivity into the computation, which is, IMO, entirely appropriate. FWIW, I've done some extensive modeling studies of horizontal and vertical antennas at various mounting heights; horizontal antennas don't care much about soil but care a lot about height; vertical antennas care a bit about height and a lot about soil. That work is on my website. I think I would use average gain of the antenna as installed as the basis for compliance with the Rules, but the question remains, what height for the dipole? :) This is, for me, purely academic. My soil being terrible, a vertical is a poor choice for 60M, and I have a bunch of high horizontal dipoles, so I'd use one of them. :) BTW -- there's a 2-part piece on this topic by Rudy Severns in QEX this past summer, specifically addressing very short verticals for the 630m band. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Wes (N7WS)
But why would a filter for a band that the operator had never used fail?
Vic 4X6GP/K2VCO > On 13 Nov 2015, at 11:52 PM, Wes (N7WS) <[hidden email]> wrote: > > Why would one filter, that like just like all of the others is switched into the circuit by a relay on each end, fail while none of the others do not? > >> On 11/11/2015 1:32 PM, Jim Brown wrote: >> >> The LPF is on the output of the amplifier. One possible cause of failure could be lightning. ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Jim Brown-10
Probably best to change the topic of this, as it has drifted into a different area.
Eric /elecraft.com/ On 11/13/2015 9:01 PM, Jim Brown wrote: > On Fri,11/13/2015 1:30 PM, Wes (N7WS) wrote: >> Note, there is no mention of any directivity, or lack thereof, so I would >> take it that this is a theoretical free-space value. > > One could do that, of course, but your original post brought ground > conductivity into the computation, which is, IMO, entirely appropriate. > > FWIW, I've done some extensive modeling studies of horizontal and vertical > antennas at various mounting heights; horizontal antennas don't care much > about soil but care a lot about height; vertical antennas care a bit about > height and a lot about soil. That work is on my website. > > I think I would use average gain of the antenna as installed as the basis for > compliance with the Rules, but the question remains, what height for the > dipole? :) > > This is, for me, purely academic. My soil being terrible, a vertical is a poor > choice for 60M, and I have a bunch of high horizontal dipoles, so I'd use one > of them. :) > > BTW -- there's a 2-part piece on this topic by Rudy Severns in QEX this past > summer, specifically addressing very short verticals for the 630m band. > > 73, Jim K9YC > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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