Trade off PR6 vs PR6-10 pre-amp
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I have the PR6 mounted on the K3. Did successful JT65 6M moon bounce
with 11 element antenna,1000 watts, 110 foot BuryFlex coax, and appropriate switching. So this setup worked. I note that the specification for the PR6-10 has about 2dB more gain than the PR6. The MDS and dynamic range specs are the same. Would the 6 meter performance with the K3 using the PR6-10 be better or worse than the PR6 because of: 1. Wider pass band? More opportunity for out of band noise? 2. More gain? Impact on overall dynamic range and noise figure? My real question is should I sell my PR6 and get a PR6-10? I do not want to lose anything on 6 meters but perhaps could stand some improvement on 10. Aloha, John KH7T, Unrepentant Engineer ______________________________________________________________ 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 |
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John, did anyone reply to your questions? Have you made a decision? I am also wondering if making making the switch will compromise 6M performance.
73, Lou, W0FK
St. Louis, MO
"The difference between stupidity and genius is that genius has its limits." Albert Einstein |
Re: Trade off PR6 vs PR6-10 pre-amp
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For all practical purposes, the differences between the PR6 and PR6-10 PR6 NF= 0.5 dB typ, gain= 18 dB PR6-10 NF< 0.7 dB, gain= 20 dB should be indistinguishable. In the worst conditions of in-band QRM the PR6-10 may result in up to 4 dB poorer IMD3 but both interfering signals would need to be within 2 KHz of the operating frequency for that to be significant. With either preamp, system noise figure (net of feedline losses) should be less than 1 dB. Out of band noise (and blocking) should be handled by the receiver bandpass filters regardless of the preamp selected. Sherwood reports the K3's 100 KHz blocking dynamic range at 140 dB - not likely to be significantly impacted by an extra 2 dB of preamp gain. 73, ... Joe, W4TV On 7/12/2013 12:26 PM, W0FK wrote: > John, did anyone reply to your questions? Have you made a decision? I am also > wondering if making making the switch will compromise 6M performance. > > 73, > > Lou, W0FK > > > KH7T wrote >> I have the PR6 mounted on the K3. Did successful JT65 6M moon bounce >> with 11 element antenna,1000 watts, 110 foot BuryFlex coax, and >> appropriate switching. So this setup worked. >> >> I note that the specification for the PR6-10 has about 2dB more gain >> than the PR6. The MDS and dynamic range specs are the same. >> >> Would the 6 meter performance with the K3 using the PR6-10 be better or >> worse than the PR6 because of: >> >> 1. Wider pass band? More opportunity for out of band noise? >> >> 2. More gain? Impact on overall dynamic range and noise figure? >> >> My real question is should I sell my PR6 and get a PR6-10? I do not >> want to lose anything on 6 meters but perhaps could stand some >> improvement on 10. >> >> Aloha, >> John KH7T, Unrepentant Engineer >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto: > >> Elecraft@.qth > >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html > > > > > > ----- > St. Louis, MO > K3 #'s 7463 and 2513, P3 #620, KX1 #1517, KX3 #0036 > > -- > View this message in context: http://elecraft.365791.n2.nabble.com/Trade-off-PR6-vs-PR6-10-pre-amp-tp7576423p7576650.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] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > 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 |
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In reply to this post by KH7T
Lou, I have received no other replies to my message. Additional comments would be welcome. In attempting to answer my own question, I suspect that the antenna bandwidth on 6M would limit out of band issues. The slightly higher gain of the PR6-10 with the same noise figure then might be an advantage by helping overcome cable loss. At least as long as strong signals are not overloading the front end. I will probably not switch. I presently have a good antenna on 24 and 28 MHz and do not really feel the need for more gain there. Perhaps if I did not have the trusted PR6 I might purchase the PR6-10 instead. 73, John Kh7t Lou, <[hidden email]> wrote 7/12/2913: John, did anyone reply to your questions? Have you made a decision? I am also wondering if making making the switch will compromise 6M performance. 73, Lou, W0FK KH7T wrote I have the PR6 mounted on the K3. Did successful JT65 6M moon bounce with 11 element antenna,1000 watts, 110 foot BuryFlex coax, and appropriate switching. So this setup worked. I note that the specification for the PR6-10 has about 2dB more gain than the PR6. The MDS and dynamic range specs are the same. Would the 6 meter performance with the K3 using the PR6-10 be better or worse than the PR6 because of: 1. Wider pass band? More opportunity for out of band noise? 2. More gain? Impact on overall dynamic range and noise figure? My real question is should I sell my PR6 and get a PR6-10? I do not want to lose anything on 6 meters but perhaps could stand some improvement on 10. Aloha, John KH7T, Unrepentant Engineer ______________________________________________________________ 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 |
Re: Trade off PR6 vs PR6-10 pre-amp
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John Buck <[hidden email]> wrote:
> > In attempting to answer my own question, I suspect that the antenna bandwidth on 6M would limit out of band issues. That, plus the K3's multi-section 6-meter low-pass filter (assuming you're connecting the PR6-10 between RX ANT IN and OUT). > The slightly higher gain of the PR6-10 with the same noise figure then might be an advantage by helping overcome cable loss. At least as long as strong signals are not overloading the front end. Unlikely; both the PR6 and 6-10 are very high-intercept amplifiers. > I will probably not switch. I presently have a good antenna on 24 and 28 MHz and do not really feel the need for more gain there. That is probably the case for most K3 owners. We had some requests for 10/12 meter coverage and realized we could create a PR6-10 with a few circuit changes, but the rig's sensitivity on these bands is adequate for the vast majority of operators. * * * Earlier, KH7T wrote: > > Would the 6 meter performance with the K3 using the PR6-10 be better or > worse than the PR6 because of: > > 1. Wider pass band? More opportunity for out of band noise? > > 2. More gain? Impact on overall dynamic range and noise figure? The differences in specs will be insignificant in nearly all cases. > My real question is should I sell my PR6 and get a PR6-10? Only if you need to hear butterfly wings flapping 10,000 miles away on 10 and 12 meters. 73, Wayne N6KR ______________________________________________________________ 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 |
Re: Trade off PR6 vs PR6-10 pre-amp
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That is going to greatly benefit us Floridians. Those wingbeats are what starts hurricanes, you know!
73, Mike NF4L > > Only if you need to hear butterfly wings flapping 10,000 miles away on 10 and 12 meters. > > 73, > Wayne > N6KR > > > > ______________________________________________________________ > 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 ______________________________________________________________ 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 |
Re: Trade off PR6 vs PR6-10 pre-amp
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In reply to this post by KH7T
Am 13.07.2013 21:09, schrieb John Buck: > > The slightly higher gain of the PR6-10 with the same noise figure > then might be an advantage by helping overcome cable loss. How should that work if the preamp is mounted at the K3 between RXANT in & out? It's after the cable then, isn't it? ;-) If you want to overcome cable loss buy a mast-mounted preamp. 73, Olli - DH8BQA ______________________________________________________________ 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 |
Re: Trade off PR6 vs PR6-10 pre-amp
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Olli,
I agree if the frequency is higher than 6 meters, but at 50 MHz and down, the cable loss does not appreciable degrade the noise figure (unless the feedline is exceptionally long). That does not equate to those frequencies above the 50 MHz band. The real answer depends on your particular situation (antenna gain and feedline loss). 73, Don W3FPR On 7/13/2013 8:03 PM, Oliver Dröse wrote: > > Am 13.07.2013 21:09, schrieb John Buck: >> >> The slightly higher gain of the PR6-10 with the same noise figure >> then might be an advantage by helping overcome cable loss. > > How should that work if the preamp is mounted at the K3 between RXANT > in & out? It's after the cable then, isn't it? ;-) If you want to > overcome cable loss buy a mast-mounted preamp. > ______________________________________________________________ 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 |
Re: Trade off PR6 vs PR6-10 pre-amp
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Don, > I agree if the frequency is higher than 6 meters, but at 50 MHz and > down, the cable loss does not appreciable degrade the noise figure > (unless the feedline is exceptionally long). Cable loss *always* degrades noise figure because it increases the system noise figure on a dB for dB basis just like *any* attenuator present before the first amplifier. The question is whether that increased noise figure is significant in the upper HF (20 - 30 MHz) range ... and I would argue "it can be". ITU/CCIR studies show man made noise levels between 15 and 20 dB higher, on average, than thermal noise in that range - meaning background noise will run from -127 to -132 dBm in 500 Hz or -120 to -125 dBm in 2.4KHz. Sherwood measured the K3's MDS at -130 dBm (presumably at 400 Hz) with preamp off which equates to a noise figure of 17 dB. 3dB of feedline loss (200 feet of "RG8X" - not "exceptionally long") ahead of that would directly impact performance. Even with the K3's stock internal preamp (NF= 7.5 dB, gain 12 dB), 3 dB added to the 9.5 dB system noise figure (MDS= -138 dBm @ 500 Hz) could reduce system sensitivity to a point that it was insufficient in an exceptionally quiet location. 73, ... Joe, W4TV On 7/13/2013 8:14 PM, Don Wilhelm wrote: > Olli, > > I agree if the frequency is higher than 6 meters, but at 50 MHz and > down, the cable loss does not appreciable degrade the noise figure > (unless the feedline is exceptionally long). That does not equate to > those frequencies above the 50 MHz band. > > The real answer depends on your particular situation (antenna gain and > feedline loss). > > 73, > Don W3FPR > > On 7/13/2013 8:03 PM, Oliver Dröse wrote: >> >> Am 13.07.2013 21:09, schrieb John Buck: >>> >>> The slightly higher gain of the PR6-10 with the same noise figure >>> then might be an advantage by helping overcome cable loss. >> >> How should that work if the preamp is mounted at the K3 between RXANT >> in & out? It's after the cable then, isn't it? ;-) If you want to >> overcome cable loss buy a mast-mounted preamp. >> > > ______________________________________________________________ > 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 > 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 |
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