Re: [Elecraft] KX3 Roofing Filter Question
Mark, If the roofing filter was added to your original order, it will be calibrated at the factory (even if it is a kit). If you add the roofing filter later, you will have to do the calibration for optimum results. 73, Don W3FPR On 1/29/2018 5:31 PM, Mark Petiford via Elecraft wrote: Re: "If you do choose the roofing filter, be certain you do the calibration if it is a kit." Don, My kit build KX3 instruction manual says that I don't have to do the calibration if I ordered the filters WITH my KX3 kit: "If you received the optional KXFL3 filter with your kit, you do not need to perform theReceiver Sideband alignment procedure referenced in the Owner’s manual and describedin detail in the KXFL3 option manual. That procedure was done for you at the factory." __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
[Elecraft] KX3 Roofing Filter Question
Hi Stan, I ordered mine with the roofing filter and no regrets. When its on its like the radio is a horse with blinders on. Any nearby flailing distractions are removed from view so the horses brain doesn’t have to process it. Its not that often I need it but when some other strong signal is close enough to your frequency and shows up on your pan adaptor the front end of the KX3 is negatively influenced and it will compromise the receivers s/n ratio and ability to receive the content to want even though you can hear it. The roofing filter will save the day and you can hold your ground and not have vacate the frequency. I use it on SSB and digimodes as well. I was recently doing QRP on the beach in the bahamas and after I got all settled in on a frequency and started a few pile ups some commercial shortwave station came on the air. It must have been very close because i Message: 22 Date: Mon, 29 Jan 2018 16:20:06 -0500 (EST) From: stan levandowski <sjl...@optonline.net> To: Elecraft@mailman.qth.net Subject: [Elecraft] KX3 Roofing Filter Question Message-ID: <765520bb.1faf0.16143ca985b.webtop...@optonline.net> Content-Type: text/plain; charset=UTF-8; format=flowed I am going to order another KX3 this week. Probably tomorrow.? The last one I ordered in 2012 did not have the roofing filter option and I do not THINK I missed it. I use ONLY CW and I do NOT contest.? I like to CASUALLY chase DX and I play in low stress sprints like NAQCC but mostly I just like to RAG CHEW. My antenna is an EFHW installed as a "half square" in trees at 30 feet (MyAntennas 4010). I have reviewed the Elecraft site notes, and done a fair amount of Googling and I now am more confused than ever.? It seems that the real value lies in dealing with strong signals, crowded bands and ferocious contesting conditions. My bottom line question is this:? If I DO NOT get the roofing filter option will my KX3 receiver be LESS SENSITIVE?? The Sherwood report shows a pre-amp off sensitivity of .9 uv which improves to a very impressive .09 with the preamp on.? Is this somehow related to the roofing filter? I am especially concerned because I remember doing an A/B comparison on a weak signal between my previous KX3 and my 55 year old Drake 2B and the 2B beat the crap out of the factory built KX3.? I can't help wondering if the roofing filter I didn't buy in 2012 had something to do with this. I sure could use a real simple answer:? buy it or don't buy it?? CW sensitivity is my ultimate goal because if I can't hear 'em I can't work 'em. Thanks and 73, Stan WB2LQF __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KX3 Roofing Filter Question
Stan, If you use the 8 KHz receive offset, you can not use the roofing filter; it is disables when you invoke the SHFT. So, having it will do you no good. And, that's the simple answer. I have my KX3 set to the offset as it cleans up the spectrum display that I use; I've never looked into the performance difference of using the offset or not. I did use my KX3 for causal DX, contesting, and everything in between. It's a wonderful radio. I have since purchased a K3s, so the KX3 has been relegated to Field Day use only. Be careful of system sensitivity specs. Most receivers are more sensitive than ambient conditions will allow. The .9 uV number you show is absolutely fine for the lower end of HF, but you could use a little more at the upper end. I live in an urban environment with power lines and neighbors with noisy TVs, heat pumps, and solar arrays. I'd be more than happy if I could use a sensitivity of a 1 uV on 80. 73, Barry K3NDM -- Original Message -- From: "stan levandowski" <sjl...@optonline.net> To: Elecraft@mailman.qth.net Sent: 1/29/2018 4:20:06 PM Subject: [Elecraft] KX3 Roofing Filter Question I am going to order another KX3 this week. Probably tomorrow. The last one I ordered in 2012 did not have the roofing filter option and I do not THINK I missed it. I use ONLY CW and I do NOT contest. I like to CASUALLY chase DX and I play in low stress sprints like NAQCC but mostly I just like to RAG CHEW. My antenna is an EFHW installed as a "half square" in trees at 30 feet (MyAntennas 4010). I have reviewed the Elecraft site notes, and done a fair amount of Googling and I now am more confused than ever. It seems that the real value lies in dealing with strong signals, crowded bands and ferocious contesting conditions. My bottom line question is this: If I DO NOT get the roofing filter option will my KX3 receiver be LESS SENSITIVE? The Sherwood report shows a pre-amp off sensitivity of .9 uv which improves to a very impressive .09 with the preamp on. Is this somehow related to the roofing filter? I am especially concerned because I remember doing an A/B comparison on a weak signal between my previous KX3 and my 55 year old Drake 2B and the 2B beat the crap out of the factory built KX3. I can't help wondering if the roofing filter I didn't buy in 2012 had something to do with this. I sure could use a real simple answer: buy it or don't buy it? CW sensitivity is my ultimate goal because if I can't hear 'em I can't work 'em. Thanks and 73, Stan WB2LQF __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to k3...@comcast.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KX3 Roofing Filter Question
In general, filters have little to do with sensitivity. On the other hand, filters do provide selectivity. In crowded band conditions where one is attempting to dig out a weak signal among stronger signals, the roofing reduces the likelihood that the stronger signal will impact the overall AGC, thus diminishing the apparent strength of the weaker signal. Otherwise, the added roofing filter certainly can't diminish the receiver performance but may, under certain conditions, enhance receiver performance. Conclusion: buy it! 73 Bob, K4TAX On 1/29/2018 3:20 PM, stan levandowski wrote: I am going to order another KX3 this week. Probably tomorrow. The last one I ordered in 2012 did not have the roofing filter option and I do not THINK I missed it. I use ONLY CW and I do NOT contest. I like to CASUALLY chase DX and I play in low stress sprints like NAQCC but mostly I just like to RAG CHEW. My antenna is an EFHW installed as a "half square" in trees at 30 feet (MyAntennas 4010). I have reviewed the Elecraft site notes, and done a fair amount of Googling and I now am more confused than ever. It seems that the real value lies in dealing with strong signals, crowded bands and ferocious contesting conditions. My bottom line question is this: If I DO NOT get the roofing filter option will my KX3 receiver be LESS SENSITIVE? The Sherwood report shows a pre-amp off sensitivity of .9 uv which improves to a very impressive .09 with the preamp on. Is this somehow related to the roofing filter? I am especially concerned because I remember doing an A/B comparison on a weak signal between my previous KX3 and my 55 year old Drake 2B and the 2B beat the crap out of the factory built KX3. I can't help wondering if the roofing filter I didn't buy in 2012 had something to do with this. I sure could use a real simple answer: buy it or don't buy it? CW sensitivity is my ultimate goal because if I can't hear 'em I can't work 'em. Thanks and 73, Stan WB2LQF __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to rmcg...@blomand.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KX3 Roofing Filter Question
Re: "If you do choose the roofing filter, be certain you do the calibration if it is a kit." Don, My kit build KX3 instruction manual says that I don't have to do the calibration if I ordered the filters WITH my KX3 kit: "If you received the optional KXFL3 filter with your kit, you do not need to perform theReceiver Sideband alignment procedure referenced in the Owner’s manual and describedin detail in the KXFL3 option manual. That procedure was done for you at the factory." That was back in 2013, so maybe things have changed. Mark, KE6BB __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KX3 Roofing Filter Question
Stan, I am not going to give you a terse answer, but I can say that the sensitivity of the KX3 does not depend on the roofing filter. However, the roofing filter will give you more rejection of unwanted signals that you may encounter in crowded band conditions. If you do not operate when the bands get crowded, you will not notice the difference with or without the roofing filter option. If you do choose the roofing filter, be certain you do the calibration if it is a kit. If you order the factory built KX3 with the roofing filter option, that calibration will have been done at the factory. 73, Don W3FPR On 1/29/2018 4:20 PM, stan levandowski wrote: I am going to order another KX3 this week. Probably tomorrow. The last one I ordered in 2012 did not have the roofing filter option and I do not THINK I missed it. I use ONLY CW and I do NOT contest. I like to CASUALLY chase DX and I play in low stress sprints like NAQCC but mostly I just like to RAG CHEW. __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
[Elecraft] KX3 Roofing Filter Question
I am going to order another KX3 this week. Probably tomorrow. The last one I ordered in 2012 did not have the roofing filter option and I do not THINK I missed it. I use ONLY CW and I do NOT contest. I like to CASUALLY chase DX and I play in low stress sprints like NAQCC but mostly I just like to RAG CHEW. My antenna is an EFHW installed as a "half square" in trees at 30 feet (MyAntennas 4010). I have reviewed the Elecraft site notes, and done a fair amount of Googling and I now am more confused than ever. It seems that the real value lies in dealing with strong signals, crowded bands and ferocious contesting conditions. My bottom line question is this: If I DO NOT get the roofing filter option will my KX3 receiver be LESS SENSITIVE? The Sherwood report shows a pre-amp off sensitivity of .9 uv which improves to a very impressive .09 with the preamp on. Is this somehow related to the roofing filter? I am especially concerned because I remember doing an A/B comparison on a weak signal between my previous KX3 and my 55 year old Drake 2B and the 2B beat the crap out of the factory built KX3. I can't help wondering if the roofing filter I didn't buy in 2012 had something to do with this. I sure could use a real simple answer: buy it or don't buy it? CW sensitivity is my ultimate goal because if I can't hear 'em I can't work 'em. Thanks and 73, Stan WB2LQF __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KX3 Roofing filter question
Joshua, If you primarily operate CW or other digital modes, try using Rx Equalization and drop anything above about 800 Hz by anywhere from 0 to -16dB. I think if you operate primarily SSB you are stuck with having to have Rx Equalization pretty much open above 800 Hz. 73, Tom - W4BQF -Original Message- From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Fred Jensen Sent: Tuesday, March 24, 2015 10:49 PM To: elecraft@mailman.qth.net Subject: Re: [Elecraft] KX3 Roofing filter question Joshua, Probably not. The ultimate BW of your receiver is set by the DSP and noise power is sort of proportional to BW. The purpose of the roofing filters is to protect the ADC sampler at the head end of the DSP from very strong signals that could drive it to saturation. Noise, other than atmospheric and galactic, needs to be attacked at the source. Like getting rid of your switching wall warts and power supplies. So long as the atmospheric noise is not saturating the ADC, reducing the DSP BW is the only really effective way to reduce it's impact, and that's a lot easier on CW than on SSB. Different roofing filters are not likely to make much difference at all unless they're more narrow than your DSP setting. On 3/24/2015 7:24 PM, Joshua Gould wrote: All, Would the roofing filters help reduce atmospheric noise? I'm having a heck of a time hearing anything over the S5 noise levels that I seem to be dealing with of late. But at least it's better than the S9 noise I was getting from switching power supplies under my desk... 72, Joshua Gould K8WXA EM89pn __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to alderm...@windstream.net __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KX3 Roofing filter question
If you have lots of atmospheric noise, you may have too much gain in your revive chain, and should maybe consider switching off the preamp/switching on the attenuator. There is also the NR noise reduction feature which may be useful. However on CW I find that narrowing the PBT bandwidth cuts out a lot of the band noise. As someone else stated, a roofing filter is not going to help you with this sort of problem; a roofing filter is to protect against strong stations on nearby frequencies so you don't get problems like AGC pumping and undesired mixing products. 73, Matt VK2RQ On 25 Mar 2015, at 1:49 pm, Fred Jensen k6...@foothill.net wrote: Joshua, Probably not. The ultimate BW of your receiver is set by the DSP and noise power is sort of proportional to BW. The purpose of the roofing filters is to protect the ADC sampler at the head end of the DSP from very strong signals that could drive it to saturation. Noise, other than atmospheric and galactic, needs to be attacked at the source. Like getting rid of your switching wall warts and power supplies. So long as the atmospheric noise is not saturating the ADC, reducing the DSP BW is the only really effective way to reduce it's impact, and that's a lot easier on CW than on SSB. Different roofing filters are not likely to make much difference at all unless they're more narrow than your DSP setting. On 3/24/2015 7:24 PM, Joshua Gould wrote: All, Would the roofing filters help reduce atmospheric noise? I'm having a heck of a time hearing anything over the S5 noise levels that I seem to be dealing with of late. But at least it's better than the S9 noise I was getting from switching power supplies under my desk... 72, Joshua Gould K8WXA EM89pn __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to matt.vk...@gmail.com __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
[Elecraft] KX3 Roofing filter question
All, Would the roofing filters help reduce atmospheric noise? I'm having a heck of a time hearing anything over the S5 noise levels that I seem to be dealing with of late. But at least it's better than the S9 noise I was getting from switching power supplies under my desk... 72, Joshua Gould K8WXA EM89pn KX3# 7480 NAQCC # 7704 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
Re: [Elecraft] KX3 Roofing filter question
Joshua, Probably not. The ultimate BW of your receiver is set by the DSP and noise power is sort of proportional to BW. The purpose of the roofing filters is to protect the ADC sampler at the head end of the DSP from very strong signals that could drive it to saturation. Noise, other than atmospheric and galactic, needs to be attacked at the source. Like getting rid of your switching wall warts and power supplies. So long as the atmospheric noise is not saturating the ADC, reducing the DSP BW is the only really effective way to reduce it's impact, and that's a lot easier on CW than on SSB. Different roofing filters are not likely to make much difference at all unless they're more narrow than your DSP setting. On 3/24/2015 7:24 PM, Joshua Gould wrote: All, Would the roofing filters help reduce atmospheric noise? I'm having a heck of a time hearing anything over the S5 noise levels that I seem to be dealing with of late. But at least it's better than the S9 noise I was getting from switching power supplies under my desk... 72, Joshua Gould K8WXA EM89pn __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
