KRX3 vs APF on weak signals ??
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Hello folks.
I operate cw 98% of the time. After 'rag chewing' for several years I'm becoming more interested in DX'ing. Also I'm eager to try my luck on 160 meters despite my QTH and antenna restrictions. I've been considering purchasing the KRX3 (second receiver) for a year or more. However with the recent firmware upgrades and now the APF (audio peaking filter) feature on the standard K3 I'm wondering if the second receivers 'diversity receive' capability would be that much superior to the APF for weak/fading signals? (My results vary using the APF; abort 1/3 of the time it helps, 1/3 of the time I get 'clearer' copy with very narrow DSP bandwidth and no APF... the final 1/3 is a no copy either way.) If the APF approaches the effectiveness of the KRX3 on weak/fading sigs I may just go for a P3 instead. Thanks for any advice. chuck AF4XK |
Re: KRX3 vs APF on weak signals ??
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On Tue, Jul 12, 2011 at 5:27 PM, callen1155 <[hidden email]> wrote:
> ...I'm becoming more interested in DX'ing....I've been considering > purchasing the KRX3 (second receiver) ... ========== Chuck, the second receiver does more than just offer diversity. A lot of CW DX is worked split, and it's tremendously helpful to be able to listen to your xmit frequency in one ear and the DX in the other. The key is to track down the guy he's working and position your signal so it's in the right place at the right time. It's even more helpful if your station is modest, as you imply when you mention antenna restrictions. I use split mode 100% of the time, even if the DX is listening on his frequency. Being able to slide to one side or the other can make all the difference. And BTW, if you have two dissimilar antennas, diversity is really neat. Tony KT0NY ______________________________________________________________ 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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Your question reads like, "Do I have enough rocks in this bucket, or
do I have more hammers in this bucket?" The APF does not do what diversity does for you. APF is a monaural concept. Diversity allows you to spread the noise while signals remain discreet. This is something which your ears already do in listening to a conversation in a crowded. K3 diversity leaves separation to your BRAIN, which is very good at it. Also the second RX has many more uses besides diversity, but to evaluate diversity, you need to go somewhere and HEAR diversity from a dual RX K3. Then you'll have the sensory answer to your question, whether you decide to get it or not. 73, Guy. On Tue, Jul 12, 2011 at 6:34 PM, Tony Estep <[hidden email]> wrote: > On Tue, Jul 12, 2011 at 5:27 PM, callen1155 <[hidden email]> wrote: > >> ...I'm becoming more interested in DX'ing....I've been considering >> purchasing the KRX3 (second receiver) ... > > ========== > Chuck, the second receiver does more than just offer diversity. A lot of CW > DX is worked split, and it's tremendously helpful to be able to listen to > your xmit frequency in one ear and the DX in the other. The key is to track > down the guy he's working and position your signal so it's in the right > place at the right time. It's even more helpful if your station is modest, > as you imply when you mention antenna restrictions. I use split mode 100% of > the time, even if the DX is listening on his frequency. Being able to slide > to one side or the other can make all the difference. And BTW, if you have > two dissimilar antennas, diversity is really neat. > > Tony KT0NY > ______________________________________________________________ > 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: KRX3 vs APF on weak signals ??
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Thanks for the responses but I'm at a loss as to why the question is confusing. I'm trying to determine the most efficient method to hear weak/fading cw signals.
I have read on here many times where folks brag on the 2nd receivers' ability to overcome fading band conditions via diversity receive using complementing antennas. I have read and experienced the benefit of APF under those same band conditions as well. I understand diversity receive and APF go about it two totally different ways but the end result is an improved ability to hear weak/fading signals. My question is simply, under weak/fading band conditions when you're straining to copy the cw sig (assuming you have both APF and diversity receive to choose from), which would you choose to improve your copy and make the contact? thanks again. chuck |
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If it is signal to noise ratio is weak but steady, no QSB, then APF
ought to do the trick if the CW speed is compatible with the APF bandwidth. If it is a rotating signal through the ionosphere (QSB, fading), then diversity (including diversity */with/* APF enabled). 73, Lyle KK7P > ... > > My question is simply, under weak/fading band conditions when you're > straining to copy the cw sig (assuming you have both APF and diversity > receive to choose from), which would you choose to improve your copy and > make the contact? ______________________________________________________________ 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 callen1155
You insist on making this an either/or kind of choice, and it simply
is not. APF does not make a result in your brain, it simply listens to slower CW with a very narrow bandwidth. It seems to have times when it will pull something out of noise, and other times not, by use of the narrowness. Diversity does not narrow what you hear. The randomness of noise causes it to spread around the audio "compass" while discrete signals will appear to come from a single direction, and signals going through fades will do a "rotation" at the bottom without actually losing copy. The spreading around of the noise is sometimes worth 10/15 dB of "separation" with whisper level signals in the clear, and undetectable in the monophonic, even with APF. With different kinds of noise, only the APF seems to work to pull out a signal. This and APF are not an either/or thing. I use one or the other, and rarely, both at the same time. If you can get a chance to listen to a K3 on diversity, you will understand. IF for some very silly reason I was forced to chose between APF and diversity, I would chose diversity, because of all the other uses of the excellent second RX. Go hear one. 73, Guy. On Tue, Jul 12, 2011 at 10:39 PM, callen1155 <[hidden email]> wrote: > Thanks for the responses but I'm at a loss as to why the question is > confusing. I'm trying to determine the most efficient method to hear > weak/fading cw signals. > > I have read on here many times where folks brag on the 2nd receivers' > ability to overcome fading band conditions via diversity receive using > complementing antennas. I have read and experienced the benefit of APF under > those same band conditions as well. > > I understand diversity receive and APF go about it two totally different > ways but the end result is an improved ability to hear weak/fading signals. > > My question is simply, under weak/fading band conditions when you're > straining to copy the cw sig (assuming you have both APF and diversity > receive to choose from), which would you choose to improve your copy and > make the contact? > > thanks again. > chuck > > -- > View this message in context: http://elecraft.365791.n2.nabble.com/KRX3-vs-APF-on-weak-signals-tp6577049p6577528.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 |
Re: KRX3 vs APF on weak signals ??
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In reply to this post by Guy, K2AV
To get a good taste of diversity for weak signal cw reception, plug a pair of stereo headphones into your computer's soundcard and listen to these: http://n1eu.com/K3/rz0af_160M_8nov08_2255Z.mp3 http://n1eu.com/K3/4s7ne_80M_26Dec10_2350Z.mp3 73, Barry N1EU |
Re: KRX3 vs APF on weak signals ??
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In reply to this post by Guy, K2AV
Thanks for the explanations and your patience gentlemen. I've got it now. 73. chuck AF4XK |
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In reply to this post by callen1155
Hi Chuck,
Diversity reception may not work for everybody. My brain can't handle it. Having a near identical sound in both ears with one side fading in and out doesn't seem to make it easier for me to copy. I prefer to just switch between two antennas and listen to the one that sounds best. To do this you need a separate receive antenna and the KXV3A I/O board. I still love the Sub RX and use it frequently but not for diversity. 73, Mike K2MK
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Re: KRX3 vs APF on weak signals ??
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I guess I'm the opposite. I use diversity virtually all the time on 160M-20M. Even when the rx antenna + subrx isn't necessarily making the signal more readable, I find the stereo effect very pleasing to listen to. 73, Barry N1EU |
Re: KRX3 vs APF on weak signals ??
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In reply to this post by callen1155
Whichever works better or BOTH if that works better.
They do different things so I don't think you can answer the questions which is better. I think you are trying to justify why to buy the KRX3. And the answer is a question (sorry): What is your intention for its use? You stated an interest in: 1) 160m 2) Weak/fading CW APF works pretty nice in peaking weak CW (and its free with the K3). But my understanding of 160m (not QRV there - yet) is that using a low-noise reception antenna in diversity mode can make a significant improvement in fading signals. Ideally (on 160m) that would be use of a long wire like a Beverage or smaller low-noise antenna like Pendant (but this depends a lot on how much real estate you have). On 600m as WD2XSH/45, I tried a 930-foot Beverage-on-Ground (BOG) and it did not work as well as my transmitting antenna which is a 43-foot vertical by 130-foot inverted-L. The signals with the Inv-L were 20-dB stronger (farthest Rx DX from Alaska is Buffalo, NY). The Beverage is moot as my neighbor removed it when he needed access across where it lay (I had it run along side his private airstrip). My next attempt for Rx antenna will be a shielded 6-foot diameter loop (rotatable) with preamp. (600m DX season is Oct. - Mar.) I run 100w RF output on 495-KHz to the base-loaded Inv-L with about 0.8% antenna efficiency (hard to make a 1/4 WL vertical at 600meters - 492 foot). My 4.15w ERP signal has been heard in Vancouver, BC about 1300 miles. (lots of info on my website) 73, Ed - KL7UW K3/10 with KRX3 ------------------------------ Message: 21 Date: Tue, 12 Jul 2011 19:39:42 -0700 (PDT) From: callen1155 <[hidden email]> Subject: Re: [Elecraft] KRX3 vs APF on weak signals ?? To: [hidden email] Message-ID: <[hidden email]> Content-Type: text/plain; charset=us-ascii Thanks for the responses but I'm at a loss as to why the question is confusing. I'm trying to determine the most efficient method to hear weak/fading cw signals. I have read on here many times where folks brag on the 2nd receivers' ability to overcome fading band conditions via diversity receive using complementing antennas. I have read and experienced the benefit of APF under those same band conditions as well. I understand diversity receive and APF go about it two totally different ways but the end result is an improved ability to hear weak/fading signals. My question is simply, under weak/fading band conditions when you're straining to copy the cw sig (assuming you have both APF and diversity receive to choose from), which would you choose to improve your copy and make the contact? thanks again. chuck 73, Ed - KL7UW, WD2XSH/45 ====================================== BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 50-1.1kw?, 144-1.4kw, 432-100w, 1296-60w, 3400-? DUBUS Magazine USA Rep [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 |
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