[Elecraft] What is a dB worth was: Re: KX3 vs. K3 and other rigs?
It is pretty widely accepted in contesting that an improvement in *either* receive or transmit capability of 1 dB will yield a useful increase in the number of QSOs over a 48-hour contest, even if it has an indiscernible effect on 99.5 percent of your contacts. 73, Pete N4ZR The World Contest Station Database, updated daily at www.conteststations.com The Reverse Beacon Network at http://reversebeacon.net, blog at reversebeacon.blogspot.com, spots at telnet.reversebeacon.net, port 7000 On 6/7/2011 8:23 AM, drewko wrote: There is another way of looking at it-- how many additional contacts would potentially be available by utilizing an increase of just 3db? I don't know the answer but there is a somewhat analogous situation in astronomy having to do with the brightness of stars. They are also measured on a logarithmic scale, called magnitude, each magnitude representing twice or half the brightness level of the following or preceding magnitude. A difference of one magnitude does not appear very large to the eye, yet the ability to see one magnitude fainter can yield three times as many stars. I imagine some similar effect might pertain to radio waves. BTW, I'm not asking for more power in the KX3; would be quite content with 10 watts, same as my K3. 73, Drew AF2Z On Mon, 06 Jun 2011 08:56:48 -0700, Alan N1AL wrote: On Mon, 2011-06-06 at 08:10 -0700, juergen wrote: However from a communications effectiveness point of 20 watts is a much more realistic power level, especially for SSB QSO's. The difference between 10 and 20 watts is only 3 dB, half an S-unit. Compared to the 20-30 dB of QSB you often find on the HF bands, you would hardly even notice such a small difference. I think it is quite rare that 3 dB would be the difference between making a contact or not. Alan N1AL __ 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 __ 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
[Elecraft] What is a dB worth was: Re: KX3 vs. K3 and other rigs?
There's a saying among VHF / UHF'ers in reference to coax and connector losses that every .5db counts. 73! Ken - K0PP __ 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
Re: [Elecraft] What is a dB worth was: Re: KX3 vs. K3 and other rigs?
True at UHF/VHF. The world if HF is quite a different place for most of us. If your purpose is to find that sweet second or two where a very brief exchange might be confirmed on HF, a difference of a few dB might count, as Pete notes. But for communications involving a lengthy exchange of information such as in a rag chew, typical QSB on HF means one must have a lot more than a dB or two of headroom above the minimum readable signal to be successful in most situations. I'm one of the great many Hams who is not a contester nor do I focus on brief 5NN exchanges with a DX station, so I never expect anything less than a 6 dB change - an S-unit - to be noticeable *over time* on HF. I start getting really interested if I find the opportunity to make a 10 dB difference. That said, many places where one might throw away a dB or so adds up. It's the difference between managing your station's system gain (or loss) 'budget' and deciding whether any single change is worth making. 73, Ron AC7AC -Original Message- There's a saying among VHF / UHF'ers in reference to coax and connector losses that every .5db counts. 73! Ken - K0PP __ 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
Re: [Elecraft] What is a dB worth was: Re: KX3 vs. K3 and other rigs?
Well when I was in to EME on 2m I was hunting for every .1 dB I could find. /Jim SM2EKM -- On 2011-06-07 16:42, Rose wrote: There's a saying among VHF / UHF'ers in reference to coax and connector losses that every .5db counts. 73! Ken - K0PP __ 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
Re: [Elecraft] What is a dB worth was: Re: KX3 vs. K3 and other rigs?
On 6/7/2011 6:14 AM, Pete Smith wrote: It is pretty widely accepted in contesting that an improvement in *either* receive or transmit capability of 1 dB will yield a useful increase in the number of QSOs over a 48-hour contest, even if it has an indiscernible effect on 99.5 percent of your contacts. On the basis of statistical analysis of scores, one of the guys in our contest club came up with the number that 1 dB is good for a 2.6% increase in a Sweepstakes score. 3dB would be good for 1.026 x 1.026 x 1.026 = 8%, 7dB would be good for 20%. The advantage can show up in several ways -- your ability to get over the other guy's noise, to hold a frequency, to get answered sooner when there are multiple callers, to pick up a rare multiplier. It doesn't matter how you get the advantage -- better antenna, low loss in the feedline, or power amp, and as you noted, it also helps to be able to hear better, whether by reducing RX noise, using dedicated RX antennas, choking noise sources, choking feedlines to reduce noise pickup, exploding the chargers for power tools and mobility scooters, etc. :) 73, Jim K9YC __ 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
Re: [Elecraft] What is a dB worth was: Re: KX3 vs. K3 and other rigs? [Thread already closed]
These threads were closed earlier this morning. Please take the discussion off-list. 73, Eric List moderator (Really! ) On 6/7/2011 11:26 AM, Jim Brown wrote: On 6/7/2011 6:14 AM, Pete Smith wrote: It is pretty widely accepted in contesting that an improvement in *either* receive or transmit capability of 1 dB will yield a useful increase in the number of QSOs over a 48-hour contest, even if it has an indiscernible effect on 99.5 percent of your contacts. On the basis of statistical analysis of scores, .html __ 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
