Re: [Elecraft] K2 Ser no. 3181
Hello Ron, Your AGC threshold has a huge effect on the range of adjustment of the RF gain control. If the AGC threshold is set too high - meaning that you are generally operating with very little AGC action - your RF gain control will have very little effect. If you lower your threshold, you'll find that the RF gain control will have a much greater effect. Just a reminder, R1 on the control board is what controls this threshold, and in the K2 manual, the information relating to this adjustment is located right next to the info about the S-meter alignment. (page 46 in my Rev D manual for S/N 3039, so it's probably the same version as yours). Hope this helps. 73, Dale / WA8SRA Ron Lorenz wrote: Love this little rig. One slight (mini) probem. Based on over 50 years of radio operating, amateur, commercial and military I always leave the RF gain on max for best SNR. With my K2, turning the control to any position, (max to min and back agin) makes no difference in gain (Noise) except to shift the position of the S meter reading, ie, iaw the HI and LO Cal procedure. Any ideas? 73 Ron VA6RL ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
Re: [Elecraft] K2 Ser no. 3181
Ron, The 'RF Gain' in the K2 is actually an IF gain control and it only controls the gain after the selective elements. All the stages ahead of the IF amplifier operate at fixed gain levels. In many receivers where the RF stage is gain controlled, my experience is that the gain can be made excessive and actually results in added noise when it is advanced to maximum - this is contrary to your experience, but it goes to show that the noise floor of any receiver is the result of careful design for minimum noise. The K2 is in the category of such careful design. The K2 AGC works similarly - only the IF amplifier gain is changed with the AGC. The 'RF' Gain control changes the resistive network that sets the AGC level - so the net result is that the RF Gain and the AGC interact to set the IF amplifier gain. You may wish to check the AGC threshold just to be certain (although it does sound like it is set just fine). Switching from AGC on to AGC off should cause no increase in the noise level when listening to a quiet band (local noise sources CAN produce broadband noise, so use a band where such noise is at a minimum for your location). If the AGC Threshold is set in this manner, one can expect little or no change in the K2 noise floor when the RF Gain control is rotated. 73, Don W3FPR - Original Message - Love this little rig. One slight (mini) probem. Based on over 50 years of radio operating, amateur, commercial and military I always leave the RF gain on max for best SNR. With my K2, turning the control to any position, (max to min and back agin) makes no difference in gain (Noise) except to shift the position of the S meter reading, ie, iaw the HI and LO Cal procedure. ___ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
