Hello Lou: The changes introduced by the stiffener are not consistent over all rigs and all operating setups. That's why I didn't mention the possibility of reducing birdies in my earlier e-mail. Clearly additional shielding is always a good idea and Wayne agrees, although it's impossible to quantify the improvement for every K3, so it's not mentioned to avoid setting unrealistic expectations.
The underlying reason for the stiffener is to avoid acoustic modulation of synthesizer VCO and, as Lyle noted, that can cause some receive issues as well as transmit issues, so that's another reason to modify both synthesizers. Again, most K3 owners never noted any issues in transmit or receive, even though they used the K3's internal speaker. Following Elecraft's policy of ongoing design improvements, the stiffeners were introduced into the K3 design and, again according to Elecraft's policy of not forcing existing rigs to become obsolete, the modification kit was made available to all current owners who want it. To me, that's one of the major points the sets Elecraft apart from other manufacturers that I am aware of. It have K3 S/N 10 dating back to early 2007. It's the K3 you see in all the assembly manual photos and the various mod kit instructions. With those mods installed it is functionally and electrically identical to the K3's being shipped today. If you are thinking of Carlos, IK4ISQ, who rerouted his KRX3 cables to eliminate some birdies, Wayne asked me to try his idea last year. I found an improvement. Wayne then had a number of other fellows repeat the test and they found *no* significant change. Go figure, Hi! That demonstrates just how "situation specific" this issue remains. So Carlo's mod was not made an official part of the K3 design. What we do know and can demonstrate is that the cable routing is important. That's why there are specific routing instructions in the KRX3 manual. That arrangement is the one Wayne developed originally as being the best and it's the one the factory assembled K3's use. But that does not mean that some other routing might help in your case, just as it obviously helped Carlos. Some birdies are inevitable in a complex rig like the K3. You simply cannot have that many oscillators operating in close proximity and not have them interact in ways that will occasionally put a mixing product strong enough to be heard inside the receiver bandpass. And now with the P3 you see birdies that you would not otherwise ever hear because they remain outside the bandpass all or most of the time but can be seen on the wideband display. Ron AC7AC -----Original Message----- All: A local friend just received his K3 Kit and took some photos of the assembly. I noticed the stiffeners right away and contacted Gary at Elecraft Support regarding aquiring two for my rig. I seem to have some annoying birdies and figured this shielding would help in at least reducing them. Gary mentions in his email that they would do nothing for the birdies. He sent along a pictorial of a Italian gent who has rerouted his TMP cables in such a way to substantially reduce receiver birdies. This is on my "to do" list for the radio next time I take it offline. But, frankly, its much more fun to USE it than to WORK on it! (as an ex Triumph Spitfire owner, I've been there and have several hundred T-Shirts!) I had stopped considering the shields... But Wayne inferred here that they *DO* add shielding... And with the size of the birdies, some shielding is better than no shielding! (PS, I *HATE* the software birdie removal... It punches holes in the bands! I would rather put up with the birdies than mask them!) So, Elecrafters, do we need these "stiffener plates" for sheilding or for the removal of microphonics, or do they contribute to both? (BTW, I dont expect them for free, but I dont expect to pay $50 plus shipping for them, either!) I never use the rig with the internal speaker, as I have external speakers and 99% of the time I use a headset... But I might take it portable someday. Yes or no on this "modification"? Will it or will it not help the annoying birdies? I work hard to keep my rig at the latest "factory standard". Is this an "elective" or a "requirement"? -lu-W4LT- K3 #3192 ***** Message: 13 Date: Tue, 07 Sep 2010 08:53:20 -0700 From: Lyle Johnson <[email protected]> Subject: Re: [Elecraft] K3 Synthesizer Stiffener Plate Mod To: [email protected] Message-ID: <[email protected]> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Loud internal speaker audio can cause small VCO sidebands. If present, it causes them on receive as well as transmit. 73, Lyle KK7P > As you say you only transmit on the "main VCO" so putting the shield on the > main vco would deal with speaker rumble issue so putting it on the subvco > maybe to improve shielding? ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] 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:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
