Stewart, Heard you several times on 3.727 over the last few weeks (and spoken to you in the past) and I must say your audio is v. nice (usual British conservative statement!) Do you have any details of the work you have carried out published? Would make interesting reading.
Apologies if your info has bone out via the reflector only my mailbox cleanup has conveniently deleted everything over a couple of days old. Regards, Paul. -----Original Message----- From: Stewart Baker [mailto:[EMAIL PROTECTED] Sent: 31 August 2004 08:31 To: Elecraft Reflector Subject: Re: [Elecraft] VOX clicks with Yaesu MD-100 microphone On Mon, 30 Aug 2004 13:44:02 -0400, Don Wilhelm wrote: > Stewart, > If I understood the root cause of your 'problem' correctly, that is a good > indicator that you have created a very sensitive VOX. In that case, it may > even my work with my normal voice - I will be looking forward to trying it > soon. > 73, > Don W3FPR Hi Don, The subject of the K2 VOX sensitivity is a complex one, and even after considerable investigation I don't pretend to understand it fully. What is important is to get sufficient (but not too much) audio voltage from the microphone into the KSB2. This may mean using a pre amp. If this audio voltage is not sufficient, both the VOX operation and SSB output power will suffer equally. My original intention when creating an Anti-VOX capability was to incorporate a pre amp in the design and use this to get more mic audio and a separate feed into the VOX detection circuit. Although this worked OK at low power and on the lower frequencies it was very susceptible to RF and because my circuit was separate from the KSB2 PCB tracking, rather prone to instability. For the time being I have put that idea to one side and concentrated on the Anti-VOX problem, which is much easier to solve. I now have a fully working Anti-VOX, but to get reliable VOX operation I use a 20dB mic pre amp with the MD-100 and use the K2 set to mic input position 2 with the compression set to 4:1. With this set up the sensitivity is about right and it gives me 100% VOX operation with no tripping from the speaker audio. As I said I do not fully understand the internal (firmware) workings of the K2 VOX, namely why I have to use 3:1 or 4:1 compression to ensure that the VOX does not drop out when the 1:1 setting provides sufficient audio to activate it. There should be more than enough audio to prevent this drop out. It would help greatly to have a bit more of an insight into the design. The microphone 'click' situation showed that I have sufficient mic gain, but for a while everything in the K2, and in my design was suspect. WHEW ! 73 Stewart G3RXQ _______________________________________________ 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 NNC's UK Operating Companies : NNC Holdings Limited (no. 3725076), NNC Limited (no. 1120437), National Nuclear Corporation Limited (no. 2290928), STATS-NNC Limited (no. 4339062) and Technica-NNC Limited (no. 235856). The registered office of each company is at Booths Hall, Chelford Road, Knutsford, Cheshire WA16 8QZ except for Technica-NNC Limited whose registered office is at 6 Union Row, Aberdeen AB10 1DQ. NNC's head office and principal address is Booths Hall and the switchboard number is 01565 633800. The NNC website is www.nnc.co.uk Any information or opinions in this message which do not relate to our business are not authorised by any of the above companies. Where this message does relate to our business the content is sent to you by the relevant company (as above) and is confidential and intended for the use of the individual or entity to whom it is addressed. The contents do not form part of any contract unless so stated. If you have received this e-mail in error please notify the NNC system manager by email at [EMAIL PROTECTED] _______________________________________________ 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