Hi Peter, I'll try to play with the crystal (inside the K144XV, right?) In fact, I have, probably, have missed the Elecraft recommendations. Just got RIGOL DSA815-TG 1.5 GHz Spectrum Analyzer so will be able to see the LO specrtum purity. Will let VHF folks know the results. Regarding the MMIC, I was just referring to LO level difference at the mixer LO port. Will check the relays info. Thank you so much for your help and ideas! 73 Vic
-------------------------------------------- On Mon, 5/5/14, Peter Torry <peter.to...@talktalk.net> wrote: Subject: Re: [Elecraft] Possible bad KREF or K144XV Ref Lock or ??? To: elecraft@mailman.qth.net Date: Monday, May 5, 2014, 8:49 PM Hi Victor, Thanks for the update - most interesting. I am using the K144XV in conjunction with the REFLock and found that the crystal and its grounding was the problem. May I suggest that you experiment with earthing the crystal can as suggested by Elecraft and / or changing out the crystal. As far as small RF relays are concerned I use the Teledyne TO5 can type 732 that will fit easily in the enclosure and have reasonable isolation across the contacts. I have not found any problems using MMICs and will continue to use them. In fact I use a PGA103 in my masthead preamp without a problem. Hope the above is of some help. 73 Peter G3SMT On 04/05/2014 09:28, Vic Goncharsky via Elecraft wrote: > Hi Harry, > Hope the info that follows will be useful. > I have made some research of how to make the internal K144XV Elecraft transverter be useful in contests. > Originally it was almost useless due to many parasitics all across the band even from S9 signals. > The stronger – the worse and there were a lot of them even here in KN29AU. > So in July, last year, during IARU R1 3-rd subregional VHF contest, the band was full of clones. HI HI. > > Comparying the schematics of both internal and external Elecraft 144 transverters shows three major differences that could have caused the different dynamic performance of the internal one. > Firstly - the usage of three diode switching components in the Front-End chain up to the ADEX mixer. > Secondly - usage of MMIC instead of BFR96 in the LO amplifier stage. > Thirdly - the K144XV PHASE LOCK BOARD > > Here are some findings and possible solutions. > 1.Remove (do NOT install) the K144XV PHASE LOCK BOARD! > In this case transverter is using just its own Xtal generator and spirious signals caused, possibly, by leakage from the synthesizer are gone. > 2. Bypass the input diode T/R input switch by using separate receiving path. Remove the shorting block from pin1-2 of the P3 connector and connect separate coax to pin2 – RF, pin3 – ground. > This requires adding some front-end filtering and RF relays in PA, LNA or wherever you like. > (I would have prefer to get rid of all diode switching in RX RF path but have no idea of RF relays small enough to fit into K144XV box). > I have tested this setup in September during IARU R1 VHF championship and compared to July's event it looked like day and night. > ______________________________________________________________ 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 Message delivered to us...@yahoo.com ______________________________________________________________ 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 Message delivered to arch...@mail-archive.com
