Don't think I've seen that kind of model number before, Jack. What is it and who makes it? Thanks and 73 Bob N6WG
----- Original Message ----- From: "Jack Colson" <[EMAIL PROTECTED]> To: "Jack Smith" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> Cc: <[email protected]> Sent: Wednesday, July 30, 2008 4:37 PM Subject: Re: [Elecraft] Re: K3 6m pre-amp > I personally would use a MGF-1302. > > 73 > Jack, W3TMZ > > ----- Original Message ----- > From: "Jack Smith" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Cc: <[email protected]> > Sent: Wednesday, July 30, 2008 6:48 PM > Subject: Re: [Elecraft] Re: K3 6m pre-amp > > > > Don: > > > > The U310's are not too easy to find these days. Vishay seems to be the > > most common (only?) new production supplier and the one-off price is > > about $14 from Mouser or Arrow. Digikey, Allied and Newark only stock > > the SOT23 plastic surface mount version. TO-92 plastic case parts, the > > J310, are around 25 cents each. The U310 and J310 are supposed to have > > the same die, so differences should be attributed to the case, but who > > knows what goes inside the package these days, particularly if it is > > from China. > > > > If I were building a pre-amp based upon a U310, I would start with a > > J310 and get it thoroughly debugged before experimenting with U310's > > at $14 a pop. > > > > It's something like the 40673 dual gate FET - once ubiquitous and now > > difficult to find and expensive when found. > > > > > > Jack K8ZOA > > > > Don Wilhelm wrote: > >> Bob, > >> > >> While I cannot speak from my own measurements, but in EMRFD, Wes > >> Hayward recommends the U310s for VHF/UHF rather than the J310. The > >> case of the U310 is connected to the gate, and when used in a > >> grounded gate configuration, the case can be mounted (upside down) > >> into a hole in the PC board, and I believe that alone should provide > >> better input to output isolation. The Vishay data sheet indicates a > >> slightly lower noise figure for the U310. > >> > >> I would suggest that you try the J310s. If you find them lacking, it > >> should be easy to change to U310s, I would guess that at 50 MHz, it > >> may be a 'toss-up' decision. > >> > >> 73, > >> Don W3FPR > >> > >> Bob Tellefsen wrote: > >>> Hi John > >>> I've been looking at this circuit for some time. > >>> I have a number of J310s, but no U310s. > >>> Do you know whether they are the same > >>> animal, just in different casings? > >>> 73, Bob N6WG > >>> > >> _______________________________________________ > >> Elecraft mailing list > >> Post to: [email protected] > >> 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: [email protected] > > 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 > > > > No virus found in this incoming message. > > Checked by AVG - http://www.avg.com Version: 8.0.138 / Virus Database: > > 270.5.7/1581 - Release Date: 7/30/2008 6:56 AM > > > > > > > > _______________________________________________ > Elecraft mailing list > Post to: [email protected] > 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: [email protected] 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
