https://www.eham.net/ehamforum/smf/index.php?topic=34680.0;wap2
Bob K3DJC On Tue, 18 Sep 2018 16:53:01 -0400 (EDT) [email protected] writes: > Hi Wes, > > > Thanks for forwarding the information about DG5MK's new FA-VA5 > VNA. What is its current selling price? > > > If you use many BNC connectors, you'll notice a distinct difference > in > connector quality especially above 100 MHz. Avoid using BNC male > connectors with weak tension when you turn the bayonette > to engage the connector. If the bayonette turns too easily it > doesn't > maintain sufficient engagement force to keep the RF connections > in proper alignment. > > > 73 > Frank > W3LPL > > > > > ----- Original Message ----- > > From: "Wes Stewart" <[email protected]> > To: [email protected] > Sent: Tuesday, September 18, 2018 5:51:45 PM > Subject: Re: [Elecraft] loss of RX sensitivity > > It's difficult to argue with Frank's experience and expertise. That > said, fools > rush in... > > I own some network analyzers, 1) an N2PK which I built with type N > connectors, > 2) a DG8SAQ VNWA-3, supplied with SMA connectors and 3) a RigExpert > AA-55 Zoom > with a SO239. Professionally, I've used analyzers with type N, 3.5mm > (beadless > SMA) and K connectors. With the exception of the AA-55, which only > goes to 55 > MHz, all of these can be calibrated with "precision" calibration > kits that can > cost thousands of dollars. So far, Frank is right, not a BNC in the > bunch. > > But that has changed with the introduction of the DG5MK's FA-VA5, > one-port > vector analyzer. I am on the reserve list to buy one of these. The > thing to > note is that it is supplied with a BNC connector. There has been a > lot of > anguish, heartburn, etc about this on the VNWA Yahoo group but the > consensus is > that it will be fine and BNC calibration kit has been developed and > tested > without issue. https://www.youtube.com/watch?v=X8Z7veGV57o > > There are tens of thousands of BNCs on oscilloscopes and other > instruments and > I've seldom had an issue with them in 30+ years of lab work. For > quick > disconnect I also use short jumper cables with BNCs to break the > connections > between the hardline running to the tower and the cable entrance to > the shack > during lightning season. Admittedly, I'm only running 500 W. When I > can leave > them more permanently connected I revert to type N. > > Wes N7WS > > On 9/17/2018 5:04 PM, [email protected] wrote: > > If you have a vector network analyzer you'll discover that BNC > > connectors aren't all that great at VHF and above, l oss and > > impedance vary with connector axial alignment because the bayonnet > > > shell doesn't support aligh the connector body very well. Strain > relief > > is extremely important with BNC connectors. TNC connectors are > > far superior but not widely used. > > > > > > While professionally installed N connectors have superb RF > > characteristics, all too often they're improperly installed -- > even by > > professionals -- leading to damaged connectors if the male pin is > > > misaligned, or unreliable contact if the pin or socket depth is > just a > > few millimeters less than the manufacturers specification. I use > > only captive pin male N connectors, avoiding the most severe > > problems. I never use female N connectors on cables, the N sockets > > > are much too fragile. > > > > > > Its hard to beat high quality silver plated UHF connectors at HF > and > > 6 meters. But its important to use a tool to tighten them. That's > a > > small price to pay for a very reliable connector. > > > > > > 73 > > Frank > > W3LPL > > > > ______________________________________________________________ > 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 > > Message delivered to [email protected] > ______________________________________________________________ > 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 > Message delivered to [email protected] > ______________________________________________________________ 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 Message delivered to [email protected]
