I liked the idea of the ceramic based knife switch! That ought to take most anything us hams could throw at it at pretty much any VSWR! :-)
Charlie, K4OTV -----Original Message----- From: Topband [mailto:[email protected]] On Behalf Of Tom W8JI Sent: Sunday, October 20, 2013 6:39 PM To: Joe Subich, W4TV; [email protected] Subject: Re: Topband: Antenna switch rating for high SWR? The rub with any of this is the contact-to-coil breakdown. ----- Original Message ----- From: "Joe Subich, W4TV" <[email protected]> To: <[email protected]> Sent: Sunday, October 20, 2013 12:57 PM Subject: Re: Topband: Antenna switch rating for high SWR? > >> I know that T/R switches inside amps are fairly small in physical >> size, however they are designed to operate into a fairly low SWR >> load. I have no idea of what rating of a DPDT switch I would need >> (per the diagram) in my application - perhaps I'm making a bigger >> deal of something that isn't so critical.? > > Fire up ELNEC or your favorite modelling software and run your > specific combination of flat-top length/height and feeder length > to find out what the voltage and current are at the input of the > feed line. That will tell you what you need for the relay. > > Remember, you can use *TWO* high voltage/high current "contactors" > and mount them on Lexan or similar non-conducting surface to increase > the voltage to ground rating if necessary. > > 73, > > ... Joe, W4TV > > > On 10/20/2013 12:04 PM, John Harper wrote: >> Morning all, >> >> >> >> I am planning to put in a DPDT switch (or relay) to allow me to easily >> switch from using my 80m dipole as a vertical (T-top) antenna on 160m: >> >> http://www.ae5x.com/docs/antennas/160mT.jpg >> >> >> >> The dipole is fed with 450-ohm ladder line and used 10-80m in that >> configuration so there is a high SWR on the line. I sometimes use a kw >> output. >> >> >> >> I know that T/R switches inside amps are fairly small in physical size, >> however they are designed to operate into a fairly low SWR load. I have >> no >> idea of what rating of a DPDT switch I would need (per the diagram) in my >> application - perhaps I'm making a bigger deal of something that isn't so >> critical.? >> >> >> >> John AE5X >> >> http://www.ae5x.com/blog >> >> >> >> _________________ >> Topband Reflector >> > _________________ > Topband Reflector > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2014.0.4158 / Virus Database: 3614/6755 - Release Date: 10/16/13 > _________________ Topband Reflector _________________ Topband Reflector
