Unless you're planning to use your T1 as a wheel chock to keep your car from rolling downhill, I think you'll find the stock case plenty strong. I'm not sure exactly what plastic they used for the case, but keep in mind that plastics can be stronger than many metals. (Most military and civilian aircraft are held together in the air by plastics these days ;-) After several years, my T1 still looks new.
Even though toriods are nominally self-shielding, they aren't perfect, so a metal enclosure might have some deleterious effect. You need to push buttons on the T1 to turn it on and initiate a TUNE cycle, so if it's going to be where you can't reach it, you'll need some sort of remote control cable. The T1 is excellent with random wire end-fed antennas. Like all tuners today, you do need to avoid exactly 1/2 wavelength long wires. Keep in mind that's *electrically* 1/2 wavelength, which is not always what the 468/f formula says because of the effects of the surroundings. And there's the challenge with an end-fed wire: you want to be as close to 1/2 wave as you can for maximum efficiency since the power is divided between the antenna and ground with the most power going to the higher impedance load, but not so close to 1/2 wave that the T1 can't find a match. And the closer you are to a 1/2 wave long antenna, the more important it will be to have a 1/4 wave long wire attached to the case to establish a low RF voltage on the outside of the case of the T1, the coax connecting it to the rig and on the outside of the rig itself, to avoid "RF on the rig" issues. But don't get too upset if you can't get close to 1/2 wave up in the air for an end-fed wire. Note that if your radiator is only 1/4 wave long, and your ground wire is 1/4 wave long, you lose only 3 dB - half of your RF- to the earth. That may sound like a lot, but many Hams in their home stations would love to have an antenna that efficient; many, many Hams have much lower efficiency antennas and get out just fine. Just keep in mind that as you drop below 1/2 wavelength, the ground becomes more and more important. It's not a linear effect. The losses start to skyrocket really fast as the antenna length drops below 1/4 wavelength, so use 1/4 wave as a minimum length wherever possible. In this case we're talking about *physical* lengths, not electrical lengths. Adding loading coils can change the impedance to something easier to match, but does nothing to help the efficiency of a short antenna. A short antenna with a loading coil is still a short antenna, Hi! 73, Ron AC7AC -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Saturday, July 11, 2009 7:08 AM To: [email protected] Subject: [Elecraft] New list member/T1 tuner questions Hello to the group ! I'm Rick - KC8AON, in Southern Ohio. Just joined the Elecraft group because I am thinking of buying a T1 tuner kit to go with my Yaesu FT-817. I have been reading some of the reviews of the T1 on the web and most seem to be good reviews except for the enclosure they put the T1 in. I guess they use plastic to save on weight and expense ? Anyway, was wondering if anyone has mounted their T1 in a more robust enclosure to offer more protection in the field and if so did a metal enclosure effect the tuning properties of the tuner ? I have a nice small modem case that would make a very nice rugged enclosue for the T1 that has an extruded aluminum chassis and a slide on vinyl covered steel top. But again, will a metal enclosure effect the tuning properties of the T1 ? I would rather go ahead and build it into the more rugged enclosure as I build it than I would to put it in the plastic box that comes with it if it will work ok in the metal enclosure. Also, does the T1 work well with endfed wire antennas ? I'm thinking maybe non resonant lengths with counterpoise wires to eliminate the high Z of half wave length wires so the tuner will not be trying to tune a very high impedance and to move the feedpoint to much lower voltage point on the antenna. So, if the T1 will work with end fed wires, what are some good lengths that have been proven to work well with the T1 for 10 thru 40 meters, 10 thru 80, and 10 thru 160 ? Most of my portable operations are 10 thru 40 meters, but I do like to work 60 & 80 meters on occasion, and even 160 on scarce occasions. Now, when using the T1 with the FT-817, is the special control cable absolutely needed ? If so, how long is the cable and can it be easily lengthened ? My planned purpose for the tuner is to put it at the feedpoint of the endfed wire when operating portable to eliminate coax feedline loss between the antenna and the radio, so if the T1 will work fine without the control cable, that would be much better. If not, the cable would need to be at least 8 or 10 feet long to reach the feedpoint of the antenna where the tuner will be. Thanks for the bandwidth ! 73 - Rick McKee, KC8AON Southern Ohio - EM88sn www.angelfire.com/electronic2/qrp With God all things are possible ~ ><(('> ~ ______________________________________________________________ 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 ______________________________________________________________ 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
