+++++++++++++++++ From: "Russell Boutell" To: elecraft at mailman.qth.net Date: Tue, 08 Apr 2003 16:44:24 -1000 Subject: [Elecraft] QRO auto antenna tuners Here's an interesting new tuner that can handle 1000 watts SSB and 750 watts CW (not quite legal limit) from LDG electronics ($599.00): http://www.ldgelectronics.com/at-1000_description.html Looks like some beefy toroids in this one. 73, Russ W9EL Bob WA4FOM wrote: ... Unfortunately, apart from the revered Heath SA-2500, I haven't seen an *automatic* antenna tuner capable of honestly handling the legal Amateur limit ... +++++++++++++++++ Date: Tue, 08 Apr 2003 20:32:15 -0700 From: Vic Rosenthal To: Elecraft Subject: Re: [Elecraft] QRO auto antenna tuners Russell Boutell wrote: > Here's an interesting new tuner that can handle 1000 watts SSB and 750 > watts CW (not quite legal limit) from LDG electronics ($599.00): > http://www.ldgelectronics.com/at-1000_description.html > > Looks like some beefy toroids in this one. Well...I hope they are beefy enough. #16 wire, smallish relays, and 2500v capacitors. I have had 'interesting' experiences with various 160-meter antennas, 800 watts CW and 3000v capacitors. The current ratings of capacitors in this service are important also. The matching network I'm using now for my inverted L has mica caps that are about 2-1/2" x 2-1/2" x 1" in size. 5 KV doorknobs (larger than the micas used in the LDG) got hot enough to cause serious tuning drift. I am not saying that the unit will not meet their specs and perform adequately if you are very careful to follow their instructions and stay within specified limits. I'm sure they have tested it thoroughly. However, you can get tremendous voltages and currents with QRO, especially with reactive loads. I will be very interested in the QST review when it appears, particularly with regard to 160 meter performance. Vic K2VCO ++++++++++++++++