[Elecraft] QRO auto antenna tuners

[Vic Rosenthal]

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