I’ve been remoting my K3, KPA500, KAT500 station via the RemoteRig boxes and 
K3/0 mini for two years with solid results. Later this year, I want to make 
several enhancements, including the replacement of the KPA500 and KAT500 with a 
KPA1500. The amp/tuner should be a fairly straightforward hardware replacement, 
but it does necessitate a few station changes which I’m not certain how to 
implement. Let me explain and hopefully the masses have ideas/approaches for 
consideration.

1. I feed a HyTower vertical (optimized for 40M & 80M) on all bands. Where the 
driving impedance is close to 50 ohms on 40M & 80 (my bands of interest) there 
has been no attempt to match the HyTower on other bands. With the KAT500, 
matching was not a problem and I reduced mismatch losses on the feed line by 
using hardline from the in-shack tuner to the antenna.

When I switch to the KPA1500, operation on the unmatched bands might prove 
problematic. To address this, I plan to provide switchable matching networks to 
transform the HyTower drive impedance on each band to something the KPA1500 can 
match. I can design the required impedance transformation networks, but not 
sure how to automatically select the various (relay based) impedance networks 
required for each band. Clearly, I need to grab band data from the K3, but 
what’s the best hardware to use for this task? 

BTW, I want to power the KPA1500 ON with the K3, which requires a Y-cable 
modification, or perhaps one of the N6TV boxes? 

2. I want to interface a K9AY RX antenna 4 position switch to some sort of UI 
that I can access remotely. I can design an electrical interface to the K9AY 
switch, but controlling and monitoring remotely is the issue. Ideas?

3. I have a Windows computer available at each end of the radio circuit. The 
only other hardware is a SignalLink used for digital mods.

4. Configuring the station for future antenna enhancements (e.g. SteppIR if we 
live long enough to see sunspots return!) are great if they come without 
significant reliability impacts.

Any ideas how to accomplish the required switching/monitoring? 

Thanks
Dennis, K7FL
Currently in Panama City, Florida
Station in Battle Ground, WA





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