[TenTec] QSK switching diodes in Scout

[Gary J FollettDukes HiFi]

Switching DIODES!


> On May 15, 2016, at 8:04 PM, Gary J FollettDukes HiFi <dukeshifi at comcast.net> wrote:
> 
> I tried searching before asking the reflector for a solution to this issue, no luck, so, here goes…
> 
> I have a Scout that works perfectly up through 30 meters.
> 
> Above 30 meters, the TX power drops a LOT after a few seconds transmitting.
> 
> I know why it does so. The two diodes D3 and D4 on theLLD/ALC board get very hot and allow TX power to leak through. This causes a pullback in output power as the perceived impedance of the load drops.
> 
> If I lift one of the switching diodes, D3, everything is fine, full output as long as I want to stay keyed, even on 10 meters. Of course, there is no receive as D3 is the receive signal path from the antenna.
> 
> My question is, does anyone know why Ten Tec chose to use 1N3007 diodes here? This would seem to be a poor choice as these are not particularly fast diodes.
> 
> Has anyone tried PIN diodes here? If so, what type was successful?
> 
> I guess I could select some but would rather benefit from others' successes.
> 
> Gary
> 
> W0DVN
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