[hpsdr] SWR Problems with PennyLane

[Mark Leone]

Thanks, Phil. After posting I noticed that the external tuner requires 1 
watt minimum input, and the LEDs are indeed indicating no RF. However, I 
tried again with the 50 ohm dummy load connected to the output of 
PennyLane, and there still seems to be a problem.

Using PowerSDR, when I press Tune on the GUI or key the transmitter in 
CW mode, I see 0 Watts Forward and Reflected Power. I measure the 
voltage across the dummy load's diode detector, and I see it go up 
slightly, from 2 milliVolts (TX off) to 12 milliVolts key down). This 
equates to less than 1 milliWatt PEP, so something's not right.

I have the Drive control on the main screen set to 100, and I tried 
adjusting the per-band gains on the PA Settings screen. Setting the 
minimal value in the latter gave me a slight increase in TX-on voltage 
from 10 milliVolts to 12 milliVolts. I also found some settings on other 
screens that pertained to transmit level, but increasing these did not 
make any difference.

Perhaps I've mis-configured PennyLane. I didn't find a manual explicitly 
for PennyLane, so I used the Penelope manual. I understand the 
differences are minimal, but when I look at the picture of the circuit 
board showing the jumper settings, I see different jumper locations on 
my board compared to the picture in the manual. Nevertheless, I didn't 
muck with the factory jumper settings other than the PTT, Bias, and Aud 
jumpers. For those, I have them all removed per the manual instructions, 
since I have no mic connected to PennyLane. I have only a CW key 
connected to the DB-9 port on Metis.

FWIW I get different behavior when I boot into Linux and run ghpsdr. 
When I key the transmitter, I see rapidly-changing SWR values in the 
GUI, never settling down to a usable value. I'm happy to work with 
PowerSDR to figure out the problem, but perhaps the ghpsdr behavior is a 
clue. I'm surprised to see this behavior with only a dummy load 
connected. It's behaving as if there's a tuner in-line when there isn't.

Mark - K4XML

On 2/4/12 9:41 PM, Phil Harman wrote:
> Hi Mark,
>
> First test your PennyLane board by connecting it directly to a 50 ohm 
> dummy load. Your PC code should indicate 500+mW output in Tune mode 
> and the LEDs on the board (which form a power bar graph) should all be 
> on.
>
> The change in flash rate of LED 7 happens when the PTT is active - I 
> need to add this to the documentation.
>
> It may be that 500mW is not enough power for your ATU to  tune 
> correctly  - I suggest you check the specification.
>
> 73 Phil...VK6APH
>

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