[hpsdr] SWR Problems with PennyLane

[Scott Cowling]

Hi Mark,

Make sure that there is a jumper on JP2 pins 1-2. That jumper is used 
to separate the DAC/filter circuitry from the PA stages. If it is 
missing (or on pins 2-3), you will get no output.

If you want to check the "drive" level to the ADC, you can put your 
meter on J7 pin 17. This should be a voltage level commensurate with 
the drive control. (This point is also the junction of C23 and R45, 
which might be easier to put your probe on than the fine-pitch IC 
pin.)  If you get zero volts there, it is probably because you either 
are using an old revision of Pennylane/Penelope FPGA code, or you 
have checked "Penelope" instead of "Pennylane" in the setup.  Just 
something to look at if you want to dig into it.

The voltage may only be there during transmit, maybe Phil could 
answer that question.

73,
Scotty WA2DFI





At 12:18 PM 2/5/2012 -0500, you wrote:
>***** High Performance Software Defined Radio Discussion List *****
>
>I forgot to mention: I still see 0 power level indicated on LEDs 2 
>through 6 (i.e. none of them lit) when I key down or Tune with the 
>Dummy Load connected.
>
>Mark - K4XML
>
>On 2/5/12 12:04 PM, Mark Leone wrote:
>>***** High Performance Software Defined Radio Discussion List *****
>>
>>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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