[hpsdr] Problems Calibrating Pennylane and with LPU, Could Use Some Help

[Phil Harman]

Bob,

The automatic Power out calibration  function in PowerSDR does not
function with Penny or PennyLane - we need to talk nicely to one of our PC
programmers to get this changed.

In which case the manual method is to one to use for now. I set the
'Gain-By-Band' so that I get 100w out of my attached PA when the Drive
slider is set to 100%.

Can't help you with the 'pop' since I don't use the LPU but very pleased
to hear that you are not letting the smoke out of any of the chips.

73 Phil...VK6APH


> ***** High Performance Software Defined Radio Discussion List *****
>
> Hi:
>
> I've been trying to calibrate my new Pennylane card HPSDR per the
> instructions on Page 12 of the Penelope Manual.
> (http://openhpsdr.ogr/wiki/images/4/4c/Penelope_manual_v_1-2.pdf)
>
> I have just installed the Pennylane card in my HPSDR Pandora which
> has Magister and Mercury all powered from the LPU.
> I installed the 17-Nov-2011 version of PowerSDR1.16 from W5WC (I
> prefer its look to the "skin" of PowerSDR1.19) and have
> no problems in receiving with Mercury. Firmware versions are 18 for
> Magister, 29 for Mercury and 13 for Pennylane. I am using
> Winows XP SP3 on an Asus based PC.
>
> I have connected a 50-ohm dummy load to the Penelope output BNC.  I
> have my scope connected across the load resistor so
> I can measure the output voltage and its frequency and look at its
> waveform. I do not have a microphone connected as yet.
> The "Drive" level is set at 100. Everything seems to perform as
> expected except for the output power adjustment.
>
> A problem occurs when I try to run the calibration routine in the "PA
> Settings" Tab as recommended on Page 12 of the
> referenced manual. The initial "Gain By Band" settings are all set to
> 49.0 dB. When I click on "Calibrate", Pennylane
> starts stepping thru increasing amplitude signal values at 160 meters
> until at the 4th step the signal begins to overdrive
> the output of Pennylane and the signal on the scope shows clipping.
> After a couple of more steps, the routine stops with
> an "Invalid Gain Found" message. The clipping level is just under 20
> volts peak-to-peak (0.5 watts). The amplitude of the
> output first step of the calibration measured 10v p-p on the scope,
> the second 15v p-p, the third 16v p-p and the 4th and
> following steps are heavily clipped at 18v p-p. The TX Meter "Fwd
> Pwr" read successively 251, 408, 624, 628......mW.
>
> After trying various settings,  I found that if I crank the "Drive"
> down to 4, the calibration runs without bombing. In this case
> the amplitude of the output remains constant as the frequency is
> stepped to each band in turn. However, after the calibration,
> the "Gain By Band [dB]" values are not changed from their initial
> settings as I expected they would be.
>
> Since Pennylane was checked out at IQLabs, I assume I have not set
> something up right but I can't figure out what it is.
> Or does Pennylane not work the way Penelope does?
>
> Can someone explain just what is being calibrating and how it is
> done. Apparently Pennylane is feeding different input signal
> levels into its input and is reading the output so as to set the
> system gain on each band to get the same output at each rf
> frequency. Also, what is the "Advanced Calibration Technique" that is
> selected by checking the box in the "PA Settings" Tab?
>
> I have found that I can do the calibration manually. For each band, I
> set the "Gain By Band [dB]" to 49.0 and slowly crank it down
> until the "Fwd Pwr" as read on the TX meter reads 500mW. This is with
> the "Drive" level set back to 100. This appears to work
> properly and gives me a consistent 0.5 watt output on each band.
>
> However, if I hold the output at 500mW for too long, I hear a "poof"
> from Pandora and everything goes dead!  All the red lights
> go out and the program stops. If I turn my power supply off and back
> on again, things seem to recover. I suspect maybe a fuse
> blowing because of excessive current drain but the total Pandora
> current drain including the fan only measures 1.670 amps. LPU
> has 2 amp fuses in both its 12 and 5-volt outputs.
>
> I have no experience with the type resettable fuse used in LPU. Do
> they make a noise when they blow? Are they fast acting or
> slow acting? They are 2-amp fuses (unless I got them mixed up) with
> only 1.670 amps thru them. What sort of accuracy may be
> expected for their blowing current? Maybe I should measure the supply
> current on my scope and see if there are any high
> transient currents. Anyone's experience on these matters would be most
> helpful.
>
> Thanks for any information or any ideas.
>
> 73,
> Bob Mahrenholz
> K4QQK
>
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