Lost Power out piHPSDR

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Brian Comer

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Oct 23, 2020, 6:00:13 PM10/23/20
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Hi All

 

I have HL2 build 8 with the N2ADR filter board.

 

I setup the PA currents using the windows test and setup utility.

 

The Filter Board was set to N2ADR, with the Tune Percent set to 10 with tune pushed I had an indication of 5W on the piHPSDR and an indication of 3 watts of drive on an Elecraft KPA 1500 set to bypass into a 50 ohm load. The Tune Percent was changed to 100 and  tune pushed again. I now only get a piHPSDR reading of 1 watt for tune percentages of <19 and 1.2 for 20 and above. There is no indication on the KPA1500 but that only means the input is less than 1w.  I have the equipment to measure the power accurately but have not done so.

 

Retesting using the windows test and setup utility the bias current still measures about 200mA.  In SSB mode with the mic set to 0 the current is also about 200ma.

 

Is it likely something  has been damaged or have some setting been corrupted?

 

 

 

 

 

73 Brian KF6C.

 

Steve Haynal

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Oct 24, 2020, 12:29:32 AM10/24/20
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Hi Brian,

Do you see the 3 watts drive again if you reduce back to 10 percent? Do you have the N2ADR filters set properly so that they are set to pass the appropriate frequencies?

73,

Steve
kf7o

Brian Comer

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Oct 24, 2020, 12:38:40 PM10/24/20
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Hi Steve

 

I moved the setup to my lab where I could make better measurements.  I have no idea why but on testing again the power indicated was 5.8 W, that was closely confirmed by measurement on a calibrated spectrum analyzer.

 

This time I changed the tune percentage to 20 and keyed tune again.  The same thing happened, the power output dropped to 1 W. Changing back to a tune percentage of 10 still left the power output at 1W.

 

Prior to this I had reset both the computer and HL2 neither of which caused the power to return.  I also switched from a pi4 to a pi3 with all newly installed software, this was done for ease of moving to the lab. This new setup was tested prior to moving to the lab, the power still at 1W.

 

I will be doing some more experiments to see if I can understand what is needed to bring the power back to what it should be.

 

 

73 Brian KF6C.

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DL1YCF

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Oct 25, 2020, 6:33:27 AM10/25/20
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If you compile from the sources activate these debug lines in old_protocol.c


//if(last_power!=power) {
// g_print("power=%d\n",power);
// last_power=power;
//}


They tell you about the „drive level“ settings sent to the HL2.

This will nail down whether the problem is in the HL2 or in piHPSDR.
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Steve Haynal

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Oct 25, 2020, 11:47:56 PM10/25/20
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Hi Brian,

I don't recognize this problem. Some reasons for low or no power out in the past have been:

* PA must be enabled, otherwise power is via low power out.
* Filter selection must be set properly, otherwise you may be burning power in the filter.
* Most software has per band power limits set by default to protect an external PA. Often these must be reset to a higher value. See the videos.
* Some software may have different output levels and slider settings depending on the mode. You safest test is to key transmit with an external CW key.

I'd recommend trying some different software to see if it is a software setting. LinHPSDR, piHPSDR, SparkSDR and Quisk all can run on a raspberry pi.

73,

Steve
kf7o

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"Christoph v. Wüllen"

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Oct 26, 2020, 4:28:08 AM10/26/20
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In addition, keep in mind the high non-linearity of the „drive level“ with the HL2.
Only the top 4 bits of the 8-bit drive level word are used, so there is little
sense in „fine-tuning“ the „tuning power“ with the „tune per cent“ slider.
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Brian Comer

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Oct 26, 2020, 9:15:24 AM10/26/20
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I have now tested the HL2 with windows PowerSDR and it has a reliable output of 4.45 Watts.

The piHPSDR seems to go into a low power 1 Watt mode at the slightest provocation. I have not found out how get it back to the 5 Watt mode reliably except maybe uninstalling and reinstalling piHPSDR. After running well on windows the power is still at 1 Watt when moved back to the piHPSDR.

I cannot see how to download the piHPSDR souce code, I need to do some studying before I can go much further with the piHPSDR and HL2.


73 Brian KF6C.

"Christoph v. Wüllen"

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Oct 26, 2020, 9:31:21 AM10/26/20
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When starting piHPSDR for the first time, the settings in the „PA menu“ are all at
about 53 dB. They have to be reduced to about 41 dB for the HL2 (just in case this
is the reason).

As to compiling piHPSDR:

The attached document contains a very detailed instruction how to download and compile
piHPSDR on Linux machines (Desktop, Laptop, or RaspPi). Most can skip section A) since
this is super-elementary.


Linux-CompileFromSources.pdf

Brian Comer

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Oct 26, 2020, 7:06:40 PM10/26/20
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Thank for the help. The document has been very useful and educational.

I followed the instructions without uninstalling the previously installed standalone pre complied code. This seemed to cause some corruption.

Starting again from scratch, did a clean installation of raspberry pi and followed the instructions in the document. The HL2 is now providing up to 5.4 watts in tune mode that is fully controllable with either the "tune percentage" or the drive control.


73 Brian KF6C.



-----Original Message-----
From: "Christoph v. Wüllen" <DL1...@darc.de>
Sent: Monday, October 26, 2020 9:31 AM
To: Brian Comer <br...@kf6c.com>
Cc: herme...@googlegroups.com
Subject: Re: Lost Power out piHPSDR

Steve Haynal

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Oct 26, 2020, 11:31:17 PM10/26/20
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Hi Christoph,

Thank your for preparing this helpful document. I have added a link to it on the wiki so others can find it more easily in the future:

73,

Steve
kf7o
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