HL2 - Output/Drive control functions with PA disabled

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m3ghe
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Re: HL2 - Output/Drive control functions with PA disabled

#11

Unread post by m3ghe »

I didn't realise SDR console switched the PA off. In that case you are right some thing within SDR Console is changing the behaviour of the sliders.
Do we know exactly how the PA is disabled?
Martin
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Simon G4ELI
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Re: HL2 - Output/Drive control functions with PA disabled

#12

Unread post by Simon G4ELI »

These are SDR Console sliders! If Drive is at zero and there's output then we really need to see screenshots of the output.

When Drive is at zero the IQ is 0, should be no output.
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Re: HL2 - Output/Drive control functions with PA disabled

#13

Unread post by m3ghe »

Simon G4ELI wrote: Mon Jul 26, 2021 5:37 am These are SDR Console sliders! If Drive is at zero and there's output then we really need to see screenshots of the output.

When Drive is at zero the IQ is 0, should be no output.
I realise they are SDR Console sliders, what I'm getting at is if it also switches the PA off, then at the same time it is altering the behaviour of the sliders. One behaviour with PA on, another with it disabled.
Martin
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Max
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Re: HL2 - Output/Drive control functions with PA disabled

#14

Unread post by Max »

Simon G4ELI wrote: Mon Jul 26, 2021 5:37 am These are SDR Console sliders! If Drive is at zero and there's output then we really need to see screenshots of the output.

When Drive is at zero the IQ is 0, should be no output.
OK Simon, NP, but what can I show you in a screenshot that is not in the screenshot I have not already sent? There's no indication within SDRC of output unless the PA is engaged. In the screenshot I sent in Post #3 of this thread, TX is enabled, Tune mode is engaged, Drive slider is at zero and yet there is output from the low power output of the HL2 as I have described (as witnessed by output from the transverter fed from RF1 socket on the HL2. If I can send any other screenshot that's of use let me know what you want. I can send picture of the physical power meter on the output of the transverter if you like but what's the point in that? I don't have anything here that will readily monitor the low level output of RF1 socket on the HL2 other than listening to it on another SDR and sending screenshot of the received signal. Not much value in that I would not have thought?

By the way, it's functional as a TX. I had FT8 contact on 6m with the transverter and also SSB. It's just that the slider action is unexplained that is the irritant.

I can post on Hermes Lite group to ask if any other users using the low level output socket with SDRC. Maybe I'm the only one to have tried it? I know there are others on there using HL2 low level output to drive transverters but not with SDRC. Alan Hopper for example, but of course he uses his own Spark SDR software.

Is there anywhere within SDRC where I can show or monitor that IQ is outputting a signal to the HL2?

73

Max

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Re: HL2 - Output/Drive control functions with PA disabled

#15

Unread post by Simon G4ELI »

Max,

What I'm getting at is this: with a second SDR let's see what signal is being sent from the HL2. If the drive is 0 then the IQ is 0, so at this stage I really need to see what's being generated by the HL2, the only way to do this is to use another SDR and grab a screenshot. The screenshot in #3 only shows what we think should be happening, monitoring the signal is now needed.

ETA: I expect we may be seeing some low-level carrier or other signal from the HL2's TRX chip.
Simon Brown :shock:
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Re: HL2 - Output/Drive control functions with PA disabled

#16

Unread post by Max »

Simon G4ELI wrote: Mon Jul 26, 2021 2:23 pm Max,

What I'm getting at is this: with a second SDR let's see what signal is being sent from the HL2. If the drive is 0 then the IQ is 0, so at this stage I really need to see what's being generated by the HL2, the only way to do this is to use another SDR and grab a screenshot. The screenshot in #3 only shows what we think should be happening, monitoring the signal is now needed.

ETA: I expect we may be seeing some low-level carrier or other signal from the HL2's TRX chip.
OK Simon. So please see my Post #8 in this thread from yesterday. I describe how I did exactly this and I verified it's definitely not carrier. I verified that with tone at the input I hear tone on the output as verified by the other SDR receiver, but by all means I will post a series of screenshots that show this. I don't have time right now but I will do it later today if I can find some time free to do it. If not, then tomorrow.

But to be clear, with USB mode selected, Drive at zero and no audio input there is no output at all, but applying tone to audio in, tone is generated at the RF1 output even with the Drive set to zero.

Will be back with screenshots.

Max

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Re: HL2 - Output/Drive control functions with PA disabled

#17

Unread post by Simon G4ELI »

OK,

I really, really can't help without the screenshots.
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Re: HL2 - Output/Drive control functions with PA disabled

#18

Unread post by Max »

Simon G4ELI wrote: Mon Jul 26, 2021 4:41 pm OK,

I really, really can't help without the screenshots.
Understood. Coming soon. Want to take care over them to make sure they are useful.

Max

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Re: HL2 - Output/Drive control functions with PA disabled

#19

Unread post by Simon G4ELI »

Max wrote: Mon Jul 26, 2021 7:17 pm
Simon G4ELI wrote: Mon Jul 26, 2021 4:41 pm OK,

I really, really can't help without the screenshots.
Understood. Coming soon. Want to take care over them to make sure they are useful.

Max
I really just want two screenshots, one showing Console and the HL2 in TX mode, the other showing the received signal.
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Re: HL2 - Output/Drive control functions with PA disabled

#20

Unread post by Max »

OK Simon. So herewith 4 screenshots.

Each screenshot shows, on the left, HL2 in TX with tone applied and SDRC tone generator set to single tone, 1 kHz tone. On right of screen is the receiver (RSP2Pro with no antenna attached to prevent front end overload).

For every shot I used the same small tail of wire connected to the relevant output socket on the HL2 for each mode, so socket RF1 for screenshots 1 & 2 (PA Disabled) and RF2 (Ant/PA output) for screenshots 3 & 4 (PA Enabled). In this way the RX S-meter readings should consistently represent true power out from the HL2 (relative to each other for each picture).

So what I found surprised me. All was not what I had previously guessed, namely I discovered there is definitely power out of even the PA/Antenna socket when the PA is enabled, and Drive is zero. It's just that it's small enough for me to have never noticed it when connected to an antenna. So as an experiment, I connected the HL2 Antenna socket (RF2) to my transverter input, and with TX DSP control set to Zero, and in TX mode, I applied the 1KHz tone. Boom....... Transverter transmitted flat out (designed to need about 20dBm drive maximum).

Be totally clear. This is NOT carrier. You can see very clearly from the screenshots it's the 1 KHz tone that's being transmitted and appearing bang on 28.001 MHz.
So what I discovered is it's not just a Low Power mode (PA disabled) issue. It's both with PA either disabled OR enabled that there is power out from the HL2 with the TX DSP Drive control set to Zero.

Will leave it with you. Let me know if you need anything else to diagnose. I actually wonder if it might be worth seeing if anyone sees the same with other rigs or if the issue is strictly limited to the HL2? It's such low power output with the Drive control at zero that it would easily be missed in normal operation.

Max
Attachments
1 - PA Disabled - OP Power Min - Drive Zero.jpg
2 - PA Disabled - OP Power Max - Drive Zero.jpg
3 - PA Enabled - OP Power Min - Drive Zero.jpg
4 - PA Enabled - OP Power Max - Drive Zero.jpg

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