VFO A signal drops 20+ dB when VFO B is set to 6M

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VFO A signal drops 20+ dB when VFO B is set to 6M

Postby NC3Z » Sat Dec 16, 2017 4:02 pm

Not sure if this is a 200D specific or PDSR.

When VFO A is on HF and VFO B gets tuned to 6M the signals on VFO A drop 20dB or more. This happens regardless if MultiRX is on or even if RX2 is enabled.

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Re: VFO A signal drops 20+ dB when VFO B is set to 6M

Postby w-u-2-o » Sat Dec 16, 2017 5:50 pm

With only RX1 enabled, VFO A and VFO B are fighting for control over the preselection filter bank and/or the 6M pre-amp. Turn off the preselector (ALEX button). You might also need to go into Setup > General > Ant/Filters > HPF/LPF and disable the 6M LNA on receive. Not sure, because I don't have a 100D or 200D set up right now, but it should be a quick experiment. MultiRX will have no effect on this, it only affects audio routing.

I would not expect this to happen if RX2 is enabled, unless you have RX2 assigned to ADC1. Do you? If not, if it is assigned to ADC2, then that sounds like a bug in PowerSDR.

73,

Scott
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Re: VFO A signal drops 20+ dB when VFO B is set to 6M

Postby NC3Z » Sat Dec 16, 2017 6:00 pm

Turing off Alex does restore the level.

RX2 is indeed on ADC2.
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Re: VFO A signal drops 20+ dB when VFO B is set to 6M

Postby NC3Z » Sat Dec 16, 2017 6:01 pm

Oh, and disabling the 6M lna on RX does not do anything to resolve the issue.
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Re: VFO A signal drops 20+ dB when VFO B is set to 6M

Postby Joe-W4WT » Sat Dec 16, 2017 6:35 pm

I ran into this some time ago. If you keep VFO Sync enabled (top of window) when not using RX2 or MultiRx, you don't need to disable Alex for things to work properly.

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Re: VFO A signal drops 20+ dB when VFO B is set to 6M

Postby NC3Z » Sat Dec 16, 2017 7:41 pm

That keeps VFO B with A, but in the case I was trying to do was receive on 6M on RX2 and HF on RX1, so guess that is not possible.
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Re: VFO A signal drops 20+ dB when VFO B is set to 6M

Postby w-u-2-o » Sat Dec 16, 2017 10:43 pm

Can you use RX2 with the preselector off?
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Re: VFO A signal drops 20+ dB when VFO B is set to 6M

Postby NC3Z » Sun Dec 17, 2017 1:33 am

I didn't think the 200D had a preselector on RX2.
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Re: VFO A signal drops 20+ dB when VFO B is set to 6M

Postby w-u-2-o » Sun Dec 17, 2017 1:55 am

It does not. Neither does the 100D. Only the 8000 and 7000 do. That was why I was surprised when you said that activating RX2 (ADC2) caused the problem. However, I was thinking that maybe the bug would be worked around by turning off ALEX with RX2 active. Is that in fact the case? The answer may be important in terms of reporting any bugs.

73,

Scott
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Re: VFO A signal drops 20+ dB when VFO B is set to 6M

Postby NC3Z » Sun Dec 17, 2017 2:53 am

Yes turning off Alex when RX2 is on 6M does clear the issue on the 200D.
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Re: VFO A signal drops 20+ dB when VFO B is set to 6M

Postby w-u-2-o » Sun Dec 17, 2017 12:01 pm

Ok, so that latter issue appears to be a bug, because obviously RX2, when assigned to ADC2, should not affect preselector operation.
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Re: VFO A signal drops 20+ dB when VFO B is set to 6M

Postby NC3Z » Sun Dec 17, 2017 12:26 pm

That was my understanding what should happen, but it is not.
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Re: VFO A signal drops 20+ dB when VFO B is set to 6M

Postby WW4UW » Mon Jan 08, 2018 11:49 am

Not exactly the same problem I'm having with my 8K DLE but similar. I
noticed the unit has a low intermittent receive on 75/80 meters. I would
have to click the PTT a couple of times and the receive would pop back up
to the normal level. I thought at first it was my T/R relay on the AL 1200,
so I bypassed it and the problem was still there. I really did not notice
it on 40 meters, my primary band of operation.
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Re: VFO A signal drops 20+ dB when VFO B is set to 6M

Postby w-u-2-o » Mon Jan 08, 2018 12:12 pm

It could be a bad relay on your 8000. Bad relays have been a recurring failure point on all model radios.
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Re: VFO A signal drops 20+ dB when VFO B is set to 6M

Postby WW4UW » Mon Jan 08, 2018 2:26 pm

Yes that was my guess too "a relay" Doug W5WC has it now so I'm confident he will get to the bottom of it...

Thanks Scott

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