Instructions for using the PA bias setting tool?

[radi...@mail.com]

I've searched the Spark manual and on here, and also Hermes Lite Wiki, but cannot find the instructions on how to use the PA Bias tool in Spark. I'd rather use Spark than Quisk if at all possible as I can't get on with Quisk at all especially all the faffing about with Python etc.

I'm particularly confused in Spark as to why three settings for bias? 0,1, and MRF101? Thought there should only be two?

Over about a year my HL2 PA bias current has drifted up from 200 mA to about 240mA.

Any help or guidance appreciated. 

73

Max

[ahop...@googlemail.com]

Hi Max,

the way I do it is:-

Select sig mode and set all the levels to 0.

Open the radio settings and go to the PA tab.

Ensure PA is enabled.

Enable bias setting.

Click the ptt button.

The top two bias controls are for the pa, they do no show the actual setting until first moved.

Adjust one and set it back to zero then adjust the other until you get 100ma.

Remember the setting and set it back to zero.

Adjust the other to 100ma.

Adjust the first one back to the remembered setting.

click the store button.

The other bias control is for the 100w amp.

I'll copy this into the help.

73 Alan M0NNB

[Mike Brown]

Hi Alan

I assume that needs to be done with the rig in a mode like USB, with no input, so the only PA current is quiescent.

It sounds like the pots set bias independently for the PA transistors. Is that correct?

I know the PA transistors are at end of life. I bought two spares just in case but it is good to know the PA current can be tweaked if different devices had to be used. 

73

Mike

G4RAA

--
You received this message because you are subscribed to the Google Groups "SparkSDR" group.
To unsubscribe from this group and stop receiving emails from it, send an email to sparksdr+u...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/sparksdr/afef2984-bafb-432d-b18f-579ef2a74cc8n%40googlegroups.com.

[radi...@mail.com]

Hi Alan

Sorry for delayed response. That's great. Just what I was looking for. Should this be added to the Spark manual perhaps?

Many thanks indeed.

73

Max