Hi there,

I plan to use a feed point tuner (mAT-40) with wire antenna. That tuner will come with an ICOM style control cable (4-pin molex).

Pin layout is:pa0fri.home.xs4all.nl/Diversen/IC-7300/ic-7300%20&%20jc-4%20s2.gif

EXT CTRL jack layout offers some usable connection points:www.qsl.net/ba4alc/chinese/sunsdr2pro/sunsdr5.jpg

Possible mapping:
My questions:

a) Am I correct with above assumptions regarding the molex pin meanings?
b) Would that mapping be okay, without any further electronic components? Just the cable?
c) How do I connect X5 ("manual tuner start") to SunSDR2 PRO's tuning process within ExpertSDR2?


Thank you guys!

Manuel

Hi Manuel,
I cant answer your question regarding Icom interface, however some other things.

1. You need to know logic levels, as an example PTT_ON is normally "Low". In you case PTT and Start.
2. Due to that outputs on the ESDR radios is open-collector you might need a pull-up resistor to get "High" logic levels. This is suitable if we have low current logic to the tuner but it might already be internally pulled-up.
3. You also need to check currents on the tuner control inputs to know if #2 above is the right way to go building the interface cable.

Then you have the manual tuning, not sure how this works? Is there an automatic way?

BR,
/Tomas

Hi Tomas,

thank you for your advice. So I need first to check, what the tuner is really doing on those pins. Indeed, I've read the EXT CTRL hints in the manual and was aware, that there might be some stones in the way.
The current draw is a point. Although I think that tuner will work below 1A, I'd better spare that power tap for a smart fan solution, like it seems to be designed for. The tuner will be outside anyways, so the power can be from a power supply set up anywhere else. Not connecting the tuner to the SDR would be a more wise decision for lightning/over voltage protection. I have a Zigbee network, so I could use some wireless relay array from there, to remote control the tuner using the smart home dash board or smartphone app.

About the automatic options the mAT-40 has, I don't know. The product descriptions and the manual, all refer to the use of one of the three control cables available. Maybe I'll give the unit just some power and watch, if it does something. Maybe a simple trigger switch can be a first workaround, to start a tune cycle manually.

Thanks again,

Manuel

Please share the function documentation and interface specification here, and Ill try to help.

For sure you need something more than cable between Icom tuner and SUnSDR trx.

The ICOM tuner communication is simple, you need transmit at small power level ~5W, then for short time (less than second) trigger the "start" line to low (open collector transistor is ok for it, no pullup needed), then wait until tuner stops tuning, then unkey the transmittion.

Look at #15 here: eesdr.com/en/forum-en/others-acc/9572-sunsdr2-dx-with-icom-ah-4