I'd be pleased to hear from anyone who has done this successfully. PTT works for me but there is no audio output. The connections I have are as follows:

MD2 8 pin microphone connector RJ-45 SunSDR MIC2 connector

pin 1 AF pin 5
pin 2 PTT pin 6
pin 6 5v bias pin 3
pin 7 mic ground pin 4
pin 8 PTT return line pin 7

I have tried keeping the two grounds separate and also together by shorting pins 7 and 8 in the MD2 8 pin connector.
No audio at all! I am quite happy to wire to MIC1 as an alternative, but then I have to have a separate PTT line which is not
such an elegant solution! I have made sure that I have selected MIC2 in the SDR software.

I'd be pleased for any advice,

Thanks and 73,

Stephen G4SJP

I did wonder whether the formatting of the posting might go all wrong, and it did!

In the paragraph of pin numbers, the first referred to the pin number of the 8 pole mic connector on the microphone, whilst the second number referred to the pin number on the RJ-45 connector.

I haven't made any further progress on this since my first post.

Thanks,

Stephen, G4SJP

I have this all working now using Mic 1 and a separate lead to the PTT input on the back of the SunSDR2 pro. Never did have any luck connecting via Mic 2 and gave up!

My biggest error was to assume that the bias resistor was already present in the Heil mic, it was not! So a 5k6 resistor between tip and ring of the plug sorted that, with the mic element connected between tip and sleeve. As I have already mentioned, a separate single screened cable from PTT and Earth on the Heil to the PTT socket on the rear panel.

Further details available on request, if needed.

73 Stephen, G4SJP