I'm ordering a Sennheiser G4 transmitter/receiver set-up. Will I need an impedance matching cable (Kopul?) if I want to plug my dynamic Rode Reporter mic into the transmitter? Or can I just use a regular XLR to 3.5mm cable?

You should get a SKP-100 plug on transmitter.
The SK-100 body pack Tx is unbalanced so you need to make or purchase a custom cable, preferably with a bias voltage blocking capacitor. The wiring would be;
XLR pin-2 to the 3.5mm plug's Tip terminal
XLR pins 1 and 3 to the plug's Ring and Sleeve terminals

Thanks Rick. Is this cable from Kopul similar to what you suggested? Unfortunately, I can't find the pin-outs for it. Also, will that bias voltage damage a dynamic mic?

Kopul | Technology for Broadcast & Studio Applications (http://www.kopulcables.com/product/5034/Kopul-LMT_100-Low-to-High-Impedance-Matching-Transformer-(1.5)')

John. If you want a simple and efficient way of doing it follow your own suggestion of using a Kopul LMT100. This is exactly what these were designed for and the price isn't outlandish.

Chris Young

https://www.bhphotovideo.com/c/product/885062-REG/kopul_lmt_100_lo_to_hi_impedance.html/BI/2855/KBID/3801

Thanks Chris, will the Kopul cable also block the bias voltage that Rick mentioned? If not could that voltage damage my Rode Reporter dynamic mic?

in some cases, bias current can produce noise.. I have never heard of it causing damage. OTOH, Phantom Pwr can fry a mic or other device through an unbalanced cable.

Thanks to both of you for your help.

+1 as Rick said!

Chris Young