There are several online marketplaces where you can sell old and new satellite equipment. Some of the popular options are:

eBay: eBay is a well-known online marketplace where you can sell a wide variety of products, including satellite equipment. It has a large customer base and provides various selling options such as auction-style, fixed-price listings, and more.

Amazon: Amazon is another popular online marketplace where you can sell satellite equipment. It has a large customer base and provides various selling options such as individual and professional selling plans.

Craigslist: Craigslist is a classifieds website that allows you to sell a wide variety of items, including satellite equipment. It is free to use, but you need to be cautious while dealing with buyers.

Facebook Marketplace: Facebook Marketplace is a platform where you can buy and sell items in your local area. You can create a listing for your satellite equipment, and interested buyers can contact you via Facebook Messenger.

Satcom Resources: Satcom Resources is an online marketplace that specializes in selling new and used satellite equipment. It has a wide range of equipment available, including satellite phones, modems, antennas, and more.

Ultimately, the best marketplace for you will depend on factors such as the type of satellite equipment you are selling, the selling fees, the customer base, and more. You may want to consider using multiple marketplaces to maximize your reach and find the best deal for your equipment.