RF Connector – Identifying Vintage 3-Pin Connector Configuration

Assuming the ruler is showing millimeters, I'd say that the connector is of JST-XH-2.5 mm type with two pins. Sometimes, these connectors are sold and marked with 2.54 mm in their name, since that is a common spacing for inch-based measurements. Such connectors are commonly used for battery packs, so you might be able to find one, or a cable with one attached, in stores that sell equipment for radio-controlled planes/cars/boats etc.

My guess is that the radio was intended for use with a small loop antenna, such as one depicted in this photo from Wikipedia:

Most likely, two ends of such antenna would be connected to the appropriate female connector and then plugged into the radio.

In my almost 40 years of tearing apart electronics, I have only seen what you are specifically asking for once or twice in the SIP form-factor, and each time it was a custom OEM part that wasn't available on the open market.

Although they are rarely seen these days, 90 degree DIP sockets were at one time popular back when discreet non-multiplexed LED display modules were common. They still appear to be available, at least to some limited degree:

So, I guess the proper term would be "8 pin 90 degree vertical SIP socket", but like I said, such a thing does not exist on the open market as far as I can tell.