Dummy load antenna for radio testing

I want to do some bench testing on a new to me radio before installing into my panel. If the radio stays in receive mode only do I still need an antenna or dummy load on the antenna input? Can anyone recommend an appropriate dummy device that can be used on an aircraft radio or a circuit that can be fabricated without too much trouble? How about something like the Diamond DL30A https://www.hamcity.com/store/pc/DL30A-p1874.htm. Thanks.

Use an antenna from a handheld perhaps you already own.
Jim

Yes, I also use a rubber ducky for bench testing.

If you want to fabricate something, you could take a chassis BNC connector (male) and solder 10 carbon resistors of 500 Ohm (or 470 Ohm), 0.5 Watt in parallel from the center conductor to the ground. This makes for a 50 Ohm (47 Ohm), 5Watt load.
Don't use a 50 Ohm power resistor as those are mostly wire wound, which would be an inductance.

If you are sure that you are not going to (accidentally) switch to transmit mode, you can do without an antenna, but with a rubber duck easily accessible, I would not take that risk.
If you accidentally transmit you might damage your RF power amplifier.

3U

I recall there are a few older threads on antennas. I think one said not to use a handheld antenna, or maybe the radio manual said that, I'm not sure, but it's easy to check. For bench testing a friend uses a home made dipole antenna in his ship, which I also tested. Just search the web for "home made dipole antenna". I tested one flying to root cause a antenna problem and it worked pretty well. You only need coax of the correct ratings and single conductor wire or metal rods.