If you need portability, don't have a lot of room, and / or don't have a lot to spend, here is a simple, low cost, and highly effective solution to enhancing signal reception on the ATS 20 & 25. BNC plug (plugs antenna into your BNC EXT ANT jack on the back of the radio).
eBay
Hello To All SWL'ers, New & Seasoned. WDX2RADIO Mission WDX2RADIO VISION Thousands of Bare Copper Longwire Antennas Sold Worldwide, Across 7 Continents, and all 50 States. If you have up to 50' to install a longwire, then THIS is your Shortwave Antenna.
eBay
50' of 14g Super Strong Professional Ham / Shortwave Bare Copper Antenna Wire. See also our Shortwave Antenna Kits, Parts, and Accessories. Thousands of Bare Copper Longwire Antennas Sold Worldwide, Across 7 Continents, and all 50 States.
eBay
Sony ICF-2010 PLL Shortwave Radio Receiver - AIR FM/LW/MW/SW/HAM. the antenna is a little loose when pulled out but the radio works. No power plug. You will get what you see. Working ….
eBay
We've done all the work—testing, assembly, and firmware flashing—so you can get on the network right out of the box. It's the easiest way to get started. Custom-Fit Alley Cat Case: A rugged and stylish enclosure for protection.
eBay
On the initial model the NRD 505, Japan Radio reportedly made less than 1,000 units and this receiver broke new ground for enthusiasts with its high construction standards and precise digital readout.
eBay
RadioShack DX-398 tabletop radio receiver stand.
eBay
Hear it all live on Shortwave! This is The Globestar. A Highly Effective 25' foot, Bare Copper Long Wire Antenna Kit for Outdoor/Indoor installation. Nothing beats a Longiwire Antenna for Global Shortwave Reception.
eBay