You, or someone, is going to have to make an inventory of major items and probably you will have to obtain some help from a trusted person with knowledge of vintage radio collecting in order to make the list.  If you advertise in any form, folks are going to want to see that list of items… Even if you are not faced with a need to dispose of the estate right now; you may find it helpful to video tape or photograph the collection. A video tape of your collection in your bank safety deposit box and a duplicate tape at home could be helpful if you ever have to make an insurance claim for fire, theft, vandalism or natural disaster losses.  Note the need for a duplicate tape….  Your bank safety deposit box may remain sealed until an executor obtains control.

You have to advertise after you have determined the method of sale….  Presently one of the better ways to reach a large number of qualified buyers is to advertise in Antique Radio Classified.  I would recommend a ¼ page ad placed in at least two consecutive issues.  The ad should give sale dates, a brief description of the kinds and quantities of merchandise to be offered and a mailing address where folks can request a detailed listing of items for sale.  I would not include a telephone number in the advertisement unless you are really familiar with the items in the collection.  Save that for the detailed listings you mail out. 

Another way to advertise to qualified potential buyers is at www.antiqueradio.com.  There are forums where you can post your items or make announcements of sales.

There are various vintage radio clubs that publish journals that include space for member advertisements.  You can place announcements of sales and general listings of equipment for little or no cost.  Just look around the estate holdings for these newsletters and publications and then contact the editor.   More and more regional clubs now have web sites where announcements can be posted.

Advertising via Craigslist.org 'gets a lot of eyeballs' these days.
 
My experience has been that advertising in large local newspapers has minimal value.  The little 4 line ad placed in the auctions listing AND the antiques & collectibles listings seem to be just as effective as a 4 column-inch ad costing several hundred dollars.