Coins without diameters, when searching by diameter

If your search includes a diameter range, you do not see coins with no listed diameters.

A better behavior, I propose, would be to return the coins that match the diameter range and the coins with no diameter. 

I have recently been trying to identify older German coins from my grandfather's collection. Some have no legible writing and not date. What I do know is the weight, diameter, and composition. If the matching coin has no listed diameter, then the only way I'm going to find it is to expand the search by removing the diameter parameter and then look past all the coins that are clearly the wrong size. And it's the older coins, without obvious text, that are more likely to not have a diameter. 

Apologies if this subject has been raised already.

thanks, Michael

There are 49,746 coins in the catalog with no diameter listed.  Even with eliminating ones that don't match the weight and composition that's a lot of coins to sort through. It should not be automatic to add all those with no diameter listed when a diameter is entered. Most searchers won't want that.

Maybe you first do the search with the diameter entered then redo the search only for coins with the diameter missing.

thank you, I did not realize you can search for a “missing” parameter. That accomplishes what I am asking.

Numista could add some hints at the end of search pages:

• If you search by diameter, add a hint about coins with no listed diameters and a link to the same search with the explicit diameter replaced by missing.
• Similar for weights.

Any other suggestions?