Hundreds can buzz over Russian positions in eastern and southern Ukraine at any one time.

But the drones can be hit and miss.

Many of them are hastily and cheaply assembled by volunteers.

And the lack of quality is affecting Ukraine's ability to survey and attack Russian positions.

This drone video footage provided by Ukraine's military, which could not be independently verified by Reuters, showed the recently made device in action.

And as this soldier, known by his call sign "Sam", soon discovered, this particular drone didn't pass the test:

"Most common problems are problems with the video link and with the control link. And most of them are because of low-quality parts that are used very often to make the drones even cheaper."

At an undisclosed location along the eastern frontline, the "Raroh" squadron says they would rather have 10 well-made devices than 50 less reliable ones.

Drone pilot "Pit" says the unmanned aerial vehicles should be standardized so operators know in advance how to use them.

"A problem that we faced is when you take many drones of different types for one day. You work a lot and have to do one flight after another, while the drones differ a lot. One drone has different controllers, another - different settings, and so on. When under pressure, it happens that you miss a detail and it leads to missing a target."

Using what are known as First Person View (FPV) drones in battle has been one of the more successful low-cost strategies for Ukraine.

But as another drone operator "Fest" points out, Russia has expanded its own fleet and improved its ability to block the devices.

"If we want to win, we must be creative. The problem is that the enemy learns from us and uses our own weapons against us. Now, the infantry's most urgent issue are means of protection from enemy drones."

Despite the drones' potential impact, artillery remains an important weapon against Russian forces using fortified trenches and dugouts.

And Ukraine has told its allies it is running short of ammunition.

Ukraine's defense ministry did not immediately respond to a Reuters request for comment on the soldiers' remarks.