multiple receivers and identification

[cslondon]

To optimize parameters (frequency, gain,filter width) I connect 2 different receivers to try to optimize one by another, trying step by step to receive more data after each period by optimizing the one receiving less (from a high number of senders in various locations).
Antennas are about 20cm apart.
Although these are different receivers (model, manufacturer), they show both up as
lsusb:
Bus 001 Device 006: ID 0bda:2838 Realtek Semiconductor Corp. RTL2838 DVB-T
Bus 001 Device 004: ID 0bda:2838 Realtek Semiconductor Corp. RTL2838 DVB-T
Only comparing verbose, they do actually differ in

iManufacturer 1 Nooelec
iProduct 2 NESDR SMArt v5

iManufacturer 1 Realtek
iProduct 2 RTL2838UHIDIR
, but for example not in serial number as both manufacturers don't bother and just set the serial fix to 0000001.
My problem is to distinguish the devices, as I believe the device ID depends on the order I plug them in. So how do I identify them?
I can start tfrec -d 0 and tfrec -d 1, I can quote whatever, I don't get -d ? working as tfrec just starts and dosn't give out a list of IDs, and I don't see a way to check which device is '0' and which '1' ? Any solution?

Thanks for any feedback.