Sketchy parts descriptions masquerading as real specs are worse than no specs at all....
What are the conditions for 0.7 dB insertion loss?
Minimum they ever measured for the best hand picked part at the best frequency???
Guaranteed max??? 99.99 percentile??? And my favorite: "typical".
Minicircuits has an extensive line of 4:1 Baluns. Fol. is typical 1.24 dB loss at 700 MHz:
As America Ferrera once said, "Real specs have loss curves."
They also carry 1:1 Baluns, such as fol. with half as much loss:
Since their on-line search engine is very difficult to use, suggest ordering their catalog.
And here's an article re an even lower insertion loss Anaren Multilayer 4:1 Balun:
See Fig 4 for VHF/UHF band loss. Call for more info, I didn't find it on their website.