Homemade vs Commercial 1:4 balun

[rheb1026]

I'm in need of a 1:4 balun for a personal project I'm working on to convert a 50 ohm impedance to a 200 ohm impedance for an op amp input.

I have two commercially made 1:4 baluns kicking around my parts bin and thought I'd try putting together a quick prototype since I'm not terribly confident in my abilities in the RF area.

The commercially made balun (Pulse Electronics CX2074NL) turned out to be very imbalanced in my quick test (~25% amplitude imbalance).

I then decided to quickly throw together a homemade 1:4 balun using a small #43 binocular core and 26 AWG magnet wire. The amplitude imbalance in my handmade balun was about 8% at worst.

I was really hoping to just be able to buy a premade balun to use on my board, but this quick test has me a little concerned. Just for completeness I did the test setup in the same way for both baluns: 50 ohm signal generator across the balun primary with the secondary terminated with a 200 ohm resistor. I'm scoping both sides of the output resistor.

The datasheet for the commercial balun doesn't specify the imbalance, where as some others I looked at from Mini Circuits and MACOM had this specification. Is this balun I have just a crappy one?