40dB Resistive Tap

I have constructed a few 40 dB resistive Taps using a T resistive divider attenuator pickup, to pickup a small amount of RF for measurement purposes. The initial Taps that I build have been VK3AZQ 40 dB Taps. Checkout Lou's nice write up of how to build a 100 W tap. Below is a photo of two of the units I build using Lou's kits they are good to 440 MHz at about 50-75 W, above that they tend to get rather warm. Do the maths and you know why.

Because the ½W resistors in Lou's kit get rather warm at about approx. 80 W, I build a unit that can handle approx. 150 W without the disintegration of the resistors. The resistors used are VISHAY 3 W Metalfilm 5% (PR03000208200JAC00). The Tap is usable up to 150 MHz. The Tap consists of a series arm of three 820Ω 3 W metal film resistors and a 51Ω ½ W at the end of the series arm as a shunt. Other values could be 2.4 kΩ 3 W or 2 x 1 kΩ + 470Ω 3 W.

Measured attenuation is close to 40 dB and for high-power measurements.

And below the measured through loss, which is minute.