HF Amplifier in Original Size FLEXI-BOX

  The price of the HF Amplifier FLEXI-BOX is dependant on the connectors required. To find the price for your connector preference or to make a purchase, select your connector requirements in the boxes beside the photograph above and then hit "Add to Cart".

Description

  The High Frequency amplifier is built in an Original size FLEXI-BOX on a dedicated PCB. The screened box has one 50Ω input and one 50Ω output. It can be used as a test measurement aid or a general purpose HF amplifier. The DC input is fitted with a feed through capacitor with a solder tag. The RF connectors can be selected from BNC, N, SMA and TNC. Other connector types could be fitted if required in quantity. It could therefore be used in many applications that require a HF amplifier not just in the lab. We can build and test these at Chemandy with a minimum gain of 14 dB and a 1 dB compression output power of greater than +11 dBm at 30 MHz, the gain ripple is less than ± 0.2 dB from 3 MHz to 30 MHz. Input and Output return loss better than 20dB.

Circuit

  The amplifier is built around the BFS17 in a shunt series pair configuration. A full description of this amplifier and how we built the prototype is available at Building a HF amplifier in a FLEXI-BOX Part 1. This article shows several photographs of using the FLEXI-BOX for circuit development. The amplifier is referred to as being an HF amplifier but it can be seen in Figure 1 that the 3 dB frequency response is far wider than the HF band and it could also be used as a LF amplifier or a MF amplifier.

Figure 1

Figure 2

The isolation S12, has been omitted because it is better than -65 dB from 0.3 MHz to 50 MHz and would cramp the scale of the other measurements.

  The above results were obtained with SMA connectors and the performance will most probably be marginaly inferior with any other type fitted.