Procom Duplexer Tests

From UK D-Star Technical Wiki

From Iain Phillips, G0RDI posted to the DStar-UK YahooGroup on 17/03/08:

The duplexer that's in GB7ML is composed of two components: firstly, a Procom DPF70/6 (initially tuned for the 6 MHz split), plus a bandpass filter in the TX leg. This BPF was measured at 1.2 dB insertion loss, so it's quite expensive in those terms. It does, however, improve the shape and response of the total filter package.

As found, tuned to the original "LPD" frequencies, the network analyser plot looked like this for the RX path:

and like this for the TX path:

After tea and twiddling, they looked like this:-

and

I would have to say that while they're not brilliant, for the money that's changing hands for these, you'd have to say that it was a fair performance, all things considered.