I've made some measurements on the output. My analyzer only goes up to 3GHz but here are the results:
This is the spectrum of the DTX1 set to 1275MHz
DTX1 set to 437MHz
DTX1 Spectrum
DTX1 Spectrum
We are told to use a filter on the output because of unwanted signals
I've made some measurements on the output. My analyzer only goes up to 3GHz but here are the results:
This is the spectrum of the DTX1 set to 1275MHz
DTX1 set to 437MHz
I've made some measurements on the output. My analyzer only goes up to 3GHz but here are the results:
This is the spectrum of the DTX1 set to 1275MHz
DTX1 set to 437MHz
Ashley
G8DPH
G8DPH
Re: DTX1 Spectrum
They don't need a filter any more than any other kit IMO. - certainly at the 70cm & 23cm frequencies.
The closer in spectrum is really very clean as long as as the output level is being used generally at more than about 50% (so the wanted RF signal is well above general digital noise etc.) I measured non Harmonic related spurii at better than -60dB on 437 with the output at 100% on the unit I have here. Harmonics of the wanted are obviously not a concern as the amps/PA will have their own LPF/BPF (or should
)
Antennair are just being safe / cautious I suggest. (- sensibly)
Mark
G4WVU
The closer in spectrum is really very clean as long as as the output level is being used generally at more than about 50% (so the wanted RF signal is well above general digital noise etc.) I measured non Harmonic related spurii at better than -60dB on 437 with the output at 100% on the unit I have here. Harmonics of the wanted are obviously not a concern as the amps/PA will have their own LPF/BPF (or should
) Antennair are just being safe / cautious I suggest. (- sensibly)
Mark
G4WVU