The question that a lot of users seem to have on their mind is "What benefits, if any do I get by using ICOMS DPD in conjunction with a Solid State Power Amplifier (SSPA)"
Well, I measured a 6dB improvement.
Measurement setup:
- SPECAN: SDR-IQ
- TAP: VK5HW (50dB)
- ATT: 20dB
- PWR: 1000W
- ANT: Dummy Load (VSWR 1.08:1)
- Software: SpectraVue V.3.44 Beta 0
DPD off
Two tone test:
Result:
1st Value -31.311dB
2nd Value -31.455dB
3rd Value -52.398dB
4th Value -53.545dB
IM Max -22.2dB
IM Avg -21.6dB
NOTE: 1st and 2nd are the two tones and 3rd and 4th are IM3.
Look at IM3 and IM5, they are nearly the same in strength.
And the below using my Voice Caller calling CQ:
1st Value -23.996dB
2nd Value -31.168dB
3rd Value -49.526dB
4th Value -53.689dB
IM Max -29.7dB
IM Avg -24.0dB
DPD ON
Two tone test:
Result:
1st Value -31.168dB
2nd Value -31.311dB
3rd Value -58.996dB
4th Value -59.139dB
IM Max -28.0dB
IM Avg -27.8dB
Well, we do see about a 6dB improvement on the two tone test which is better than a Mosquito fart. But I believe the below is quite a good example on how well it improves your VOICE signal!
And below, using my Voice Caller calling CQ:
Result:
1st Value -20.840dB
2nd Value -27.582dB
3rd Value -57.750dB
4th Value -60.143dB
IM Max -39.3dB
IM Avg -34.7dB
On average we see an improvement of 7dB again better then a Mossi fart.
So I'd say any improvement, be it only 6dB is an improvement. As such I would recommend to upgrade the IC-7610 firmware and enable DPD however, YMMV ....
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