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FT-817 - Current Consumption by KA7OEI (via Nasota


#1

Found this useful article by KA7OEI for all those Yaesu FT817 users seeking to use less current whilst activating. Thanks to Michael VE3WMB for flagging it up on Nasota website. Look at http://www.ka7oei.com/ft817_pwr.html

Rob H G0HRT


#2

In reply to G0HRT:
Nice article, thank you for the link - I don’t yet own an 817, but this answers a lot of questions :o)

Adrian
G4AZS


#3

In reply to G0HRT:
Thank you Rob, This is very informative and essential info when operating /P. I run the 817 on 5W all the time. If it did 10W that’s what I’d set it to. As this article rightly implies; it’s the RX current which is really important as it’s there all the time your on. On transmit you have more control on length of your overs, power setting etc, so although it takes more power it is arguably less important.

I wish there was a similar treatise for the IC706 which draws over an Amp on receive. The only thing I can do is to turn off the illumination and rely on a headlamp. I haven’t tested my 817 but the high power 706 rig’s transmit current is really surprising. It takes 20 Amps at 100W (only produced at 13.8V input). However in round figures, it takes over 5 Amps to produce 2 Watts. 7 Amps to produce 5 Watts and 9A to produce 20 Watts. This means generally that it’s pointless trying to save power on TX. You may as well run 40 Watts or more, put out a more readable signal and get through the QSO’s that much faster to save current in that way.

Thanks again, John


#4

In reply to G0HRT:

Hi Rob,

That’s an interesting article. I have returned to using my FT-817 with a 25 watt external 144MHz linear (with preamp) rather than the FT-857 on account of the much lower receive consumption. Running LiPo packs with NiMHs piggy backed allows me to run the 817 off the LiPos and the NiMHs add the extra volt and a bit for the linear. Battery performance has also been improved by paralleling packs. The only downside to this arrangement is that I have less umpf on HF, but the 4 watts or so output usually suffices.

73, Gerald G4OIG