FT817 erratic CW keying

on my activation last Saturday of EA2/NV-070, after logging on 20m SSB, I moved to CW. It all worked fine for a while until the CW became unstable. In my iambic, the dash paddle refused to work, and the dit paddle produced alternative dits and dashes . - . - . - . - . -

I rebooted the 817 but stayed the same.
I thought a problem of my iambic. Hopefully I conected my second emergency iambic (http://reflector.sota.org.uk/t/homebrew-micro-paddle-cw-with-paper-clips/10615) and could continue but soon again, erratic dits and dashes made me do an early termination of the activation.

As far as I remember it’s not the first time I suffer from this and I think that perhaps it could be linked with low temperatures.

Yesterday the day was cold, about 2C and quite windy at operating position, the rucksack lying over the snow on the summit.
Once I arrived home, in the afternoon, after some rest, I connected my primary iambic and all went fine… Problem disapeared!

Do anyone else have experienced similar troubles with the built in electronic keyer of the 817?

Mine is the first version (not ND).
73 de Ignacio

Hi Ignacio,
I have never experienced such problems with my FT.817ND but I want to give you an idea which may work well for you to avoid or minimize such failure.
It may be of interest for you to keep your rig inside an isothermal plastic bag like those sold in supermarkets for putting the frozen products inside during the trip home. Also putting some polyexpand around your rig may help to keep it isolated from the cold around when you place it on the snow.
You know I have my SOTA KIT inside a wooden box, as well as you. Well, my wooden box with the SOTA KIT is inside 2 plastic bags and then inside the rucksack. One of the bags is isothermal and the other is not. I use them in order to keep the SOTA KIT dry in case I get some rain while out in the mountains.
I also have put some pieces of polyexpand at the bottom of the rucksack so the SOTA KIT gets well isolated from the cold when I place the rucksack on the snow, as well as well protected against possible shocks if I slip and fall down (as it has come to me some times) when descending a steep and slippery slope.
I will show it to you when we’ll do our next joint SOTA activation. I’m looking forward for it.
Thanks for the S2S QSO Saturday morning despite the errating keying.
Best 73 de Guru

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I’ve had the same problem with the the 817 (ND). I dropped the key out of my bag and into the snow, I knocked the snow off and plugged it in with the same erratic sending you described. The key jack must have still been a bit wet. I unhooked the jack, dried it off, and rolled up a bit of paper towel to clean the inside of the connector. After cleaning I hooked it up and it worked FB.
Best of Luck

This is a problem FT8 series by Yeasu … :frowning: soo my old Icom 706MKII h’is working properly.
Over 40 lpm Yaesu changing signs :(.

Hi Bob, thanks for your clue.
Yes, I think it can be linked to humidity more than to temperature. I’ll consider cleaning paddles next time with a dry paper towel.
My iambic is made out of long aluminum sheets and maybe it is more sensible to wet climate than other type of iambic.

Thanks also Guru, look forward to that joint activation…

73 de Ignacio

I agree Ignacio. I have operated my FT-817ND between minus 10C and plus 40C without any such issues. Yet operating in damp conditions I often have to dry the key contacts to stop the rig going onto constant carrier. Fortunately I only have a straight key to deal with, so it certainly makes itself very evident - no alternate dots and dashes as you get with a paddle. It can still be very frustrating when trying to work a pile up!!

73, Gerald G4OIG

I can’t recall but I think there is a bit of a design shortcoming on the 817 microcontroller. I don’t have the time to check now but I think the microphone PTT and the dot and dash paddle inputs go straight to the microcontroller. No input filtering (RF supression) or low impedance buffers at all. That means your inputs are straight onto the CMOS high impedance inputs. There may well be weak pullups inside the chip or maybe not. They may not be deployed by the software running on the chip.

What this boils down to is that the input impedance may be 10MOhms or so in which case high humidity may be enough along with atmospheric dirt on the contacts to cause this false keying. Either in the key, or the socket on the back panel or even inside the 817.

You could always build in a opto isolator. I did this on my homebrew DSP transceiver more for protection on the DSP I/O lines. You don’t need any RF suppression then, well I have found it to be sufficient anyway.

Problem is you need 5V from somewhere. Andy makes a good point, its often the case that the keying lines are used for the PTT as well in most modern transceivers.

You could combat the cold this way.

I like the OH6DC Rubber Stamp key Home - Rubber stamp CW key

Ideal for SOTA CW QSOs :smile:

73 Andrew G4AFI

The key’s fine. Not sure I could manage to carry the desk as well though :wink:

There’s a 5V supply on the '817’s mic connector, not sure of current rating. Useful for an electret certainly :smile:

73 de Paul G4MD