ft817

Equipment Radios & Power
21

In reply to G8ADD:

Yes, the “green wire mod” allows charging rechargeable cells in the disposable cell case.

Unfortunately, the charging current is set to charge the original low-capacity pack that Yaesu supplied. There are some disadvantages to charging a pack in the radio.

  1. The charger is not smart. It charges for 6hours or 10hours.
  2. The charging current is designed for the old smaller packs so 10hours won’t
    fully charge a custom pack.
  3. Series charging NiMH cells is not ideal for performance and longevity.

As long as you accept these limits then it all works VY FB as they say.

For maximum performance you should charge the cells in a parallel smart charger. That will ensure each cell gets the right amount of charging. However, series charging works and with the very low cost of cells you may not be bothered with the additional hassle to get the absolute maximum performance and life from your cells.

Andy
MM0FMF

22

In reply to MM0FMF:
Many thanks to Brian and Andy for explaining the green wire, etc; so far I have always used an external battery pack and just kept the original internal pack in reserve. I read the Yaesu warning about using rechargeables in the dry cell holder and have not done so.

The main advantages of using the externals instead is that I have 11 cells and a fuse, so I get 13V and some short-circuit protection. After use the cells then take their turn in a parallel charger as Andy suggests. (I can also split the pack and use 5 cells + fuse with my VX-3 and double the power.)

Rod
m0jla

23

In reply to M0JLA:
I meant to add that I use the Yaesu soft case at all times (except indoors) and carry the radio (in the soft case) inside my rucksack in a strong polybag. I rely on the fleece, waterproof etc for shock absorption. In transit I use a large old audio cassette case which has room for the mike, battery packs and pocket fast charger antennas etc as well. A bit of bubble wrap stops it all from rattling around.

Rod

24

Thanks for getting back on subject! I do enjoy how postings can go in all manner of direction.
I have some ideas now for storing/carrying the rig and also for the batteries. I am not sure I want to plug the radio into the scooter batteries. I have visions of either a) getting stuck without scooter power or b) some sort of runaway scooter problem. There are all sorts of warnings about using RF whilst on electric scooters. I can’t imagine the terror of hanging on to my scooter whilst its out of control at 4mph. Terrifying :wink:
The other questions is a headset. There don’t seem to be many specifically designed for the FT817. The RJ45 type plug is a bit of a problem. Does anyone do an adapter? My shaky hands aren’t great at the best of time but wiring one of those things up is beyond!
Then there is the matter of mobile HF aerials…
Q GW3BV

25

In reply to GW3BV:

Then there is the matter of mobile HF aerials.

5-10% efficiency antenna, 5W SSB and today’s bands all adds up to what I’d politely refer to as “challenging conditions” :wink:

Andy
emm emm zero eff emm eff

26

In reply to GW3BV:

A good point about a headset, although I take it you mean earphones with a mike as there is a side socket for plain phones. I dont know of a source but if there is one I wouldn’t mind getting an adaptor!

With regard to antennas, and bearing in mind Andy’s point about efficiency, and with restricted mobility you would not want to be messing about with dipoles or my favourite W3EDP, it might be worthwhile looking at a Rybakov 806. You could assemble it whilst seated and fix it to the steering using that good old standby, duct tape, and take it down without moving. A 10 metre roach pole (shorter if you don’t want 80 metres), some wire, a ferrite ring and a small project box, you could knock one up in less than an hour. It would certainly outperform a loaded mobile whip and give you all bands from 80 metres to six metres as the name implies - though I guess on six a lot of RF would be going skywards!

73

Brian G8ADD

27

In reply to GW3BV:

Hi Quentin and Brian

There is a microphone adaptor for the FT817/857/897.
It is Yaesu part CT-26, and has the RJ45 plug on one end
of a short lead and an 8 pin round connector on the
other end. I believe the 8 pin round is a socket, so
all you would have to do would be to wire the 8 pin plug
to the headset, and provide a suitable PTT switch.
Available from Radioworld for £20.39.

Kind regards

Dave G0ELJ

28

I think Heatherlite mobile mics. may again be in production.
Check W&S website. You’d still have to find some headphones to plug into the external spk socket, but that shouldn’t be a problem.

73 Graham G4FUJ

29

In reply to G0ELJ:

Available from Radioworld for £20.39.

Quentin, whilst I know there is no afterlife, I’m fairly sure I would rot in hell for all eternity if I allowed you to spend in excess of one “Smithy” on a few bobs worth of plugs and sockets. I’ll solder one together for you if you want.

Andy
MM0FMF

30

In reply to MM0FMF:

Hi Andy,

You’re absolutely right about the price!
I found a lead to use with my 857 and fitted
an 8pin socket to use with a dynamic base
mic. It seemed to work fine at low power
but I had RF feedback into it using 40 watts
on 5MHz. I think this was probably due to there
not being any screen on the audio wire. Someone
suggested to me that slipping coax braid over the
lead, taking it to earth at the 8 pin plug, and
securing it overall with heat shrink tubing might
do the trick. I haven’t tried that yet, but
perhaps the lower power from the 817 wouldn’t
cause the same problem

Kind regards

Dave G0ELJ

31

In reply to G0ELJ:

The answer to RF feedback is to put one of those clip on ferrite beads on the lead at the rig end.

32

In reply to GW3BV:

Hi Quentin,

I doubt that using the Scooter’s battery (assuming it is 12V & not 24V as some can be),to power your FT817 would cause any problems, & I very much doubt that any problems it did cause could cause the Scooter to run away on it’s own. I have to say the vision you on a runaway scooter with a 25ft aerial flailing about did make me chuckle HI!

On the subject of aerials for HF, if you are physically mobile enough yourself to erect a “proper” wire antenna, that would be the way to go, but obviously you could only operate stationary. There are many ideas & a dipole for the band you wish to work will certainly out perform any compromise antenna. If you wish to work many bands, a multi-band linked dipole, examples of which are used very successfully by many SOTA activators will make the most of the 5 Watts you have available.

As soon as you start to look at truly mobile operation, & more so, multi-band HF mobile operation things do get a little more difficult. As already mentioned, the inefficiency of loaded mobile whips primarily designed for mounting on a vehicle, would prove awkward to mount effectively on your scooter& with only 5 Watts would be not much better than a dummy load, even if you could get them resonant. A mobile whip with a trailing counterpoise would work better, but still not very well.

The lack of a substantial amount of metalwork would therefore seem to rule out a simple mobile whip, so that would make the Rybakov antenna more appealing & would probably be the way I would go myself if I was in your situation.

On the other hand, an article by Dave Starkie G4AKC, in the August 2010 Radcom about bicycle HF mobile may interest you. He does use up to 250 Watts when needed with a trailer for extra carrying capacity, but some of his aerial ideas may be of use in your situation.

If you don’t have access to that particular article let me know & I will see what I can do. His pedestrian mobile station certainly works & I have him in my log on 80m SSB when he was walking along the beach at Blackpool.

True 80m mobile working will still present some serious challenges from your scooter Quentin, but with inter-UK conditions on 40m becoming more reliable again, it will be much easier to chase relatively near UK summits on that band.

I’m not sure if you can use CW, but if you do, much of the above becomes irrelevant as you can work on 40m & 30m at times using not much more than a wet piece of string. It does needs a decent ground system though HI!

Best of luck with the project & as already mentioned, don’t pay through the nose for basic things like microphone adapters simply because you can no longer handle fiddly components, there are many here more than happy to help.

Best 73,

Mark G0VOF

33

In reply to G8TMV:

Hi,

Many thanks for the tip.

Kind regards

Dave

34

Thanks for all the advice and the offers of help.
Andy, I would be very grateful if you could make something for the headset. I will cover any costs of course. However it seems that a Rybakov aerial is highly rated. Would anyone be able and willing to build the unun for me? The rest of the antenna I can manage and I do have an idea for being able to mount it on the scooter. However the soldering etc could be tricky. I appreciate that I might be pushing the boat out here…
Yes Mark I’ve read and recently reread the Bike mobile articles. I do pretend to be a qrper but perhaps more power will be the way to go in due course. I think I’ll see how I get on with the FT817. I have dabbled in CW but currently it is very rusty indeed. Something else to work on. I will be at the Newark Hamfest for the RAIBC AGM so hopefully I can pick up a few needed bits and pieces there.
Andy and anyone who might be willing to help could they email me off list? qcruse at gmail.com
Cheers and thanks for the advice
Q GW3BV

35

In reply to GW3BV:

The other questions is a headset. There don’t seem to be many
specifically designed for the FT817.

Cheap computer headsets can be easily adapted for this purpose. Although I have not tried myself there are plenty of examples on the web if you search and some demos on YouTube that will show how good the quality of the audio can be.

No need to think about the RJ45 too much, just get an Ethernet cable and lob six inches off and either make a little adapter box to plug in your head set or wire it direct.

73 Steve

36

In reply to GW7AAV:
Steve,
Adapting a computer style headset for use with the FT-817 is not quite as simple as you imply. As you know, the stock mic supplied by Yaesu for the 817 is a dynamic type, whereas computer headsets are usually electret. Apart from requiring a DC feed, the levels, impedance and frequency response of the electret mic will have to be tailored to the 817, to ensure satisfactory results.
Richard, G4ERP has published, on this forum his recommendations, which are below.

I’m sure Richard would provide any additional information to GW3BV, if needed.

'It took a while but I think I finally got there and now have a lightweight headset that works with the FT-817. Thanks everyone for putting up with the intermediate attempts and thanks for the nice comments on the audio today. It was slightly more of a challenge than I expected.

Briefly, it is based on a Hi-Tex BEP-55NC electret (condensor) noise-cancelling microphone from Maplins. There are three key points.

  1. A 470uH / 1nf filter on the mic input to stop feedback on HF.
  2. A 10uF decoupling capacitor to stop DC pickup from the noisy 5V supply getting into the mic. Bias for the mic is via a 47K resistor.
  3. A sock over the mic. No, not the type you wear but the type commonly fitted to professional headsets. This gets rid of some of the "S and “F” problems.

The weight? 36g. That’s a bit lighter than the 170g of the standard Yaesu MH-31 mic. It will be going with me on my re-scheduled South Downs Way trip in a couple of weeks.

73, Richard '
G4ERP

37

In reply to GW7AAV:

The original thread can be located by searching the reflector for:

FT-817 Lightweight Microphone / headset

or some subset thereof.

73 Rick

38

In reply to G3RMD:

Adapting a computer style headset for use with the FT-817 is not quite as simple as you imply.

It is fairly simple and should be within the capability of anyone with an idea how to solder. Even if you bought all the bits from Maplins it should not cost more than a couple of pounds. For anyone with a junk box if the cost is more than 40p plus the £1.99 for a headset then you either don’t have much in your junk box or you are trying to do a super professional looking project, which is fine but it probably will not work any better.

My experience in this field was making hands free mics for CBs (back in the day) which was more tricky as they were usually mounted further away (on the sun visor) than headsets and you could drown out the audio with road and ignition noise if you did not get it right. The electret inserts I used cost a lot back then and I had to wait for a radio rally to stock up. I used broken elements from 2m ZL-specials for the stem of the mobile mics and fitted the insert in to the end of a TV coaxial plug. Remember all those CBs also had dynamic mics so there was a 9v battery in the switch box.

Regards Steve GW7AAV