FT817
Glitch in the charging circuit. This can happen when the radio is fed with a quick on/off power supply like a broken supply cord. When you switch the radio on you don't have audio and display flashes. Solution. Insert some half charged batteries in the FT817 (so that the charger sense circuit knows that the batteries can be charged). Switch on the rig with a 13.8v PSU and follow the procedure to charge the internal batteries). This involves setting one menu to 6 hours time, and then on the 3 F-keys turning the charger on. Switch the rig off and the LED on the front panel glows orange. Allow the charge cycle to complete. Disconnect the rig PSU. Switch radio back on using the internal cells. Pull out one of the AA cells to make it look like the battery has depleted it's voltage. Now plug the rig back on to the main 13.8v PSU and switch the rig back on.
Better AM modulation. The FT817 is actually very capable of producing very good quality AM. But it needs a very minor tweak. Boot up the rig whilst holding down the three F-keys. Spin around to menu 69 - AM CAR. It's usually set around 228. Now listen on the 21Mhz test frequency that the menu specifies and reduce the level down to about 219. That's not a lot but it makes a huge difference to the quality of the audio. These figures are nominal, so listen with a receiver to determine the correct ones. Always have the mic gain at 100%. The tone switch on the back of the microphone is VERY important on AM. Select position number one, usually the one that cuts out the lower frequencies. Oddly enough on FM/SSB the tone switch barely makes any difference.
Speech processor. Many pundits complain about the lack of a speech processor. Trust me,the rig doesn't really need one. TX audio is great, just keep the mic gain at 100%. I did experiment with one of those SSM2167 type modules that are sold by some dealers but the quality was dreadful. I built one into the microphone and the RF feedback appeared to be incurable even at the 500mw RF output setting! However in the GQRP club magazine SPRAT #185 Winter 2020/21 on page 39, a user describes having good results by using 100uH chokes in series with the microphone input, output and DC lines with a 1nF cap to ground, and also leaving the preset gain levels at the supplied defaults. Also here's some data on the Ebay modules.
Internal battery pack. The supplied pack is utterly useless. Using the empty cell case for AA's is hopeless when using alkaline or zinc carbon cells as they cannot produce a steady voltage when even small currents are drawn. Also the contact resistance due to the cell case spring contacts is too high and thus limits the maximum current drawn. So even if you use high current cells, you'll have difficulty using the rig at the 5w output level. At best, you get to use the rig for longer at the 2.5w level. I recommend Eneloop AA cells for the FT817. This new breed of NiMh cells clains to hold it's charge for 10 years ! Other NiMh will lose charge after about one month. If you leave these cells without charging them soon afterwards then they become irreversibly damaged - fact. I have had excellent results with the Windcamp brand of Li-Ion pack, 3000mah for use as an internal pack. Cost about £70. You'll get about 2.5 hours of solid CW operation out of that, more if you are not ragchewing. Otherwise for portable ops I recommend a 7aH Gel Cell. [UPDATE - April 2023] After 5 years the Windcamp died. This is yet more confirmation that Li-Ions, regardless of the life that they have endured, will ALWAYS die at 5 years old. You are then left with a plastic cell cover for the FT817 with a small charger PCB. So far I have not found out a way of re-using what is left. So for now I've thrown it in the junk box and gone back to using a basic 7ah gel cell. It's a shame that the FT817 battery compartment didn't accommodate for just an extra 5mm of space, and that would have made it so easy to the end user to build custom 18650 battery pack etc. And you did keep the original FT817 battery compartment cover didn't you ?
The DC connector. The DC connector used on the FT817 is a 1.7mm/4mm outside diameter. Be careful, don't knock it or you can damage the PCB. ONLY use a right angled version of this connector. Yaesu supply it with a 90 degree connector for a very good reason. If greatly prevents damage to the PCB if it gets knocked.
Improved 100 - 600Khz sensitivity. Hint - on an FT817 you'll find that switching the pre-amp or IPO to the OFF position will increase receiver sensitivity. The pre-amp was never really designed to be used down there, and so it tends to act as an attenuator.
An ATU for the FT817. For portable work I use one of my general purpose ATU designs. I use the same basic circuit on all my equipment but I vary for working voltage or type of components depending upon what power I need to put through them. They all use a T-match, with the inductance going to earth. In this version, a very small and compact "switched array" of toroids works and looks better than one large toroid, where the terminations for each tap point look ugly. The toroids are a mix of FT50-61 and -43 to achieve the following values - 0.27 / 0.5 / 1.3 / 2.1 / 2.8 / 3.7 / 5.0 / 7.3 / 11 / 15 / 20 / 37uH. [I use -61 for the first set of lower values, and then switch to the -43 for the higher values]
There is one T37-2 toroid used for the 0.27uH value (seen mounted in the centre of the switch). This nicely tunes a 7m vertical wire with a 3m long radial nicely from 160m - 10m. I also have a replica unit on my QRSS transmitter with a 10m random horizontal wire and the earth side connected to the copper water pipe system in the house. The -61 material is used to accurately build lower values, and then the -43 material is used for the higher values. This means that typically on each core you need between 2-7 turns in order to build up the 0.27 to 37uH inductance. You can use 20 or 22 AWG / SWG enamelled copper wire. Wind tight (don't break the toroids!) so that the toroid doesn't flop about when it is finally mounted on the rotary switch. And don't get those toroids mixed up! Mark them with some paint or something.
Optional Guanella 1:1 balun design (image by VK6YSF). Wires can be twisted pair. Either side can be input / output. My versions used a single FT50-43 toroid, good for 10-20 watts.
A nice view of operating down the beach on a summers day.
