I've had my awesome FT-817 for a while now, in fact I pre-ordered it with DSE months before release, but I have never really used it as much as I wanted to. I am going to go through a lot of detail in case I missed something in my diagnosis. But the short version: FT817 is now giving HSWR on HF & 6 (maybe?), no matter what I plug in.
In the last 2-3 years I was getting weird things happen, I always put it down to a faulty [homebrew] coax, [homebrew] antenna, etc... Which put me off doing proper SOTA/VKFF activations. I caught up with VK3ZPF during JOTA (October last year) to help out and he plugged the 817 into his watt meter, everything worked properly.
This weekend was yet another test run, but participating in the vkshires contest. I entered as a Rover, only because I wanted to join in from a campsite, threw up an antenna in the trees in one shire, made 2 easy contacts (tried a few more, but 5w is really pushing it for a contest like this) and planned on going to 2 shires more the next day. Everything was working 100%.
Set up camp about 7 made a few more contacts. About 8, everything went south, SWR kept on spiking and nothing would get it down (LDG Z-817 plugged in) and when trying to tune up on 80m, a relay kept buzzing (sticking?), a good tap on the back of the radio solved that (this is the first time this problem occurred). 40m was getting quite so I decided to get an early start in the morning. 7am, same issue, had up the 40m halfwave from night before, changed over balun, put up and tried the squidpole 40m vertical, still getting high SWR. Then about 8 it all came good and I made another 30+ contacts.
As the sun disappeared behind clouds and trees about 12-1, temperature went down the the SWR problem kicked in, the tuner kept working as if if had found a good match, but the radio kept playing up complaining of HSWR. Tapped and wiggled the radio and the SWR started drifting up and down (at this stage I am running at lowest power setting in case there is an SWR issue) and not fast, slowly, about 20 minutes later I worked out if I moved the tuner cable plugged into the ACC port around it would come good.
Getting towards 3 pm it was hit and miss, and then no go. Took the lid off and found that pushing down on the rear connectors gave some relief. Dry joint? By 3:30 I made contact with VK3ZPF, he mentioned that my audio was a bit odd part way through the over, HSWR flashing as I was talking and then it never came good again. 100% HSWR, tuner still finds a match, both front and back no-go. With the provided Yaesu rubber duckie antenna (with 6m extension): 2m appears to be unaffected (1-3 bars SWR), 6m has near full scale SWR, 70cm floats about 3/4 bars SWR.
I don't have a watt meter, [working] SWR meter or dummy load, but I will try and get in contact with the local radio guys in Wagga; and I could probably make up a dummy load with the resistors I have kicking around. I've (carefully) taken the top board out of the 817 and had a look, nothing obvious.
FT-817 Strange Fault - High SWR (HF)
Re: FT-817 Strange Fault - High SWR (HF)
I would get yourself a dummy load and then check. Don't rely on a antenna tuner to check your swr by
and certainly not the almost useless rubber ducky antenna that came with it. Personally I would not even
rely on the inbuilt swr indication but that's just me and my preferences.
and certainly not the almost useless rubber ducky antenna that came with it. Personally I would not even
rely on the inbuilt swr indication but that's just me and my preferences.
73 Phil...VK6ADF
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VK3TST
Re: FT-817 Strange Fault - High SWR (HF)
Yeah, I'm suspecting the inbuilt SWR meter not working as I have had reports of good reception when it was complaining of high SWR. Might be a good excuse to buy / build / fix an SWR meter; I have an old heathkit that I got as a freebie here that's needing a complete rebuild.
Re: FT-817 Strange Fault - High SWR (HF)
Hi Marcus,
Tapping the radio or pushing on the PCB is ok once or twice but I wouldn't rely on that as a good way to stay on the air. Perhaps you're seeing the effects of common mode currents on the feedline? Touching the tuner control cable and seeing the SWR change almost certainly indicates some kind of RF issue and I imagine that once the tuner has found the best match the control cable is siting idle. It shouldn't affect the tuning.
As Phil said, don't trust the rubber duck whip for testing purposes. Whilst it may 'work' it relies on you being in close proximity to the radio or holding the case to work effectively. Indications of HVSWR would not be unusual using the whip.
There are many many ideas on the internet for making dummy loads and SWR meters - don't leave home without one.
Tapping the radio or pushing on the PCB is ok once or twice but I wouldn't rely on that as a good way to stay on the air. Perhaps you're seeing the effects of common mode currents on the feedline? Touching the tuner control cable and seeing the SWR change almost certainly indicates some kind of RF issue and I imagine that once the tuner has found the best match the control cable is siting idle. It shouldn't affect the tuning.
As Phil said, don't trust the rubber duck whip for testing purposes. Whilst it may 'work' it relies on you being in close proximity to the radio or holding the case to work effectively. Indications of HVSWR would not be unusual using the whip.
There are many many ideas on the internet for making dummy loads and SWR meters - don't leave home without one.
Lou - VK3ALB
Being right doesn't excuse bad behaviour
Being right doesn't excuse bad behaviour
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VK3TST
Re: FT-817 Strange Fault - High SWR (HF)
Alright, tested!
160m 4.5w
80-6m 5w
2m 2-3w - this is the band I have mostly used since buying the radio
70cm 5w
Fault developed briefly whilst testing 70cm, SWR went to 3 bars and no RF output. Wiggled my finger in the ACC socket and came good.
Sounds like a temperature triggered dry joint, this is not going to be fun. Lots of SMD's and all on the wrong side of the board. Considering my options, including getting a new 817ND.
160m 4.5w
80-6m 5w
2m 2-3w - this is the band I have mostly used since buying the radio
70cm 5w
Fault developed briefly whilst testing 70cm, SWR went to 3 bars and no RF output. Wiggled my finger in the ACC socket and came good.
Sounds like a temperature triggered dry joint, this is not going to be fun. Lots of SMD's and all on the wrong side of the board. Considering my options, including getting a new 817ND.
Re: FT-817 Strange Fault - High SWR (HF)
Marcus,
It seems that your radio really is responding to a detected high SWR condition. The high SWR condition might be caused internally or externally. Here are a couple of things to check:
1. Your coax patch leads. Have you got intermittent opens or shorts in the connectors? The fault could be external to the radio. Check your cables for continuity/shorts with a multimeter. Wiggled the connectors when performing these tests.
2. Does the fault appear regardless of whether the front or rear antenna socket is selected, or just on one of them? The radio might have a dry joint on one of the antenna sockets, or on the circuit board to which the socket is soldered.
Chas
VK3PY
It seems that your radio really is responding to a detected high SWR condition. The high SWR condition might be caused internally or externally. Here are a couple of things to check:
1. Your coax patch leads. Have you got intermittent opens or shorts in the connectors? The fault could be external to the radio. Check your cables for continuity/shorts with a multimeter. Wiggled the connectors when performing these tests.
2. Does the fault appear regardless of whether the front or rear antenna socket is selected, or just on one of them? The radio might have a dry joint on one of the antenna sockets, or on the circuit board to which the socket is soldered.
Chas
VK3PY