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Ok. Let's see if anyone can give me a tip on where to look for my FT818.
I have a strange behavior on the 2 meter band, the output power (indicated by the display) is not constant when pressing the PTT.
Sometimes it reads 100%, sometimes 30%, sometimes 0. And actually the output power is different, it's not just the display. The SWR is slightly higher at low power, but not significantly.
It's not the antenna: I tried two, and one is a 70cm/2m dual band and on 70cm everything works great. It happens with any mode on 2m and on all other bands everything works.
I suspect a relay, but any tips on what to check would be appreciated.
73, I2OIM
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Are you on SSB mode? That will show fluctuations on TX.
On Sep 10, 2024, at 05:25, Pietro Molina via groups.io <pietro@...> wrote:
Ok. Let's see if anyone can give me a tip on where to look for my FT818.
I have a strange behavior on the 2 meter band, the output power (indicated by the display) is not constant when pressing the PTT.
Sometimes it reads 100%, sometimes 30%, sometimes 0. And actually the output power is different, it's not just the display. The SWR is slightly higher at low power, but not significantly.
It's not the antenna: I tried two, and one is a 70cm/2m dual band and on 70cm everything works great. It happens with any mode on 2m and on all other bands everything works.
I suspect a relay, but any tips on what to check would be appreciated.
73, I2OIM
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It happens with any mode on 2m and on all other bands everything works.
I2oim
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Does it do this on both front and rear outputs?
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Pietro,
Does your display flash HSWR by any chance? My 818 would do this from time to time. I thought something was wrong with feedline, antenna or something else. I examined everything. As a last resort, I restored factory defaults and the problem went away. It seems that software became corrupt due to a power connector and the outcome was the radio software misinterpreting the output power and SWR. When the SWR becomes high (as sensed internally) the radio output is reduced. Save your settings and memory (use CHIRP or some other software for memory) and reset to factory defaults.
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Al Skierkiewicz
WB9UVJ
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I didn't check it. The 2m bans works on the front connector, a will try.
Tnx, 73
Pietro
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@ Al WB9UVJ
No, it neaver succeded. I check antenna connectio tryng wit a different one (2m/70/23cm vertical) and the problem remain.
Some days it work at full power, other days it work bad with the two antennas...
73,
I2oim
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Hi Peter, I had the same problem on the FT817 and I solved it by replacing the Q3003 and Q3005 HSU277 diodes. I hope this helps
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Hi I had a 817ND that 2m tx was not working, I had to replace a diode,
If you look for my post
Dave 2E0DMB
Hi Peter, I had the same problem on the FT817 and I solved it by replacing the Q3003 and Q3005 HSU277 diodes. I hope this helps
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Thanks to both. I'll check the diodes
I2OIM
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@
Thanks Al.
That's what I was hoping for. No luck...
Pietro I2OIM
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Pietro, just for a little more info can you take a picture of the display when this is occurring and post it here?
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Al Skierkiewicz
WB9UVJ
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Which Display? Power, SWR or?
I2OIM
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I got the pin diodes but suddenly, yesterday, it starts to work at full power. Astonishing, disorienting...
I2OIM
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Hi were did you get them from in the end,
Dave 2E0DMB
The radio doesn't want you to do surgery on it! LOL Ken, N2VIP On Oct 17, 2024, at 11:17, Pietro Molina <pietro@...> wrote:
I got the pin diodes but suddenly, yesterday, it starts to work at full power. Astonishing, disorienting...
I2OIM
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Just like going to the dentist. Did Ali Express finally deliver? I’m hoping my battery pack gets her soon. We ordered our parts about the same time. Mike Davis WA1MAD
On Oct 17, 2024, at 2:24 PM, davebb123456 <davidbrowne76@...> wrote:
Hi were did you get them from in the end,
Dave 2E0DMB
The radio doesn't want you to do surgery on it! LOL Ken, N2VIP On Oct 17, 2024, at 11:17, Pietro Molina <pietro@...> wrote:
I got the pin diodes but suddenly, yesterday, it starts to work at full power. Astonishing, disorienting...
I2OIM
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Pietro,
Sorry to have been away for a few days. I looked at your pictures of the display and the SWR does seem a little high. The radio cuts back on power when the SWR goes up to protect the finals. In the photo the radio is making power. Now, many people have reported that the output relay does seem to go intermittent from time to time. I believe that is do to either dirty contacts on the relay or reduced input voltage that is preventing the relay to make the switch. Just for myself, I know the contacts are somewhat self cleaning when the relay operates. Since I have several memories programed, on HF, VHF and UHF, I programmed one memory to use the front antenna connector. By switching between that memory and a normal memory using the rear antenna connector, I can exercise the relay several times rapidly. As a reminder, Yaesu designed the radio so that the front connector is the normally closed contact of the relay. To use the rear connectors, power is supplied to the relay coil. AS this is the most often used output, Yaesu kind of missed the definition of "low power" since the radio uses more power for the rear connector than the front.
I had a unique situation on my radio in that in UHF, the SWR always showed a little higher than the VHF. And it showed different that an outboard SWR meter. So I went looking for an issue inside the radio. What I found was a small cap that must have fallen into the radio during assembly in the UHF SWR circuitry. All of the other parts were correct. So I removed the cap, readjusted the SWR bridge and checked the software. Now the internal SWR meter agrees with an external meter and I no longer have HSWR warnings. My previous 817 also suffered from the relay contact issue.
Good luck
Al Skierkiewicz
WB9UVJ
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As a reminder, Yaesu shipped the FT-817, FT-817nd, and FT-818 with not only a battery pack, but also an antenna collection (2m, 6m, and 70cm) and shoulder strap. They obviously viewed this as a portable radio which could also be used in a shack.
In that context, defaulting to the front panel BNC makes sense, or, at a minimum, isn't a 'mistake' when considered logically.
The power consumption of the antenna select relay is 20 mA/hr ( http://www.ka7oei.com/ft817_pwr.html ), if an operator kept that relay energized for the entirety of their operating session, how much shorter would their operating session be? In un-squelched receive the radio consumed 450 mA, full-power transmit 2,000 mA. In pure, un-squelched RX, it would reduce operating time 20 mA / 450 mA, or about 4.45%. If keying down constantly, 20 mA / 2,000 mA, or about 1%. If we were running constant, worst-case FT8 (15 seconds of RX, then 15 seconds TX, -continuously), then the reduction in operating time would be 20 mA / 1,225 mA, or about 1.6%.
That's a loss of about 1 minute for each anticipated hour of operation.
Is this really something we need to consider as a meaningful "waste" of battery power?
I don't think so, but I understand opinions vary.
/soapbox
On Oct 17, 2024, at 14:05, Al WB9UVJ <markaren1@...> wrote:
As a reminder, Yaesu designed the radio so that the front connector is the normally closed contact of the relay. To use the rear connectors, power is supplied to the relay coil. AS this is the most often used output, Yaesu kind of missed the definition of "low power" since the radio uses more power for the rear connector than the front.
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Pietro Molina
Kevin - K5KTM
M0RON
Al WB9UVJ
Franco Corsi
