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Re: Frequency programming keypad
开云体育What is the app? Assume it's Pocket RxTx? How does the app control the radio? Wired or wireless? Looks like the idea is to use a cat cable & usb OTG adapter I think the OP was looking for something to use in the field to punch in frequencies, as if the radio had a keyboard on the front of it, this is a bit more than that... Ken, N2VIP On Aug 13, 2024, at 15:13, davebb123456 <davidbrowne76@...> wrote:
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Re: Frequency programming keypad
You could always use a android phone/tablet Ptxrx lite app,free of charge, Dave On Tue, 13 Aug 2024, 20:59 Peter Burnett via , <g4bll.peter=[email protected]> wrote:
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Re: Frequency programming keypad
开云体育Hi DaveBHI no longer manufacture that unit it was called a “Radiomate” I have one but it is not working properly, no beeps. I bought it on eBay and I have seen another one come up recently.? G4BLL P Burnett On 13 Aug 2024, at 20:30, Dave Martin <kc7nj73@...> wrote:
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Peter Burnett G4BLL |
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Re: Frequency programming keypad
I'm interested as well. Years ago there was a small company called Stone Mountain Engineering making them and I have to say that they're a wonderful device. A friend told me a long time ago it could be done with an eprom. Maybe there's another way now.
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Joe N1KHB?
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Re: Blown final club? I think I have a membership
The FT817/818 charge circuit would not really cause issues if "overcharging". The radio is built for NiCD / NiMH cells and the charging regime is 14 hours times 0.1C, so 14 hours times 10% of the capacity of the cells. The "fourteen times 10%" is to make up for losses in the charge / discharge process; "ten times 10%" would charge the cells but the process has losses. Hence 14 hours.
However, NiCD cells no longer exist (environment!), and NiMH cells have grown in technology. I think the original packs had a capacity of roughly 700 mAH, so a charge current of 70 mA. Today's cells are often closer to 3000 mAH, and hence a 70mA charge current won't charge the cell in 14 hours, you need much more than that. ?
With a low charge current like this, "overcharging" won't affect the cells unless you do it continuously. The cells will dissipate the energy they can't store. They get warm, but not hot. The amount of energy is not very high.
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The charge circuit is just a current source. If you look at the schematic, it is Q1103 with R1435 defining the charge current and Q1101 enabling the circuit.
There is a second charge circuit, Q1105 and R1436 with Q1102 enabling. This is a trickle-charge as NiCD/NiMH are known to self-discharge. The "green wire" disables both charging circuits (charge and trickle) which is just as well because trying to charge alkalines is likely to cause them to leak. I have changed R1435 to match my cells; you will need to revise yourself if you want to do this, and please mind the dissipation and max Ic for Q1101 and Q1103; I have not blown my finals but I *have* blown the charging circuitry at some time. To add, the FT817/818 doesn't charge 14 hours, but selectable 6-8-10 hours. The result is that even a 10-hour cycle won't get close to charging them modern high-capacity NiMH cells and two cycles won't hurt the cells. We're not talking "ultra-speed 30 minute fill charge", the battery chemistry is 30 years older. |
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Re: Self destruct finals
On Tue, Aug 13, 2024 at 01:01 PM, Peter Burnett wrote:
This has only served to convince me that my old 817 receiver will remain just that.I am pretty sure if you call Yaesu UK they will be able to sell you a FT818 output module that will fit your FT817 and it won't mortgage your house. The techs are pretty nice to work with. |
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Re: Self destruct finals
开云体育Thanks for highlighting the full extent of what’s involved here Geert. I watched a video on UT which covered the physical aspects of replacing the finals but didn’t go in to the re-setting necessary. This has only served to convince me that my old 817 receiver will remain just that.?Cheers 73 Peter P Burnett On 13 Aug 2024, at 11:32, Geert Jan de Groot via groups.io <pe1hzg@...> wrote:
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Peter Burnett G4BLL |
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Re: Self destruct finals
On Mon, Aug 12, 2024 at 09:42 PM, Ron Wright wrote:
What is the part number for the transistor in the FT817/8's PA.? I'd like to get some.You may want to reflect on this one. For one, there have been a number of PA module revisions because the semiconductor devices have changed (the old device is out of production). Unfortunately, the different devices need different matching and hence the matching circuit changed between different revisions of the PA PCB. So, you can't just swap between different devices because the circuit needs to change. ?
At the very least, if you want to order spare semiconductor devices, you must check the module you have to check the devices your module has.
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And there is a second issue. The devices consist of a ceramic substrate with two edge contacts (gate and drain) and a big contact in the middle, that serves as source, as well as heat sink. The source is connected to the assembly to remove the heat as well as provide a good ground contact. Replacing the devices is a non trivial exercise, not to mention the small 0204 devices in the vicinity that fly away if you use hot air (don't ask how I know).
So, replacing the semiconductor itself is non trivial. You probably want to swap the module. And there is another issue. I am pretty sure that, after replacement, you will need to adjust the BIAS settings and adjust the gain of the full TX chain - you need to do this for replacing the devices and certainly when replacing the PA module. All in all, it is not as easy as replacing a 2N2222, it is more involved.
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Geert Jan |
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Re: Self destruct finals
G4BLL, What is the part number for the transistor in the FT817/8's PA.? I'd like to get some. I like dealing with Digi-Key for they do sell what they list, actual manufacture's parts.
On Monday, August 12, 2024 at 01:27:39 PM EDT, Ken N2VIP <ken@...> wrote:
Peter, Pretty much everything you've said is correct, I think you've got a good handle on the situation, BUT I want to point out that our discussions so far have been about Yaesu America, your distributor may have stock in repair boards and may even still be repairing FT-817s. I'd encourage you to contact Yaesu near you and enquirer- you may get lucky and your FT-817 may get a reprieve and get a new set of finals! Good luck, Ken, N2VIP On Aug 12, 2024, at 11:57?AM, Peter Burnett via groups.io <g4bll.peter@...> wrote:
Thanks for your input Ron.? There has been a lot of useful stuff posted on this issue, some of it confusing (to me) and some contradictory.? I wanted to ensure that my 818 was in no immediate danger but should I invest in some replacement output transistors as insurance for the future. This would appear to be a sensible course of action. However, one contributor quite rightly pointed out that there are a lot of inferior Chinese copies flooding the market place. Another contributor suggested a source of supply where it was reasonably certain they would be genuine. Hmm! The second conundrum is it going to be worthwhile to try and get my old 817 back up and running on tx, or just be content to use it as rx only. Is it really going to be a practical proposition anyway? The general consensus is that the 818 board can be “shoehorned” into the elderly 817s, but there aren’t any available and Yaesu can’t advise a delivery date or are not interested ( my interpretation). Another suggestion was to find a company/person willing to produce a short run copy, buy the output transistors and populate the rest of the board as required. I don’t mind admitting this is a non starter for me unless I can find someone in the UK to do the job for me. It is starting to sound like an expensive exercise.? I think the sensible thing at this stage is to sit tight, see if, in fact, the 818 boards become available from Yaesu and someone does succeed in grafting it into a dead 817.? Hope my interpretation reflects the current state of play.? G4BLL P Burnett On 12 Aug 2024, at 01:13, Ron Wright via groups.io <lt_wright_flg@...> wrote:
-- Peter Burnett G4BLL |
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Re: Self destruct finals
开云体育Peter,Pretty much everything you've said is correct, I think you've got a good handle on the situation, BUT I want to point out that our discussions so far have been about Yaesu America, your distributor may have stock in repair boards and may even still be repairing FT-817s. I'd encourage you to contact Yaesu near you and enquirer- you may get lucky and your FT-817 may get a reprieve and get a new set of finals! Good luck, Ken, N2VIP On Aug 12, 2024, at 11:57?AM, Peter Burnett via groups.io <g4bll.peter@...> wrote:
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Re: Self destruct finals
开云体育Thanks for your input Ron.?There has been a lot of useful stuff posted on this issue, some of it confusing (to me) and some contradictory.? I wanted to ensure that my 818 was in no immediate danger but should I invest in some replacement output transistors as insurance for the future. This would appear to be a sensible course of action. However, one contributor quite rightly pointed out that there are a lot of inferior Chinese copies flooding the market place. Another contributor suggested a source of supply where it was reasonably certain they would be genuine. Hmm! The second conundrum is it going to be worthwhile to try and get my old 817 back up and running on tx, or just be content to use it as rx only. Is it really going to be a practical proposition anyway? The general consensus is that the 818 board can be “shoehorned” into the elderly 817s, but there aren’t any available and Yaesu can’t advise a delivery date or are not interested ( my interpretation). Another suggestion was to find a company/person willing to produce a short run copy, buy the output transistors and populate the rest of the board as required. I don’t mind admitting this is a non starter for me unless I can find someone in the UK to do the job for me. It is starting to sound like an expensive exercise.? I think the sensible thing at this stage is to sit tight, see if, in fact, the 818 boards become available from Yaesu and someone does succeed in grafting it into a dead 817.? Hope my interpretation reflects the current state of play.? G4BLL P Burnett On 12 Aug 2024, at 01:13, Ron Wright via groups.io <lt_wright_flg@...> wrote:
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Peter Burnett G4BLL |
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Re: Self destruct finals
The problem was not the internal battery running down to 0 volts, but rather like running down to around 5V or some low voltage.? The PA in the 817 and 818 are wired directly to the power input or internal battery all the time and are not switched with the ON/OFF switch.? Most rigs are wired this way. What would happen at the low out of spec voltage the PA would start to self oscillate on it's own and kill itself.? I am sure this happen to my FT817 when I had stored it with rechargeable batteries, after 6 months turned the rig on and the PA was dead.? When replacing the PA it was advised to reverse the input and output RF coax connections to help prevent this. But I had understood Yaesu in their new redesign f the PA in the mid to late life of the 817 supposedly corrected the oscillation issue, but I also understand Yaesu never admitted it happening.? There were some who took variable power supplies and did verify the PA would self oscillate on it's own.
On Sunday, August 11, 2024 at 03:30:06 PM EDT, Peter Burnett via groups.io <g4bll.peter@...> wrote:
Thanks Ken.? P Burnett On 11 Aug 2024, at 20:14, Ken N2VIP <ken@...> wrote:
The self-destruct finals feature is unique to the original, non-nd, FT-817. Your FT-818 should be fine, but I'd suggest pulling batteries out of the unit if you plan on storing it for an extended period, similar to almost any battery-powered device. Ken, N2VIP On Aug 11, 2024, at 13:57, Peter Burnett via groups.io <g4bll.peter@...> wrote:
-- Peter Burnett G4BLL |
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Flight of the Bumblebees Pictures, Etc.
Flight of the Bumblebees Pictures, Etc ? 120 FOBB Results are listed on 3930scores.com ??85 Bumblebees.?? 35 Home Stations. ? ?Congrats to K0TTW who is sitting at top of the Bumblebee List. ? Congrats to AB8CA who is sitting at top of the Home Station List. ? Check to see all FOBB results (It still open for entries if you are a procrastinator) ? Bumblebee Pictures are still being accepted with an email to ?fobb-pictures@...??? Be sure to include your call sign, name, and location so I can tag your photos properly. ? The 2024 Bumblebee Pictures that have been submitted can be found at ?? ? Next Sunday, 18AUG24, is the annual QRP Skeeter Hunt. 1700-2100 UTC.? Get you Skeeter Number now and participate.? See for information and rules. ? The first Monday of every month is the ARS Spartan Sprint. See information and rules at ?????? ? 72, Jody – K3JZD? and? Phil - K4PQC Adventure Radio Society Trustees |
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Re: Blown final club? I think I have a membership
Which can result in an overcharge depending on what the charge circuit is. SMH.
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Joe? N1KHB?
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Re: Self destruct finals
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On 11 Aug 2024, at 20:14, Ken N2VIP <ken@...> wrote:
-- Peter Burnett G4BLL |
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Re: Self destruct finals
开云体育The self-destruct finals feature is unique to the original, non-nd, FT-817. Your FT-818 should be fine, but I'd suggest pulling batteries out of the unit if you plan on storing it for an extended period, similar to almost any battery-powered device.Ken, N2VIP On Aug 11, 2024, at 13:57, Peter Burnett via groups.io <g4bll.peter@...> wrote:
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