Radio Station Rebuild

[PanBiker]

As reported in the other thread, I have now deployed the linear PSU after one or two modifications. Ideally I need to get some heavy duty spade terminals for the power lead for my HF transceiver, they are currently bare ends which will be better terminated in spades. The PSU is working OK though, fan ticks over all the time and is silent running and the unit is considerably less noisy on the bands from an RFI point of view.

[Stanley]

Pop round and look in my terminal kit Ian......

[PanBiker]

Thanks Stanley but I checked last night as a little light bulb came on in my head. Found some in a box of bits I packed up 20 years ago. You never know when they will come in handy.

[Stanley]

That's why my treasure chests are so full!

[PanBiker]

My main station transceiver (Yaesu FT-897) has developed a fault, it has gone "deaf" (insensitive on receive) on the VHF bands. After a bit of investigation the fault turns out to be the ceramic IF filters on the main board in the transceiver. These are small plastic encapsulated filters, the originals fitted by the manufacturer are made by TOKO and have been found to have been encapsulated in a type of plastic that retains moisture. As the equipment cycles through heat and cold during normal operation, residual moisture within the plastic condenses and effectively rots the component from within. The fault manifests as salts which appear on the outside casing of the filters. It's well documented on the internet and YouTube so I have ordered up some replacements of a different make, they are type and pin for pin replacements. I will document the repair over in the homebrew thread as it's under the lid repair stuff.

The filters have arrived but after a thorough search I realised that I no longer have all of my anti static bench mats and ancillary earthing gear. I don't want to cause any static damage when I disassemble the transceiver so I have ordered up a small anti static mat suitable for my bench top, it should arrive tomorrow. I still have my wrist straps and a few leads which I always carried in my outside service kit for field service.

[Stanley]

I always knew you were a live wire.....

[PanBiker]

Just realised that I posted my transceiver and computer communication problem in the wrong thread as its station related, never mind.

Replacement lead turned up the other day, 9pin mini DIN from the transceiver to a serial converter opto isolated USB plug. This end makes the USB appear as a standard COM port. Biggest problem was finding where it lived within the devices in Windows 10. I have a six way hub plugged into the ex firewall box and it sits on one of those ports. Took me about 10 minutes to sort out which one was allocated to COM3. The transceiver can link at up to 38400 baud so I set the COM port to the same, 38400baud, 8 bits, no parity and 1 stop bit, no handshaking protocol required.

When I start my data modes client software now it starts receiving on the same frequency that my transceiver is tuned to, selecting a different band or frequency within the software will be tracked by the transceiver and it does the same the other way, software follows any setting I do directly on the radio. I now have about 100 different data modes to play with including Contesia, Domino, RTTY, Throb, Thor, PSK, Olivia, MT63, Navtex, Wefax, CW and even some video data modes.

[Stanley]

Crankshaft making is simple compared to this. Deep respect!

[PanBiker]

A while since I have posted in here and it's directly related to my last post in the thread. The kit and caboodle noted above all stopped talking to one another and this time it has taken about two days (or sessions in the station) to sort it out. I think it went up the swanee after the last Windows update.

It forgot which COM ports were allocated to the various devices. Anyway the failure has made me update the data comms program that I use which has two components. One for integrating with and controlling the transceiver and the other that handles all the various data modes. With a lot of trial and error and individually testing the separate component parts of the system I have discovered that now I have to power them up in a particular sequence to get them to work. The software that interfaces with the transceiver is first, followed by the USB Signal Link which is effectively an opto-isolated sound card and then finally the mode control bit of the software. If I do them in any different order I don't get the audio feed from the transceiver data port and the visual waterfall display of the signals on the PC.

All this is complicated by the fact that I only have one spare USB port on the converted Firewall box that I have re-purposed for use as a PC. I have to use the powered hub to expand the number of ports. One of which has to be allocated a new COM port number above the standard two provided by the OS (COM3) in my case.

By the time I had sorted it out today the HF bands were dying from the grey line effect as we rotated into darkness so signals were few and far between to have a proper play.

[Stanley]

Funny thing about this post is that as before, I am about to make a crankshaft and it's child's play compared to the above. Didn't understand 90% of it.

[PanBiker]

Aye, and I wouldn't know where to start with a crankshaft.

[Stanley]

.

[PanBiker]

My equivalent for homebrew.

[Stanley]