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Kenwood SP-31Last piece of my Kenwood TS-850-line has arrived! The Kenwood SP-31 speaker. I already had the chance to play with one when the TS-870 for the club was temporarely in my shack. A beautiful speaker, not only to look at, but also the filters do a fantastic job. And most important: my TS-850-line is complete now! I’ve got the TS-850 transceiver, the PS-52 power supply, the SP-31 speaker and the MC-60 microphone!

I always wanted to build a piece of wooden furniture for this Kenwood line. Something that I could put on my desk so the gear is not placed directly on the desk but a little higher. Better view on the display, easier to operate and safer in case if anything wet (drinks) falls on the desk. It should be something fancy like mahogany or so. Nice shiny and chic! Mahogany is too expensive at this time, but I will make something more suitable.

Kenwood TS-850-line

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Yaesu FT-817My precious FT-817 still is lying around in the shack unable to transmit. I’ve studied the service manual and did some measuring around in it. Regular readers of my blog know that a while back suddenly my Yaesu broke down due to shortage. It seems like a capacitor on the voltage input blew and took something with it. I let the input fix by a local service shop but that alone cost me already 75 euro’s. So now the Yaesu is able to receive again, but still no transmit.
My intention is to fix that myself. The local repairman told me it’s probably due to blown finals that the rig isn’t transmitting. That would make me a member of the “Blown Finals Club”. But I’m not quite convinced by his story. When only the finals are blown, you should get a very faint signal as output. But there is absolutely no signal at all. Not even when I take another receiver and poke around with that antenna in the transmit line of the Yeasu, no signal at all. So maybe the oscillator or driver stage must be (also) broken to get this behavior.

This would be my very first big repair job, there for I’m not in possession of various measuring equipment. The only measuring device I have is a multimeter. That won’t bring me very far in this case. Fred, PA3YH has a Multimeter which can measure HF-signals. A RF-millivolt meter, such as referenced to in the service manual. But it has a maximum reading frequency of 100 KHz. The RF-millivolt meter reads like 2,6 volts AC on the output of the oscillator (the service manual says it should be 66mV). But the output signal from the oscillator has a frequency of 65.875 MHz. So it’s logical the meter is not reading the correct voltage.
Okay, so I don’t know if the output of oscillator is correct, but I DO know that the oscillator has output! So I guess now I should look to the first driver stage.
But I think I’ll look for someone with a good scope first. It’s easier to check all the checkpoints in the service manual and also check if they have the correct value.
If anyone has good tips on how to find the problem, let me know!

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A while ago I’ve bought a DSP-speaker from bhi, the NES10-2MKII. The results with this speaker are unbelievable. The background noise is totally pushed away and you’ll be able to hear signals that are normally buried in noise. So the DSP-algorithm is very good. However…… I’m not satisfied with the LF-amplifier in the speaker itself. It hums and makes noises when it has no input. When you crank up the volume too high the speaker starts making distorted sounds. First I thought it was the speaker itself, but when I put the thing inline between my rig and the Kenwood SP-23 speaker the distorted sound appears from the Kenwood speaker. Really unsatisfying when you take in consideration that the DSP-unit itself is doing a great job.

BHI nedsp1061I would really like to add the ‘bhi-experience’ to my TS-850 and TS-450. But I prefer a way without the crappy LF-amplifier from the NES10. I’ve a external speaker for as well the TS-850 as the TS-450. So it would be an option to put something in there. But I don’t want to drill extra holes in those speakers. It would also be an option to put a DSP-unit in the transceiver itself. I read from the bhi-site they have an unit for building in transceiver too: the NEDSP1061-KBD. Although tis unit is mainly made for adding to a Yaesu FT-817 or a Kenwood TS-50, it is possible to build it in other transceivers according to this manual to build it in a TS-440.

Now would it be possible to also build the NEDSP1061-KBD into a TS-850 and TS450? Does it have the same performance as the NES10-speaker as regards to the DSP-functionality and I’m I rid of the bad LF-amplifier behavior this way?

Just some questions and it would be great if someone have already experience with the NEDSP1061-KBD. Let me know!