Amateur Radio Station K6JEB

from beyond the horizon

Archive for December, 2007

Adding W4RT Filters to my Yaesu FT-857D

Posted by Jack on 14th December 2007

Being a proud owner of a Yaesu FT-857D, I have most of the must-have accessories for the rig, but I had one dark secret: I hadn’t yet put in any sort of audio filter. Oh sure, I still think I have pretty good ears. And the Digital Signal Processing on the radio does a pretty good job of taking down the noise and interference. But during contests or pile-ups, or even a busy weeknight, it can be tough to pull out a signal, especially on SSB.Probably long before I even considered buying a Yaesu, I was aware of Collins filters. You can read all kinds of reviews and look at pretty bandwidth plots but until you sit down and actually listen to how much a difference one of these can make on your radio; you most likely think you can live without one.

I shopped around and found the Collins filters from W4RT.com were getting high praise. Earlier this year I purchased an LDG Z-11Pro Ultra Plus from them and I felt quite happy to give ‘em my money again.

The filters are individually wrapped for fresher taste and to keep rotten QRM and QRN from seeping into the package. :)
Removal of the FT-857D top cover is a simple matter of taking off the seven Phillips screws, per the directions in your Yaesu FT-857D manual (page 120).
Once the rig is open, you can see the empty filter slots in the upper-left corner.
The top cover comes off easily once you disconnect the speaker from the rig chassis.
“Gaze into the crystal . . . filter”
The 500Hz filter installed. The 2300Hz filter fits right next to it. The filter boards can go in only one way. If you have difficulty, take a look at the pins in relation to the holes they go into on the Collins filter.

Since I installed the filters, I’ve been enjoying much better reduction in nearby QRM. The 500Hz filter is still wide enough to not ring. And it REALLY works beautifully with the DSP as well as the IF Shift.

The 2300Hz filter makes a slight difference, at first glimpse. But you’ll hear the difference when the conditions get crowded. Also, on transmit, you can select to have transmitted audio pass through the filter, giving your voice signal a bit more ‘punch.’ (update – 20080228):  The sideband filter really makes a HUGE difference!  Now that I’ve had time to use this filter in contests and pile-ups, I can certainly say that without the audio filter, I would not have made many of the contacts I did (including huge pile-ups for VP6DX).  The filters both make use of the DSP and IF shift MUCH more effective.  I’m also noticing that when I turn on the filter, the signal I’m trying to tune-in actually ‘pops out’ and makes copying a LOT easier.  My advice to new and old FT-857D owners: BUY IT!

All in all, I have found the W4RT filters to be a much-needed improvement to my FT-857D.

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Assembling the ATS-3B band Filter Boards

Posted by Jack on 5th December 2007

So on Saturday, December 1st, 2007, I began assembling my ATS-3B QRP Transceiver. I had decided to start with the six filter boards since they each had three toroids and only one SMT component. I figured I’d save the fun part for last (I have come to really enjoy/prefer SMT) :)

This write-up is to record my initial thoughts and show the process for those considering construction of an ATS-3B.

Checking the surface temperature of the electric skillet I use my multimeter to check the surface temperature of my electric skillet. I have found that bringing this warming surface (with the pc board already on the surface) close to 200 degrees Fahrenheit makes the amount of time I need to wave the hot air tool over the components quite short; on the order of maybe ten or twenty seconds.
Craft Mates make an excellent SMT holder I found these Craft Mates bead storage containers at Michael’s Crafts. They keep the contents inside each of the compartments. You needn’t worry about your SMT components getting mixed in these. You can see what’s inside without opening. There’s a spring-loaded latch lock which keep the compartments closed.
null Five of the six band filter boards have an SMT resistor on the side opposite the toroids. I did all five at once time using Cash Olsen’s Hot Air Method. I use the Rival 12″X12″ electric skillet for the warm-up surface. I also use the skillet as my assembly tray because it has nice raised sides.
A close-up of the process This whole process took less than ten minutes. Of course after the solder paste is melted, you should turn off the heat on the warming surface and let it cool down slowly.
Initially the paste will appear a dull grey but will turn very silver and sometimes give up a tiny puff of smoke.
inspection of the connections After the process is complete and the board is cooled-down, you can pick up the pc board and inspect each connection. I use a combination of my lighted magnifier plus a jeweler’s visor to get a real good look at my work.
This is how I wind my toroids. There’s a zen to it actually. Using a chopstick in a nice, place the toroid over the tip of the chopstick and the wire, pull the wire taut, and repeat. My hands stay free and without cramps. I can take a break and go grab another beer. :)
Here’s a finished toroid. Can you guess which one?
When winding toroids, I usually have some music on or something to keep me slightly distracted. This is not a conducive environment for keeping track of windings on a toroid. So I get it really close, and then I scan the toroid my computer and zoom in using any decent graphics program (I use the free Fast Stone image viewer) and count the windings without any pain. I’m usually within one or two windings anyway. Even if you use the pencil+hashmark, it still pays to check your work this way.
The toroids mounted on a band filter board

The through-hole components were quite easy. I’ve done one board per night in less than an hour each. Two more to go (one tonight and one tomorrow night) and then I begin on the main ATS-3B circuit board.

And as I mentioned last time, our dogs, Honey and Shaggy, had decided to show their superdog wrestling skills right at my feet:

Stay Tuned and 72/73!
Jack, K6JEB

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