Month: February 2016

OK, well…I guess I’ll be buying a SignalLink like everyone else, because I cannot get the Plug-And-Play to key up the FT-7900.  No matter what I do, nothing works.  Sure, the PTT lamp lights on the PNP when I engage TX in FLDIGI, but nothing happens to the radio.  And I know the PNP itself works because I’ve been using it for months with my FT-450D.

There’s no rig defined in FLDIGI because there’s apparently no rig-level FLDIGI support for the Yaesu FM rigs at all.  Which is fine, because so far as I can tell, the PNP ought to be triggering PTT just by taking RTS high.  Other than finding the FT-7900R in West Mountain Radio’s compatibility list for the PNP, I can find NOTHING indicating that anyone has actually tried the combination for NBEMS.

I imagine it would work with my FT-857D, but that rig is a little big and a lot overkill for what I want to do with that box.

So I’m going to order a SignalLink and associated cable for the FT-7900, and I’m going to install a PS/2 passthrough connector in the lid of the box so I can easily change from the packet TNC to the SignalLink as required.  I hate doing it by using patch cords but I haven’t found an appropriate switch for a PS/2 line.  Lots of KVMs have them, but again, that’s overkill for what I want to do.

Arghh.

Well, as soon as I made up my mind, I changed it.  I said:

The fuse block is going to go on the sidewall of the box instead of glued into the handle depression in the lid.

Well, no, the fuse block is NOT going to go on the sidewall of the box.  I wanted to put it on one of the short sides for better stability, but the block was just long enough that it wouldn’t lie flat on that side.  So yes, damn it, I RTV’d it into the handle depression in the lid.  But my fuse block isn’t laying on its side, so I think I have a reasonable chance of getting a fuse out if I have to change it.

I also discovered at the training that, while I have a great packet TNC installed, it doesn’t do me a bit of good for NBEMS via FLDIGI.  (Remember, I’m fairly new at this.)  But I was able to receive and send using “acoustic” coupling (e.g., set my handheld next to the mike for receive, and hold the microphone about an inch and a half from the speaker for send).  The next step is to install a sound card interface in the box, and I’ll probably use a RIGBlaster Plug-and-Play for that purpose, since it’s set up out of the box to work with the Yaesu 6-pin data port.  I have one currently installed on my FT-450D for my digital work, so I’ll probably pull that and use the RIGBlaster Advantage that I bought a while back and stopped using because I couldn’t get the COM port splitter driver to work properly.

I’m dithering, then, on whether I should pull the TNC out of the box and install it in my regular go box (which also has an FT-7900 installed) or try to homebrew a 6-pin A/B data switch so I can have both in the same box.  I can’t find anything like that short of computer KVM switches, which are typically too big for my purpose and switch too many things I don’t need anyway.  But I might find an old one and take it apart to see if I can use the parts.

Or maybe I’ll buy a used FT-1900 and hook that up to the TNC as a dedicated VHF packet rig.  I’m still interested in packet, but I think the need for a portable NBEMS-capable box is more acute.

I’ll have more pictures and a schematic after I do some cleanup (need to velcro-tie some wires and do a couple of other things before I’m done, but as proof of concept it worked quite well yesterday — and got some interest from some of the ARES folks, too).

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* I found a newer version of that driver last night and I have the Advantage working with the 450D now, but NOT with port-splitting; there’s no need for it since I already have CAT access via the RT Systems programming cable for that machine, and don’t need to run it through the Advantage.  The one thing I dislike about the Advantage (and all of the old-fashioned RIGBlasters, for that matter) is that I have to run the output through the microphone port rather than the data port.  But that’s a topic for another day.

 

I’m working on the packet box from a couple of posts below.  One of the hardest parts was trying to decide how to bus-bar the power to the fuse block, until I remembered that I had a bunch of “piggyback disconnect” crimp connectors left over from my battery box project last year.

Et voila.  The two fuses on the left are for the negative lines to the radio and the TNC.  Probably overkill, but Yaesu ships their power cables with both lines fused, so what the hell.

The fuse block is going to go on the sidewall of the box instead of glued into the handle depression in the lid.  The more I looked at that in the K4NHA go-box, the more I wondered how he planned to pull the fuses if one blew — it just looks awkward to me.  And I don’t care if the box is 100% waterproof or not, although I’ll use some RTV around the bolt holes just because I have it.  I’m also going to install a third bolt for a common negative post, and I’ll RTV that, too.  All the positive lines feed directly from the fuse block so there’s no need for a common positive post at this point.

While I don’t have everything wired up yet, I’ve at least got the battery power to the main switch and wired through to the voltmeter.

I decided against installing a dedicated RJ45 port and DB9 jack for the radio control head and the computer link to the TNC, and simply installed one of those plastic grommets furniture makers use to run cables through desktops.  Cheap at Home Depot, and took the same 1-1/2″ hole that the fans did.  I’ll just coil the cables up and store them inside the box between uses.

My plan was also to install a dual USB power port underneath the Powerpole connectors.  I’m still going to do that, but I couldn’t get my hands on one in time to finish this up by the weekend.  We have an ARES training session tomorrow featuring NBEMS over packet radio, and they said “bring your rig and we’ll help you set it up for NBEMS.”  Since I have FLDIGI installed on the laptop that’s going with this go-box but haven’t quite figured out how to make it talk to the Kantronics TNC, I thought I’d take them up on the offer.

The main power switch is a 20A DPST toggle, to the left of the voltmeter.  The two toggles to the right are 20A SPST and they are for switching the TNC and the fans separately from main power — for instance, I might want to run voice rather than packet, so there’s no reason in that case to have the TNC drawing power, or I might be outdoors in the cold with the box and not need the fans running.  All the toggle switches came from Home Depot, for significantly less than I could have gotten them from the auto store or a ham supplier.

NHA also used a soldered bulkhead connector for his antenna.  I prefer something more modular*, so I used a DX Engineering “Silver Plated Female SecureMount Bulkhead Connector Kit” and a DXE-532 right-angle connector on the inside of the box.  I use the same combination on my main “home and go box” and it works pretty well there.  I’ll use a short RG-8X jumper cable to get from the radio to the right-angle connector.

Here’s a shot of the inside of the lid so far.  Remember I haven’t wired much of anything yet.

When I’m done, I’ll provide a wiring schematic.  I notice that most hams don’t do that when they post projects, which is fine if you just want to brag about your mad 1337 skillz, but hell on those of us who might want to try building something similar.  And mea culpa on me; I meant to do that for my battery box and I’ll probably do that one of these days, but I actually drew a schematic for this one before I started.  It just needs a couple of revisions and cleanup before I can post it.

More later.

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* I can solder fine, thanks (those Y-connectors for the Powerpole unit are soldered and shrink-tubed).  I just don’t like messing with soldered coax connections when I don’t have to.

20 meter shield for the Raspberry Pi 2 that is set up for digital modes like WSPR.

Would be more interesting to me if it were built for 30 meters.  Seems like nobody wants to build SSB gear for 30 because…well…because SSB voice is verboten on 30, I guess.  SSB digital modes are perfectly legal on 30, but there’s nothing small and inexpensive for 30 meter SSB like there is for many of the other modes.  And now we’re in a circular argument….

I finally got around to buying a Kantronics TNC (KPC-3 Plus) so I could fiddle with FM packet, and was considering how to build a go-box with internal battery power for a spare FT-7900 that I’ve had sitting around (it used to be in the car before I replaced it with the TYT TH-9800) and the new TNC.

So looking around the web for some examples, I found this:  VHF/UHF Go-Box Complete

It’s a nice build, but it has features I don’t need, and lacks other features that I do need.  For instance, I don’t see the point of having the internal line-voltage power supply when you can feed the box from the PowerPoles.  NHA also doesn’t really explain how he gets the line voltage power into the dry box.  One assumes that if he’s added a connector for that on the outside of the box, the box is no longer waterproof (or he’s RTV’d the heck out of it).  Of course, with all the holes cut into the lid, even under the hinged cover, it isn’t really 100% waterproof anyway.  I’d just prefer not to violate the integrity of the box itself.

Since I can charge the batteries through the PowerPoles with my little float charger, or hook the whole thing up to a car battery, dedicated battery box, or external power supply ditto, I’m not going to bother with the line voltage supply.  That removes a couple of switches and makes room for a DB9 connector for the TNC, which will be inside the box with the radio.  Otherwise my build will look a lot like his.  I admit that I’m not sure why he used a TH-9800 for this, unless he’s planning to tote 6 and 10 meter antennae around with him.  My plan is to use a Slim Jim J-pole with the radio and TNC.  I’ve already been using that setup in the shack with the Slim Jim tacked up to the wall, so I know it works.

I’ll have more on that as the build progresses.  I’m still gathering parts at the moment 🙂