nq4t.com:

Station Page Updated

2023-01-21T17:33:03+00:00

I’ve finished updating the station page with previous rigs I owned along with pictures.

Sudden RF In The Shack

2023-01-20T16:21:22+00:00

Updated since first posting

We all hear about it, we’ve probably experienced it, and we’ve all done our fair share of fighting with it. So what happens when RF decides to suddenly appear in your shack? How did I solve this latest problem? How the hell did I even notice it in the first place?

Last night while on a weekly video chat with some other hams, I decided to fire up the rig and run some FT8. Everything seemed normal until I went to tune my antenna. I was greeted with funky operation from my rig, and the sudden death of everything plugged in to that USB hub. That one was easy; turns out the shield connection to the USB Hub (which has seen much much better days) had broken from the board. The solution was a 40 minute operation where I removed the old, short, flat USB cable; and replaced it with a spare. Nothing complicated here, just a simple cut and solder job. Being essentially a glorified electronics technician by trade for almost 20 years, I learned my way around a soldering iron. The tight quarters of a small “travel” USB hub did add to the difficulty, but I’ve got the small tips needed for the job.

This went smoothly. After wiring up the new cable I plugged everything back in and not only did it work; but no more cutting out on TX. But there was a new problem, one that most hams probably don’t have in their shack.

I was getting RF in to the audio system.

My shack does double duty; it’s both a shack and an office. Since I’m an audio guy at heart, I keep my “good” sound system down here. Sometimes it’s nice to listen to something while working FT8. But during the test TX for the hub, I noticed the other RF problem. My audio was buzzing before cutting out. It will do this on 17 and 15m; due to the fact I do have an antenna practically running over my head. But not on 40m; and not enough to make the audio cut completely out. It wasn’t a problem the other week, so I knew something had changed.

My first step was trying to see where the problem was coming from. Was it the headphone amplifier, the pre-amp, the DAC, or the EQ? I turned volume knobs down and quickly determined it was either the EQ or the DAC; and watching the status of my devices along with the DAC display told me it wasn’t that. It left one culprit, my Sansui SE-8 Graphic Equalizer. This thing has had it’s issues in the past; both from RF and age. I blew the spectrum analyzer circuit years ago with a 10m FM transmission; watching all the bars max out and blink before dropping silent. No big deal. It was also the source of some of the buzz on 15m when TXing; since that’s one of the few times the spec-an on it registers any activity. But this buzzing and going in to it’s power-on-reset was new, especially on 40m.

I checked a few things inside, rearranged some wires, and verified I still had ground connections. All of that was fine, no change there. But what changes had I made since putting the antenna back up and getting the FT-1000MP on the air? Well, nothing; at first. But I recalled some behavior that lead me to my next path, the antenna. I had noticed that when my tuner wasn’t properly tuned; I’d get more buzz. I run a balanced-line fed doublet; and then I remembered I had risen and lowered the antenna due to bouts of wind recently. I went to the “interconnect” I have from the tuner to the feed-line coming inside. The level of noise was not dropping nearly as much when both sides were connected. AH-HA. I bet one of my solder joints broke.

I wish I could explain why I soldered my feed-line vs crimping it; it was just something I felt like doing. I’ve actually built two versions of this doublet, my original from 2015 and a replacement in 2018; but I kept all the balanced line. Sure it might look rough and be kinked in spots; but it’s still perfectly usable. In 2018 I had one solid un-spliced run on my antenna; it performed no better or worse than the previous one with splices everywhere. I had once read the most important thing when working with this stuff, aside from keeping it away from metal, is to maintain the spacing of the conductors. This was one of the reasons I stuck with the stuff; not only was it’s performance suited for the application, but you can actually splice it back together. There’s no worry about water ingress damaging it like coax, so even the old pieces I tossed under the shack for storage were easily able to be put back in to service.

How do I keep it from falling apart and stranding my antenna in it’s raised position? Zip-ties. I run a couple of zip-ties through the “windows” to act as somewhat of a physical strain relief, but mostly backup support. If things broke at a splice…the ties would still allow me to lower the antenna.

So, I went outside, loosened one leg of the antenna, and began lowering it via gentle tugging on the feed-line. It was then I saw it; one of the splices had broken. “This explains everything,” I thought to myself. The one side’s solder joint was still strong, only the one had failed. It was the last one of the repair job, so I was likely tired and having issues getting it to flow; that solid core just sucks up the heat and the flux core in my “antique” solder probably isn’t much good anymore.

I cut the wire from the center insulation enough to jam a crimp splice on to it, making sure to keep the overall length matching the good leg and crimped it down.

Of course, while doing this; the wind decided to blow the feed-line out of reach while working on it. It was probably too windy to safely keep the antenna up, so I’ll have to wait and confirm my repair worked. However, I’m really confident it will do the job. The other splice was still intact and since the radio was still receiving things; I knew the patched-up leg wasn’t an issue.

Update: With the winds diminishing after the sun went down; I pulled the anntenna back up to operating position and confirmed the problem had been solved. No more buzzing on 40m and my expected tuning solution had been restored.

Mirroring Page Up

2023-01-19T03:47:48+00:00

I have completed (I hope) modifying all of VK7ZJA’s pages for mirroring and have created a page where I will list those and future mirrors. The link is in the sidebar/menu. 73.

Jason-VK7ZJA Has Passed

2023-01-18T20:51:12+00:00

I have just received word that Jason/VK7ZJA passed away on the morning of 17-JAN-2023. I never spoke to him, but he did write a very detailed page of modifications and technical documentation for the Anytone 878 DMR HT; as well as a few others.

Though I currently don’t own one, I may in the future; and the amount of work and information Jason put on to the page is too valuable to lose. As a service to the ham community, I am mirroring his pages so that they may be reliably available in the future (or for however long I can keep my hosting). I am currently working my way through modifying all of his HTML pages to facilitate mirroring, removing external and unnecessary file hosting links, and adding SK notices. All of these will be collected on a page when the project is finished. However, the 878 page is complete.

Jason/VK7ZJA’s Anytone 878 Page

FT-1000MP MKV DVS-2 Article Posted

2023-01-15T05:58:05+00:00

One of the reasons I started this site back up was to have a place to write about my experiences building a digital interface to the FT-1000MP MKV and some of the lessons learned while doing it. So it makes sense it was one of the first things I did after the long process of building the site.

Read it here.

Why The DVS-2 Port Is Better For Digital Modes

2023-01-15T04:05:58+00:00

Recently over the holidays I took possession of a Yaesu FT-1000MP MARK-V. It’s an “extended loan” arrangement thanks to a couple of guys from the local club, KG4NXT and N7QLK. One of the reasons this rig was available to hand-off to me is they are serious FT8 operators; and they claimed they could not get the MKV to operate FT8 reliably. I took this as a challenge. I poked around the internet and found that many indicated they had similar problems operating the MKV on digital modes; and a little more searching showed why.

The Packet Port

Conventional wisdom says to use the PACKET or DATA port on your radio. On a few of my previous rigs that lacked an internal USB codec, this is how it was done. Both of these rigs were also iCom. It’s also not uncommon for the audio on the this port to only be available in a data mode as opposed to normal LSB/USB mode. But the hangup with the FT-1000MP is that this port is “locked” to LSB mode. It is literally designed to be just for packet communications, which usually happen in LSB mode.

But while the default mode for the PKT mode is software-locked for LSB, there’s a little trick hiding in the menus; User Mode. It is possible to specify a custom “User Mode” for PKT that you activate by holding the button for .5 seconds after entering the mode. Page 18 of the manual even talks about setting the User Mode to PS31-SU for USB mode. KN4LF even confirmed this in a 2004 mailing list posting. He even mentions the very confusing fact that the radio will continue to indicate LSB mode even when in User Mode set to PS31-SU. The sheet of paper clipped to the manual (as I did get the physical book) which talks about doing FT8 on this radio said to leave User Mode off.

So, at this point, I was pretty sure I’d cracked the problem. It was in fact a menu option that was getting missed compounded by bad information from the radio. I wouldn’t have to resort to the universal hack of interfacing with the MIC and headphone jacks. I just had to wait for the parts to build my interface to arrive. When they did, I wired everything up, set the radio’s User Mode to PS31-SU, and was working FT8 reliably. All I had to do was flip the main and sub VFOs to User Mode rather than let WSJT-X do it. Even this could be set-up to take advantage of the “front/back” VFO feature you get when tapping a band button a second time; as they remember the previously used mode. I think the radio would even flip to the “back” VFO when the frequency was set over CAT. Either way, I was off to the races and operating FT8; right?

Well, not entirely.

PKT Filtering

One of the issues I became aware of after a day or two was the IF filtering in PKT mode. The MKV has no shortage of filter configurations as you can see from the image taken from the manual; and even those can be configured from within the menu. But take a look at the PKT options. The widest you can make this is 2.4khz. Since my previous rigs were either barn-door wide or at least 3khz; this meant I was missing activity above 2500 on the FT8 spectrum. People do operate up there, so it might be nice to not exclude them. But, thankfully, my desire to DIY/hack together everything I could for this radio lead me down another path, the DVS-2 port.

Any Port In A QSO

One of the things on my list was to see about home-brewing a DVS-2. I didn’t feel like spending the money to find one on that auction site, in fact I refuse to do any business with that place to start with. I knew the port had some additional control lines other than just audio and PTT, so I did a little digging around to see what they might do. That’s when I stumbled across VA3CR’s page (SSL expired) about the DVS-2 as well as GM0ONX’s page about an interface that used the DVS-2 port. Both pages provided information about interfacing with this port, with VA3CR’s page providing a truth-table for the control lines. Though I’d originally planned on making a hardware device for voice-keying, this was just single-tracked thought. Both of these pages gave me the solution I really needed: just interface with the DVS-2 port. The muting of the microphone when keying the port properly would avoid issues I had with my IC-725 of needing to unplug the microphone, it would allow me to work digital modes with wide filtering, and it would allow easy operation of software voice keyers, like N1MM, in a contest in a seamless fashion. Audio from the PC when the DVS-2 port is triggered, audio from the mic when I key up. The interfacing was also quite easy. While I would have normally provided some isolation on the key lines; the DVS-2 port being designed for an external device made me skip all of that. In fact, GM0ONX’s diagram of driving both control lines from the RTS line along with a transistor for PTT seemed too good to be true.

Now We’re Cookin’ With RF

The results with this method were absolutely outstanding. I think the screenshot speaks for itself; a nice flat response all the way to 3100 and beyond, right to the limit of 5000 the software will handle. Of course, I have my “Normal” IF bandwidth set to as wide as I can get it. I can let WSJT-X set the modes of the main and sub VFOs to USB; and all I have to do is disable eDSP so it’s not filtering/modifying my transmissions. Although, even if I forget to do that; it doesn’t affect FT8 operations.

I’m not upset about all the work I did to get the thing going with PKT. While I’m sure PKT mode is nice for packet; I’ve only actually run packet once doing APRS on 30m. Even if I wanted to do that again, I could still do it through the DVS2 port. I could look in the manual to see what, if any, advantages PKT offers for actual packet. But I did it through Direwolf on my IC-725 which had zero special features. All in all it was a great learning experience all around. I have a fantastic rig that’s ready to operate just about anything I want it to do. It’s a really nice rig for being a few generations back. I can understand why people who have them are reluctant to give them up.

Welcome to the new NQ4T.com

2023-01-14T20:46:54+00:00

Hi,

I’ve decided to revive the website. I had no real content on the previous one, so we’re starting fresh. Please be patient as I work on getting everything up and new stuff finalized.

73, NQ4T