I promise I'm not going CB on you (not that there's anything wrong with that....)  

     Okay, now that I have both a teasing jab at CB, and a reference to a very popular 90's sitcom out of the way, I'll get down to the real business at hand - fun with Ham radio!
     The real reason for this post being titled "Breaker Breaker" is not because I'm trying to jump in with emergency traffic, or talk to truckers on channel 19 - it's because I just took delivery of a bunch of (6) actual breakers today....

     Apparently there were a lot arc fault breakers manufactured that were RF sensitive, and they can end up tripping from the RF produced by our Ham radio stations.  For a lot of people this is old news, but for new hams like me, it is new old news, if that makes sense.  The ARRL has a pretty good write up on it here, which includes contact info for whom to call if you have the variety in question, like I do.    

     The station works well considering that the antenna is the downspout and rain gutter, and the ground connection is a piece of steel re-bar (should we take bets on how long it takes to rust out?)  The radio is just my mobile rig that I pull out of the car when I want to operate from the house.  Anyway, while playing radio this winter, a week or so before Winter Field Day, I tripped the breakers and was reminded about the issue.  They even tripped when doing some digital stuff at 20 watts.  The big problem was that the breakers it was tripping included one of the circuits that includes one of our two pellet stoves that heat the house.  If I am forced to choose between playing radio and having a warm house, the YL will let you know in no uncertain terms that having a warm house is more important (I can't argue with that since we have 2 young kids.....)
     So, last week I finally got around to e-mailing the two gentlemen listed in the ARRL article, and within a week I had my new breakers, free of charge, sitting on my doorstep.  Now I just have to find time to...  *Ahem*  Now "my certified electrician" has to find time to replace these breakers (all kidding aside - changing breakers isn't a DIY project if you don't know what you are doing - consider yourself warned!) Once that's done, I'll be good as new, playing radio AND being warm!

     One of the first parts of my mobile shack project that I shared was how I made the panel to fit in the space under the climate controls in my car, to give me a location to mount the control head of my radio.  It looked pretty good, but over time, I started to notice 2 things:

     The first thing I did was to pop the old part out, and clean all the adhesive off the trim where it had been mounted.  While this was off, my first order of business was to fashion a way to attach the new panel a little more firmly.  

     I decided to go hard core, and screw something fast.  I had a piece of aluminum bar left over from another project.  I cut it to length, so that I could screw the ends of it to the back of the trim on either side of the panel, and then I would be able to use the metal to attach whatever mounting arrangement I came up with for the panel.  I didn't even bother taking the bar code sticker off, because this would end up hidden behind the new panel part, so in the pictures showing the aluminum bar, you can plainly see the label proclaiming that this is, in fact, the brand of aluminum bar you can get at any of the big box home centers.  Where did we buy our random stuff before Lowes and Home Depot?  Oh wait....the hardware store!  Almost forgot about that place!

     After tracing the outline of the old panel, I drilled a hole in the upper left hand corner of the new one, for the bulkhead RJ45 connector.  After having it in the lower left on the first one, I realized that I wanted more wiggle room for my fingers on the buttons on top of the radio, so to shift the radio down, I needed to move the mic jack up.  I also decided that I would use the same screws that attach the radio head to the panel, to attach the panel to the aluminum bar.  This way all the mounting screws would be hidden from view, and I would only need 2 screws to attach both the panel and the radio head.  With this thought in mind, I drilled holes in the new panel for the screws to pass through and hold the remote head mount.  I also drilled a larger hole for the control cable to come through to the back of the radio head.  I then pressure fit the part in place, to use it as my drilling guide to transfer all the same holes to the aluminum.

     I didn't randomly pick my hole sizes.....I used a drill bit that fit my 10-24 tap, so that the screws that hold the panel and the remote head mount could just thread into this, instead of having to work with nuts, wrenches, etc. in the small tight space behind this location. After doing this, I popped the panel back in place, verified that my holes lined up, and then put the screws in.

     After doing this, it was just a simple matter of feeding the control wire through, hooking everything up, and popping the control head back onto it's mount:
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     After a very cold Winter Field Day, the weather got mild fast, and it rained hard for a day, so our snow is almost gone, and the temperatures are back above freezing.  As promised, this means that I am now revisiting the unun that I recently installed in my vehicle, to do more antenna tuning.  In a previous post I explained the slight lack of clarity in the directions that came with the unit, and talked about my hunch about a better way to go about the process.  
     I basically decided to "start from scratch" so that I could talk you through what I did, what measurements I took, etc.  With that being said here we go.......

     The directions that come with the unit I purchased tell you start by tuning for lowest SWR without the unun in line.  Since I was working with my 40 meter Hamstick, I decided to target the center of the voice portion of the band (I don't plan on doing digital modes and such while driving!)
     The analyzer I have is the RigExpert AA-54, so I exported the charts to my computer after taking my readings - it was my first time playing around with this feature.  I didn't realize how powerful it was!  As I tune the rest of the Hamsticks I might take my laptop along out and use it in the "live" mode.  After tuning for lowest SWR at 7.212 this is what I had:

    Some interesting notes on this.  The range of the graph covers just slightly more than the 40 meter band.  The SWR at its lowest is 2.05:1 which will work, but isn't great.  The 857d doesn't like SWR levels more than 3:1 per it's manual, so that puts the 3:1 frequency range at 7.138 to 7.282 which is a bit short of covering the whole voice portion available to Extra's.  
     Also, take note of the subset box.  You can see that at the lowest SWR the impedance of the anteanna is 58.5+j38.6.  In my mind this seems like a funny place to start matching from.  My gut (Elmer's jump in if I'm wrong!) tells me that I should be starting from a point where the antenna impedance is pure resistance, i.e. starting from a resonant point, instead of a low SWR point.  I actually had two of these points "relatively" close to the low SWR point.  One of the neat things with loading the data from the analyzer onto the computer is that I can show you those two points on the same graph:

     The first resonant point, above,  is actually just below the lowest frequency on the scale.  At the very bottom of the scale, we're almost there at 7.7 +j0.2 Ohms.  This would be a 6.48 SWR at resonance.  
     The second resonant point, below, is up at about 7.261MHz (thats as close as the resolution of this graph will show anyway). At that point we've got an impedance of 125.1 +j2.2 ohms for an SWR of 2.5:1 which isn't horrible.  

    So where should I tune my antenna to, before starting my matching?  

     From an SWR standpoint - awful, but I'm still hanging my hat on the fact that it's better to start at resonance and then match from there.  This however, is where the directions that come with the unun could leave you wanting.  At this point they say just click through the setting and use the setting with the lowest SWR.  this makes it sound like one of these setting ought to get you close to to 1:1.  This isn't the case.  I ended up re-graphing on each setting, and choosing the setting that had the lowest dip, the closest to 7.212.  This was actually relatively far from where I was.  I had to graph with a really wide frequency range to find the setting with the lowest dip:

     So after doing these steps, with the unun in line, the lowest SR is 1.13:1, but all the way down at 6.972 MHz.  Time for the final Step.

     So, for the final re-tuning of the antenna - re-tuning to get that 1.13:1 SWR point up to 7.212 MHz, which meant shortening the antenna a bit.  After a number of consecutive shortening and re-measuring activities, I ended up here:

     So after all that, was my thought process sound, and is my final result a good one, or have I unknowingly made this way more complicated than it needed to be, and screwed something up without realizing it?  Hello?  Is anybody out there?
     Oh - on a final note, I re-tuned my 75 meter Hamstick too.  Resonance was very close to low SWR on that one, so the adjustment's weren't nearly as extreme, or as exiting, so I didn't bother sharing the graphs of those.