The Dummyloads

Where ham brains come to fry

Where ham brains come to fry

Amateur Radio

Kids and Amateur Radio

I’ve recently had a break through with the kids.

As a dad, one of the great struggles in life is how to help your kids develop their God-given talents.  This must be balanced with not losing yourself at the expense of your children believing the world revolves around them.  OK. . . this isn’t a parenting blog.  It is possible that we won’t agree on this, but. . . I think we all want to share what we are passionate about with our kids.  I enjoy the outdoors, hiking/camping, and amateur radio.

My daughters are forever telling me radio, is for boys.

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My Rig Expert AA-230 Broke!

When I was evaluating who I was going to purchase my Rig Expert from, I spent some time studying up on which vendor I should buy from.  You can get them from DX Engineering, PNC Engineering, Amazon, Giga Parts, etc.  I chose to order from PNC Engineering because of this statement from their website. (italics added for emphasis)

Why Buy From PNC Engineering?

PNC Engineering covers all RigExpert Analyzers under our United States “in-house” warranty center. Out of warranty repairs may also be contracted through PNC Engineering. RigExpert products purchased from other vendors must be serviced in Canada or in the Ukraine where RigExpert Analyzers are manufactured. This will require the customer to pay the shipping costs of their product to one of those out of country locations. With PNC Engineering your shipping expenses are considerably less, and shipping times much faster due to our ‘local’ U.S. location. 

I mentioned in my initial assessment of the analyzer that it had given me infinite readings initially.  Being a newb to this tool, I just assumed that I had neglected to fasten the N to SO-239 adapter correctly.  I finally got it to give me a flat reading on a dummy load and was happy with the measurements.

My friend Myron WV0H mailed me a few N adapters and 50 ohm loads.  No longer would I need to do SO-239 to PL-259 to BNC.  The adapter stack was getting out of control. . . So I connected the N to SMA and an SMA 50 ohm load.  Infinite SWR.  Hmmm. . .  Well, the loads are ham fest deals so maybe its a dud.  Lets try another.

Infinite.

OK. . . lets do a dummy load I know works.  So I do the N to BNC adapter.  Then a short coax jump to my dummy load.

Infinite.

OK. . . lets do a known adapter stack that has worked previously.

Your guess is correct.  Infinite!

Then I started loosening the threads on the N connector and I got an accurate reading.  Hmmm. . . this is not good.

**********Do NOT EVER do what I am about to do***********

I turn off the machine.  I take the adapter stack off and look down into the N connector.  All looks normal.  I then take a screw driver and make contact with the center pin.  It moves!!  It moves a lot and I am not putting any effort into touching it.

******You CAN DO everything below this line safely************

So I fire off an email to PNC Engineering.  They send back a form letter that is intimidating.  I kindly respond with the situation and assure them I’m going to mail this thing back for repair under warranty.  A few pages of paperwork and $20 in mailing and insurance later, the device is in the mail to California.

A few days go by and I get a confirmation they received it.  The next day I get a note that they are going to repair it under warranty and send me a new one.  I am looking forward to it arriving!

So. . . I’m hear to tell you that PNC Engineering is good to their word.  (Although the shipping time is a week)  It’s possible I could have just returned it via Amazon and bought another.  Maybe I’m not getting a great deal since I had to pay shipping.  I really like the device and have LOTS of plans to measure stuff and report back!

KF5RY

My Rig Expert AA-230 Has Arrived

I cannot express to you how excited I am about this thing.  Unfortunately I have a grand total of zero N type connectors or devices that have N type connectors on them.  Fortunately Rig Expert provides an N to SO-239 adapter.  I can get from SO-239 to pretty much anything else I might need.

An example of what you can see with a Rig Expert.

Strangely upon getting this thing I had a heck of a time getting it to give me a legit measurement.  For some reason I kept getting an infinite measurement.  The first thing I wanted to test was my dummy load.  No luck.  Then I decided I wanted to see what the Smith Chart looked like on some conventional Transformers I had built some time ago.  I know that the inductance checked out on the windings, but I had never had a measurement device capable of showing me if it actually worked.  So I found a 200 Ohm resistor to test my 4:1 conventional transformer.  This should give me a reading pretty near 1:1 SWR.

Infinite.

Maybe I got a bad resistor.  After wiggling things a bit and trying a new resistor.  BAM. . . I have a reading.  It checks out.  I go on the the 2:1 transformer, etc.  All tests come out showing that I did in fact make these things correctly!!

If you can read this, you will now know how bad the match is on my 630M antenna

The next thing I do is put the analyzer into the front end of the receiver I built so that I can peak the input filter to be right at 7 MHz.  It turns out I was off by quite a bit!  I made some adjustments and will have to get back to you on whether it makes a difference in receiving actual Amateur Radio frequencies.

I go on to measure my 630M antenna.  I’ve known for a while that the phase of Voltage and current have not been right in sync so my tuning network was off a little.  I had tuned it and thought I had it as close as I could with the scope match.  Turns out as I had my rig expert attached I was able to get the waves in phase.  YEAH!  Unfortunately the magnitudes are not equal, but hey #firstworldproblems.

I plan on working on a better matching network for the 630M set up eventually.  I would sure like it to take up a little less space and I would like to put a little more power into it.  As it stands now my ERP is in the micro watt power level.  It would be great if I could get to milliwatts.  🙂

OK. . . More things to measure. . . I will keep you all posted on what I find!

KF5RY

 

Rig Expert AA-230 Zoom

For sometime I have had a MFJ-259B that I had purchased from an SK estate.  I have treasured the device for a number of reasons.  I knew what I had paid for the device was helping that ham’s family and I felt like I needed to honor his memory by using the analyzer.  Use it I did!  KB5NJD even helped me mod it so it would give us readings down to 470 kHz and I could tune my 630M antenna.  As my knowledge has improved, I came to find that there are a lot of things this model of antenna analyzer does not do and that made me think about getting a different device.

One:  It doesn’t resolve the sign of X.  i.e. is my load inductive or capacitive?  W2AEW has a great video on how you can actually resolve the sign of X using a smith chart using an MFJ 259B style analyzer.

Two:  The oscillator in the machine is not particularly stable in my opinion.  i.e. what freq I was measuring was in doubt by up to 20hz.  This isn’t a deal killer for measuring impedance in the field, but is frustrating in a lab environment.

Three:  The freq. knob is too sensitive in my opinion.  I suppose it makes sense given the tuning range within each band the analyzer covers, but I wanted a little more precision.

Four:  All it provides is Freq (approximate as noted above), SWR, R and X (unresolved whether it is positive or negative.)

Again — As a new amateur, it is perfectly adequate as an antenna analyzer.  But I wanted something a bit more capable.  As it turns out a friend has an AA-600.  He was showing me his conventional transformers and how he could measure the frequency response with the AA-600.  Not only will it define the sign of X, this thing draws a Smith Chart.  It will auto sweep over the entire spectrum of the oscillator enabled on your machine.  You can do live measurements where it will show you the rectangular format of impedance and the vector form of impedance.  This is a genuine scientific instrument.

Now the question is what frequencies should I cover?  I genuinely only have an interest in HF, BUT satellite contacts are interesting. . . and I’ve recently started doing some VHF fox hunts with a local club.  At some point I’d really like to build some kind of 2M yagi.  If I was doing satellite contacts, it would be ideal to have a 440 beam as well, but the cost differential and the likely hood I would ACTUALLY build such a thing. . . I’ll probably just by a satellite antenna, it’ll be close enough.  🙂

If I decide I really want to experiment at 440 MHz I can always up grade later.

 

KF5RY

Where Does The High Voltage Come From In Mag Loops?

For a long time I have wondered WHY do people always scream a warning at you if you plan on using a small magnetic loop.  “Be careful, there is a lot of voltage across the capacitor!”  yeah, yeah. . . OK, whatever. . . I’ll be careful.

But Why?!?

I asked a number of friends.  I heard a lot of explanations.  The one that stood out to me was that a mag loop acts like a auto transformer.  uhh. . . I’m sure someone reading this is going, “yeah!”  You could have told me that it has to do with a wind storm on Mars and particle entanglement.  This seemed just as plausible to me.

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Tuna Tin 2 Finished

As you may remember I left you at a metal can with a hole cut out to an incorrect size and then mashed over.  You may also remember that there were a few components that I needed to acquire to complete the kit.  While I definitely had a stock of BNC panel mounts, I did not have a supply of SPDT switches.  This involved me scouring

the interwebs looking for inexpensive, panel mount, SPDT switches.  I ultimately chose to order from danssmallpartsandkits.net.  If you are thinking that this guy must be a real niche market seller and cater to his customers. . . You’d be 50% right. . . It’s definitely a niche market!  From what I can gather he is a nice guy, but he has rules that must be followed.  Read carefully and follow the instructions.  I’ve never had a problem.  I also always order a bunch of other random parts I don’t “need”, but hey. . . next time when I need an NPO bypass cap, I have a stock of them.  This is a practice that was recommended to me by an elmer some years ago.  It’s why I have parts on hand. . . not always enough, but sometimes enough and sometimes enough to make it inexpensive to order a couple other parts.  Get what you need plus 2-3 items you don’t need, but are generally speaking useful.

So a few weeks pass by and a boring, worn package shows up.  In it are my parts.  They smell as if they have been living in a smokers attic for at least a decade, but they seem to pass the test of working and that is all I need!  The next step is getting the case ready for the board.  I installed a coaxial power jack from my stash, 2 BNC panel mounts, and the SPDT switch.  I choose to wire up all of the internal components so that when I am ready to connect the board there is little work to be done.

This is where I made my second mistake of the build.  If you follow the manual, you will build the transmitter.  Then when you are done they will give you some options to improve the performance.  I read the manual in advance and had opted to install the circuit for preventing chirp ahead of time.  IF one were to build this radio and intend to build it with this mod installed from the beginning, one would not burn themselves with a soldering iron while trying to put an electrolytic capacitor between the coaxial power and a ground lug on a BNC ground lug because that capacitor is NOT necessary assuming the anti-chirp mod is installed. The joys of homebrew!

Anyway. . . I had the can wired up and it was time to start on the board.  The manual has great step by step instructions.  I won’t belabor them other than to say that in the last step, they have you run a capacitor between two terminals near an inductor on the bottom of the board.  If you read the manual in advance you would choose to put the capacitor in before the inductor.  I think it looks nicer and is less likely to short out any traces.  It also fits through the hole just fine if you put it in ahead of time and just bend it over out-of-the-way.

The last step was to build up the home-brew anti chirp mod.  It’s a simple circuit and I had all the parts on hand thanks to some prior orders from kitsandparts.com.  See how my advice from earlier has paid off in this build!  If I had it to do over again, I would use fewer of the manhattan pads.  I laid it out exactly as the schematic showed, but you really only need about 5 islands.

The rest of the build was uneventful.  I made a short video to show the first smoke test, but unfortunately I must have hit the slow motion button as the video is completely unwatchable and 20 minutes long for something that took about 2 minutes.  You’ll have to just enjoy the pictures.  It does work and I hope to make an actual contact at some point when the bands are cooperative!

More projects are in the works.  Stay Tuned!

KF5RY

 

 

Flight of the Bumblebees

The FOBB is a contest put on by the Adventure Radio Society.  These are the people who also host the spartan sprint once a month.  The idea is to get portable and operate your radio.  The FOBB and NJQRP Club Skeeter Hunt are the events that I actually learned radio doing!!  I’ll never forget the first contest I took part in, I worked Greg Lane N4KGL.  How he copied anything I sent and the fact I copied anything back is a miracle!  But. . . I still follow Greg on Google+ and we trade emails occasionally.  He has been a very helpful elmer over the years.  You’ll hear him in my video!  (This is actually just a bizarre coincidence!  I happened to hit record right before he responded to me.

JD (K5HH) has been showing me up by Vlogging.  I doubt I become a Vlogger, BUT. . . I did make a video of the contest and figured I would share with you.  Check it out, share with your friends.  Tell me what I can do to make it more useful for the upcoming Skeeter Hunt in the comments below!

 

Tuna Tin finished post coming soon!

KF5RY

 

The Tuna Tin 2 Build

Trying to figure out the center with the intent of cutting out and around

I mentioned previously that I had won a tuna tin 2 at a NORTEX QRP meeting.  Well, I’ve finally started building on it.  Step 1 is to read the manual.  I know. . . shocker. . .

The Manual is pretty straight forward, but I was surprised to learn that it doesn’t actually come with all the parts required to make a working transmitter.  You need your own antenna jacks, your own T/R switch, and not surprising. . . Your own tuna can.

For those of you unaware, my wife (KG5WCI) is a vegetarian.  Before we got married our prenuptial agreement consisted of this.

  1. I promise not to cook bacon or eat tuna in the house.
  2. She agrees to never have a dog that she carries in a purse.

Now. . . before we continue I think I need to address the elephant in the room.  Many people feel like I made a poor bargain.  But lets be real. . . when I got married my diet consisted of frozen Tony’s pizzas, Burger King (nearest fast food), and Jersey Mike’s (around the corner from work).  So its not like I was cooking a lot of bacon.

Back to radio!

You can see I left an edge which in retrospect was an error.

As you can see, its not like I can run out to the store and buy a can of tuna.  Consuming it at home is not in the cards and consuming it at work, well. . . thats complicated.  Primarily because I’ve not made my own lunch in at least a decade and given rule number one exists it’s not like the YL is going to make it.

Luckily. . .

I have friends.  A friend at work was listening to my dilemma and rather than running scared, as one should do. . . she mentioned that the next time she makes tuna casserole she will bring me the empty can and even rinse it out. (So as not to even come close to rule number one. #blessed)  This actually worked out incredibly conveniently as this friend and her husband are expecting now and canned tuna is expressly not permitted for expecting mothers.  Not to mention, she is likely to enact rule number one in her home at least for the next 90 days.  🙂

Chicken of the Sea topless and bent over

A week or two later a chicken of the sea tuna can wonders into my life and the adventure it seems is officially ready to start.  The first step was to map out the can and figure out the dimensions and how the top will fit mechanically.  The manual gives a couple of options, but I’m enamored with the concept of the full open can.  This means the bottom of the can needs to be cut out.

Here my friends is where I exhibit the first word in Amateur Radio.  What I should have done was put the PC board on top of the can and got a sense of where the hole in the can needed to be.  i.e. how big the finished hole should be.

THE tool for cutting metal

Instead. . . I tried to leave a little bit of the can so I could mount the PC board to the can.  Unfortunately after cutting the can out, I discovered that I couldn’t orient the board in a way that did NOT short out a trace.  In addition, the edge of the PCB will go right to the edge of the can no matter how big the hole is.  There is no need for “structure” to attach it to.

It was time to cut a bigger hole.  Unfortunately once I had a hole, it was nearly impossible to cut more metal with a nibbler.  It was just too flimsy and wouldn’t “bite” off, which means I just had to bend the metal over.  Not an ideal solution, but it worked.  We are off to a good start.  Hole is cut and its time to mount the hardware.

More to come soon. . .

 

KF5RY

Camping and Radio

Some friends and I decided to go on a camping trip recently. Camping in June, in Texas is generally NOT a great past time. BUT. . . My friend’s dad had passed away recently and we all felt like we should get together and enjoy nature. Much as his father had.

As with all camping trips, on my list of items to pack is a radio and an antenna. For this particular outing we were going to be at Huntsville State Park in Texas. Since I was the only amateur on the trip, I opted for a small footprint antenna and brought my Buddistick to pare with my KX2.

We arrived late in the day and were greeted with some interesting signs. . .

Like all good trips we had a lot of fun.  I managed to set up my buddistick and do a lot of CQing.  Unfortunately our location was not very favorable.  We were in a low spot and the antenna was vertically parallel and near a very tall tree.

I’m confident that some of my radiation went directly into cooking some of the grubs in the tree.  I called CQ for about 20-30 minutes the first night and managed to only work one station (XE1XR).  While he didn’t answer my CQ, I did work him.  I shut down for a couple hours and came back around midnight Central (0500 UTC) and called CQ again for about 1/2 hour on 30M.  Not a single spot.  Good SWR so I’m not sure what went wrong other than the location.  I did enjoy tuning around the band late at night.  I don’t do this much, but I heard an “F” Station and some “I” stations.  They obviously didn’t hear me, but it was fun to have a chance!

I forgot to take any pictures of my set up.  A couple of noteworthy things you would have seen in my picture. . . had I taken one.  The picnic tables at Huntsville State Park are extremely thick concrete tables.  I couldn’t get my clamp to open up big enough to go around any part of the table in order to mount the antenna.  I was also very close to the water and therefore not very high.  So I mounted the antenna to a handicap railing at the base (read bottom) of the stairs up to the vehicles.  Again. . . not a great location, but it is what I could do with what I had. . . Next time I’ll bring the PPD.  There is plenty of room in most campsites to set that up.

Since the bands were not hopping I opted not to do radio and instead went fishing on the 2nd night.  Where I ran into this guy. . .

As you can see I made it home to type this, so it all ended OK. I’ve never seen one in the wild and never dreamed I would be so close to one in the wild.

KF5RY

How To Set Up a Park Portable Doublet

We had our park outing and I took some time to make a video on how to set up the park portable doublet.  If you have any questions on how to set it up or make your own, let me know in the comments below.