Still a bit chilly...

I went out with full intention of getting this antenna going.  After I put sheets on the clothesline my hands were already chilly.  What I decided to do was start fiddling with my support pole idea.  My plan is to make a pole by connecting 2"x2" pressure treated end to end until I reach the height I need to sufficiently support the center of the doublet.  Because it will be guyed I am not too concerned about strength.  What I will do is place four twelve inch 1"x2" around each joint to provide support.  It won't be pretty but should do the job.  I will guy the pole at the top and again at some midway point.

My biggest dilemma was what to do at the top to hold the antenna in place while still providing for some up and down movement as the antenna flexes with the wind in the trees.  In the barn I found a 3' fiberglass section from a 20' Shakespeare Wonderpole fishing pole that I used to use for portable dipole setups at parks.  The tip had broken off when I dropped it from the second story roof peak one time (on purpose...I thought it would land flat but it didn't).  Anyway, I plan to drill a 1/2" hole in the top end of the top 2x2 section and glue it in place.  I also drilled a 1/2" hole in the top of the plumbing T so it will slide over top and sit on the top of the pole.  The photos below of my plan explain this better than my words can.  I just did this in a scrap of wood to prove to myself that it should work.

The T is able to slide up and down on the fiberglass shaft by as much as 2'6" and I will put something on the tip of the fiberglass shaft to prevent the T from sliding up and off the top completely in strong winds.  Now I need to investigate what length of pressure treated 2x2 I can get (10', 14'...16') because I'd prefer not to use 8' lengths so I can have as few joints as possible in the mast.

The other thing I did was measure out the antenna wires on the ground at 73' each.  I left them on the ground for now and called it a morning.  If it warms up I will go out and solder the center connections.  I can make and put the antenna up without the support pole.  The pole is just an addition I will install to steady the antenna in the wind I will inevitably get here in farm country.  I am also still trying to figure out how I will get the para cord over the top of the 60' tree.

Cheers for now,
72/73 de Scott

Doublet length

So I had decided to install the 40m (and higher) doublet to save on weight even though I had the space for the 80M doublet.  My original thinking was that some day it might be neat to compare the EFHW 80M antenna with the 80M doublet since my QRP Guys tuner that I plan to use with the doublet does not support 80M.  Then I read that a doublet will actually provide better performance on a given band if the antenna were resonant on odd harmonics for that band so I thought that since the doublet length is not critical I could play with the length to give a boost to a favourite band.  I knew there are websites out there that will calculate this for you so I went searching.

I looked at a couple and then found this page on Spookmate.com.  I was able to put in the frequency for 80M in the calculator and see what my options were.

As you can see where the harmonics are listed that 10.5 is the 3rd harmonic.  This is very close to 10.110 where I like to operate on 30M.  I then adjusted the frequency at the top until the 3rd harmonic was where I wanted it to be.  3.37 MHz does the job and the legs of the doublet would be 72.9' long.  The key with the doublet is that the antenna is not resonant on 80M if I want to use 80M.  It is not (although it may be too close) but I am not using the antenna on 80M so I'm not concerned about that.  Really I'm taking advantage of the 3rd harmonic which I would not have if I were to put up the 40M doublet.

The harmonic frequencies gave me no joy for the 17M band which I also enjoy so I will go with the 73' length.  This is what I plan to experiment with when I put this doublet up, hopefully this weekend, weather permitting.  I'm not sure how much luck nor do I have a way to get tangible results but my random wire is currently working well on 30M only so I can compare the two.

Now you may remember I was going to avoid the 80M doublet because of weight concerns but I have come up with a plan for a guyed wooden support pole.  It'll be a little "interesting" looking but I think it should do the trick.  I'm fine tuning my idea in my head daily and am almost there.

Cheers for now,

72/73 de Scott

Doublet Dilemmas

When it comes to installing my, yet-to-be-built, Doublet antenna my biggest concern is weight and whether it will need a center support.  If it does need a center support what will I use and how strong will it be?  My original intention was to install an 80M doublet just because I have the space but that antenna will be significantly heavier than one for 40M.  The QRP Guys Multi Z Tuner that I just completed only tunes 10-40 so an 80M doublet is definitely overkill so it only makes sense to only put up what I will need in the immediate future.  As well, I have my random wire that will be modified to be my 80M antenna with the addition of the QRP Guys EFHW mini-tuner kit for 80M.  Once these projects are ready to test I will do so using my FT-817.

Here is the image from the QRP Guys website:

If I still need support for the doublet I have a couple of options I've been contemplating.  I could use a guyed wooden support made from pressure treated 2" x 2" or I could use a guyed PVC water pipe mast with about the same 2" diameter.  I live in a windy location but the center of the doublet will be somewhat shielded from the wind by my small barn but I still worry about it.  The wind on the antenna wire is not my concern as much as the window feedline is.  It is both heavy and easily caught by the wind.  Only putting it up will tell how these factors play out in real life.  The height this antenna will be remains unclear but I am hoping around 40' up.  One end support is the 40 foot TV tower attached to my house and the other end is a tree over which the para cord will be tossed so the actual height of that end support remains to be seen.

The center of the antenna, since I am unable to 3D print at the library is going to be something I have used before for dipoles, although this one is a bit larger.  It is a PVC water line "T".  It's durable and lightweight and I can easily drill or melt holes for the wires to pass through :

Cheers for now,
72/73 de Scott

QRP Guys Multi Z Tuner completed

Carrying over from yesterday the last thing I had to do with the tuner construction was to wind and install the transformer.  There are 3 windings on this transformer: a primary with a center tap and 2 secondary windings of different sizes.  I wound it all up once but it was too sloppy so I removed all the windings and made it a lot tidier and tighter.  Below are the 3 stages of installing the first, second and third windings.

 Once that was wound I had to ensure all the enamel was off the leads and tin them.  I then fed them through the appropriate holes.  When I did this the first time I saw that there was some enamel still not scraped off so I pulled it back off the board and did a better job of stripping the enamel with the Xacto knife.  I then reinstalled it in the holes and soldered them in place.

Now the final touch was to install the PCB washer to hold the transformer in place and put the rubber feet on the back.

I have also included the circuit design which is also available in the assembly instructions on the Multi Z Tuner page on the QRP Guys' website.  

My next step now is to build my doublet and get it up in the air.  That will be happening in the next week or 2 weather permitting.

Cheers for now,

72/73 de Scott 

QRP Guys Multi Z Tuner started

I got down to making the QRP Guys Multi Z Tuner 10-40 this evening.  The first thing I noticed was that my eyes really aren't what they used to be.  Even with glasses on I could have really done with a pair of these:

                                  or this    


My ageing eyes aside, I dove in and got started.  The project does not have a lot of components so the construction isn't too difficult however there are some challenging bits to keep you on the ball but the instructions are top notch.  The first step is joining some PCB pieces together with solder to create the "chassis".  Once complete I began installing parts per the checklist:

Aside from the standard components there is a small toroid to be wound with a center tap.  This went fine.  It's been a while but it all came back pretty quickly.

By the end of the evening I had everything together except for the most challenging part, the large transformer.  For that I will wait until my eyes aren't tired and there is some natural light.  Here is the finished product for this evening.

Back at it tomorrow.  Cheers es 72/73 de Scott

During these times...Projects

With everyone pretty much stuck at home in isolation it's a great opportunity to think of antenna projects and other things like that.  I installed a random wire antenna last fall but with my Z11 tuner is not tuning it at all (I'm not sure if it's broken or just a bad setup) I can only operate it on 30M which is fine by me as it's one of my favourite bands.  That being said, i ordered 2 little kits from QRP Guys.  The first kit was the EFHW Mini tuner.  There are 2 versions to choose from and I chose the 80M version.  This little rig will hopefully help me turn that random wire antenna into a dedicated 80M EF antenna.  I will have to lower it down and add about 10 feet of wire to get to the recommended 135' starting point.  The below photo is from their site.

The second kit I purchased was for the Multi Z Tuner 10-40.  My plan with this little gem is to use it with the doublet I plan to install over the coming weeks.  I have the wire and space to install up to an 80M doublet and I figure I might as well go that route even though this tuner will only help down to 40M.  This kit is a bit more involved but shouldn't be too bad since there are no SMT components involved.  Here is the photo from their website:

A few years back I bought a good length of 450 ohm window line for a project that never came to fruition so now I can use it for this.  I have heard a lot about these antennas and the multi-band properties make it attractive.  I've always been one for using tuned dipoles but in my windy location they are a challenge to maintain.

I did have a plan to have the center support insulator 3D printed.  I found a nice one on  Thingiverse but the local library, which has the printer, is closed until further notice so I may just have to fashion one up.

I will post my progress with the Multi Z Tuner as I tackle that kit first.

Cheers es 72/73

Scott

Spring is Here Today

With the lengthening days, warmer temperatures and the reality of being stuck at home due to work policies surrounding the COVID-19 "situation" has me thinking about radio a lot more often these days.  Last weekend I decided to do some outdoor operating using my random wire antenna.  The temperature was 4C so it was quite bearable and I also had a nicer view than I would have had I sat inside looking at the barn wall.  Basically I sat just outside the barn window and ran a short length of RG-174 out the window to a chair.  The other end was connected to my LDG 9:1 Unun.  I set up and in 30 minutes I had 3 nice contacts on 30M and two of them were 2xQRP which always makes me extra happy.

 I have my rig, battery, key, clock and ear buds in a small Pelican case which I lined with "Cubed Pick Foam" from the local Canadian Tire store.  This allows me to keep everything organized and works a lot better than the computer carrying case I used to use.  The battery is a 7mAh and is heavy and would crush the other things in my bag.  Now it's held snugly in place by the foam. 

I have a small collapsible camping table and it worked great for keeping things off my lap.   I enjoy being outside again and with the COVID crisis looking like it's not going to end any time in the near future it will give me a chance to operate more often that I otherwise would have time for.  I am also taking some of my spare time to brush up on my code rx speed.  I started out using the standard G4FON program I installed years ago but have been found two other resources that are extremely helpful at increasing character and word recognition which will help with head copying and get past the barrier that exists when you try and write everything down during a QSO.  One of these resources is Kurt Zoglmann's Morse Code Ninja site which is full of links to Youtube videos he's created with all sorts of words, prosigns, call signs, etc at various speeds for aural practice for word and character recognition.  He has learned Morse Code to the extreme where he has even had books converter to code and listens to them.  He's pretty hard core on code.

The second site is called Morse Camp and it is quite simply laid out and easy to use for word recognition.  It plays words for you at a predefined speed (default appears to be 30WPM) and keeps repeating them until you think you know what it is and hit the space bar.  This shows the word or letter/number combination and you indicate with a left or right arrow whether you were correct or not and it moves on.  You can select word length but as you progress it increments on its own.

I think this seclusion we are all experiencing can be a challenge for those who suffer from anxiety or depression, let alone the rest of us who are also feeling the stress of the unknown be it job security, financial security, or even toilet paper security, apparently.  They say the key is to make sure to get out of the house for a walk or a hike or some other stress relieving activity.  Radio is that for me and I plan to do it as much as I can fit it in.  I don't need to sit there for hours...30 minutes is plenty and even just 1 QSO makes me happy when operating QRP.

72/73 de Scott ve3vvf