Showing posts with label soldering. Show all posts
Showing posts with label soldering. Show all posts

Friday, 17 April 2020

Antenna Launch Success

I lowered my random wire antenna this week so that I could make the length a little less random.  I added 8' to it to help avoid half wavelengths on multiple bands by using a chart I found on this website.  The chart at the bottom shows you the wire lengths to avoid depending on which bands you plan to use.  You can visit the page for an explanation of the chart but basically you want to choose a length where the fewest amount of colour bars are present.  I chose somewhere just above 135'.



I lowered the antenna and added the length of wire to it and I was hoping to get it anchored higher in the tree with the newly purchased fishing reel and slingshot from Canadian Tire (Curbside pickup, of course) so I let the support rope come all the way down.  Bad Idea.  I was quite disappointed at the lack of punch this slingshot gave me.  The wind was also working against me.  I tried a few times and from a few different angles but it just wasn't working.  What I ended up doing was using the fishing reel attached to a screwdriver stuck in the ground (thanks Michael, ve3wmb) aimed at the tree top and I created a sling with a piece of broken brick and 6' of para cord.  I tied the fishing line to the brick also and then I rapidly started spinning the rock in an overhand fashion (think David and Goliath) and let the rope go at just the right time for it to sail towards the top of the tree taking the end of the fishing line with it.  This really did the trick.  It took a few tries before I was happy with the placement and height but once it was there I let the weight of the brick bring it to ground level where I detached the brick from the fishing line and tied a new rope to the fishing line and pulled it back up the tree and over the branch and down to me.  I wrapped some tape around it to help keep it from getting snagged in a notch or branch. I could then attach the antenna to it.  I pulled it up using the antenna rope and it was perfect.  I was very happy.  I seemingly bought a slingshot for nothing but you just never know.



Once my Random wire was back up it was time to get the rope in place for the doublet I plan to put up on Saturday.  Now that I had the method down pat it only took 2 tries to get the fishing line over the top of the tree my doublet support rope will be draped over.  Now on Saturday (tomorrow) I will lower the random wire because the doublet will pass over top of the low end of the random wire.  I'll attach the other support end of the doublet to my TV tower at 40' and once up I can raise the random wire again and I will have 2 antennas up...an all band doublet that I will use from 10-40M and an 80M end fed once I get the final toroid from QRPGuys in the mail, whenever that is.

I'm excited to try this doublet fed with balanced window line and the QRPGuys MultiZ tuner.  I'm hoping for a better match than I was getting on the random wire.  I will know tomorrow and there is also the QRPTTF (To The Field) "contest" all day tomorrow.  I say "contest" with quotes because it's low pressure which is right up my alley.  The theme this year is OPERATE FROM HOME.  Do not go out to parks etc but just go out in the yard instead because of the COVID-19 isolation rules currently in place.

That's all for now,
Cheers es 72/73

Saturday, 28 March 2020

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

Tuesday, 24 March 2020

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 

Monday, 23 March 2020

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