Yes, this was the last day of my 3 weeks off the job. Before this holiday I imagined a sea of time to spend with the hobby. But it turned to be just a few hours in the last 3 weeks. There were so many other things I had to finish and of course I spend time with my family because it is their holiday too.
But today I wanted to spend some radio hobby time. You see, I constructed a new shack......well not really. It is near the antenna tower though. It is our new (used) garden shed, primarily for my XYL but we can join her as well of course. It is ideal to conduct some experiments from. Like testing the portable gear.
I do not operate portable often. And so the equipment isn't used for a long time. I changed some things like adding a upconverter to generate continious 13,8V from my portable battery. 11V is just too low voltage to keep an output of 5W from the FT-817. It is the grey box below the red battery. I wanted to test if it generates more noise as normal (it didn't). Watching the photo I now realize that I have to get rid of all the unnecessary connectors and cables I don't really need.
So, I thought to test the MLA (Magnetic Loop Antenna). Homemade a few years ago after many experimentation projects. It is simple, with a unique homemade reduction and added a tune indicator with the use of a simple FSM (Field Strength Meter). It always worked well, but now I had some tuning problems, like something was loose or broken. But at some point it worked. Listen to 20m first, couldn't hear a single SSB signal although I received SSTV on 14.230 well. And signals over S5 on the FT8 channel. Down to 40m it goes, I received OE8XDX and DB7LG as only ones on SSB. Not really strong but very good to understand. I tried to call them a few times but had no luck. From what I heard is that they struggled with low signals as well.
So, I though something was wrong with the antenna again. And tried to tune it with the full 5W FM carrier on it. Suddenly, probabely due to the high SWR, the LCD screen went blank. Did I blew the final? Oh no, every time I switched PTT the radio went off. I saw only 8V on the voltage meter at the display now. Something was wrong with the battery I assumed. After some measurements I quickly determined that the fuse in the cable from the battery to the upconverter had blown. It was a 2A fuse and probabely the high SWR made the current to the final too high. I had no other fuse so it was end of the experiment with the FT-817.
Hopefully there is nothing wrong with the FT-817. I didn't test it yet. I should buy another internal battery as well since the original one is useless after so many years. I can charge it but it will be drained after a few minutes again.I wanted to see what the problem was with my MLA first now. And quickly discovered a bad solder joint at the pick up loop. Have repaired it now. Hopefully it will not break again. In case it brakes again I will have to solder the coax directly on the pick up loop.
I then discovered an old battery in the garage. Quickly measured it still had some juice inside.
Hello Bas, I hope you'll give your MLA another try. Conditions the past two days have seemed very erratic with fast and deep QSB. Your MLA and reduction drive look great and it's obvious you've put a lot of work into them.
ReplyDelete73,
John
Hello John, actually it was more work to build the garden shed ;-). What I still want to do is connect an extra cap with the red switch in series with the variable cap to have 10m band capability. Another experiment would be adding an extra loop in series with the exsisting to extend to the 80m band. Need to figure it out. 73, Bas
DeleteHere's a calculator someone recommended for finding the capacticance/circumference necessary for a loop to cover a range of frequencies:
Deletehttps://www.66pacific.com/calculators/small-transmitting-loop-antenna-calculator.aspx
73,
John
Hallo Bas, aan alles komt een eind, ook aan vakanties. Maar ik snap dat je ook tijd aan je gezin wil besteden. Je bent lekker bezig in de shack. De FT817 is een prima rig daarvoor. En als straks cyclus 25 echt aanbreekt dan kunnen we nog leuke verbindingen maken. 73 Paul
ReplyDeleteIk was juist niet bezig in de shack Paul. Dit was vanuit het tuinhuisje. Mijn XYL noemt het haar she-shed. 73, Bas
DeleteHi Bas, as your holiday ends, mine soon begins. I have two weeks off work from the 20th August and I have plans to play lots of radio with the 705 and Alex Loop. BUT i know that it will turn into lots of non-radio related things instead probably, LOL.
ReplyDeleteGlad to hear you had a nice break and got to play with the 817 & MLA.
Take care, Tom, M7MCQ.
Tnx for the comment Tom, I wish you and yours a happy holiday. 73, Bas
Delete