Monday, June 24, 2013

More Fun with End Fed Antennas Part 2

This is Part 2, Part 1 may be found here:

There is was, early (like 03:00 early) Sunday morning, and I was stuck with a film canister full of fail. I thought that maybe if I let the goop inside dry, the SWR problem would clear up! Makes sense right?

After waking up very late Sunday morning, I decided to check out the SWR, and it was still high, but not as high, 2:1 as opposed to OMG:1. I decided to wait some more, but in the mean time, I had a couple of other things I wanted to try. First of all, I wanted to try and build the antenna inside a sturdier box. Something that wouldn't let the antenna connector rotate, like the film canister does.
After wrapping and prepping a second iron donut/capacitor combo, I checked SWR again. Instead of going down, it went back up! over 4:1 this time. Time to cut my losses. I chopped out the matching unit, and opened it up, check out what I found:
It is green
Let me assure you, that things were not that color when I put it in the canister! Figuring this was a "Well there's your problem!" type moment, I prepped a small radio shack container I had left over from a previous antenna project. I stuck an eye-hook in one end, drilled out the other, and affixed a BNC on the cover.
EFHW Box Mark II
after buttoning things up and ensuring that the internals were shorting themselves out, I deployed it, and tested it.
EFHW, 20m model, DEPLOYED!

Boom, Match!

I got everything set just in time for the afternoon thunderstorms to move in and ruin the radio fun...
no more QSOs just yet, and I'm going to make some more refinements, but as it is, it works!

Next up, EFHW and W3EDP Showdown at the Shack in the Back!

Sunday, June 23, 2013

More Fun with Endfed Antennas Part 1

This is part 1.
Click for Part 2
and Now we even have a part 3!

I'm participating in this year's "NJQRP Club Skeeter Hunt" as a skeeter, and I decided to limit myself to one band and one antenna, mainly for simplicities sake. I don't have a multiband QRP rig, and I'm figuring 40 will be dead or noisy while the sprint is active, so 20m it is! Because I'm limited in both power and frequencies, using a dedicated antenna makes sense. I began researching antennas, when twitter gave me an idea.

W0EA is an awesome ham. So far, I've only worked him once. I hope to change that though. He regularly builds things, and has given good reviews about the various kits he has built. Recently, he decided to make a very small very portable station, choosing for his antenna an end fed wire with custom tiny matcher. He calls it, the "Micro-Matcher". The Micro-Matcher is basically a shrunken version of the Par-End Fedz matchbox.
Parts List:
  • 35' 1" of antenna wire, I used wireman #544 , 14 gauge Flexweave,  with the Army Green vinyl cover. Good stuff!
  • 1 FT50-43 core, the biggest different between my matcher and TJ's. he used a smaller size 37 core. I have some 37's, and I have no idea how he wrapped 27 turns on it. 
  • length of enamelled magnet wire, 24 gauge. It's what I had in the shack.
  • 1 fujifilm film canister. Old school! 
  • 1 BNC connector
  • 2 UMHW pulleys, used for an end insulator, and suspension point for the antenna.
  • 1 150pf capacitor. Mine is marked 151J, making it a 50v NP0 ceramic disc cap. I wish I had a higher voltage rated monolithic cap, but I decided to give it a go. 
The eldest child came outside to help me build the antenna last Friday when her sisters fell asleep. She's been a good helper in my antenna building efforts. 

Cores and Cap

I had "fun" looking for the cap. Some time ago, I purchased several ceramic disc assortment from Radio Shack, I sorted some of them, but have a drawer with nothing but disc caps! Fortunately, I'd already sorted out some 150pF caps.

Notice the size of the core, FT37-43s are even smaller.

Before I wound the iron donut I decided to go ahead and cut the wire and prep it so that the kiddo could stay involved. She helped me cut and prep the half wave section of the antenna, notice from the pic below that I didn't solder the wires, they are merely twisted together. This was strong enough to allow for testing, but temporary, so it was pretty easy to trim to match.

End Insulator, held by 1st harmonic

Iron donut, wrapped! 

I wrapped the primary and secondary on the iron donut. The secondary on this one goes on first. It's 27 windings, and the primary is 3 windings. in this picture, the short leads are for the secondary, the long for the primary. When it got to this point Friday night, I had to go in because the skeeters were about to carry me away, and the kiddos were waking up from their nap hungry for supper. I went to bed hungry for QSOs...

hooked up for preliminary testing.
Saturday morning, I headed back outside with the kids, and we played around, then I went to the shack, and spent about 30-45 minutes hooking everything up. I had time to deploy once, and check the SWR, before going to work. It was high. I posted my results to Twitter, and made plans to cut some wires when I got home.
talkin' shop Saturday morning

While all the cool hams went about participating in Field Day, I was at work. Next year, I have GOT to take FD off! I bided my time at the office, and when I got home, I couldn't rest until I got out to my shack and got to work matching the antenna.

That which I trimmed
I made it a point to have the antenna preset in the air so that I could easily get it up and down for the matching process. I cut the ends of the wires, re-twisted them onto the end insulator, and measured the reflected power with my trusty NoGA QRP wattmeter. It took about 45 Minutes to get the match to look like the pic below.
We have a Match!
funny thing, as I was trimming, I noticed a definite change in received racket with each snip. When I got the final trim done, I even noticed a few stations still operational on 20m for Field Day.
I tuned to a dead spot on my dial, and attempted to make a test video. I wasn't happy with the way it went, so I reset, and started filming a second time, check out to see what happened:

That was the first live QSO with the new antenna! WOW! how can you argue with results like that?
So now it's time to button things up. I get out some DAP sillicone and the big boy soldering gun. First I permanentified the end of the antenna, soldering the twists so they won't come undone. Then I made a mistake...
Thinking that the DAP was ok for antenna use because I didn't notice a strong vinegar smell coming from it, I decided to squeeze a bunch into the film canister, and around the connector. It's an insulator right?
I knew something was wrong because as soon as I got everything together, the racket quieted down, and I couldn't hear anything, a quick press of the key told the tale. My near perfect match was gone, and I was defeated.
to be continued....

Wednesday, June 19, 2013

New W3EDP Deployed.

Sorry Central FL folks, it looks like my desire to deploy two W3EDP's caused a tropical storm :) Andrea was named the day after I successfully deployed W3EDP antenna number two. It runs North/South (NS).
Some notes,
So far, tuning is similar to, but not exactly like the East/West (EW) antenna.
Here's how they differ in configuration:
  • The NS runs more like an L antenna than the EW. The far end of the NS does drop down about 6-8 feet but it finishes its drop significantly higher than the EW. 
  • The NS Feedline has 1 extra bend in it. It goes up from the tuner, bends to the eave, and chicanes out of the soffit into the sky at about a 60-70 degree angle. The EW antenna only has one chicane out of the soffit, and goes up at about a 60-70 degree angle.
  • The EW runs flattish (sag in the middle, but not enough to count) at height. See My "Yearly W3EDP Antenna Post" for a diagram of the shape of the antenna. The NS gets to a little below the height of the EW and slopes up to significantly higher than the EW antenna. I'm not able to precisely determine the difference as the far end of the NS antenna isn't very accessable.
  • The NS antenna touches the tree it's mounted in at the far end. This probably plays the single biggest role in changing the impedance of the antenna. I tried to keep it off the limb, but can't because of where I can mount it. It was pull the far end over a limb, or cause the feedline and antenna to orient at an acute angle.
Some beauty shots:
Sighting up the Wire

Close on the feedline

Transition from Feedline to Antenna

The Thin White Line about midframe is the Antenna
 Of course, now I must confess to being the worst ham in the world, because while I've deployed this antenna, and I've tuned it up, I've yet to sit down, focus, and make a QSO using it and comparing it to the EW.


construction notes:
both EW and NS are exactly alike, the wire came from the same length of Wireman #523 ("Silky" see, the "Feedline" section came from the same roll of Wireman #553, both antennas use banana plugs from the same Radio Shack, and they both use Army pants buttons for the end insulators. I made them both the same night, to sell at a conference. The EW has been deployed longer, but the wire is still bright and has weathered well.

Monday, June 17, 2013

Mrs. Happy

I was sitting there in Church wondering what the scene must have been like in the Lord's presence Saturday morning. Jesus is there, and a sizable crowd has gathered some sitting and some standing, at the "pearly gates" awaiting something. I imagine that many of the faces I see are familar to me, maybe not as I knew them, but I know who they are, I've known some of these people all my life.
  Suddenly, a voice comes up from the edge of the crowd closest to the gate, "Here she comes!" As one, a great chord is struck, and crowd stands stands, faces the gates, and the crowd sings as one:

"Praise God from whom all blessings flow,
Praise Him all creates here below,
Praise Him above ye heavenly host,
Praise Father, Son, and Holy Ghost.

Know that song? I've sung it after communion service in churches all over the place, even sung it in Haitian Kreyol. The first time I remember hearing it though, has been at First Christian Church of Cheneyville, La. Mrs Margaret "Happy" Tanner struck the chord every week, we all stood, and all sang it together after communion service every week. Today however, Mrs Happy is the one coming thru "the gates", she's being welcomed into the Lord's Presence. I'm so glad to have known her, and I'm on the edge of tears thinking about her.

There's no tears left for her though. She won't cry, nor does she feel pain. Her arms are better, and her heart is healed. She doesn't look the same, but we will know who she is, and as she looks around, she sees many faces she knows.

I imagine the first person she recognizes is Jesus. I imagine the embrace, and the thunder in his voice "Welcome home, my good and faithful servant". I imagine she'll see Mr Buster, big happy grin on his face. She'll see other friends, some family, and faces from the far away places, people who were saved because of the time, money, and prayers she put into the Lord's work.

It's great there.

Here we mourn.

Not as others mourn, though.
Even now, our mourning becomes a song:

Praise God from whom all blessing flow...

Edit to add, Mrs Happy's obituary can be found here:

Wednesday, June 5, 2013

Hamstyle Recycle

Much of Amateur Radio relies on using, or reusing things in ways which the equipment designer didn't intend. I've seen rectifier diodes used as variable capacitors, small signal diodes used as voltage doublers, high speed switching transistors used as buffer amps, and oscillators. I've even used flourescent light bulbs to test for Radio Signals emminating from my antenna. That's where this piece of Vintage Junque comes into play:
I got this for free when visiting a fellow ham, and he said "It might work..." I plugged it in and PPPPBBBBXXXZZZZZZZZZZZZZZT! went some electrolytic capacitor in it.

Ok by me, it has tubes and sockets, and a power transformer inside! I decided to dismantle this stately relic from bygone days in between QSO's while hangin' out in "The Shack in the Back". If I can't bust the pile up, might as well bust up a pile of junk!
Once upon a time Heathkit was a company that "Made builders out of ordinary people" and I've got to admit, most of the time, I'm pretty ordinary. Looking inside the monitor, we see a plethora of old mil surplus parts. That is correct, one of the things that made Heathkit possible in the era of time in which it existed was the presence of a large and cheap supply of surplus parts.
Nothing like that exists today.
I suppose that's why Elecraft costs so much.
 Inside this station monitor you find several interesting things, notice how big the carbon composition resistors are, and how they are %10 tolerance resistors. Don't find them in Radio shack these days! No sir! they have them fancy pants %5 parts. High tolerance that is.
Cleaned out some.
Cleaned out the chassis some in this pic, let's take a closer look at the sockets I removed:

Socket to me!
Once I'm done cleaning this thing out, it will be perferct to serve as a test bed for all sorts of MOPA's, VFO's, Regen RX's, or whatever I think to stick in it!
Let's just hope it survives the rain we will be getting over the next couple of days.