Twin Tube Operational Update

Been a while since I posted on the NoGA Twin Tube 80 (link opens the first article in the series, see Ham Radio Masterlinks for a list of all the articles), figured I'd post an update, and talk about some project ideas I have for this set up.
Not long after successfully using the transmitter, I ran into a difficulty. The next time I tried to use it, I powered the radio up, I got sparks when I keyed down! Hmmm, that's not right! I also was getting no power out.
I decided to give the rig a break for a lil' while, and focused my efforts elsewhere. Since I was going to be up, I took the transmitter back out, and began poking about.
2 months hadn't improved the situation, it still didn't work.
Power supply was good,
I suspected the transmitter had shorted something out when I tried to go poking about the last time I successfully used it, I wiggled wires, and mushed down parts. Still no dice.
I replaced the three 33pf capacitors and checked the 100microhenry inductor for continuity.
I then inspected the pins on the tube sockets, and sighed when I saw that pin 6 had a loose hookup wire.
hmmm, soldered that puppy down, made sure everything is bent to not short out, and closed the case back up. I think that the use of an Altoids tin in this situation is a mild gamble. It works decent enough, but there have been several times when I've come dangerously close to knocking something seriously out because the tin is somewhat flimsy when you begin poking holes in it.
I plugged the transmitter in, and things began to glow.
no Smoke, and no fires. That's a good sign.
Glow in the tube, antenna is a dummy load, DVM on, and keydown.
20V on the meter!
that's 1 watt folks.
we back in business!

The Thermionic Energy is Astounding!

These two glowing eyes
Voltage amplification
This is hollow state.

Of course, now I need to find someone to QSO with late at night on about 3582 KHz. The crystal is 3579.4 KHz, nominally, but it pulls a little higher in this circuit, I'm guessing that I need to add some capacitance somewhere to pull it back down. That gets me to my next point.
Back when I was building this thing, several suggestions for experiments were made to me, but it's not easy to swap parts out of this altoids tin. I've got a couple extra tubes that will work in this getup, and I'm thinking of building a breadboard that I can plug parts in and out of. I need some more tube bases first though.
The schematic is availble for view HERE. KL7H has done a great job of documenting this and Mike's 12 v regen project.
Any suggestions for substitutions?
Should I attempt to wire one tube as an oscillator and the other as an amplifier? (MOPA esque?)
Suggestions for boosting power?
73!

World's Ugliest Dummy Load Pt 1

In the last post I mentioned making a dummy load, and things not going quite as expected.
Things are turning out down right UGLY! LOL!

Pretty Is as Pretty Does

So far, it's going well, but when I got the leads prepped for adding a UHF connector, I found the Junque box fresh out! hmmm, I have plenty of BNC's but no UHF. Time for a trip to RadioSnack I guess.
I figured out what I'm doing wrong with this, and the solution. I tried adapting K4EAA's methodology, he uses a drilled brass plate to hold things together, I thought I was being slick using circuit boards. My problem came when I tried to line up the resistors to insert into the second board. Dadgum thing refused to go together!

I forgot this part in K4EAA's article:

Note on easy assembly - Solder all 20 resistors to one plate, and then, starting at one corner, and working toward the opposite corner, cut the lead lengths starting from your minimum length, to progressively longer as you work towards the opposite corner.  This will allow you to insert a few leads at a time as you combine the two plates.   If they are all the same length, it will be very hard indeed to thread the 20 resistor leads into the bottom plate!

My Daddy told me once that "Common sense isn't", and boy I relearn that lesson about every week, hi hi! In reality, I should have been listening to my inner voice that said "4 resistors on strips, like they come in bulk". I dismissed it as a dream, I don't have Dremel (generic or for real) so making strips out of PCB is tough. I tried cutting a double side PCB to make some paddles out of it, and it takes a LONG TIME with a hacksaw. I need to get a Dremel to finish that project. This morning I had my epiphany though. Being a QRP operator, I have an Altoids addiction. I claim I use them for the tins, but in reality, I just like munching the things down. As a result, I have a container that has nothing but Altoids tins in it.

Don't Judge, chances are you have one too.

:)
So at some point in time in the nearer than the further future, I will be modifying this project.

1. I want to remake the dummy load with 3 watt resistors instead of 2 watts. That way I will have have a 100+ watt DRY Dummy load.  The nominal rating of this one is 88 watts (44 2 watt, 2.2KOhm resistors) I will probably order the resistors the same time I order some MV21's and binding posts to capture the Peak voltage of the circuit.  If I decide that the cost is too high, I may just reclaim the resistors off of this board. I don't think it will be too hard to get them all apart (famous last words, hi hi)

2. I will make it using strips of 4 resistors each (11 strips total). Airflow will be better, and appearance will be better. Fun to be had by all.

OTHER NEWS:
N8VCL has become a Kitbuilder!
See his excellent adventures assembling a NS-40. Note the lack of any iron donut winding. That's kitbuilding HERESY! :) Check out the video of his kit in action. I hope he QRVs and QSOs with it soon.
Looks to be a neat kit, and N8VCL (Scott) certainly did a better job than I did the first time I tried to assemble anything. He's been added to to the ham radio bloglist on the right panel.

73!

Cliches and Operating

You that old saw, "It's not a failure if you Learn something"?
I've always hated that statement. I try to learn from my failures, but failure is failure, and for something to fail means that I wasted time doing something, and time is really my most precious commodity.
So here's what has failed, and here's what I've learned.
1. I wanted to build an antenna that would cover 10m, 20m, and 40m. I failed because I didn't understand the nature of what I was building. Instead of making it small wavelength to big wavelength, I needed to make the calculations for the whole antenna first, and build the whole thing, then tune from the smallest wavelength to the biggest wavelength.
2. I attempted to operate from the field (work parking lot) twice this last week, both times was a bust. My semi-success with the 4SQRP outing in October. I had to learn lessons there too, like, easy setup is more important than antenna efficiency in times of expediency. I think something like the St Louis vertical, or the St Louis Loop is a better choice for time sensitive ops, where the W3EDP is a better choice for times when you have time to set up. As an operational note, W1AW was 599 to my QTH on 40m Monday night.
3. Right now, I'm building a dummy load out of 2 watt resistors. 44 of them in parallel to be exact. Even that has had "Learning opportunities", namely when it comes to lining holes up. That has changed from being something pretty and elegant to downright ugly. I just want it to work.

Tonight, I think I might just go to bed, leave the soldering iron cold...
sigh.
or maybe I won't...
stay tuned!
73

Operating is the Trick

So my antenna woes continue at the home QTH. I've decided that the 10/20/40m dipole I'd been planning was a boondoggle, at least in the manner in which I had planned it out. I might be able to make something out of it but not before I get some more ladderline. I'm not cuttin' up what I have now because I can use it to depoly an all band no fuss "Double extended Zepp" type antler for 80m. I'll just run 450 ohm feedline for that sucker, and call it a day!
To get myself out of the ham radio doldrums, I decided to play radio from the field, well, kinda from the field at least, so it's time to operate KG4GVL from the work parking lot in the FYBO contest.

Ready to Deploy!

The antenna I decided to use is the W3EDP. I've featured  it several times on this blog, and it is my favorite antenna. I use a sister antenna to this one at home for my primary antenna right now. They are generally stealthy, simple to deploy, and tune well on all the bands, except 10 and 30. I've gotten them to tune there, but not without struggle. Getting it to deploy was a mild challenge, I arrived at work 15 minutes before I had to clock in just so that I could deploy the thing, and maybe even strike up a QSO or 2 before clocking in. Murphy struck a couple or three times, and I barely got the antenna up before clockin time.









Ready to Operate!





Notice the picture on the right? I'm using "The Killer Watt Radio", my trusty ZM-2 antenna tuner, battery power, and a straight key. I have the world's worst callsign for contests, but hey, I like it just fine for most of the hamming I do. In the middle of the lid is my "Highly Calibrated Whistle Thermometer." It will provide real time temperature readings, and serve as a handly emergency signalling device should the need arise.
Because I'm using "The Killer Watt Radio", I am stuck to 40m only. That's ok, but it's times like this I do miss having an FT-817.

Check out www.qrpspots.com for KG4GVL when I get QRV!
Follow up Post to come later.
73!

Ham Life: The Struggle

Well now, seems like we had ourselves a little storm or something last night.
I knew this had happened:


Fallen is the Dipole!



Fallen is the W3EDP!



because I'd seen it on the ground the day before. There was a mighty wind a'blowin'. What I didn't know was that the W3EDP had lost a support too.



Woe is me! I got to thinking about the situation. My reason for going ahead with the stubbed antenna project was because the dipole had fallen. No better time than the present to go ahead and make something better. First things first though, I needed to secure the W3EDP in a position where if it's going to be up at all, I want it to be usable.

I broke some rules about how you are supposed to orient ladder line:



Yep, it's Bent!

 It's all good though, pragmatism trumps theory all the time.
Right now the W3EDP is deployed to a single support. It does not touch the tree the support wire drapes across, and is in free space as an inverted-vee. I checked it to see if it got noise, and sure enough, it's noise on 40m, and tunes up nicely. Tonight I may try to get "The Killer Watt Radio" on the air, and see if it can't snag me some tasty DX.

After doing my "radio check" I decided to roll up the 40m dipole. I need to work on it some, the whole thing is over ten years old, and it's beginning to look a little worn. I plan on using the spot it was in to deploy the new antenna I introduced yesterday. Don't tell anybody, but I'm also thinking about putting up a dipole for 80m, and fed with ladder line. The W3EDP will tune 80, but I have a plan for getting another antenna up high, like about 50' high.




What does ten years do to an antenna?

A bit Crufty She Is

Makes the outside go from copper red to dirt brown/black.
Funny thing is that when this antler was in the church attic, it didn't get too bad over the couple of years it was there. It spent a lot of time in storage, and was sitll a lil shiny when I deployed it in the yard the first time. Now it has almost a film on it. Strange. I'm thinking I should replace the wire at a minimum. The wire is about coming out of the ears where it attaches to the balun too. Not too bad I don't think. The UHF Connector still shines good. Must be something to using Coax seal and electrical tape over the connection...

Now tonight, if I'm still awake when I get home, I'll get the Decoupling Stub Antenna on the workbench!
If you have a copy of "More Wire Antenna Classics Vol2" by the ARRL, it's Chapter 3, page 17 should you want to follow along.
73!



******UPDATE******
Ok, Last nite I got the first phase of the antenna built. I attached a center insulator to two 8 foot pieces of ladderline. Then I realized I was doing it wrong! LOL!
Pics during testing phase to follow...

Antenna Modeling and Making

I've literally been working on this post for a while, just haven't had the time research what needed to be researched. Still not done researching either ;-) This is what I would call a first effort.
After reading the latest antenna-centric issue of QST(way back in March 2012), I was a little disappointed. I knew I would be when I saw the front page and read "Special Ad Section Inside!"
hmmm,
I was hoping to read more about actual antennas. That is not to say that what articles there are not excellent, they are well worth reading. I guess I just can't get enough reading in on antennas. I'm always looking for a good idea or three. After looking through the magazine, I decided to work on modelling a multiband antenna project from the book I received when I rejoined the ARRL.
The idea is simple, you use shorted quarter wave stubs off the end of the antenna to isolate resonant sections. That's easy enough to understand, right? Ok, so I needed to see this antenna, and think about it for a second, and then I got it.
PROS:
Multibands without tuners!
   This is a big win for me, anytime I get to avoid a tuner is a good time.
Relatively simple to build!
    450 ohm Feedline, antenna wire, solder, insulators, and measuring tape. No traps to wind, no coils to dip, no ultragreezy uber kul big dollar capacitors either. Just wire, lead, tin, plastic.
CONS:
Mostly full size on lowest operating band.
    OK by me, I've got room for a 40m Dipole in the back yard.
Needs three supports.
   Could be a big deal to get all straightened out.

The model:
https://gist.github.com/1935227
Click on the link, and copy and paste the NEC file into a text file, save the text file as a .nec.
I'm pretty sure I'm doing it the wrong way :)
The internets so far have been no help, they simply don't know how to model this.
The build:
I will build this antenna in stages, testing each stage as I complete it, the object being a permantly install, no tuner triband antenna on 10, 20, and 40m.

Tonight begins the build. First Up, 10m Section.

Short Note on RF Absorption and Coil Forms

Recently, on the "Glowbugs" google group, there was a discussion about whether a pill or vitamin bottle was suitable for use as a coil form for a tank curcuit, or other more general RF use (loading coil form, etc).
According to that fine bunch of OMs and YLs, the test is temperature after being microwaved for a bit. Here's how the test works:
1. Take a microwave safe dish, and put a cup of water in it. Make sure dish is shaped so that both dish and test bottle can fit in the microwave oven without one being on top of the other.
2. Clean and dry the container you want to test. I tested a bottle that held fiber, that's what's in the picture. Trickiest thing about the prep work on this baby is that you want to make sure all the metal from the freshness seal is removed from the rim.
3. Place both the test bottle and the cup of water in the microwave. Take note of the temperature of each, "room temperature" is as precise as this measurement needs to be.
4. Nuke it for a minute. (see below for further advice)
5. Compare temperatures: the test bottle should still be at room temperature, and the water should be noticably hotter (scalding hot on some microwaves, so be aware!)

Them what was tested.

Above is my test bottle, a repurposed fiber containment vessel. Errr, it's not mine man... I'm to young to take a fiber supplement! (maybe...)

K5KVH had mentioned the RF microwave test, and this is what hed had to say way back in 2011 on the Glowbugs list:

PVC is easy to verify if it has additives to increase loss. You can

check your PVC easily with the microwave test. Put a sample of the pvc
on a paper towel in the microwave oven. Put a cup of water in there
next to it. (no metal trim on cup, plain china).

Set the microwave to 3 or 4 minutes. When you see the water is boiling,
stop the oven. Carefully test the pvc with a wet finger tip, to see if
it got warm, ie warmer than the hot air around the cup.

If not, it is good for HF for sure. This is based on a formula for
dielectric loss that shows such loss is directly proportional to
frequency, the higher the test frequency, the higher the loss would be
for a given material. Thus, no heating at microwaves means it is
a good insulator at HF.

Ok, I will buy that.

My test results indicate that this material is good for winding tank circuits, or whatever, at HF frequencies.

It is made of "Recycle Material Number 2", ie High Density Polyethylene (HDPE).

I recently acquired some more tubes, so I'm probably going to be using this soon.

I also have pillbottles.

73!