1 pill blueprint?

[iparodyall]

So my antenna is reaching out but my area is quite wooded. I want to start small, i'm still learning about electronics and i want to practice making a small amp.

I built my antenna and i don't want to run alot of power into it because I'm not certain it can handle it, does anyone have any tips or suggestions?

also what gain should i expect from 1 transistor?

[Bluerunner]

I have a 1 pill amp. The only one I personally ever saw or heard of (except the little boosters they put into the radios). It is about 8" X 10" X 2" and very little inside it. I got it at a pawn shop, no brand name or history known.

It does about 30 watts max. Not many parts, but the coils & torroids are specialized. I think it is a pretty demanding project for a novice electronic / radio tech. I expect it would cost more in parts to build a 50 watt amp than a used 100 watt one can be had for.

For a detailed Power vs Distance chart and enlightening comments you may want to go to CBMagazine.com, and check out under "General Knowledge", a article called "Power in Perspective".

The chart can be misleading as it refers to theoretical LINE OF SIGHT only transmissions. It doesn't take into account of different antenna heights or "radio horizon" signal blocked by the curve of the earth. Look up Radio Horizon Line of Sight calculators. For instance, the chart indicates 1000 watts will go 95 miles LINE OF SIGHT, but that means both antennas need to be 1000' high above sea level. LINE OF SIGHT, unobstructed distances, are considered the maximum distance for RELIABLE communication.

For example two antennas, each 30' high only have a direct line of sight (just glancing off of the horizon between them) of 16 miles. This is pretty absolute for UHF / VHF radio transmissions because high band signals don't bounce around and just shoot off into space. However the low band CB signal actually slightly follow the earths curve a little an may squeeze out a bit more Line of Sight distance in practice.

CB signals also bounce off different atmospheric layers (skip) so profoundly greater distances (although unreliable) may occasionally be accomplished.

All that to say that a 100 watt amp is good, a 500 watt amp is better. Anything after 500 watts has a diminishing returns factor where it takes lots more power (and money) to make smaller gains in distance. That is Ok if you have a rich wife, and more is always better, just expensive.

Most guys junk a burned out 100 watt amp because the cost of new pills and the chore of replacing them is more than a good used amp can be had for.

If you try to build an amp, I wish you luck (and patience) and that somebody gives you a free bucket full of the parts you need. I think you may see greater (and more economical) gains in performance by elevating and optimizing your antenna.

Might try a quad antenna. Two sticks of bamboo in a cross, 36' of wire around it, a little tuning and you are good to go. Works better than a stick antenna at lower heights and doesn't need a ground plane. Should just about double your transmit & receive signal. However it is directional off the broadsides so keep the stick antenna too for local omni directional use.

The cross might keep vampires away too.

[MDYoungblood]

I agree with Bluerunner on it would cost more to build than buying one off that auction site or even a small mosfet RM Italy off one the the forum sponsors. There are the tanks to design, Teflon wire, caps, resistors, board, heat sink, connectors, and a box to put it all in. You might want to build a small tube amp first. Looking for plans,, peruse the amp section of CB Tricks, plenty of schematics and a few have parts list.

3's

Greg

[iparodyall]

I agree with Bluerunner on it would cost more to build than buying one off that auction site or even a small mosfet RM Italy off one the the forum sponsors. There are the tanks to design, Teflon wire, caps, resistors, board, heat sink, connectors, and a box to put it all in. You might want to build a small tube amp first. Looking for plans,, peruse the amp section of CB Tricks, plenty of schematics and a few have parts list.

3's

Greg

Thanks, i went to CB Tricks but they only have 2 pill blueprints, thats okay though i think i'll try checking out buying something like you suggested.

[iparodyall]

The cross might keep vampires away too.

I've been reading alot about frequency and line of sight of CB radio waves so i know a little bit about what you're talking about, i think a CB wave travels about 1.3 times futher than actual line of sight because the frequency is just low enough to hug the ground slightly like you said.

And you're right, if i get my antenna higher up and put it in omni-directional mode (right now its in an L shape to try and talk to the locals. (the front lobe reaches about 15 miles in this configuration) but i know i could theoretically get 15 miles or more in ALL directions from a 1/4 wave according to charts.

I've looked into 5/8 and 0.64 wave antennas and the radiation pattern has a higher db ground wave but limited sky waves and i think the trees may block alot of that ground signal. So i'm probably sticking with my 1/4 wave but i agree it needs to be much higher.

But i have no clue where to put it. Plus i would need 50 foot of coax to put it in the nearest tree. I thought about putting up a higher mast but i worry about lightning. Of course with the trees being 200 feet tall i guess the lightning has better places to hit, but even still i worry about it.

Tomorrow i'll try getting it on the roof and see if a few extra feet help.

[Bluerunner]

If you have a problem buying coax, very often cheap or salvaged TV 75 ohm coax will do in a pinch.

My experience from long ago when I was desperate and getting involved with CB was that the slight mismatch was far outweighed by the gain in elevating and better positioning the antenna.

I find that the solder-less "twist on" coax connectors work well with TV coax if a little care is used in assembling them. Gotta get the right size for the coax used. Can't solder the aluminum foil wrap & shield.

I use the twist on connectors all the time for 50 & 75 ohm coax "temporary" experimental projects. However, if the project works well they often get left alone and become permanent installations. Some have lasted for many years outdoors wrapped in rubber tape.

If you have trees nearby, shoot some fishing line with a hefty sinker over a branch with a sling shot (or weighted arrow) and use that to pull up some rope or stout cord. Tie it to the top of your antenna and hoist it up. It will work just fine hanging from a tree branch with no mast supporting it. The further from the tree the better. I have several wire antennas hanging from tree branches. Hung my Starduster from one for a while at 60' until I built a tower to put it on.

I have just spliced coax using wire nuts and then wrapped up in tape too. I put my power meter & dummy load at the end of the 50' coax run and could see no detectable loss in spliced coax compared to unspliced coax at 2 watts up to 100 watts. Couldn't see any difference in spliced coax with received local signals ether. I don't recommend it if you have other options, but it will work and pretty well too. Desperate times call for desperate measures.

[iparodyall]

I might have to look into making a dipole out of cable tv coax. The impedance I think should be fine seems like they almost match up

only problem is it's about 200 feet before I reach ground level so i need alot of it.

of course maybe just raising it up 50 feet would help enough to get out of this hole I live in

also i might need to look into getting a power meter, i'm missing alot of equipment, i think i'll try to find stuff at the flea market because the prices on ebay are way too much.

I'm just starting to learn this stuff so it'll take time to figure out how electronics and radio works, but I've learned patience as I've gotten older so i'm not in a rush.