The OZARK PATROL

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The picture on the left, from the 4 State website, shows one method of bending the component leads.
I chose to make the leads longer to avoid any damage from the soldering iron, especially to the transistors.

This is a capacitor added to tune the antenna. It doesn't come with the kit. To couple the antenna to the radio, a very low value capacitor is used. It's made by twisting two pieces of wire together and is called a "gimmick." A gimmick capacitor has a value of about 1 picofarad per inch, depending on how tightly the wire is twisted. I wanted to be able to vary the capacitance.
 
The capacitor used was 0 to 28 pF, which is too high. I could only mesh the plates a tiny amount and then it was too much.
I put a 4.7 picofarad capacitor in series with the variable. What do you suppose that did to the value of the variable capacitor?

To calculate the value of two capacitors in series, the formula is C1 x C2 / C1 + C2.
 
So (28 times 4.7) divided by (28 plus 4.7) = 131.6 divided by 32.7 (I used a calculator) = 4.02. The variable capacitor is now 0 to 4 pF!

It is perfect for this. You don't really need it if you're building the kit; the gimmick will work fine. I just happened to have the variable capacitor available, so I used it.

Gimmick capacitors. You'll put your eye out with those things!

 
The audio output of the radio is disappointing. The volume is so low It was actually in competition with the noise from our refrigerator while listening to it. Then I plugged in a pair of headphones and the difference was amazing.

Don't bother trying to improve the sound by swapping the speaker. It did improve the sound, but the two transistor amplifier just can't drive it with very much volume, so the speaker that came with the kit was put back into service.

Once you listen to the radio with headphones you probably won't use the speaker. The volume in the headphones is so loud that you'll have the sound turned almost all the way down.
 
The speaker frame is very close to the terminals on the regen control, so be careful when attaching it.

In another effort to get more volume, I replaced the 2N3019 transistors with some 2SC458s that I had left over from the Astro Commander walkie-talkies (seen elsewhere on this site). I don't think it made a difference. The level of sound from the speaker was still abysmal, and It wrecked the cool look of those silver and brass metal 2N3019s. DON'T DO IT.

The "Pittsburg style" construction lets you swap out a transistor in less than a minute. This came in handy when comparing the performance, since listening conditions on the short wave bands can change from minute to minute.
 
Then it suddenly hit me. The 4 State QRP Group considers the "Ocean Hopper" an ancestor of the Ozark Patrol. The Ocean Hopper DIDN'T HAVE A SPEAKER. Instead of trying to improve the dismal volume of the speaker in the Ozark Patrol, just ignore the fact that it even has one.
 
Perhaps the Ozark Patrol should be made without a speaker. It would be cheaper and nobody would spend time trying to "improve" the sound. They could include a cool 4 State QRP Group decal to be placed where the speaker used to be.
 

 ...and then I had an idea. 

 
 
While watching some YouTube videos of other Ozark Patrols, I got another idea. Yes, another one. That's a total of FIVE, no, THREE ideas! The videos show an external amplified speaker plugged into the headphone jack. So why not make the amplifier INTERNAL or on-board?
 
For a buck you can get this amplifier kit from China on ebay. No postage! I ordered three. I mean, five.
If you hold the PC board in the light the right way, you can see the traces. The soldering pads are very small.
 
The first one I assembled didn't work. Instead of troubleshooting it I just made another one, but more carefully. I think the flat tip on the soldering iron wasn't able to heat the small solder pads, so I used a different soldering iron, with a small pointed tip.

 
To install the amplifier you take the leads going to the speaker and plug them into the amplifier board. The leads from the amplifier then go to the speaker. Power comes from the on / off switch on the front panel. Set the volume on the amp to where you want it, then forget it. You still control the volume from the front panel, but now you have some SERIOUS volume.
 
You can pick up the negative voltage for the amplifier from any of the screws that mount the speaker.
The amplifier does not affect the operation of the headphones in any way.
 

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