Thank you kindly!

Apparently, among electronic enthusiasts, potentiometer is becoming like a generic trademark for anything that has a dial and rotates, doesn't matter if it's an actual pot, variable caps, rotary encoders, just anything like it.

Glad it helped!

It may cause an ark on the contacts, but more importantly it could damage your radio because between each click on the inductor you have an open circuit. With the more expensive roller inductor there is constant contact. If your radio still tx you’re probably ok. 73

We've all made mistakes in this hobby, but we learn from them and do better. I've had a homebrew tuner with sparks arcing across the capacitor plates a few times. I also know a ham who told me he burned a hold in a capacitor once. I've never done that thank goodness.

How much loss is typical? I've never used a manual tuner.

@@gooberclown I understand 1 db might be about typical (roughly 20%).

Glad you liked it!

The cross-needle meter gives you a sense of actual transmit power AND the SWR. Radio transmitters tend to have a percentage power output, but it typically isn't actually measured. So 50 percent of what, exactly? Then there's the problem of where exactly in the coax is the meter. The radio might read perfect 1:1 and the tuner meter might show something dramatically different (or vice versa). That will happen when there's standing waves on the coax itself and you just happened (or deliberately) placed the radio or tuner at a "null" in the standing waves. What happens is a quarter wavelength of coax becomes a type of transformer and it inverts the impedance, sort of a fulcrum over 50 ohms. So if the antenna is 25 ohms (typical for a vertical), a quarter wave section of coax will see 1/2 below 50 ohms at one end and transform it to 100 ohms at the other end (1/2 above). But a half-wave simply replicates and keeps the antenna impedance. Values in between produce an impedance in between, but with a reactive component. Tuners exist to nullify this reactive component. If the antenna is "capacitive" in reactance (ie, too short), add inductance. If inductive (too long) add capacitance on the antenna side. The transmitter side has its own matching capacitor and the inductor is shared. It is because of the shared parallel inductance that it is typically set first, and then the capacitors, but doing that sometimes necessitates a small adjustment of the inductor again. Manual operation of the tuner isn't quite a simple as this video suggests.

It's just the beginning. These videos and a Baoefeng are gateway drugs.

@@toddkj7jhhthat’s what just happened to me! Bought a booofwang and a month later I have my tech license and my bank account is almost 2 grand lighter 😢

covid is a lie bro!!!!

Thanks for that!

Thank you!

Cheers!

Agreed, they're also matching units' not tuning units.

Yes, just verified in the manual pdf. Easy find with search engine. I thought the same. Manual is just a couple of pages.

pots would do no good. variable caps

Learning by rote does not generate understanding, which is a pity as many people are losing out on theenormous scope of our hobby...

Glad it was helpful!

I'd say that's one thing that could have been added to this, how it works. Why we need one, like our resonent antenna is closer to the round, etc.

Great suggestion! I only have a Drake receiver at this time. But I'll keep an eye out for a good boat anchor transmitter :D

Definitely an art as much as science back in the day.

Oh, that would be a good one, and compare to a log periodic

Thanks for watching. Yeah, I can explain how a yagi works. Thanks for the idea.

Matching stubs are transformers. A curious phenomenon is the quarter wave matching section. 1/4 wave of coax inverts the impedance; a 25 ohm feed point impedance, one-half the coax impedance, becomes twice the coax impedance at the other end. Yagis work because current lags voltage when inductive (too long) and current leads voltage when too short (capacitive). The parasitic elements are "excited" by the driven element, and because of different lengths, produce a phase shift that augments the signal in the forward direction and partly cancels in the back and side directions.

Log periodic is basically the same as yagi but with the important distinction that all elements are driven all the time. One of the elements will be resonant and that will be the principle radiator, others will be too short or too long, becoming directors and reflectors. The relationship of the elements is such that you can tune a band and it maintains a uniform SWR across the band, whereas a Yagi has only one driven element and thus a distinct frequency preference (but also generally more directivity because of that).

It might be confusing no? Since the dummy load is 50 ohms to begin with.

Ham Radio Crash Course not tuning with the dummy load but using the dummy load on the tuner for its intended purpose.

@@HamRadioCrashCourse "It might be confusing no? Since the dummy load is 50 ohms to begin with." But the RADIO might not be 50 ohms! That's why there's two variable capacitors; one for the antenna and one for the radio. Anyway, yes, it is trivially easy to match a dummy load 🙂

Yes, that is a good way to look at it!

Auto-tuners tend to be limited to matching up to a 3:1 SWR where manual tuners can usually handle 10:1 mismatch. The big roller inductor tuners have nearly infinite matching range but of course if your antenna is that far out of resonance it probably won't go anywhere anyway.

Yes!! Extremely quiet environments actually makes it harder!

Not really. Auto tuners generally require transmitting power through the matching device which would be transmitting out of band for many of SWL frequencies.

You know it might.

Longer wire is almost always better than short. It is the wire that radiates, more is better! But there's some caveats. The 50 meter wire can fit 2.5 wavelengths of 20 meter. That's going to give you 6db or more gain in its preferred direction which won't be completely obvious. 40 meters of wire would be more predictable; two full wavelengths and you'd probably drive it 10 meter from one end for low impedance feed or at the end for a high impedance feed. SWR *by itself* is harmless. Ignore than SWR behind the curtain but with some understanding. You send a radio wave to the antenna. If matched, it flies off into space. If not matched, some of it will bounce and come back to your radio. your radio doesn't want it, so it bounces back again toward the antenna, adding to the next wave your radio is sending to the antenna. So now with double the strength, that reluctant antenna is persuaded to radiate. All of the power leaves the radio! It might take seven trips back and forth through the coax to finally get radiated (each bounce being reduced). the effect of SWR therefore is the signal takes extra trips through the coax, losing a db each trip. Maybe more than 1 db. Thus the transmit power is consumed in the coax and turns into heat (not much heat, but its there) and never radiates. A side effect of SWR is that it increases the voltage on the power transisistors because they see not only the battery voltage, but the reflected voltage from the antenna and this could cause failure. It also increases the voltage on the antenna and if people touch it could get a shock or burn. But the ends of a dipole antenna always have a much higher voltage than the feed point anyway (in a center fed dipole). End-fed antennas require a high voltage push just to get electrons to go in, they don't like end fed antennas. The G5RV antenna uses 600 ohm ladder line, which has very low loss and very high SWR anyway, it is part of the design. Who cares about SWR when you are using ladder line or random wire? Just match it and go!

Poorly

​@@randykitchleburger2780that would depend on the feedline

do you run an amp with it? I was considering getting one cuz my dipole swr is 1.6

While I see your point. I doubt it's going to catch on.

Manual tuner uses variable capacitors; automatic tuners use stepped capacitors arranged in a binary progression such as 1, 2, 4, 8, 16,32 picofarads (for instance) allowing to choose any value from 1 to 63 pf in 1 pf increments. What the computer does is scroll through the combinations rapidly. Same with inductors. Naturally you want to dial down the power on your transmitter since it will try a possibly large number of wrong combinations reflecting a lot of power back to the radio while it is hunting. Manual tuners only MATCH the antenna, whether you actually radiate energy is another matter entirely. This is true of automatic tuners of course but the programming is aware of that possibility of getting a false match where the tuner itself consumes all or most of the power.

The lower the frequency the narrower the bandwidth particularly if you are using a tuner. It is a tuned circuit! So you are going to have to jiggle it if you change frequency very much. If the tuner makes a noise, that typically means it cannot find a match and that in turn means your antenna is too far out from resonance to match with a simple tuner. Manual tuners tend to have a much more tolerant ability to match almost anything. Automated tuners generally expect the antenna to be approximately resonant already. The exception is random wire tuners. They'll match almost anything but watch out for high voltage.

Generally speaking, you tune the antenna by making elements longer or shorter for VHF. Also, the low power of the walkie-talkie makes mismatch not much of an issue. the rubber duckies are horrible antennas but it doesn't bother the radio.

The radios doesn’t dictate what kind of antenna matching equipment you need. That is more for you and your budget to decide.