T&L Publications

Please read the posts before answering! This discussion was about towers on insulators. Which means RF hot tower. A hot tower needs a spark gap for lightning protection without shorting the signal. My mention of spark gap a couple posts back was for hot tower, obviously a non-hot antenna support tow...

The tower you say is 600ft not 2000ft. It supports other antennas so is unlikely insulated at the base. The mountain it is on is not relevant.

The big tube likely is waveguide, or coax.

A 1/2 wave antenna for an AM broadcast station could more than 400 ft.

(is 2000ft an over estimate?)

Electron flow, outside the source - electrons flow from the negative terminal through the external circuit to the positive terminal of the source. Inside the source the electrons are forced toward the negative terminal. The extra electrons at the negative terminal is what made it negative in the fir...

Active filter? If yes, what cutoff/rolloff of the amplifier?

(images didn't work - had to ask)

But the tower i mentioned...the insulator was at the base of the tower, not the base of the antenna..

Yes, I got that the insulator was at the base of the tower.

That means the whole tower is the antenna. I thought bolding the word "is" in my previous would have been clear enough.

A tower on insulators is the antenna. There will be a spark gap at the base. Guy cables will have in-line insulators so that cable section lengths won't resonate at operating frequency.

Super caps have a higher internal resistance than filter caps. That is lucky because you don't mention current limiting, and you didn't "blow" the LED. LEDs are not incandescent bulbs. With bulbs an increase in voltage increases current, bulb gets hotter which increases resistance which regulates th...

Thank you! (Wonder what I pushed on the calculator???)

It was indirect. He said he expected AAs to last 30 minutes. If it is rated 1300mAHr, that is 1.3A for 1 hour. So 2.6A for half an hour. (Though at high current loads you don't get the rated time.) A lot of LEDs, a LED headlight, or an incandescent does not matter for the question; "How much capacit...

Just spotted a 3500F super-super-cap.

One or two of those should do too.

(a question - is this an incandescent light? because the white LEDs I've seen need 3.8V)

Real rough. Found some nimh AAs that are 1300mAhr. So 30 minutes would 2.6A load (you won't get the rated amphours discharging them that quick) 1 RC time constant is 63% discharged. R = 2.5V / 2.6A = 0.96Ohms Time in seconds is 30min * 60S /min = 2160S T = RC so C = T/R C = 21605S / 0.96Ohms = 2250...

Had to go looking for what the "C" in "UVC" was for. It is shorter wavelength band than UVA and UVB. I agree that anyone selling UVA or UVB for sanitizing is cheating people and giving a false sense of safety. You, and anyone helping, be careful during your experiments. Living people should not in s...

A voltage divider needs at least 2 resistors. Input at top lead of upper resistor and bottom lead of lower resistor. Output to measuring circuit is junction of the 2, and bottom lead of lower resistor.

If you are only going to AC with this circuit, then you won't need the DC divider.

As far as I can tell the parts to the left of the ADC are the voltage divider. (and I don't see the 1.2K you mention in the posted diagram, nor figure 7 in the linked page.) C2 and C3 may be replaced with a single 30pF. Series caps are - Ctotal = 1 / ((1/C2) + (1/C3)) (30pF is not a standard value) ...