Sell LRL

[J_Player]

Yes, I even made some improvement in wires colour. I change wire supplier to Illuminati.

On a more serious note, for experimenters who are actually broadcasting VHF signals in their treasure hunting area, I have noticed many of them use a 1/4 wave whip antenna
(This is the kind that is a simple telescoping aerial).
This kind of antenna may not be the best to use when you are interested in broadcasting RF to simulate what you receive from a distant studio transmitter.
The simple aerial antenna will have vertical polarization if it is held upright.
But the signal is broadcast in omnidirectional strength in all directions, which means most of the signal is wasted by being sent some other direction than where you are treasure hunting. Also, what you say is true about distance. If your transmitter is within rock-throwing distance, then you will probably sending RF which behaves as near-field waves, rather than the waves that come from a distant studio transmitter.

There are several things an experimenter can do to more closely approximate the RF that comes from a transmitter.
Here are some things I would do if I wanted to simulate an analog TV VHF broadcast from a distant station:

1. First measure the signal strength of an existing analog VHF station.
You can use a meter, or if you don't have the proper equipment, you could use an old TV, and shorten the antenna until you see the signal is getting bad.
Then you will have a way to know what relative strength the signal is for an existing VHF broadcast that you want to imitate.
Later (after you build your new transmitter), you can check with your meter or with the old TV to see if the new signal is the same strength as the previous TV station was.
You can adjust the signal strength of your new transmitter by moving it at different distances from where you want to hunt for treasure, or you can adjust the gain of the power transistor by adjusting the resistors surrounding it.

2. Do not use a simple aerial antenna. Use a dipole.
A yagi antenna is an excellent choice.
You should make the dipole antenna set to the correct length for the frequency that you are transmitting.
There are many online calculators that can show you how to set up a yagi antenna for whatever frequency you are using.
The advantage of the yagi antenna or similar designs is it will focus the RF so most of it goes forward of the antenna.
A yagi antenna will send a strong signal in a 60 degree path to the front of the antenna, but will only lose a small amount of RF to the sides and back of the antenna.
The RF beam will be MUCH stronger, which will allow you to move the transmitter and antenna much farther away from the search area in order to get the desired signal strength.
The difference between a simple aerial and a yagi antenna is much the same as the difference between connecting a light bulb to a battery in the night, or using the same battery and light bulb in a flashlight that focuses the light into a beam.
An aerial will work like the simple light which makes a dim light in all directions, while the yagi antenna will send out a beam that is focused to a 60 degree angle.
Another good feature of yagi antennas is the polarization can easily be changed by rotating it so that instead of having the antenna "arms" at the sides, you can turn them to be in the up and down position, while the front of the antenna is still pointing toward the treasure hunting area. The idea is to move the transmitter as far away from the treasure searching area, and to still have the same signal strength as the old TV station sent. The distance is necessary move out of the near-field wave effects. With any luck, you may be able to simulate the signal that comes from a distant TV transmitter.

3. Connect a TV camera to the transmitter and connect the sound.
With no video camera connected to the transmitter, you will be sending only a carrier wave, with no TV picture or sound signals.
Why does this matter?
It matters because the TV picture and sound add a lot of new frequencies to be modulated in the carrier, which include everything from audio frequencies up to nearly the carrier frequency that your transmitter is set to. There is both AM and FM modulation in most TV transmitter signals that are broadcast from a station. If your new transmitter does not have these same modulated audio and video signals encoded into it, then you have not simulated the old TV station.

Final thought:
I don't think any of this will work to improve the operation of a Morgan-style PD.
But I could be wrong.
If I wanted to find out, then I would do it the way I described above.


Best Wishes,
J_P

[WM6]

Good explanations and suggestions. As usual from you J_P.

Serious LRL experimenter have to considered this, if step toward some improvement is a goal.

Otherwise a bunch of telescopic antennas on PD's look very spacey.

[Geo]

There is a new type antenna special for PDs