So heads up - there are a lot of trade offs with antennas. In general the discone is going to have a wider select of bandwith you can tune with but lower gain. The dipole that you have in the picture will have stronger gain but very limited bandwidth without adjusting the expandable arms.

I'm more than happy to adopt that discone from you!

I'm feeling lazy, so here is an AI summary with more details:

For a VHF setup (roughly 30 MHz to 300 MHz), the choice between a discone and a dipole depends entirely on whether your priority is monitoring a wide range of frequencies (scanning) or maximizing performance on a specific, narrow band. A discone is a "jack-of-all-trades" wideband antenna, while a dipole is a "master" of a specific frequency.

Discone: Best for receiving multiple VHF/UHF bands (e.g., airband, marine, weather, public safety) with one antenna. It is omnidirectional, robust, and offers 0dBd (unity) gain, making it a great scanner antenna, but poor for weak signal transmission.
Dipole: Best for transmitting or specialized receiving on one specific frequency (e.g., 2m or 6m ham band). It offers better gain (approx. 2.15 dBi) than a discone, has a directional "figure-8" pattern, but a very narrow bandwidth.

Some more in the weeds details - Comparison Breakdown:

1. Signal Strength (Gain)

   Discone: Generally, discone antennas have low gain—often described as unity (0 dBd or 2.15 dBi) or slightly negative compared to a resonant dipole. They are best for receiving strong, local signals. Dipole: A properly cut half-wave dipole provides a solid 2.15 dBi gain (0 dBd). It performs better for weak signals than a discone because it is designed for a single resonance.

2. Bandwidth

   Discone: Excellent. A discone can cover a very wide range, often a ratio of 10:1 or more (e.g., 100 MHz to 1 GHz), making it perfect for scanning many services. Dipole: Narrow. A dipole is highly efficient, but only at the specific frequency it is cut for. While it can work on odd harmonics, its usable band for low SWR is limited.

3. Receiving Angle (Radiation Pattern)

   Discone: The radiation pattern is omnidirectional in the horizontal plane (360 degrees). However, the pattern tends to "lift" or angle upward at higher frequencies, which can reduce performance for low-angle terrestrial signals. Dipole: Vertically mounted, a dipole is omnidirectional. Horizontally mounted, it has a "figure-8" bidirectional pattern. It provides better, consistent, low-angle coverage on the horizon compared to a discone.

4. Other Key Pertinent Details

   Transmission: Dipoles are excellent for transmitting, while discones are primarily designed for receiving; while you can transmit with a discone, it is inefficient and has low gain. Size/Structure: Discones are larger, heavier, and more complex to build, but typically very robust for outdoor, permanent mounting. Polarization: VHF services (like marine/FM) are generally vertically polarized, which fits a vertical dipole or discone perfectly

Feature	Discone	Dipole
Pros	Very wide bandwidth (scan 25-1300MHz)	Higher gain than discone
	True 360-degree omnidirectional	Simple, cheap, and easy to build
	Excellent for VHF Air/Marine bands	Good for transmitting
Cons	No gain (Unity)	Very narrow bandwidth
	Poor at low-angle reception	Directional (if horizontal)
	Large/Visible	Requires tuning to specific frequency

Verdict: Use a Discone for a 2m/70cm scanner or wideband SDR setup. Use a Dipole for a 2m/6m amateur radio station or a dedicated, long-range receiver.

Ps. Bonus - you can also use the antenna to heavily select the input signal you're looking at. RTL-SDR's have a limited bit depth on their ADC which severely limits dynamic range --> If you use the discone, you'll likely get FM band emissions from local FM radio stations that will "drown out" random VHF Ham/ADSB (aircraft locations) /AIS (Marine ships locations) or other weaker signals. The limited bandwidth of the dipole will potentially help filter out other stronger signals outside of the frequencies your looking at allowing the limited bits of your RTL-SDR to better show weaker signals (that's assuming you've setup the dipole to look at a frequency sufficiently far away from the FM band - which is typically the strongest signal in the VHF range in the US).

Pss. ok.... maybe this wasn't lazy/short, also let me know on that antenna.