Ice Pack

[cyberham]

I may have asked this long ago but I forget. With the high temperatures we are now experiencing (about 88F yesterday), I'm wondering if enclosing an LNB in an ice pack would improve its performance. I find that reception on my C-band dish is better at night in particular on the occasional transponder that is at or slightly below C/N lock value during the day.

Or maybe it's the fact that the Sun is behind the dish in the evening that contributes to improved performance.

 

[comfortably_numb]

Buying a Bullseye LNB eliminated temperature issues for us, here in New Mexico. Signals that would fade as the day got hot now stay steady 24/7.

I think it's worth the investment.

 

[cyberham]

I don't really have a problem on Ku. It's on C-band where I could use improvement in a few situations likely due to my dish only being 7 1/2'.

 

[ZetaMale]

I use a regular LNBF with no problems even on 100+ days. I'm using a much bigger dish than you are though (12 footer).

 

[cyberham]

I use a regular LNBF with no problems even on 100+ days. I'm using a much bigger dish than you are though (12 footer).

Your larger dish would likely compensate. In your case, you would need to graph your C/N values over several days/nights against measured temperature to see if there's any correlation. It's easier in my case since it's more noticeable. I lose a solid lock during the day but right now at 9 pm it's locked solidly.

 

[clucas]

I'm probably far off base so maybe someone with more knowledge could give a correct answer.

I started thinking (bad thing) and wondered if air density is a factor due to the air temperature not just the temperature of the LNB(F) itself (i.e. cooler, more dense air at night). A short search came up with this AI generated answer for RF waves:

Yes, air density is a factor that can affect radio frequency (RF) power, particularly in terms of signal propagation. Here's how air density plays a role:

• Refraction and Bending of RF Waves: Changes in atmospheric density, caused by variations in temperature, moisture, and pressure, lead to changes in the speed of electromagnetic (EM) waves, including RF waves. This variation in speed causes the waves to bend, or refract, as they pass through the atmosphere. Refraction can lead to changes in the propagation direction of RF signals.
• Impact on Signal Range and Strength:
  
  • High atmospheric pressure (denser air) can potentially increase signal range by providing a denser medium for the waves to travel through.
  • Conversely, low atmospheric pressure (less dense air) can reduce range by decreasing air density.
  • High humidity levels and rain can scatter and absorb radio waves, leading to signal degradation and attenuation, impacting signal strength and clarity.

A search for "is air density a factor in wave propagation" came up with this:

Electromagnetic waves (including light and radio waves)

• Density fluctuations and distortion: Random fluctuations in air density can distort electromagnetic waves, particularly at higher frequencies (shorter wavelengths) like those in the millimeter, infrared, and optical ranges. This is the reason for the twinkling of stars.
• Density and absorption/radiation: Denser air at lower elevations absorbs and radiates more energy, while air density decreases with elevation, leading to less energy absorption and radiation at higher altitudes, according to www.vaia.com.
• Refraction: The index of refraction, which depends on air density, can cause electromagnetic waves (including light and radio waves) to bend as they pass through layers of air with different densities. This bending is known as refraction.

In summary: Air density is a significant factor in the propagation of sound waves, directly impacting their speed and intensity. For electromagnetic waves, air density primarily influences propagation through phenomena like distortion and refraction, which can affect the overall power or clarity of the signal.