My basic setup: I live on the top floor of a high-rise building, and the developer has divided the rooftop area (excluding the common area where clothes can be hung) among the 8 households on the top floor. This means that the horizontal distance is insufficient to install antennas like V-type or directional antennas. Currently, the primary antenna I use is the 5.2m pull-out GP antenna pictured, which includes a 7M band switchable coil and can cover the 750M, with a standing wave length less than 1.7, below is my bedroom; using only 6-meter long cables, I was able to reach my room. This fixed-mount pull handle has been in use for over 2 years, and overall, I find it quite efficient. It's also covered a lot of ground, although the biggest issue I have is excessive background noise. Every evening or at 7 PM, I experience S9 background noise with a 7-meter cable, and around S8 with a 14-meter cable. The largest source of background noise seems to be people using electric scooters to charge inside the complex; I can clearly see thick, striped spectral lines appearing suddenly or disappearing abruptly. Because the GP antenna has a low angle of inclination, which results in high background noise, last year I installed a 4-band inverted V antenna, but due to insufficient horizontal distance and inadequate height, the antenna's angle is less than 90 degrees, making it too close to nearby conductors, resulting in impedance mismatch. In actual testing, the efficiency was not very good. However, the background noise from this inverted V antenna is significantly lower than that of the GP, at least 2S. Often, the strong electric scooter charging interference I see on the GP does not appear or is very weak on the inverted V antenna line.
The budget allows for a support structure costing no more than 2000 yuan. I had previously considered the V750, but that antenna also requires a tall mounting pole and is quite large, which I was concerned would attract unwanted attention from the property management. Using the existing pull-out mechanism seems like a viable temporary solution. I'm not sure if other vertical antennas will have the same high ground noise as mine. It's likely they will, which has caused me considerable hesitation. My current plan is to purchase the V750 and install it in the circled area in the picture. Initially, I won't mount it too high, using a 4-meter steel pipe to position it approximately 3 meters above the lightning protection net. I will adjust the rotation direction to minimize standing wave at 7M and 14M, while also keeping ground noise as low as possible. I plan to try this setup first. If the results are unsatisfactory, I will consider raising it by another 2 meters in about a year and a half.
I would like to ask my fellow enthusiasts for their experience and insights regarding antenna installation, particularly those with more extensive or diverse experiences using different types of antennas. Please share your knowledge.
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