1 Introduction Environmental testing is a common method for testing the reliability of electronic products and is widely used in various development cycles of electronic products. It is used to determine the adaptability of communication equipment to the environment. In the environmental test process, according to the characteristics of the product, select the appropriate test method, and test and evaluate the mechanical properties, electrical properties, physical properties, tensile strength and tensile strength of the product, and insulation properties. The correct test results can only be obtained by selecting the correct test method and standard test conditions. During the constant damp heat process, the product is preheated to avoid the occurrence of a large amount of condensation, causing additional stress, which affects the correct evaluation of the experimental results. 2 Overview of the tested communication products A communication device is an outdoor device that uses natural heat dissipation. It is characterized by large volume, high heat consumption and sealed cavity. Working environment temperature: a temperature of 40 ° C to 55%, the temperature rise inside the chassis is required to be no more than 20. C, working humidity: 10% to 95% (relative humidity); storage temperature: 40 ° C -85 ° C, storage humidity: ≤ 93% (relative humidity); total weight of the machine: 50Kg. The overall structure adopts a box structure. It consists of cabinet, door, mounting accessories and internal power module, two power amplifier modules, two low noise amplifier modules, two duplexers (DUP), lightning protection modules and monitoring boards. 3 Analysis of condensation problems in environmental tests For such a sealed, heat-hungry, bulky natural heat-dissipating product, if the heat inside the product is not transferred to the surrounding atmosphere, the product temperature will continue to rise. In fact, the heat generated by the product is continuously emitted to the surrounding environment. Finally, the heat generated by the product is balanced with the heat dissipated in the surrounding cooling atmosphere to stabilize the temperature of the product. Only when the ambient temperature rises (or falls) will the temperature inside the product rise (or fall) further until it reaches a new equilibrium. Since the ambient temperature chamber is affected by ambient temperature and humidity, the humidity is not much different from the ambient humidity in high temperature and low temperature and high and low temperature tests, about 48% (before at least before the heat balance is reached). The general environmental test chamber has a humidity control function. The usual humidification methods are as follows: Spray humidification: easy to produce a small amount of aerosol in the work space; Steam humidification: may cause condensation on equipment with low temperature inside the tank; Volatile humidification: a small amount of aerosol; Aqueous solution humidification: easy to cause corrosion; When the experimental sample is placed in the experimental chamber, if the surface temperature of the experimental sample is lower than the dew point temperature of the air in the test chamber, condensation will appear on the surface of the sample. Therefore, the experimental sample is generally preheated before the experiment. The dew point temperature depends on the amount of water vapor in the air, and there is a direct relationship between dew point temperature, absolute humidity and water vapor pressure. During the experiment, if the moisture content in the air and the air temperature are high, a certain difference is reached between the air dew point temperature and the surface temperature of the test sample, and condensation is generated. Generally, in the temperature rising stage of the experiment, since the experimental sample has a certain thermal time constant, the surface temperature is often lower than the dew point temperature of the air in the experimental box, and therefore, the surface of the experimental sample is condensed. When the experimental sample produces condensation in the course of the experiment, the following physical phenomena exist due to humidity: Adsorption: The amount of water vapor molecules on the surface of the experimental sample is determined by the type of material on the surface of the device, the surface structure of the material, and the magnitude of the vapor pressure. Absorption: Depending on the moisture content of the surrounding environment, the rate at which water molecules penetrate deep increases with increasing temperature. Diffusion: water vapor enters the interior of the housing through the organic sealing material; Breathing: The exchange of air and water vapor inside and outside the cavity of the experimental sample due to temperature changes, and the experimental sample of the poor sealing type, the moisture inhaled causes the internal structure of the experimental sample to be damp, or condensed into aggregated water in the cavity. The absorption and diffusion process takes a long time to reach equilibrium, and the condensation and adsorption processes are shorter. Therefore, it is a normal experimental phenomenon for the sealed communication equipment with large volume and large heat dissipation to exhibit a small amount of condensation on the surface during the experiment. The amount of water vapor on the surface of the equipment and the length of the attachment time are different due to changes in temperature and humidity in the environmental test chamber. If a large amount of water vapor and condensation occur, the experimental conditions need to be adjusted to prevent large deviations in the experimental results. 4 conclusions and recommendations 1) A small amount of condensation during environmental testing will not cause damage to the performance of the equipment. It also does not affect the analysis of experimental results. 2) In order to prevent the occurrence of a large amount of condensation, the analysis of the experimental results leads to a wrong orientation, and the product is generally preheated in advance during the environmental experiment. 3) Environmental experiments have a great influence on the experimental samples, which may change the mechanical properties, physical properties and electrical properties of the materials. Therefore, in the initial stage of product design, considering the actual use conditions, select the appropriate components, Guangdong Hongzhan Technology Co., Ltd. The use of derating design, redundant design, tolerance design, climate protection design, buffer damping design, thermal design and other means to improve product reliability. In environmental experiments, only by applying appropriate experimental conditions, exposing existing problems, and seeking appropriate improvement measures, can further determine the adaptability of the product and make the product meet the requirements for use. Hongzhan has a research institute specializing in the research and development of environmental test equipment. It has mature loop test development methods and laboratories, and gathers a group of outstanding talents and well-known experts in the industry. The strong R&D team leads the domestic loop test technology. Development direction. At present, the company has high and low temperature test chambers with independent intellectual property rights, high and low temperature wet heat test chambers, rapid temperature change test chambers, thermal shock test chambers, three comprehensive test chambers, high and low temperature low pressure test chambers, solar radiation test. The climate environmental testing equipment and customized products such as boxes, industrial ovens and walk-in high and low temperature damp heat test chambers and high wind speed rain test chambers are at the leading domestic level and international high standards. Bed Sheet for Mattress protect mattress protector HESHAN HAIMA FURNITURE CO., LTD , https://www.springmattress.com