ESAT RHM 1 Part 3 201-290

200. What circuit blocks RF energy above and below a certain limit?

201. In order to reduce the harmonic output of a high frequency (HF) transmitter, which of the following filters should be installed at the transmitter?

202. Find the signal power of the source, 10km from the load, if the line connected to the load has a degradation rating of 0.6 dB/km. The load power is 3.2mW.

203. To reduce energy from an HF transmitter getting into a television set, you would place a _______ as close to the TV as possible.

204. What are some reasons to use parallelconductor feed line?

205. As the length of a feed line is changed, what happens to signal loss?

206. Losses occurring on a transmission line between transmitter and antenna results in:

207. It is a noise having a power density that increases by 3dB per octave.

208. It is a noise that sounds the same to the ears regardless of the frequency.

209. These are background noises of the world.

210. It is a form of AM in which a single carrier frequency is independently modulated by two different modulating signals.

211. Double Sideband Full Carrier ITU emission code

212. Independent Sideband ITU emission code

213. It is inherent and unavoidable power loss because of the finite resistance of the transmission lines, and depends somewhat on frequency because of a phenomenon known as skin effect.

214. Magnetic lines of force projected into space resulting in power loss. It acts like an antenna.

215. It is a luminous discharge that occurs between the two conductors of a transmission line when the difference of potential between them exceeds the breakdown voltage of the dielectric insulator.

216. States that the longer the antenna, the higher the loss.

217. It is the simplest type of antenna feeding using open-wire parallel conductor feeders to the center of the antenna.

218. It is a type of antenna feeding wherein the feedpoint is at the current loop, which always occurs at the midpoint of a half-wavelength section of the antenna.

219. Also known as loop and is a maximum point in the standing wave,

220. A line consisting of parallel conductors separated from each other and surrounded by a solid dielectric.

221. The main characteristic of a vertical antenna is that it will:

222. What is the main reason why so many VHF base and mobile antennas are 5/8 of a wavelength?

223. Approximately how long is the driven element of a Yagi antenna for 14.0 MHz?

224. The distribution of voltage and current formed by the incident and reflected waves which have minimum and maximum points on a resultant wave that appears to stand still.

225. The device used to send the transmitted signal energy into space.

226. A band reject filter will:

227. A low pass filter suitable for a high frequency transmitter would:

228. In what values are RF feed line losses expressed?

229. If the forward gain of a six-element Yagi is about 10 dB, what would the gain of two of these antennas be if they were "stacked"?

230. If the frequency is increased, how would this affect the loss on a transmission line? (Answer bank has it wrong. Answer should be: It would increase)

231. What does an SWR reading of less than 1.5:1 mean?

232. It is the generation of unwanted sum and difference frequencies when two or more signals are amplified by a nonlinear device.

233. It is a figure of merit used to indicate how much signal-to-noise ratio deteriorates as signals passes through a circuit or series of circuits.

234. Frequencies that includes AC power distribution signals (60 Hz) and low frequency telemetry signals.

235. It is a type of analog modulation in which the angle sinusoidal reference function is varied in accordance with a modulation signal.

236. Radio station DWAZ is broadcasting on a 182- meter antenna. To tune to this particulars station what frequency in kHz will you set your manually tunable receiver to receive the broadcast?

237. What is the standard FM Range

238. It is the relative displacement of the carrier frequency with respect to its unmodulated value.

239. It is also known as a flat line or a matched line, wherein there is no reflected power in the transmission line.

240. It is a vector quantity that represent the ratio of the reflected voltage to the incident voltage or current.

241. It is a measure of mismatch between the load impedance and the characteristic impedance of a transmission line.

242. It is the process of increasing the electrical length of an antenna by an addition of inductance or capacitance.

243. It is a method of altering the resonant frequency of an antenna radiator in which an inductance or capacitance is placed along the physical length of the radiator, approximately halfway between the feedpoint and the end.

244. It is the orientation or direction in space of the electric field portion of the electromagnetic wave being radiated by the transmitting system.

245. Another name for the resonant line. This line uses tuning devices to eliminate the reactance and to transfer maximum power from the source to the line.

246. A parallel line similar to a two-wire open line except that uniform spacing is assured by embedding the two wires in a low-loss dielectric.

247. A bi-directional antenna, shaped like a V, which is widely used for communications.

248. What does a very high SWR reading mean?

249. If your antenna feed line gets hot when you are transmitting, what might this mean?

250. The result of the presence of standing waves on a transmission line is:

251. Used primarily for commercial AM radio broadcasting (535-1605 kHz)

252. Used by commercial TV broadcasting of channels 14 to 83, land mobile communications services, cellular telephones, certain radar and navigation systems, and microwave and satellite radio systems.

253. A certain point on a line located 12km from the source has a measured power of 7mW. Find the power at the source if the line’s attenuation is 0.5dB/km.

254. Seldom used for radio communications except in very sophisticated, expensive, and specialized applications.

255. Is the amount of power expressed in decibels that will not be available on the output due to impedance mismatches and signal reflections.

256. Are travelling waves that are coming from the transmitter.

257. It is a section of a transmission line, electrically a quarter-wavelength in length that is used to match a transmission line to a purely resistive load whose resistance is not equal to the characteristic of the line.

258. Separates a transmit and receive path based on signal direction and can be used for same frequency signals.

259. A a hypothetical antenna which radiates equally intense signals in all directions.

260. It is an electrically short linear antenna shorter than a wavelength that when radiating, is assumed to carry uniform current along its length.

261. If the power of a signal is 20 mW and the power of the noise is 1 μW, what is the value of SNR?

262. A resonant antenna having a feed point impedance of 200 ohms is connected to a feed line and transmitter which have an impedance of 50 ohms. What will the standing wave ratio of this system be?

263. What device might allow use of an antenna on a band it was not designed for?

264. What would you use to connect a coaxial cable of 50 ohms impedance to an antenna of 35 ohms impedance?

265. Includes electromagnetic frequencies that fall within the visible range of humans.

266. Has a wavelength of 495-570 nm

267. Has a wavelength of 620-750 nm

268. It is the ratio of deviation and the modulating signal frequency. It determines the number of significant pairs of sidebands in an FM signal.

269. It is the ratio of the frequency deviation actually produced to the maximum frequency deviation allowed by law stated in percent form.

270. It is a rule which is an approximation and gives transmission bandwidths that are slightly narrower than the bandwidths.

271. It is used to measure the power being delivered to a load or an antenna through a transmission line, moreover, it allows the measurement of power moving along the line in each direction.

272. Is a technique that can be used to locate an impairment in a metallic cable.

273. It is the graphical calculator, created and developed by Phillip Smith, used for transmission line matching.

274. It is also known as Marconi antenna, made up of a vertical mast, pole or rod that forms the main radiating conductor; it can be free-standing or supported by insulated guy wires and is placed in a location where good electrical ground is available.

275. It is a means of obtaining radio frequency ground or ground plane without the direct earth- ground connection. A grid of wire is placed just above the actual surface to provide capacitive coupling to the ground.

276. What happens when the impedance of an electrical load is equal to the internal impedance of the power source?

277. To obtain efficient power transmission from a transmitter to an antenna requires:

278. If an antenna is correctly matched to a transmitter, the length of transmission line:

279. An FM system with relatively large modulation index.

280. It is an FM generation method in which the output is already an FM signal.

281. It is an FM generator utilizing a voltage- variable capacitor diode.

282. It is a flat conductor sandwiched between two ground planes.

283. It is an individual radiator, such as a half- wave or quarter wave dipole.

284. It is an element that is not connected to the transmission line, it receives energy only through mutual induction with a driven element.

285. It is a parasitic element 5% shorter than the driven element, which tends to increase radiation in its own direction and reduces it in the opposite direction. It acts as if it were a convergent convex mirror.

286. A simple AM transmitter employs an oscillator of a 20 μH coil and 2 nF capacitor. If the oscillator output is modulated by audio frequency of up to 24 kHz what is the center frequency of the transmitter in Hz?

287. Moving the feed point of a multielement quad antenna from a side parallel to the ground to a side perpendicular to the ground will have what effect?

288. The cubical "quad" or "quad" antenna consists of two or more square loops of wire. The driven element has an approximate overall length of:

289. The primary radiating source is located in or just behind a small opening at the vertex of the paraboloid rather than at the focus.

290. A circuit consists of two amplifiers with gains of 6.8 and 14.3 dB and two filters with attenuations of 16.4 and 2.9 dB. If the output voltage is 800 mV, what is the input voltage?