158:
299:
all times. A downside to this approach is that the signal only spends a brief period of time at any one radar's frequency; depending on the scanning rate, the radar may only be jammed during certain periods, but if the rate is increased to offset this, the amount of noise in any one pulse period is reduced. More complex jammers can scan only the bands it sees being used, improving its effectiveness.
63:
22:
233:
298:
whose frequency can be adjusted across a very wide band simply by changing the input voltage. A single carcinotron could be swept through the entire bandwidth of any potential radar network, jamming all of the radars in such rapid sequence that it appeared to be constant noise on all frequencies at
270:
Early radar systems typically operated on a single frequency, and could only change that frequency by changing internal electronics. Against these radars, it was possible to use conventional radio sets to send out signals on the same band, causing the radar display to be filled with noise whenever
310:
radars, which change their frequency from pulse to pulse, force the jammer spread its signal across the entire bandwidth, ensuring the signal is diluted. Combining this with extremely powerful signals and highly focused antennas allowed new radars to overpower the jammers, "burning through" the
318:
Barrage jammers also have the disadvantage that they are very easy to detect using a wideband receiver. This can be used to track the jammer using a variety of techniques. A well developed instance of this was deployed by the
327:
network, which could track jammer-carrying aircraft with accuracy equal to a radar. More generally, a barrage jammer's signal is so easy to receive that it makes an excellent early warning signal on its own.
236:
This image shows the effect of four carcinotron-carrying aircraft on a typical 1950s early warning radar. The aircraft are located at the 4 and 6 o'clock positions, which are completely filled with noise.
302:
Barrage jamming was extremely effective against 1950s radars, to the point where there was some belief that the carcinotron might render ground-based radars useless, especially in the
311:
jamming. Simple techniques, like turning off the receivers when the antenna was pointed close to the jammer, allowed the radar to continue tracking other targets. The use of
267:
of any single radar. This allows the jammer to jam multiple radars at once, and reduces or eliminates the need for adjustments to respond to any single radar.
271:
the antenna was pointed in the general direction of the jammer. However, given that each individual radar would be operating on different frequencies, this "
73:
275:" technique required multiple radio sets in order to jam more than one radar at a time, and true wide-band barrage jamming was very difficult.
179:
387:
364:
219:
201:
49:
35:
131:
88:
259:
invisible on the display, and often those in the nearby area as well. "Barrage" refers to systems that send signals in many
103:
264:
110:
248:
172:
166:
117:
183:
232:
99:
286:
tubes to amplify a wideband noise source, An improved approach appeared with the introduction of the
41:
303:
272:
244:
357:
124:
315:
antennas and signal processing techniques that reduced sidelobes also improved performance.
320:
307:
283:
306:
role. By the 1960s a number of techniques had been introduced to combat barrage jamming.
381:
337:
312:
279:
260:
291:
287:
62:
295:
80:
324:
255:
systems by filling the display with noise, rendering the broadcaster's
252:
231:
151:
56:
15:
84:
8:
89:introducing citations to additional sources
50:Learn how and when to remove these messages
220:Learn how and when to remove this message
202:Learn how and when to remove this message
165:This article includes a list of general
79:Relevant discussion may be found on the
349:
7:
247:technique that attempts to blind ("
171:it lacks sufficient corresponding
14:
31:This article has multiple issues.
370:from the original on 2022-10-09.
156:
72:relies largely or entirely on a
61:
20:
263:of frequencies compared to the
39:or discuss these issues on the
1:
404:
388:Electronic countermeasures
358:"Photomultiplier Handbook"
278:Early barrage jammers in
186:more precise citations.
290:in the early 1950s, a
237:
235:
85:improve this article
304:early warning radar
245:electronic warfare
238:
230:
229:
222:
212:
211:
204:
150:
149:
135:
100:"Barrage jamming"
54:
395:
372:
371:
369:
362:
354:
225:
218:
207:
200:
196:
193:
187:
182:this article by
173:inline citations
160:
159:
152:
145:
142:
136:
134:
93:
65:
57:
46:
24:
23:
16:
403:
402:
398:
397:
396:
394:
393:
392:
378:
377:
376:
375:
367:
360:
356:
355:
351:
346:
334:
308:Frequency agile
294:that generates
284:photomultiplier
241:Barrage jamming
226:
215:
214:
213:
208:
197:
191:
188:
178:Please help to
177:
161:
157:
146:
140:
137:
94:
92:
78:
66:
25:
21:
12:
11:
5:
401:
399:
391:
390:
380:
379:
374:
373:
348:
347:
345:
342:
341:
340:
333:
330:
228:
227:
210:
209:
164:
162:
155:
148:
147:
83:. Please help
69:
67:
60:
55:
29:
28:
26:
19:
13:
10:
9:
6:
4:
3:
2:
400:
389:
386:
385:
383:
366:
359:
353:
350:
343:
339:
338:Radio jamming
336:
335:
331:
329:
326:
322:
316:
314:
309:
305:
300:
297:
293:
289:
285:
281:
276:
274:
268:
266:
262:
258:
254:
250:
246:
242:
234:
224:
221:
206:
203:
195:
185:
181:
175:
174:
168:
163:
154:
153:
144:
133:
130:
126:
123:
119:
116:
112:
109:
105:
102: –
101:
97:
96:Find sources:
90:
86:
82:
76:
75:
74:single source
70:This article
68:
64:
59:
58:
53:
51:
44:
43:
38:
37:
32:
27:
18:
17:
352:
317:
313:phased array
301:
280:World War II
277:
273:spot jamming
269:
256:
240:
239:
216:
198:
189:
170:
138:
128:
121:
114:
107:
95:
71:
47:
40:
34:
33:Please help
30:
292:vacuum tube
288:carcinotron
192:August 2023
184:introducing
141:August 2023
344:References
296:microwaves
167:references
111:newspapers
36:improve it
323:in their
265:bandwidth
81:talk page
42:talk page
382:Category
365:Archived
332:See also
325:RX12874
243:is an
180:improve
125:scholar
169:, but
127:
120:
113:
106:
98:
368:(PDF)
361:(PDF)
282:used
261:bands
253:radar
132:JSTOR
118:books
257:blip
104:news
321:RAF
251:")
249:jam
87:by
384::
363:.
45:.
223:)
217:(
205:)
199:(
194:)
190:(
176:.
143:)
139:(
129:·
122:·
115:·
108:·
91:.
77:.
52:)
48:(
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.