Hi Rod,
Thank you, I can go endleslsy, when you or the forum get's fed-up please say so and we can go off-board.
I have some comments.
For SES, extracts from Air Ministry Report:
Air Scientific Intelligence - Report No. 83 - Recent Developments in German Route Tracking and RCM (dated 26.3.45)
Since report No. 73 (July 1944) new developments highlighted -
1. formation of specialist RCM unit
2. spread of route tracking to GCI stations
3. use of listening recivers for guiding long-range radars
It notes that the function of the RCM unit is largely deployed in the problem of jamming Oboe.
1. RCM Development - History
Nov 1943, special detachment of German Air Signals Experimental Regiment established near Duisburg for investigating methods of defence against Oboe. The unit was able to cover most Oboe transmissions in Germany from Duisburg.
During 1944, transmissions were plotted successfully by listening and Oboe Mk I was then successfully jammed. In May 1944 the unit was commended for it's work during a big attack on Duisburg.
The unit had managed to identify and plot Oboe Mk II transmissions and thusidentify the main raids from the spoofs - being the only unit which gave a clear picture of the Duisburg raid.
The techniques developed were then passed on to the whole route tracking organisation.
In the second half of 1944, a jammer against centimetic Oboe was introduced. The unit is began to develop counter-measures against other navigational aids.
Correct, please see:
http://www.gyges.dk/jamming_service%20Oboe.htm
2. Deployment
Very little info known (since the intelligence service had difficulty tracking movements via ULTRA because of a change in unit nomenclature by the Germans). Unit concerned was IVth Abteiltung of LN Regiment 351 with 25 to 30 stations in Western Germany. Most stations were deployed in the valley of the Rhine. With Allied advances, units were forced to withdraw and deployment (at date of report) not known. Units were mobile and it was assumed that because of fuel shortage, mobile generators were not an option so they would have to be positioned close to a electricity supply.
Incorrect. Some of these units were in the middle of nowhere.
3. Listening
New procedure developed where unit claimed to be able to give "10-15 minutes" warning of target.
Correct. The morse signals exchanged between the aircraft and the ground station gave a count down to bomb release starting 10 min out. At this point the target was also frequently identified and warned, often through The Ruhr Stab. The air raid warning was sounded and the facility evacuated.
It turned out that new method was simply listening to W/T traffic between Oboe ground stations (presumedly on the continent), so Oboe procedure was tightened up and land lines used for communications more often.
Didn't help. The germans exploited the Morse signals as described above.
4. Jamming
Method of jamming Oboe Mk I was relatively simple to achieve. Modified Freya used to interrogate the a/c set
Incorrect. The reciever was a modified Würzburg Dora called the Naxburg.
, wait unit the the a/c was close to the release point and then jam the signal.
Equipment used to jam centimetic Oboe was device called "Ali-Baba Gerat" -
The German SIGINT name for Oboe was Bumerang. The jammer was thus an Anti-Bumerang Gerät. So you have the A & B. If Ali-Baba was a German nick-name I don't know.
at least three versions produced to cover metric and centimetic Oboe. This device seen as centimetic jammer employing two methods to jam -
Correct, please see link above.
(1) straight interrogation
(2) Method known as "Ball" - Korfu D/F sets
(Naxburg) are used to try to lock in on the signal (cm Oboe transmissions narrower and more directional making it hard to stay focused on the transmission).
Thus two techiques comprise 1. above: unlocked pulses due to straight interrogation of the set and 2. above: locked pulses were the jammer is tracked using "Ball".
Only in late Feb/Mar 1945 did RAF BC No. 8 Grp and USAAF 8th AF notice increased jamming. RAF No. 60 Grp took ranges and bearings on locked pulses and found originating location was at a known jamming site (location of which not given in report).
Apparently the unit mainly works during the day, according to the report, presumedly because more jamming was encountered then.
5. Aids to Flak
Refers to map captured near Duisburg which basically showed technique whereby Oboe plotting data could be fed in to flak predictors.
Correct.
The map showed the positions of Allied Oboe stations and thus, the Germans would have to guess which stations were being used at a given time for the technique to work,
Incorrect. It was the signal from the aircraft which was intercepted and exploited.
The report adds that two Oboe sites on the map were at locations were no Oboe station ever existed.
6. GEE
IV LN Reg 351 believed to be involved in tracking and jamming of GEE
Correct, please see:
http://www.gyges.dk/jamming_service%20GEE.htm
and this ocured earlier than jamming of Oboe.
7. GEE-H
In Oct 1944, captured equipment finally gave Germans clues about GEE-H system. Some Ali-Baba Gerats then converted to GEE-H frequency. It was thought that by then using "Ball" technique, it should have been possible to commence jamming of GEE-H transmissions but no effective jamming had been encountered to date.
8. SS LORAN
Germans started jamming SS Loran in Feb 1945 using noise modulation. One such jamming station identified was connected by land-line to nearest station of IV LN Regt 351.
9. Route-Tracking & GCI Stations
According to the report, the Germans had held the opinion for some time that analysing correctly the movements of the Mosquito night fighters, especially distinguishing between high and low patrols, would enable them to deduce the intentions of the main bomber force.
In Sep 1944 a special detachment of the German Air Signals Experimental Regiment was provided with "Naxburg" and told to investigate the 10cm AI signals from RAF night fighters.
Never heard of this, technically feasible using Naxburg.
Work of this unit apparently successful as most GCI stations in Western Europe issued with Naxburg and Heinrich sets.
Not correct. Cannot be confirmed in German sources and the Naxburg was produced in fairly small numbers. Heinrich is the name of the GEE jammmer and this was employed in special sites. It is also the D/F part of the Y-Linien (Benito) system. And all Himmelbett Stellungen was equipped with these systems.
According to the report, the Heinrich sets could be used to D/F the 'Jostle' support aircraft in the bomber streams, carrying jammers on the 38-42 Mc/s band. Thus it was assumed that the GCI stations were taking part in the route tracking of the RAF night fighters and 'Jostle' aircraft, while the actual analysis was still performed in the plotting stations.
Incorrect. The Heinrich-Peiler might be able to take bearings on the jamming, but neither the Flugmeldemess Stellungen, nor the Jägerleit Stellungen were affiliated with the Funkaufklärungs Dienst.
10. Use of Listening Receivers in Conjunction with Long Range Radar
In Nov 1944, a number of long-range radar sets (i.e. Wassermann, Mammut) in the coastal sectors were issued with Korfu 812 D/F sets.
New to me, but I know for fact that one Stellung in Denmark (RINGELNATTER) as the only one was equipped with a Korfu.
These were to be used to guide the radar sets onto the bombers and not for route tracking. It was thought that because RAF bombers were forbidden from using H2S
Slightly odd comment. The Pathfinders in the Bomber Stream used H2S to find and mark turning points, and it was this indiscrimite use of H2S, which enabled the Luftwaffe to track The Stream from very early on during the approach.
until close to the German frontier, the sets were being used to guide the radar on to USAAF 8th AF Bombers during their assembly over the UK.
That's it in a nutshell
Cheers
Rod