Radio Direction Finding

[Charly_Owl]

Hi folks,

 

I was very happy to see that the T1154 Radio Transmitter set and the R1155 Radio Receiver set were both implemented in the game. However, I,ve noticed that the documentation is somewhat lacking in how to use them.

 

 

As an example, I created a mission with a unit transmitting a morse signal on a set frequency (say, 8 MHz).

 

 

The following questions I have for the Eagle Dynamics team @NineLine@BIGNEWY@SUNTSAG are:

 

1. How do I set up a mission with a beacon that I can home on using the direction finder? 
2. How do I use the direction finder? Is there a step-by-step procedure you could provide us? I assume we would need to set up this frequency on the R1155 box.
3. How do we transmit on the T1154 radio? There appears to be preset frequencies but I'm not 100 % sure how to set them up. 
4. On the D/F antenna, there are two heading scales; one in red, and one in black. What's the difference between these scales? Which one should be used?
5. How do we use the Direction FInding indicator on the front panel (the one above the bomb setting panel)?

 

 

After playing with a bunch of switches, here are some of my preliminary findings. I don't know if that's the correct procedure... 

 

a) The T1154 Power switch has to be ON.

b) The T1154 Master Switch has to be to Standby in order to be able to use the receiver set

c) To track the direction of a radio signal, the aerial type selector has to be set to DF (Direction Finding), the frequency has to be set on the R1155 box  and the R1155 has to be set to Figure-of-Eight.

d) Turning the DF Loop Antenna will make the audio signal stronger or weaker since you change the orientation of the antenna. From the source of the "weakest" signal (not the strongest, as I initially thought), you can determine the direction of the radio signal source.

 

 

 

Edited September 19, 2021 by Charly_Owl

[Reflected]

+1

 

Following

[Nazgul9]

Great info

[Reflected]

OK, I did everything you listed, placed a jeep made it transmit a looped morse code on 8 Mhz, and I could hear it. But how do I find it? By guessing the direction at which the antenna is turned and that gives the loudest signal?

[Tarres]

And the ARI is functional?

 

Yes, we need some documentation about the system.

Edited September 19, 2021 by Tarres

[saburo_cz]

D/F worked with frequency ranges:

75 - 200 kHz

200 - 500 kHz

600 - 1500 kHz

3 - 7,5 MHz

 

And if you are searching for signal from beacon by only loop antena, you look for the lowest signal, not the highes.

Edited September 19, 2021 by saburo_cz
edded one frequency range

[lankypilot77]

Really appreciate the effort researching all this information to benefit everyone Chuck. You deserve unlimited access to the whole documentation vault!

[Charly_Owl]

The quest for knowledge continues. Really hoping ED can provide some help with all this.

 

I found an interesting video about the R1155 DF. Setting the R1155 Mode Selector to Visual and turning on the Beam Approach Power switch allows you to use the DF Indicator on the front panel. Changing the loop antenna orientation will make the needles on the indicator move. Not quite sure if the results I have make sense.

 

Link: https://youtu.be/POyFjwUZg_c 

 

[RodBorza]

11 hours ago, Charly_Owl said:

 

 

 

 

The following questions I have for the Eagle Dynamics team @NineLine@BIGNEWY@SUNTSAG are:

 

1. How do I set up a mission with a beacon that I can home on using the direction finder? 
2. How do I use the direction finder? Is there a step-by-step procedure you could provide us? I assume we would need to set up this frequency on the R1155 box.
3. How do we transmit on the T1154 radio? There appears to be preset frequencies but I'm not 100 % sure how to set them up. 
4. On the D/F antenna, there are two heading scales; one in red, and one in black. What's the difference between these scales? Which one should be used?
5. How do we use the Direction FInding indicator on the front panel (the one above the bomb setting panel)?

 

 

After playing with a bunch of switches, here are some of my preliminary findings. I don't know if that's the correct procedure... 

 

a) The T1154 Power switch has to be ON.

b) The T1154 Master Switch has to be to Standby in order to be able to use the receiver set

c) To track the direction of a radio signal, the aerial type selector has to be set to DF (Direction Finding), the frequency has to be set on the R1155 box  and the R1155 has to be set to Figure-of-Eight.

d) Turning the DF Loop Antenna will make the audio signal stronger or weaker since you change the orientation of the antenna. From the source of the "weakest" signal (not the strongest, as I initially thought), you can determine the direction of the radio signal source.

 

 

 

 

 

 

Hi Charly,

 

Coincidentally I was fiddling around with the radios yesterday.

 

I got to the same conclusions as you were, and my observation are:

 

 

a) The T1154 Power switch has to be ON.

There are two switches, one is the Low voltage Circuit, and the other is the High Voltage switch. They are located on  the right hand wall, below a brass knob; There is a third switch, but that is for the Transmitter function. Don't know if it has to be on or not.

 

b) The T1154 Master Switch has to be to Standby in order to be able to use the receiver set

Correct.

 

c) To track the direction of a radio signal, the aerial type selector has to be set to DF (Direction Finding), the frequency has to be set on the R1155 box  and the R1155 has to be set to Figure-of-Eight.

I didn't tested it, but for me the tuning worked at the first setting and A.V.C.

 

d) Turning the DF Loop Antenna will make the audio signal stronger or weaker since you change the orientation of the antenna. From the source of the "weakest" signal (not the strongest, as I initially thought), you can determine the direction of the radio signal source.

Yes, and you can see where the signal is coming from RELATIVE to the aircraft by unlocking and turning the ADF antenna wheel. But there is a catch. Once you turn to the signal source, you must take the antenna back to the zero position, in order to have the best signal while flying towards the radio source.

 

Regarding the Direction Finding Indicator above the panel, I observed the following:

0) Set the radio frequency to the desired station.

1) Set the Master on the R-1155 to Visual;

2) Set the Aerial Type to D/F 

3) Observe the needles getting out of their resting position, when they are crossed as shown on the picture you sent, to the direction of the station.

 

If you are centered, both needles will point more or less to the center.

If you are left of the station, the left needle will cross over to the right half of the indicator, and the right needle will be more or less centered.

If you are right of the station, the right needle will cross over to the left half os the indicator, and the left need will maintain the same position (more or less).

 

I tested it on the ground in Batumi, where there is a station at the end of the runway (430kHz - LU morse code), very easy to pick it up. I started out at the ramp, then taxied out to the runway and to the end of the runway. The needles moved accordingly. 

Then I switched to a station to Kobuleti (870 Khz - KT morse code), and it picked up and moved the needles accordingly.

The best place to test it, in my opinion, is the Caucasus map where there are a plethora of NDB stations.

 

Of course, before switching to a new station, you have to be out of the Visual mode, back to tuning mode, then back to Visual again.

 

Regarding the Transmitter, I believe it transforms the Mosquito in a flying Station, similar to a modern TACAN (minus the distance functionality). I believe this functionality can be used in pathfinder missions, where a Mosquito can be the Pathfinder and others can homing on this one. I didn't tested it in Single Player, but I believe it can be done in Multiplayer, with one Mossie being the transmitter and the other the receiver.   

 

Edited September 19, 2021 by RodBorza

[saburo_cz]

Both D/F methods work for DCS Mosquito. And it is great.

 

https://www.youtube.com/watch?v=c_GUs-WmFWs

 

I tried them and i was surprised.

[RodBorza]

Regarding the A1271 Beam Approach Receiver. It is a early form of ILS, that used aural signs to guide pilots in for landing. Not directly tied to the R1155.

 

This site has good information about it:

 

http://www.tuberadio.com/robinson/museum/command_SBA/ 

[RodBorza]

Another one from the same site, about the R1155 receiver:

http://www.tuberadio.com/robinson/museum/R1155/

 

This site has the following information:

 

"D/F CONTROLS

It has several controls for D/F which are enabled by the MASTER switch. In the BALANCE position, a dummy aerial coil is switched in, and the receiver electrical characteristics can be balanced by observing the Visual Indicator and adjusting the METER BALANCE control until the Visual Indicator needles intersect on the centre line. The needles can be moved up and down the centre line with the METER AMPLITUDE control. This may have to be adjusted later when the strength of the homing signal changes. In the VISUAL position, the aerials are connected, and the difference in the phase of the signals from the aerials shows the deviation from a course to a transmitter, which enables the aircraft to fly toward it, and home in on it. This uses the loop aerial and the fixed aerial. to do visual homing, switch to VISUAL. Set the loop "athwarthship" (ie to a zero scale reading) and ask the pilot to alter course until the needles intersect on the centre line. Then alter course slightly and observe the deflection. If the course is offset a few degrees to the left and the needles cross to the right, then this is the correct course. If they intersect also to the left, then the station is astern, and a 180 degree turn should be made. The METER DEFLECTION control can be set to HIGH or LOW which narrows the cardioid aerial pattern for easier homing. The SWITCH SPEED can be set to HIGH or LOW which changes the switching rate of the multivibrator. Since the multivibrator can be heard as a buzz on the received signal, the radio operator can listen to CW or voice, and change the buzz to make the signals more intelligible (HIGH for CW and LOW for R/T), during homing. The last position is a "FIGURE-OF-EIGHT" position (shown on the front panel as the number eight symbol) and this uses the loop aerial only, to determine transmitter direction, the 8 representing the loop aerial pattern. Since the transmitter direction can be true or reciprocal, an AURAL SENSE switch can be set to L or R to determine the correct direction.  This switches in the fixed aerial, and will make the signal louder or softer. To do this, first select the FIGURE-OF-EIGHT position and rotate the loop to a null, and observe the loop scale reading.  This will be the true course or the reciprocal. To determine which, rotate the loop Reducing the scale reading, and push the AURAL SENSE switch to R. If the signal increases, the course is Right. This is the RRR rule (Reduce, Right, Right). If it decreases, rotate the loop through 180 degrees and repeat the procedure."

 

And:

 

 

"VISUAL INDICATOR

This is used for homing or D/F. The instrument is normally in front of the pilot and/or the navigator. When the aircraft is flying towards the homing signal, the needles cross on the centre line. If the aircraft deviates, then the needles cross to the left or right of the centre line to indicate that you are off course, and need to correct. If they cross to the left, then you need to turn to the left to correct your course, and similarly for the other side. As you approach the homing transmitter, the needles will move higher up the centre line. You can reduce this with the METER AMPLITUDE control.  If the homing signal seems too broad to get an good course, then the METER DEFLECTION switch can be used to make it more accurate by switching between the HIGH and LOW positions. This control makes the cardioid pattern sharper. As you fly over the homing transmitter, the needles will collapse, and then restore to their original level as you fly away, however the sense is reversed"

 

Contrary to what I posted before, the correct use is when the needles are crossed. They go up or down depending if you are nearing or going away from the station.

 

Everything is (almost) clear now, time to go for some flight testing.

 

Regarding the T1154 information about it is hard to come by. Will keep searching.  

[Reflected]

Great info chaps, thanks!

 

using the needles is a piece of cake. 
 

my question is, why qould you fiddle with turnin the antenna instead of juat using the needles?

 

also the beam approach is something totally different, right?

 

how does that work?

[Tarres]

Yes, the beam aproach A1271 is different.

I´m testing now in the Caucasus.

I set the A1271 freq in the ME with the ILS freq of Senaki. In flight, If you set to on the A1271, you can hear a morse tone. This tone change according to the doc posted above by RodBorza

 http://www.tuberadio.com/robinson/museum/command_SBA/ 

 

Later I will try to set a A1271 beacon in the WW2 maps. 

 

Works perfect.

[Reflected]

It did not provide glideslope info did it? I’m curious how you can set it up in the ME for the ww2 maps, because you need to give a direction to the signal too. 

[Tarres]

Only aural signals that you are to the left/right or centered in the beam.

 

 

[Krupi]

Trying to understand the capabilities of the system myself. 

 

Can this be used to create the Oboe navigation system. I.e. Can this be used to direct you on to a target?

 

 

The image above shows the basic principle. The pilot and navigator would hear either dots or dashes telling them if they were on the correct radius. 

 

 

[Reflected]

Oboe is slightly different. It’s a bit more complex and uses 2 stations. It measures distance from the stations along an arc, not a direction. I recreated it using triggers and zones in one of the missions of my upcoming campaign.  Later I’ll make a tutorial about it. 

Edited September 20, 2021 by Reflected

[Krupi]

4 minutes ago, Reflected said:

Oboe is slightly different. It’s a bit more complex and uses 2 stations. It measures distance from the stations along an arc, not a direction. I recreated it using triggers and zones in one of the missions of my upcoming campaign.  Later I’ll make a tutorial about it. 

 

 

Yes, sorry didn't explain myself correctly. 

 

That is absolutely fantastic news, do you hear the dots and dashes? 

[Don Rudi]

1 hour ago, Tarres said:

Only aural signals that you are to the left/right or centered in the beam.

 

 

How do you set a direction for a beam in the editor? 

[Reflected]

18 minutes ago, Krupi said:

 

Yes, sorry didn't explain myself correctly. 

 

That is absolutely fantastic news, do you hear the dots and dashes? 

Yes, and different levels of overlap as you approach the track. So when you are still too close to the station but getting close to the path, you hear dots with faint dashes in between.

it’s not easy at first.  Originally the path was only 30-40 yards wide. In dcs I made it slightly more forgiving but still very challenging. 

 

plus I set up the distance indication codes sent by the cat and mouse stations. Oh and the release cue. 

Edited September 20, 2021 by Reflected

[Krupi]

14 minutes ago, Reflected said:

Yes, and different levels of overlap as you approach the track. So when you are still too close to the station but getting close to the path, you hear dots with faint dashes in between.

it’s not easy at first.  Originally the path was only 30-40 yards wide. In dcs I made it slightly more forgiving but still very challenging. 

 

plus I set up the distance indication codes sent by the cat and mouse stations. Oh and the release cue. 

 

 

This is excellent stuff. 

 

Can you set the altitude? I assume they would be told this at the briefing. 

 

Could this be used in multiplayer with multiple cat and mouse stations for different targets using a different frequency? 

 

My current understanding is that with the advert of the Gee, Oboe and Gee were used together to increase the range but for distant targets you had to be at a higher altitude to pick up the signal. 

[Reflected]

Altitudes and speeds are pre briefed, the pilot confirms the estimated ground speed as he approaches the target. Then the mouse station calculates the release point. 
 

you can set up as many as you like using different freqs. But one is complex enough. 
 

and yes, oboe didn’t have much range due to the curvature of the earth and the aircraft had to fly at 25-30k feet. Not ideal for Lancs but no problem for Mossies. 

[Krupi]

I am going to be first in line for your campaign. 

 

Do you have an eta? 

[Sydy]

Nice posts…

Following!