WWII Antenna "Shape"

[Another Ahab]

The German Wehrmacht fielded multiple command vehicles that had surface mounted "loop" antennas:

- These antennas frequently had a dropped leading-edge

Was this dropped/ drooped pattern serving a 1) signal function? or something else. Like maybe a practical 2) obstruction avoidance function?

Any Radio experts who might know?

 

[cbear]

Are you sure it's an antenna? It's very thick, which can change the RF properties. No to mention if it is an antenna, it would appear to be for communicating with aircraft. I suspect it's to support a sun cover or camo netting.

 

[CARNAC]

It's an antenna. It would be for long range communication and in some cases air-ground comms depending on the set installed.

 

[papabear]

I'm wondering if the rear may be hinged and the front could be raised to a vertical position?

Just thinking out loud....

 

[sigo]

The antenna was fixed in place. It didn't flip up or anything like that. It's a high-frequency (HF) antenna, commonly referred to as a "frame" or "cage" antenna. There were multiple variations depending on the vehicle, but ultimately the Germans made great use of HF throughout the war for both ground to ground and ground to air comms.

They didn't fully realize the potential of close air support as we think of CAS now, so for ground to air communication they really didn't plan for lower echelon commanders, fire support officers or air liaisons to coordinate with pilots for terminal guidance. While the Luftwaffe was very progressive and effective in their use of ground-attack aircraft, it was more like Division, Corps, or Army commanders coordinating with tactical air support. Lower echelons generally used visual signals to indicate friendly or enemy postions.

 

[Another Ahab]

They didn't fully realize the potential of close air support as we think of CAS now, so for ground to air communication they really didn't plan for lower echelon commanders, fire support officers or air liaisons to coordinate with pilots for terminal guidance. While the Luftwaffe was very progressive and effective in their use of ground-attack aircraft, it was more like Division, Corps, or Army commanders coordinating with tactical air support. Lower echelons generally used visual signals to indicate friendly or enemy postions.

Unbelieveable. HOW could they have missed THAT?!

Lucky for us on the Allied side of things that they did. It's always OK to be lucky.

Think I read somewhere that their radio capability in armor also far exceeded our capability, but we managed to overwhelm them anyway by sheer numbers.

Not necessarily the most efficient way, but -we can all say our thanks- it worked.

 

[Another Ahab]

The antenna was fixed in place. It didn't flip up or anything like that. It's a high-frequency (HF) antenna, commonly referred to as a "frame" or "cage" antenna. There were multiple variations depending on the vehicle, but ultimately the Germans made great use of HF throughout the war for both ground to ground and ground to air comms.

Digging around, and notice that loops and curves in antenna are common:

- Must be something related to signal gain/ attenuation, or something

Maybe we'll get lucky and somebody who knows more about radio will stumble into the huddle here:

 

[CARNAC]

I'm not a radio head but I have an hour to blow while waiting for an appt so I'll go ahead and hit this:

FuG1 was a listening set normally put in command vehicles. I am thinking this would be akin to the R442 receiver that many of us know.

FuG2 27,200-33,300 Kc/s with 1.4m rod was the standard listening only equipment for subordinate armored vehicles.

FuG4 was an artillery command set with a 2m star aerial.

FuG5 10w transmitter operating at 27200 to 33300 Kc/s with a 2m rod aerial giving range of 4km morse and 2km voice--standard tank set
FuG6 20w with same antenna and operating Kc/s but 8km morse and 6km voice--early command vehicles
FuG7 20w with same antenna, operating on 42100 to 47800 Kc/s with a morse and voice range of 50km--this was the ground to air set normally found in the SdKfz-250/3, 251/3 and command tanks equipped for air to ground.
FuG8 30w operating in the 1130-3000Kc/s (version a) or 580-3000 (version b) and 835-3000 (version c). Early and mid war had the big frame antenna but late war used a 8m winch mast antenna. 40km morse and 10km voice with the frame antenna. 50km and 10km with the 8m mast. This was the main division set.
FuG10 is a 30w set operating in the 950-1670Kc/s (version a) or 100-6970 (version b) and another version using 1120-3000Kc/s using a frame antenna. Range is 40km morse and 10km voice and was used in recon vehicles.
FuG11 100w operating in the 200-1200 or 100-6970 with early versions using a frame antenna and later versions a 9m mast. Used as command link to recon units and notably the SdKfz232(Fu). Range was 50km morse and 10km voice for the early frame antenna. The 9m mast gave a range of 200km morse and 70km voice!
FuG12 is 80w operating in the 1120-3000 and receiver in 835-3000 using 2m rod giving range or 200km and 70km used by late war recon vehicles
FuG13 was for 20w same as FuG6 but with 2 receivers and used in lower level command vehicles
FuG15 operated in the 23000-24950 Kc/s and used by assault gun units. range of 8km and 6km.

I have some other information but that's most of the basic sets. I have a book on German radio systems in storage. Keep in mind that their standard company level set was a 2 man carry unlike the US one (BC1000) which was a backpack smaller than either of the two halves carried by the Germans. The US also had the walkie-talkie radios down to platoon level. The forward air controllers from the US Army Air Corps operated from tanks and jeeps at the battalion level--pilots directing fellow pilots onto target. The Allied air supremacy enabled our airborne artillery spotters coordinate massive amounts of firepower at the key point at the precise moment for maximum effect.

Yep, we had some failures but I like to think the Allies learned fairly quickly and adapted. Think of the loss of experience and training potential lost by the Japanese that were not able to withdraw their soldiers. Each new battle required learning due to their inability to share experiences of what worked and what didn't.

 

[sigo]

German tactics were based on a lot of factors, but don't misunderstand me. The Wehrmacht led the way early on when it came to air-ground integration. Conditions were right for the Luftwaffe for a significant part of the war. Long-lasting air supremacy or air superiority permitted the Luftwaffe to get really good at their job. It could have been better, but despite inter-service rivalry, leadership meddling, and some technological/resource limitations, the Wehrmacht developed some good doctrine. But the tides turned and they weren't able to sustain those conditions. The Allies learned a lot in a short time, and changes in training, tactics, equipment, and conditions on the battlefields ultimately put the Allies in a position to capitalize on air superiority and support ground forces fairly well. My opinion is that neither side fully developed ground-air coordination to the extent they could have. Over time, with alot of experience and advances in technology, CAS evolved into Air-Land Battle, Full Spectrum Operations, and now Unified Land Operations; all of which make superb use of CAS and Close Combat Attack aviation. It works now because we developed the hard-learned doctrine, resource the training and resource the means for multi-echelon communications.

-break-

Antenna design is about a lot of things. For HF, the radiation pattern and efficiency for your frequency and power influence which antenna is right for you. I suspect the downturn at the front of the German cage antennas was more about avoiding obstructions than about radiation pattern. Mobile antennas often must be a compromise between efficiency and convenience. For example, you design the antenna to be easy to erect, easy to maintain, compact as possible, minimally intrusive AND offer good communications. Every mobile antenna design is a trade off between similar factors. Perhaps they decided that particular design was a compromise of good comms and good mobility. Of course I simplified things, and I'm no EE or HAM, but I did stay at a Holiday Inn once.

Edited to add: After reading CARNACs post I feel compelled to also note that I know nothing about WWII German radio sets.

 

[Another Ahab]

Now Pay Attention!

I'm not a radio head but I have an hour to blow while waiting for an appt so I'll go ahead and hit this:

.

CARNAC, you never cease to amaze:

- I stand before you totally humbled.

Outstanding!

 

[tennmogger]

Sure looks like an antenna. The droop was probably just for convenience as already stated. If this structure were a rack for holding anything, there would be more cross members and it would be loaded. The fact that it is relatively clear (except for maybe a tarp on one end) indicates a PLAN to keep it clear of obstructions.

If you search on 'German Quad' there are some good explanations of how a small loop like this works. The relative size of the loop would be closer to a full wave loop on VHF but would certainly work on HF with a tuner. The Germans were quite good with radios back then. A very small antenna (compared to wavelength) can be resonated with proper choice of capacitor. Directivity would be upwards, but that can work in favor of communications locally, if long range comms were to be avoided to avoid easedropping by the enemy. Beam signal up and take advantage of NVIS propagation. NVIS (near vertical incident skywave) is very popular with hams to communicate out a few hundred miles.

Another possibility is that this antenna is an early DDRR design, no doubt before the DDRR (direct driven ring radiator) was named in the 50's, and maybe even before the physics was understood. A DDRR benefits from the ground plane (a tank or halftrack makes a good ground!) close by underneath. Again, search on DDRR and see pictures that resemble this loop. Any of the four posts holding up the loop could contain the feed point.

Bob

 

[Another Ahab]

German tactics were based on a lot of factors, but don't misunderstand me. The Wehrmacht led the way early on when it came to air-ground integration. Of course I simplified things, and I'm no EE or HAM, but I did stay at a Holiday Inn once.

Edited to add: After reading CARNACs post I feel compelled to also note that I know nothing about WWII German radio sets.

 

[bender108]

It is a NVIS HF antenna. Google...German WW2 NVIS Antenna...There are pictures of very similar antennas on various vehicles.

 

[CARNAC]

CARNAC, you never cease to amaze:

- I stand before you totally humbled.

Outstanding!

View attachment 525156

http://www.youtube.com/watch?v=IMxWLuOFyZM

You have to know these things when you're king.

 

[Another Ahab]

It is a NVIS HF antenna. Google...German WW2 NVIS Antenna...There are pictures of very similar antennas on various vehicles.

And you KNOW that whole German mind-set:

- nothing haphazard about the design, everything about these antennas is there for a reason most likely.

I think somehow the German psyche gets a dopamine rush from precision, or something; you know?

You want a thoroughly efficient design for something, put a German-schooled engineer on it (it's how we all got into space; us and the Russians, both).

 

[papabear]

And you KNOW that whole German mind-set:
- nothing haphazard about the design, everything about these antennas is there for a reason.
I think somehow the German psyche gets a dopamine rush from precision, or something.
You want a thoroughly efficient design for something, put a German-schooled engineer on it.

That may be correct, but give a good ole American Armed Forces member the mission and they will take it out!!

 

[CARNAC]

And you KNOW that whole German mind-set:

- nothing haphazard about the design, everything about these antennas is there for a reason.

I think somehow the German psyche gets a dopamine rush from precision, or something.

You want a thoroughly efficient design for something, put a German-schooled engineer on it.

Engineering design is one thing, producing that design while being bombed, under significant base materiel constraints while using slave labor can take the best engineering design and result in a 72 ton stationary piece of metal that can't fire, can't move and can't communicate.

Dr Atwater and I use to have deep discussions about the Panther vs the T34/85. It always came back that quantity can produce a quality of it's own.

 

[papabear]

Engineering design is one thing, producing that design while being bombed, under significant base materiel constraints while using slave labor can take the best engineering design and result in a 72 ton stationary piece of metal that can't fire, can't move and can't communicate.
Dr Atwater and I use to have deep discussions about the Panther vs the T34/85. It always came back that quantity can produce a quality of it's own.

PLUS: A good ole American GI can take a bottle of gasoline with a wick, or a small explosive charge and make your day a living he11.

 

[cbear]

NVIS, interesting. So the design wasn't to communicate with aircraft as much as to bounce the signal off the atmosphere. Being HF, you wouldn't need much power to go a long way.

 

[MarcusOReallyus]

Digging around, and notice that loops and curves in antenna are common:

- Must be something related to signal gain/ attenuation, or something

Maybe we'll get lucky and somebody who knows more about radio will stumble into the huddle here:


View attachment 525145 View attachment 525146

There can be a number of different reasons for curves and loops. Sometimes it's tuning, more often it's for shaping the radiation pattern.

Here's one that will torque your brain - picture a whip antenna with a spiral connected to the base of the radiator on one end and to the ground plane on its other end. A dead short.

What's it for? Well, it's not a dead short at radio frequencies - it's actually a high impedance. At DC, it's a short, of course, but that allows static to bleed off, which is why it's there.