Black Widow night fighter - Korean War?

In article ,
(William Donzelli) writes:
(Peter Stickney) wrote in message ...

The impetus wasn't there. The German radars wer also susceptible to
active jamming as well. It's not that they weren't clever, they just
forgot that the Allies were clever, too. (As I remember it, Nurenberg
wasn't "chirping", as we understand the term. Instead, it looked for
the scintillation that a revolving propeller produces to the radar
retorn.)

This is similar to the AN/APX-15 "Ella", fitted to the AN/APG-15
radars late-ish in the war. The concept really is very simple,
involving just a small amount of circuitry.

Yes, that's true.

Everybody invented chaff/rope/window at about the same time,
(including the Japanese), and everybody held off on using it, becasue
they wer afraid of the effects on their own systems. One of the war's
ironies.

Interesting that with almost all aspects of early radar - almost
everything was invented by everyone at the same time, with the key
difference being if the things actually made it out of the labs. The
British were the quickest to get things out of the labs and into the
military (sometimes a bit too quick), but others a bit more slow...

Absolutely. Although the Brit panchant for shoving stuff out got them
in trouble in the early days. When the first Brit techs carrying an
early Cavity Magnetron, and the drawings for the same, arrived at
Harvard, they go themselves into a bit of hot water when it was found
that the innards of the Magnetron didn't even closely match the
drawings. (The first thing they did was X-Ray it to see what was
inside, not wanting to damage the only copy they had. It had a
different number of cavities, and the dimensions were all different.)

As it turns out, while the Brits had a big advantage in microwave
transmitters, our receivers were superior. Matching the two
technologies produced the benchmark systems. (Some studies done back
in the '60s indicated that, for most uses, the old AN/CPS-1 Air Search
radar, with teh addition of sidelobe cancellation, was ideal)

It's pretty amazing what could be done with wire & tubes back then.


Is that 13 KW peak radiated power? I'm thinking of power into the
system, not out. Aircraft Generators at that time were usually
capable of not more than 2.4 kw, each.

I would think this would be the peak radiated power. If not, something
was very wrong with the German sets. Even the biggest US shipboard
radars, like the VHF model SR, needed only 3.8 kW when the set was
radiating with the antenna spinning at full speed.

I'd think it would have to be. But even then, aircraft electrical
generating systems were a bit on the marginal side.

--
William Donzelli

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster

(William Donzelli) wrote:

Is that 13 KW peak radiated power? I'm thinking of power into the
system, not out. Aircraft Generators at that time were usually
capable of not more than 2.4 kw, each.

I would think this would be the peak radiated power. If not, something
was very wrong with the German sets. Even the biggest US shipboard
radars, like the VHF model SR, needed only 3.8 kW when the set was
radiating with the antenna spinning at full speed.


I don't see how the antenna rotation speed has anything to do
with it and I think that's ERP 'Effective Radiated Power' which
takes into consideration the antenna gain, a huge amount with
parabolic dish antennas (something like 40 - 50 db - a phenomenal
amount). Also Radar is pulsed therefore the average power is
surprisingly low for a quite high power set.

I believe that the radar on the Mk1 Argus was something like 3
million watts peak and I know that the alternators on that
aircraft were 40 KW each for a total of 160 KW.
--

-Gord.

Dave Holford wrote in message ...

IIRC the APS-20 was about 2.4 MW Peak Pulse Power.
Might have been ERP, but I don't think so.

Maybe the last of the line, but the "classic" AN/APS-20 is 1 MW. I
don't have data on the -G version, and it very well could have
received a new transmitter and modulator.

Antenna rotation speed effects beam dwell time on target, and thus power
delivered to the target. Obviously in the extreme only one pulse would
hit the target before the beam moved on and thus probability of
detection would be minimized.

That is true, but as far as the power supplies are concerned, they
just see more juice going to the antenna drive.

--
William Donzelli

(William Donzelli) wrote:

Dave Holford wrote in message ...

IIRC the APS-20 was about 2.4 MW Peak Pulse Power.
Might have been ERP, but I don't think so.

Maybe the last of the line, but the "classic" AN/APS-20 is 1 MW. I
don't have data on the -G version, and it very well could have
received a new transmitter and modulator.

Antenna rotation speed effects beam dwell time on target, and thus power
delivered to the target. Obviously in the extreme only one pulse would
hit the target before the beam moved on and thus probability of
detection would be minimized.

That is true, but as far as the power supplies are concerned, they
just see more juice going to the antenna drive.

Yes, I suppose so but the total of 160 kilowatts of primary
alternating current power available (and the 800 amperes at 28
VDC which was derived from that) likely wouldn't be much
concerned with the little bit of power required to drive the
antenna rotator I'd think...
--

-Gord.