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7 votes

Why are Wullenweber CDAAs obsolete?

First, there are better DF antennas now and they take up way less real estate. Some of them are .. the Pusher and "L" and "T" arrays. The electronics for these is more sophisticated than the ...
Poe's user avatar
  • 139
7 votes
Accepted

Why are Wullenweber CDAAs obsolete?

Two major reasons HF direction finding arrays like that aren't particularly useful any more (you won't find many fixed HF DF stations at all, even more modern ones): As William said, HF is not used ...
Hamsterdave's user avatar
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6 votes

Why are Wullenweber CDAAs obsolete?

First of all: why is it surprising that a radio device built in the 1960s has become obsolete? I don't know the specific reasons why this specific type of direction finder has become obsolete, but ...
Marcus Müller's user avatar
6 votes
Accepted

Is there a way to find out the location where a radio signal is intercepted?

Yes. Detecting a receiver is VERY VERY VERY hard to do. Since it is only an absorber rather than transmitter of RF energy, it requires a signal strength meter to detect a dip in RF energy. It requires ...
Katrina Petkovic's user avatar
5 votes

Receive directionality of a sub-optimal Yagi

A few things to start off with: You don't care about efficiency, unless the antenna efficiency is truly abysmal, or your receiver is of very poor quality. Efficiency on the receive side is a measure ...
Hamsterdave's user avatar
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4 votes

QRN: How to chase down a solid S9 noise floor on 40m only

Look around your neighbourhood or Google satellite imagery for new solar panel installations. We recently discovered a solar panel installation with noisy regulators creating noise at a neighbours ...
Fritz - V51WF's user avatar
3 votes

Find the the geographical North for yagi setup

So if you pick a value in the middle of your compasses (and don't forget to correct for the difference between magnetic north and true north) you'll probably be within 2 degrees of correct. Two things ...
hobbs - KC2G's user avatar
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3 votes

QRN: How to chase down a solid S9 noise floor on 40m only

If the RF noise is that strong, then you should be able to pick it up with a much smaller movable antenna. Even scrap wire or conductive tape on a large cardboard box. That may allow you to build ...
hotpaw2's user avatar
  • 13.5k
3 votes

Receive directionality of a sub-optimal Yagi

If a full-sized VHF antenna is too big, then look at how people do direction finding on HF. A longer wavelengh means bigger antennas, so HF direction finders have been dealing with the "too big" ...
Phil Frost - W8II's user avatar
2 votes

Why are Wullenweber CDAAs obsolete?

Having worked as an intercept operator at these sites in the 70's I can say that there just isn't anything to intercept on the HF bands anymore.
William's user avatar
  • 31
2 votes

How to make a "you're getting warm/cold"/"fox hunting" game based on RF signals

First the answer: When I worked for the forest service I built single-transistor transmitters where one of the leads of the transistor was the antenna. It doesn't get any more simple than that. They ...
SDsolar's user avatar
  • 2,087
2 votes

Is there a way to find the direction of a vehicle using radio?

I was wondering If I could use an Arduino to find the location of a vehicle using radio. Radio is a pretty big topic, so yes, of course there are ways to use radio technologies to locate a vehicle. ...
Caleb's user avatar
  • 238
2 votes

2m loop with sense antenna for DF

A small loop antenna is bidirectional in the direction of the plane of the antenna and has nulls that are perpendicular to the plane of the antenna. Due to its bidirectional nature, there is ambiguity ...
Glenn W9IQ's user avatar
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2 votes

Ramsey's DDF1 with a SMA connector

Here is where you'll find your answer. http://assets.tequipment.net/assets/1/26/Documents/DF1.pdf Antenna mounting begins on page 17, and on page 19 it shows how the whip antennas are connected to ...
SDsolar's user avatar
  • 2,087
2 votes

QRN: How to chase down a solid S9 noise floor on 40m only

Start by trying to determine if the noise is "conducted" or "radiated" into your receiver. Basically, "conducted" noise gets into your receiver from the power supply or a ...
Brian K1LI's user avatar
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2 votes

QRN: How to chase down a solid S9 noise floor on 40m only

I'd suggest trying a different time of day, a different radio, a different antenna, and a different location; not necessarily all at the same time though. There's probably nothing wrong with your ...
rclocher3's user avatar
  • 9,242
2 votes

QRN: How to chase down a solid S9 noise floor on 40m only

You might consider an RF choke at the interface between your radio and feed line. The choke at the feed point will help prevent common mode current reflecting from the antenna... but the outside of ...
webmarc's user avatar
  • 4,289
2 votes

Why are Wullenweber CDAAs obsolete?

The demise of the military CDAA is not an issue of capability, accuracy or even economics, but the primary driving factor is the change in mission, targets and technology. HF; whether it's SSB, CW ...
Dave's user avatar
  • 31
2 votes

Why are Wullenweber CDAAs obsolete?

Wullenwebers have been replaced by the FCC HFDF ("huff-duff") system. Several HFDF installations are located in the USA along both the north and south borders and the east and west coasts, plus Alaska,...
Mike Waters's user avatar
  • 8,071
2 votes

Find the the geographical North for yagi setup

Another way to sight along the boom at a distant point, and locate it on a map (e.g., Google Earth). You can then draw a path on the map and see its bearing to within a fraction of a degree. Even ...
Deepstop's user avatar
  • 246
2 votes

Find the the geographical North for yagi setup

You can get reasonably accurate azimuth numbers just pointing the antenna at the sun, and manually sighting down the boom or looking at the shadow. Try this at various times of day. Use your favourite ...
tomnexus's user avatar
  • 11.5k
1 vote

QRN: How to chase down a solid S9 noise floor on 40m only

I purchased a West Mountain CLR/DSP 58407-949 noise reduction unit. Seems to help but still requires a strong signal to break through the QRN. I run an FT-450D also.
AI7FF's user avatar
  • 11
1 vote

QRN: How to chase down a solid S9 noise floor on 40m only

You've received several good answers here. To Brian's answer suggesting that you should try powering it from a battery, I would add start with your own house before running around the neighborhood ...
Mike Waters's user avatar
  • 8,071
1 vote

How should I go about finding the transmitter or antenna of a radio signal?

For the purpose of this answer, I'll lump interesting unknown signals and RFI together and call them "mysterious signals", since the techniques for finding where they come from are often the ...
rclocher3's user avatar
  • 9,242
1 vote

Is there a way to find the direction of a vehicle using radio?

You have two different use cases. Position reporting and direction finding. Position reporting would be using something like APRS, Automatic packet reporting system. While APRS can transmit different ...
Jim's user avatar
  • 1,778
1 vote

Why are Wullenweber CDAAs obsolete?

Response times are not primarily driven by the antenna characteristics, but the data sampling rate (electro-mechanical, ecectronic, or otherwise), data transmission time (including both receiver's ...
Dave's user avatar
  • 31

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