Re: DFing the trunk systems

On Dec 22, 2:02�pm, Archangel <HAVE.DOUGH...@gmail.com> wrote:

A couple of questions for you:

1. I know you don't frequent that site anymore, but
how accurate is the map of the trunking system over on DLR?
I seem to recall you posting over there a while back about
a trunk site that wasn't on that map, but I can't find the post.

2. I'm not a radio geek, so sorry if this is a stupid question,
but could this equiptment be used to find the PYD NDB?

Keep up the good work!


Most of what is on DLR is correct.  I don't believe there are any
missing trunk sites for each system. There are some missing
frequencies in the NTS system on DLR, but they are not control
channels. You would have to really stake out the area to get those
frequencies since you need to be there when the system is exercised.
My recollection is one system didn't work, and I suspect it is split 3
times instead of twice. I haven't found any bugs on the EDACS system,
though I didn't DF every site yet.

You would use different gear for PYD due to frequency.  I couldn't get
a good fix on PYD before it got shut down. However, I DFd XSD without
a hassle. Here is a photo showing a loop antenna in the null of XSD.
http://www.lazygranch.com/images/radio/bigassant.jpg
I don't have a photo of it handy, but I have a 2ft x 2ft copper pipe
loop that I use for DFing low frequency beacons such as XSD. It has a
platform for mountain a compass.

For low frequency beacon, you use what is called a "small loop". The
term small means small relative to the wavelength. You move the
antenna until you reach a null. Then a vector perpendicular to the
plane of the loop points to the source.

For UHF, you use a directional antenna. You attenuate the signal to
the point where it is only audible when the antenna is pointing at the
source.

Small loop nulls are really sharp, You can get a good indication of
the direction to maybe a degree if you work at it. The UHF directional
antenna scheme is not that accurate. Maybe 3 degrees.

Lastly, I identified the trunk systems on Angles Peak by simply
removing the antenna from my radio and checking which system could be
heard. I had to drive by the campground to get one of the signals.

I scanned the map they hand out for the Yucca Mountain tour. It has
many communications sites marked:
http://www.lazygranch.com/images/nts/nts_map.gif