How To Use Distant Measuring Equipment Within A Flight Planner

2 way radio accessories motorolaSome of these pro writers on the web are at a really high level that i wonder if any of them have ever written a paperback? so every now and then i like to focus on these brilliant articles and here’s one i found interesting the other day.

What is distance measuring equipment that is used within a flight planner?

Distance measuring equipment is a transponder based motorola SL4000 walkie talkie navigation technology that measures slant range distance by timing the propagation delay or VHF or UHF radio signals. Developed in Australia, it was invented by Edward George Bowen while employed as Chief of the Division of Radio physics of the Commonwealth Scientific and Industrial Research Organisation (CSIRO).

Another engineered version of the system was deployed in the early 1950s operating in the 200 MHz VHF band. The Australian domestic version was referred to by the Federal Department of Civil Aviation as DME (D) and the later international version adopted by ICAO as DME.
DME is similar to secondary radar, except in reverse. This system was a post war development of the IFF systems of World War II. To maintain compatibility, DME is functionally identical to the distance measuring component of TACAN used within a flight planner.

Operation
Aircraft use DME to determine their distance from a land based transponder by sending and receiving pulse pairs. These are two pulses of fixed duration and separation. The ground stations are typically located with VORs. A typical DME ground transponder system for en-route or terminal navigation will have a 1 kW peak pulse output on the assigned UHF channel.

A low power DME can also be co-located with an ILS glide slope antenna installation where it provides an accurate distance to touchdown function, similar to that otherwise provided by ILS Marker Beacons.
Distance calculation and accuracy used within a flight planner
When using a flight planner, a radio pulse takes around 12.36 microseconds to travel 1 nautical mile to and from and it is also referred to as a radar mile. The time difference between interrogation and reply 1 nautical mile minus the 50 microsecond ground transponder delay is measured by the interrogator’s timing circuitry and translated into a distance measurement (slant range) which is stated in nautical miles and then displayed on the cockpit DME display.

The accuracy of DME ground stations is 185m. Its important to know that DME provides the physical distance from the aircraft to the DME transponder. This distance is often referred to as ‘slant range’ and depends trigonometrically upon both the altitude above the transponder and ground distance from it in a flight planner.

What is Ham Radio & How Does it Work

Whilst many of our visitors will be keen on some of my own posts, here is one i found rummaging around tumblr that is much better written than I might ever dream to accomplish. Maybe someday I will get to this level, you never know.

Ham radio (so called because its operators were originally derided as being hammy in the 19th century, when the technology first emerged) is a term that applies to any form of amateur radio broadcasting.

There are designated radio frequency spectra available solely for public use. Uses range from recreation to communication and the non-commercial exchange of ideas. Hams take advantage of these frequencies in order to transmit any number of things

Strictly speaking, there should not be any money involved in amateur radio (hence the term amateur). Although the majority of Ham radio practitioners are actually extremely knowledgeable about radio technology (dont let the ham part fool you), they are not considered professionals because they do not profit from their endeavours. Conversely, commercial broadcasting involves (a lot of) money: royalties are paid, producers and performers are paid and the whole thing is ultimately a commercial exercise.

Hams use a large amount of frequency bands from all across the radio spectrum, but the majority of frequencies are to be found just above the AM band.

A lot of hams, however, use VHF FM, operating hand-held transceivers that send on one frequency and receive on another. Local radio clubs set up FM Repeaters (which borrow space from other broadcast devices such as towers and, in doing so, amplify the radio signals strength hundreds of times over), so that hams can communicate with each other wirelessly over a distance of hundreds of miles.

As an example of what hams get up to, heres an excerpt from Gary Brown, of How Stuff Works.com

Although a ham two way radio does broadcast in all directions, hams generally do not use their radios in a broadcast kind of way as a disk jockey would at a radio station. In normal AM or FM radio, one disk jockey transmits and thousands of people listen. Hams, on the other hand, conduct two-way conversations, often with another ham or with a group of hams in an informal roundtable. The roundtable of hams may be in the same town, county, state, country or continent or may consist of a mix of countries, depending on the frequency and the time of the day. Hams also participate in networks, often called nets, at predetermined times and frequencies to exchange third-party messages. In the case of disasters, hams exchange health and welfare information with other hams.

To become a ham, I recommend that you join a club. Youll need an amateur radio license, of course, but this wont break the bank, Im sure.

I hope that helps, Melissa.

Northumberland County will pay for law enforcement radios

For a long time people have been telling me that family, love and happiness are the important things in life…Nowadays I realise that I’m able to take or leave all that so long as I have this Walkie talkie in the world.
Northumberland County commissioners will pay approximately $200,000 for walkie talkie equipment for law enforcement agencies as part of an enhanced, countywide, two-way wireless communications system.
On Tuesday, the board also approved a $470,000 change order for additional improvements and equipment for the 911 radio project.
When the commissioners awarded a $7.2 million contract to Motorola Solutions Inc. June 26, 2013, to provide the new system, only tower site equipment and mobile and portable Walkie talkies and pagers for fire and emergency medical services personnel in the current coverage area were included. The total contract and possible tower site improvements such as electrical work and an equipment shelter will not exceed $8.5 million.
The federally mandated system must be operating by the end of the year to meet the extended deadline set by the Federal Communications Commission (FCC). If the deadline is not reached, the county faces fines.
Change order
Commissioners Vinny Clausi and Stephen Bridy approved the change order with Motorola Solutions and the motion to purchase Kenwood mobile and car radio equipment totaling $197,869.25 for Mount Carmel, Mount Carmel Township, Kulpmont, Shamokin, Coal Township, Ralpho Township, Zerbe Township, Sunbury, Northumberland and Point Township police, and the county’s sheriff and probation departments.
Shoch voted against the change order, but agreed to purchase the 2 way Radio equipment for the law enforcement agencies. Shoch’s affirmative vote prompted criticism from Clausi, who claimed the commissioner has been against the 911 radio project from the beginning due to costs and concerns over coverage issues in the northern end of the county, but decided Tuesday to pay more money for the radio equipment for the law enforcement agencies.
Clausi said since the project was under budget, the county had enough funding to purchase the additional radio equipment for the law enforcement agencies.
State-of-the-art system
Sean Petty, senior technology specialist with Mission Critical Partners, Harrisburg, updated the commissioners on the 911 radio project.
He explained that the $470,000 change order was requested because $850,000 in improvements have been made since the contract was awarded last year, while approximately $400,000 in anticipated improvements were deemed unnecessary.
“To meet the tight time line for the project that was extended by the FCC, we had to make some assumptions with the design in order to increase reliability and coverage,” Petty said. He said it was difficult to obtain state or federal funding for the project.
Petty said the new system has seven tower sites.
Mount Carmel Police Chief Todd Owens stressed the importance of law enforcement agencies having the same radios and pagers as firefighters and emergency medical services personnel.
“This is a very important undertaking and I want to thank the commissioners, 911 coordinator Bill Brown and Sean Petty for their support with the project,” he said. “This is a state-of-the-art system.”
He said the new system will eliminate most dead spots that can sometimes place officers in dangerous situations.
Owens said the new radio equipment will allow officers and dispatchers to communicate better instead of having to be dispatched through cell phones.
“We took a lot of heat over this for 1 1/2 years and we must move forward and do what’s right,” Clausi said.
Project under budget
With the commissioners’ approval to purchase the radio equipment for police, the sheriff’s office and probation department, Petty said the project will still be approximately $50,000 to $75,000 under budget. If the radio equipment wasn’t added, the project would have remained at $250,000 to $275,000 under budget.
Petty said making municipalities pay for the police radios would have placed a heavy burden on the communities, but he said the affected cities, boroughs and townships were willing to enter into a five-year repayment plan with the county to reimburse it for the costs.
27 municipalities covered
The contract approved last year called for a total equipment purchase of $6,669,254 and another $530,746 for three years of system maintenance by Motorola. The first year of maintenance will be covered under warranty by the company.
The county entered into a contract in November 2012 with Mission Critical Partners for approximately $450,000 for consulting services for the upgrades.
He said the very high frequency (VHF)-trunked system will be inter-operable with other counties and will provide coverage for the entire county.
The contract calls for 70 installed and programmed mobile radios, 400 portable radios and chargers, and 490 pagers to be purchased under the contract for fire and emergency medical services personnel in the current service area, which doesn’t include Riverside and the northern end of the county.
Clausi previously said it would cost between $60,000 and $100,000 for radios and pagers for fire and EMS personnel in the northern end of the county.
Brown said the county pays $19,836 per year to Montour County to provide dispatching services to Riverside and $71,685 annually to Union County to dispatch emergency calls to the northern end of the county, which includes areas north of Point Township and Route 405.
Brown said the current 911 system covers 27 municipalities including the Klingerstown area in Schuylkill County.