The  'Parent' Envelope

For those who have done a few DFs already and are ready to try on their own.
First a few reminders

The Micros are easier because they are on continuously and have an A4 sheet with the triffid. The triffid acts as a cover for the tickets which you must collect.

micro           mini
Left  -  Maxi and Micro tickets will be marked by A4 sheets and covered by a triffid.
Right - Minis are only on for 1 minute in 5 and are much more difficult to spot!

These competitions are structured to allow beginners and experts to enjoy the same event:
  • Micros fairly easy, intended for teaching.
  • Maxi   bit harder but not too difficult to DF after a bit of practice.
  • Minis  deliberately made difficult, so even people with years of experience have something to challenge them.
The transmitters can be thought of as having a 'family tree' the Operator uses this as he prepares the event. It can take many shapes and this variety helps challenge the experts.  Until you become expert, knowing the tree is necessary in order to find the transmitters that are intended for you.   A link to a full explanation of the tree is below but feel free to skip it or perhaps check it later.
Tree structure of the transmitters


If you are reading this page I assume you have done a few DFs before and know how to use a DF set but are not ready to tackle the difficult Minis yet.

Previously someone has told you where to go so that you can hear the Micros.
The next step is to let you have a little more independence and also to get you listening to the Minis although you won't try to find them just yet.


You arrive on site ready to hunt

The Micros are your main quarry,  you may be able to hear a Micro as soon as you get out of the car, if so go for it.

If you can't hear a Micro, check that no 'experts' are looking and open the envelope:

Sample contents of a Parent Envelope:


Please do not let any 'expert' DFers see this! 

A  - W

  J -   (X and Y)

H - Z

Operator's mobile
0781234999
Call if you need help.

In this example the parent stations are A, J and H, the children (the Micros) are W, X, Y, Z, in other words,  the stations on the left give strong signals, using them will allow you to get close enough to hear the weak stations on the right. 

Using the example above - it tells us that Micro W is within 200 m of Maxi A.

From the frequency/time table, find out the frequency and bleep speed for W (1928 KHz).

If you can't hear W tune to 1978 KHz and wait for Maxi A to come on.
Take a bearing on A and start walking towards it.
When A goes off, check W's frequency to see if you can hear it yet:
  • if so stay tuned to W and DF it.
  • if not retune to A (1978) , as soon as you get a signal use it to correct your path towards A. Keep checking the sense to make sure you don't go past it.
Repeat this process until you are within the range of W.  You may find that Maxi A, being very strong, will overload your set so that you have to turn back the RF gain control, don't forget to turn it up again when listening for W. Also when Maxi A is on, it may block out the tiny signals from W,  this is why A is not on all the time, use the quiet periods to find W.  (If you don't understand about RF gain controls, you need to speak with the Operator, his mobile number is in the envelope).

Using the Minis in the same way

The principle is the same as for using Maxi A but is a little more difficult because all five Minis share the same frequency coming on one after another in a five minute cycle.

The white envelope above also tells us that Mini H will lead us to where we can hear Z.

First check whether Z can be heard from where you are standing at the moment.
If you can hear it just DF it ............. if not:

Tune to 1960 and listen to the Minis.
You should hear one of the Minis but is it H?
There are two ways of knowing using the frequency/time table ,  you are listening to H when:

  • the minute digit of your accurate digital watch says 0 or 5 then you should be listening to H.
  • you hear di di di di , the Morse for H.
If you are not used to Morse this will seem almost impossible at first but since we always use the same letters, in the same sequence, most people quickly learn the sounds and find it more convenient than checking their watch.

Even if you decide to use your watch, still listen for the changes in Morse speed, each time a new Mini comes on it transmits really fast Morse to legally identify itself. then slows up sending the single character for the competition.  When a new one comes on you will hear a fast bit again. When you are taking a bearing and hear a fast bit - stop - because you will be listening to a different Tx! These changes is speed can let you check your watch is synchronised with the Operator's.

Listen to the recording, H is the first one to come on - hopefully you can spot the H (di di di di)  bit,  but most important, play the whole thing listening for the fast bit each time a new Tx comes on.

Use your browser's back key to get back to this page when you have had a listen:
Sounds

Once you are confident that you know when you are listening to H the process for tracking down Z  is the same as for A - W.

You will listen for H (1960 time slot  0/5) , walk on its bearing; when it goes off check Z's frequency to see if you can hear it yet, if not retune to 1960 .... repeat this until you can hear Z and then transfer your attention to it.

Using J to find X and W.

If you can stand the ear strain you may want to listen to the recording again with your eyes closed, primed with the fact that J is

di dah dah dah  can you spot when it comes on and goes off?   A clue is that I  (di di) comes before J.

The process of tracking down X and Z using the signal from J is as before but now three frequencies are involved.
  • First can you hear X (1928) or Z (1915) without using J, if not
  • Tune 1960 walk towards J
  • J goes off, tune to 1928 listen for X (fast bleeps)
  • Tune to 1915 listen for Y (slow bleeps)
  • Repeat until you hear X or Y.
Was that the best order to do the stations in?

Probably not, but it was the easiest order to explain things in.

On the day, where you start from and where the transmitters are will determine the best order to tackle them in.
The most efficient order is to find all the Micros first ending up at the Maxi to post tickets BUT if you run out of time you may lose all your points.  For safety, competitors often make several visits to the Maxi to bank tickets. Start safe and as you get more skilled gradually increase how daring your strategy is.


When looking for W using A, you said listen on 1978 and 1928, could we have walked by a station on 1960 or 1915?

Yes!

As you get better you will be scanning all four frequencies because it very easy to walk by a station on the way to another. The danger is that you start doing a headless chicken impression continually changing your mind on what to hunt for.  Getting this balance is what sorts the winners from the rest of us!  In the early days it probably best to follow a simple plan and get some success, plenty of time to get adventurous!

If I am going to listen to the Minis why don't I try to find them?

Well you could, when you have tracked down a Micro and you know you are within 200m of a Mini you could have a quick look for it. The danger is that you will spend too much time searching deep in bushes and not find all the Micros intended for you. The fact you are getting used to knowing which Mini is which is excellent training for moving on to the next stage.

When do I start looking for Minis?

As you do more events you should find your five stations  W, X, Y, Z, A well before the end.  Once all tickets are safely banked tune back to 1960, see which Mini sounds closest and go for it. Good Luck!
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