Continuing on from my previous blog post, here are graphs for prepay TXTing.

Please note that the numbers at the bottom represent the total number of TXTs sent in one month, not the number of texts sent to each network. Also, for the first 100 TXTs or so, the figure for 2degrees is $20 as that's the minimum top up cost (Top Up Rewards is being used as a TXT bundle)

You can also get the spreadsheet which generates these figures here. 

Going back on the previous post to this, there were a few things I should have stated clearer:

• Yes, standard add-ons (TXT150/600/1500 on XT, TXT2000 on Vodafone) were included in the figures


• Limited time offers like TXT4000 and specific on-net stuff (like BestMates) were not included since you can't "calculate" them in a spreadsheet


• It's not intended to mean that people will run up bills of thousands of dollars (though if they did, they're doing something wrong)

Now that that's out of the way...


I've now fixed the spreadsheet, and to the extent of my knowledge and testing, it should be accurate.

Running through the spreadsheet again, my figures for the examples from my last blog post are exactly the same now, apart from a new range of figures that the 2degrees plan costs.

• 3000 on-net TXTs costs:
  - $50 on 2degrees
  - $210 on Vodafone Supa Prepay
  - $318 on Telecom XT One Rate Prepaid




• 1800 TXTs split equally to all three networks costs:
  - $78 on Telecom XT One Rate Prepaid
  - $66-$90 on 2degrees
  - $250 on Vodafone Supa Prepay 

I've added $10TXT on Telecom CDMA (for existing customers) and a "recommended top up" combination grid for 2degrees customers (since you can only top up a maximum of $100/day, and getting the number of texts right is not easy...)

Due to some hard-out fixing I've done, some results will be different compared to the previous spreadsheet. 


.xlsx spreadsheet
.xls spreadsheet


Again, no Google Docs as it would be far too messy to fix their converted file up.

I help around with the New Zealand Connections wiki a bit - and recently put out Plan Finder as part of changes coming in 2010. It's a Javascript based plan presenter which uses AJAX to grab the info from around the site.


I was about to get a ADSL page running with an editor (to make life a bit more easier than filling in a long form) by February, but... I lost my JS work because I needed to format my hard drive, but forgot to backup... (doh!)


So here I am recreating it during my school holidays...


I've opted to keep the old tables running, and will be putting a separate page for the ADSL table as it is completely rewritten.

An example of that is the new plan information dialog that appears. Here's a shot of it (work in progress):


Tables will have pagination and live search filter. The ADSL table has over 100 entries (I believe) so those should be great features :)


So anyway, I wanted to know:

• what you think would be good to know at a glance in a table and/or plan information page (such as Plan Finder), and


• who would be interested in helping transfer/update the information from the old table

Because Plan Finder uses data stored in a table, I hope this time round will be the last time the table will need converting for a long time.



So I'm open to comments and suggestions, and anyone who's keen to help carry over the table (in around a weeks time)

You probably heard this morning that 2degrees will be offering 2c on-net TXTs from 31 March with every top up.


This is kind of ironic since 2degrees have marketed their Prepay "Pay Now" service as being simple and without all the on-/off-net fuss.


But anyway...


I whipped up a spreadsheet for you to analyse your usage and to see whether 2degrees cuts it, along with the upcoming 2c on-net TXT rate.


* I must note that this spreadsheet and the below examples do not include BestMates or any other limited time offers. *


Here are some examples:

• 3000 on-net TXTs costs:
  - $50 on 2degrees (from 31 March)
  - $210 on Vodafone Supa Prepay
  - $318 on Telecom XT One Rate Prepaid




• 1800 TXTs split equally to all three networks costs:
  - $78 on Telecom XT One Rate Prepaid
  - $87 on 2degrees (from 31 March)
  - $250 on Vodafone Supa Prepay 

Kind of why Vodafone really need some good cross-network TXT add-ons when the upcoming changes to their Prepay plans next month occur.



Here are the links to the .xls and .xlsx files. Google Docs completely screwed the spreadsheet over, so no Google Docs unless someone really needs it - I don't want to pick up the messy pieces after the conversion. 

Spreadsheet (Excel 97-2003)
Spreadsheet (Excel 2007-)


Enjoy!


UPDATE: I have found further flaws to the spreadsheet and the model as well. I'm working on making a new spreadsheet to see if I can fix it. But for the majority of cases the current spreadsheet should give a good indication of the costs involved.

Our maths teacher recently gave us a question to solve. It was to generate the equation of two lines which are tangents to a circle but also passing through one external point.


An example of this:

(you can ignore the dotted circle)



My friend and I had difficulty trying to solve it at first. Generating a line equation is easy, but finding the gradient isn't.


We spent 3 hours over 3 days at school (we have daily 1 hour long "Study" classes, which most people don't "study" in anyway), and this is pretty much how it ended up:

• 1st day: I solved the question by using a multitude of trigonometric functions, ending up with the two gradients. But they were not in any particular form, just numbers, so weren't that great as an answer as they would not be exact answers. And it looked ugly (yes, maths can be beautiful at times...)


• 2nd day: So my friend attempted to get a surd form for this number by working through my method, and he successfully does.


• 3rd day: He wanders off and discovers a relationship between the answer and original parameters and generates a general form for the gradient for the lines!

So today I copied off all our rough work onto paper and our teacher was most pleasantly surprised!

The equation doesn't involve having to substitute one equation into another, which has significantly made calculating the gradient for any line of this sort a whole lot easier.


But I won't be posting it up. Not yet.

That's because I'm trying to find if this has been generalised before. So if anyone knows of anything which can directly generate the gradients of such lines, please let me know in the Comments section below.

Otherwise... well, you can probably guess what we will do next.