Tag: GPS

GPS Track my Cat

Have you ever thought I would really like to know what the cat gets up to during the day? No, OK its just me then. Anyhow, I was surfing one of the many ChinaBay websites the other evening and spotted a rather cheap “Pet tracker”.

Marked as D69 Pet Locator, the advert suggested it could record GPS locations and pass these to your mobile phone via a downloadable app called “there”. As with many of these Chinese products the online description is somewhat unclear, so it comes down to price and if you want to take a chance.


The online description claims the following:-
Standby time 6 Days using the  MT3337 GPS chip, and a weight on 32 Grams. Size 16x56x38 mm. Search terms seem to be GPS tracker D69 GSM, and this should locate the product for around £25 to £30 UKP.

You will need a SIM card, this can be pay as you go, so long as you have GPS data and the ability to send and receive text messages. I purchased £10 of credit with GiffGaff, as they seem to offer good value and your credit doesn’t expire to 180 days (longer if you make / receive calls)

                                     Tracking options

Real time, you click on the app and it attempts to locate your pet and return a position on the screen. Its often not clear if this is live or historical, but it does work if you have a GPS fix.




Historical, you can set the tracker to upload spots every 1 or 10 minutes.

By sending a text, you can text your pet using url# and the device will return a text message and a google maps link showing the last known locations. It will also return “NO GPS” if you don’t have a GPS fix at the time of location request.



Example of text received

Locate date:2017-1-26
Locate time:4:52:15


Calling the tracker

You can phone the tracker and speak to your pet (no I dont know why) or call and mute your audio so you can hear the location your pet is in. This can be especially handy if you suspect moggy is visiting other houses in your street.

Does it work

Yes its adequate but you need to keep in mind the following. It has two position modes GPS providing an accurate fix to around +/- 10m. If GPS fails it will use Location Based Services, this provides an approximate fix but for the purposes of tracking your pet it’s useless.

Cats often sit, rest and stalk in locations that are not GPS friendly, under cars and in bushes and this can cause the GPS fix to be infrequent.

Its also possible to setup a white list number, so only this number can call and text the tracker and Geofence your pet!


Hytera MD785G review and first impressions.

After my last article on the TYT MD380 I decided it would be nice to get a DMR radio for the home / car use. I read quite a lot online and decided to select a radio that would support roaming. The Hytera MD785G fitted the bill, and is available in both a high and low power UHF or VHF version. I selected the UHF 45w version, and purchased the programming software and lead. The ability to load codeplugs is essential, as DMR is still very much a moving target, new repeaters are coming on all the time.

The Hytera MD785G is a tier II DMR radio, UHF 400 to 470 MHz, with a 1024 channel capacity. It can be programmed with up to 64 zones (16 channels in each zone)



Size 174 x 60 x 200 mm at 1.7 kg with colour LCD display.


RF power is adjustable depending on model  from 5 to 45w (high power version) or 5 – 25w (low power version). The 785G supports GPS although the amateur DMR networks does not support GPS location data at this time.

The radio has a BNC connector on the rear for your aerial, and SMA for GPS. The resolved audio is loud, crisp and clear and the radio looks and feels solidly built.



I couldn’t find any good quality pictures of the top, front and rear online so I took some myself. Here you can see the BNC connector for your aerial, heatsink, power lead (detachable) and SMA for the active GPS antenna.




UPDATE Jan 2016

The structure of the DMR network has changed substantially since I first wrote this article, and many of the codeplugs have become outdated. New codeplugs that reflect the FEB 16 structure can be found at GB7JG and GB7CL website.


At the time of writing some previous sites have outdated codeplugs (although links retained as they may be updated) Codeplugs online are often outdated G0HWC site.  Other codeplugs are available from codeplugcentral and  GB7DD.

Hytera MD785 CPS software is available at GB7DD

You can monitor live UK traffic for DMR online, and clicking on a callsign / repeater  will filter activity just for that call / repeater.

A list of all the UK DMR repeaters is available on the UK repeaters website.

Ham radio now filmed W2XAB John giving a great talk available to watch below on DMR. He also produced a guide to DMR in PDF free to download.