Welcome to Wayne's Radio Ramble
One of our members, Wayne will be exposing sometimes interesting nuggets of information, sometimes maybe not so, but giving us all a little extra to think about.
December 2017

Must have mobile for the money QYT KT8900D

This radio is absolutely superb, the quality is fantastic. The reports I have received with this tranceiver have been some of the best . It is so versatile having 4 frequency monitoring on both 2 and 70 , fully programable via the supplied usb cable and using Chirp software to do it is easy.The radio is very sensitive while being very selective too. Other radios I have tried in my car have proved poor compared to this one. The radio is tiny but packs a punch, minimum of 25 w on 2 and 20w on 70. The manual provided is very good but there are some print issues, the numbering of the face plate buttons etc is out compared to the text, but that is only a minor point. Good description of the menu items and their function is there too. All of the menu items and buttons are accessible from the microphone as well as on the radio front. While on the subject of the mic, there are 2 types of mic that could be shipped with the radio both work very well and give good voice over the air, the newer mic is just a bit smaller and lighter but has all the same functions, my preference was for the newer one. The mic keypad is fully lit and you can key in frequency to one of the VFO's at any time. You can programme up to 200 memories with a choice of text or frequency labeling. All the usual CTCSS on tx and rx, along with dtmf functions as well. There are also several other functions that help to cut out spurious openings of the squelch and hide the tail end of repeater squelch to, but you need to use these with care as you can loose the first part of transmissions with over aggressive settings. The radio has a very clear colour screen and the colours can be changed to suit , from the menu or via Chirp, there is only one thing that is odd but the information regarding the microphone always refers to it as a speaker mic , it is not , nor can it be as there is no audio available on the mic plug, nor is there a speaker in the mic. This is of no consequence as the audio from the built in speaker is very good even in the car. I have been using this radio now for about 2 weeks and every time I cannot praise it enough. Does everything and more that you want it for. For the money you can't go wrong and with space a premium in modern cars it is a winner. The supplier ITALKIE-UK was the most helpful and understanding supplier I have come across, answering any questions before I purchased, and the after sales care second to none , would definitely recommend this radio kt8900d an the supplier ITALKIE-UK to anyone . I enquired with this supplier about the new style mic, they replied immediately and offered to ship the new mic to me free of charge if the amazon stock was the older type, which they did and it came just over a week direct from China. Can't fault that for service.
Ultimately I purchased from italkie-uk through a friends Amazon Prime account to receive the radio next day, which it did, and I am using the radio and very pleased.
There is only one defect as i see it so far and it is not a major one but if you turn the frequency encoder know too quickly it can skip or even go back position. This seems to be a common fault as i have seen others comment about this. Used slowly it is fine and if need be the up and down arrows on the mic work just as well without any bother. The power out on 2m should be 25W mine measured 28W but that could be meter calibration. The radio only draws 6A on high power so the supplied car DC plug can more than cope. The low power setting drops it down to 10W so ideal for foundation licence holders. There is a dedicated socket on the back for the programming cable and a headphone, extension speaker socket, there would appear to be 3 connections to this as not only is there audio but ptt on there too. So you can't just put a 2 pin 3.5 mm plug in or the ptt locks on, has to be a stereo wired plug to work . Like said though, the audio is fine with the built in one

All in all a very good radio for the £79
November 2017
Not strictly radio related but close and a word of warning.
I ordered a replacement lipo battery for my Samsung 8" tablet. Not genuine Samsung but alterative. Fitted it but it was failing fairly soon after, so complained to the supplier on EBay who sent me another, slightly different labeling but identical. As I had taken out the faulty one and put back the old Samsung one., which seemed to resurrect itself. note to others. I didn't fit the replacement one, but the faulty one did seem a bit thicker than when it went in. I stored it with the new one in the cardboard packaging till now some 4 months later. Looking for something else in the shack just I saw the box under a pile of papers, and thought that looks a bit porky........well the pictures tell the rest, it is safe outside now until the bomb squad can deal with it........lol or I go to the tip .
Must admit I was a bit wary handling it, and also what could have happened while away from home or if it had been on charge by the bed at night. Lesson for everyone there.
September 2017
Don't know if anyone else has tried the replacement battery type car eliminators, but the circuits in them are so rubbish that everyone I've spoken to has had the same problem , use them for a quick over and your fine stop on longer than a minute (if you're lucky) and the damn thing shuts down until you un key the radio and start again. Looking inside they are the crapest bit of kit that was never going to work. So I took out their 3 component board and trashed it keeping the cable and the dummy battery case and set about looking for something better to put inside. Looked on Ebay at the switched mode regulator boards £1.85 each delivered, see 1st pic, spec said 1.8A continuous voltage variable to suit . Perfect and tiny , too good to be true , yes they were. Lovely little boards worked a treat but the 800 mA or so the 380 draws on tx sent it roaring hot then fell over and shut down. So yes too good to be true.
Next ordered a bigger one , second pic , nice, rated at 4.5A and cheaper than the first one £1.71 each. I knew it would be too big to go in the case as it came so I re located some of the components to let it fit. See the rest of the pictures.

The trickiest was the 2 capacitors as you have to put a thin blade under the base to put some upward pressure, and keep the soldering iron on the little bit of the tab quite a while as it runs under it , all soldered to the board, but it does come up ok no damage. Lift one leg of the toroid and put a vero pin in the hole to extend it to lie it near flat, and take the pot off the board and re-attach with extension pins off the side of the board. With a bit of angling and shuffling it all goes in. Make note the + - connections before removing the old innards or leave the connection wires attached just un-solder from the old board same with the plug in lead , I drilled the back of the case to take the cable, so that when it's all in situ you can stand the radio upright.

See my pictures and it is all fairly self explanatory. I put it on a 13.8 psu and set the output to about 8.1v , tried it at 7.4 v the advertised battery voltage but only 3 out of 4 bars on the battery meter and the batteries on the 380 measure about 8.3v anyway.

Even without a heatsink it didn't get warm on a long over on analogue.

On DMR it draws less current so will be even better.

Also the bonus is that I didn't glue the battery case back together, as the back cover holds it all together when clipped onto the radio, will glue it when happy with more field tests are done, incase I have to open it up again to mod or tweek.

Thought you might like to see how easy it was the whole project only took about 1 hour Including testing.

I have also used this same board in a Baofeng dummy battery as they are the same rubbish inside, and failed after 1 minute. Both are working just great now, very clean on the signal too, no noise.

Hope you find this useful.

Wayne M5LLT
August 2017
Well August is here, and so is my new toy. Always wanted an antenna analyzer but the high cost has always prohibited the purchase of a piece of test equipment, MFJ analyzer was the popular unit to be had and then you had to look for the model that covered 430 Mhz for it to be multi purpose. Most only go to 145Mhz so extra cost again. So I looked at various options of building my own, designs are out there using the very cheap Arduino and lcd displays but setting up, getting all the parts, writing the Linux code, building the case, interfacing the rf with the Arduino etc etc......the cost starts mounting up, then is it going to work ? Let alone all the time taken. I then took the advice of G4JCP Phil, while chatting on GB3KC about this project. From the mouth of the Arduino king ......."if you can find one for 150 quid buy one" this took me back a little but made me think, so I started Googling, got a cloth and mopped it up and checked out the Internet for Analysers. There were quite a few MFJ included, kits to build and various Chinese offerings. Some only covered HF some only Vhf/Uhf then I found the Feature Tech AW07A.
This little beauty not only gives all manor of analysis for antennas , but it doesn't stop there. You can measure impedance not only at 50 ohms but a wide range , it is a wide range rf signal generator, a digital frequency meter, measures capacitance and inductors. Wow ! All this for £150.......Ok it's not a marconi lab grade piece of tech and if you read the reviews people have had bad ones, dials broken (send it back then) it drifts a little , so ? If you are checking your 2m mobile whip to make sure it's in band , you're not going to use a spot frequency are you you're using a range of them, so a bit of drift no problem , really, and it's only minute anyway from what I can see. The unit takes 8 A A batteries and comes with a DC lead, plan to replace these with enerloop A A rechargeable, will need to alter the dc socket as it is switched to stop you recharging standard batteries. The display LCD is very clear and illumination is switchable, but the front screen is only a very soft pvc film. This will be changed very soon for a more robust acrylic lens.They provide two good quality adapters from N to SO239 and BNC the unit itself terminates in N Type.
All in all this unit fits my bill and some, so looking forward to some antenna projects and checking current ones out, so far my Diamond 2/70 Colinear seems to be pretty rubbish 2m is resonant best at 146.9mhz and 70cms is 384 mhz ( perhaps I shouldn't have bought this analyzer )
You can measure 50mhz (6m) but it falls just shy of 70 mhz stopping at 69mhz which is a shame, but there may be a way to get to 70 I haven't found yet.
All in all I'm very pleased with this analyzer from China , it doesn't come with a manual but I'm downloading one off the net and the cardboard box will be replaced with a soft case soon.
Will let you know how it goes after having a longer time to play with my new toy (batteries not included)

Next month looking at meteor detection using cheap SDR


Wayne M5LLT
July 2017
July's Drivel

While trawling the internet for Digital frequencies to have a listen to I stumbled across this, whilst I knew 70 cms was a shared band I thought that we mostly shared it with key fobs and wireless pir alarm devices. It now seems that we may have other unlicensed voices both analogue and digital on the frequency. Here is the table of frequencies allocated to channels.

Every one kept saying "use it or lose it"

Extract from Ofcom

ITU Region 1 (Europe)
United Kingdom
In the UK, LPD433 equipment that meets the respective Ofcom Interface Requirement can be used for model control, analogue/digitised voice and remote keyless entry systems. There is significant scope for interference however, both on frequency and on adjacent frequencies, as the band is far from free. The frequencies from 430 to 440 MHz are allocated on a secondary basis to licensed radio amateurs who are allowed to use up to 40 W (16 dBW) between 430 and 432 MHz and 400 W (26 dBW) between 432 and 440 MHz. Channels 1 to 14 are UK amateur repeater outputs and channels 62 to 69 are UK amateur repeater inputs. This band is shared on a secondary basis for both licensed and licence exempt users, with the primary user being the Ministry of Defence.
Ofcom, together with the R.S.G.B. Emerging Technology Co-ordination Committee have produced guidelines to help mitigate the side effects of interference to an extent.