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Thursday, 18 July 2013

Update on the Kirisun - bit of a problem

Well, today I turned on my Kirisuns again, and was trying out the messaging a bit. I turned the volume up on one radio and sent it a message, and the audio went!
After that, there was no more audio coming out of the speaker when I pressed buttons, sent messages or voice calls. Very annoyed with this. I think kirisun will need to sort out this problem. Other people have said that their audio has broken too, but no one else I know of has had this happen just by turning the audio up all the way. It happened to others if they plugged in the programming lead with the radio on.
I'm going to try to get the radio replaced or repaired, and hope that the other radio doesn't produce the same problem.
I've tried turning the radio on and off, even removing the battery, but still to no avail. I think it's definitely a hardware fault.
Chinese manufacturers really need to get their act together and properly test their products before selling them to people.

Saturday, 13 July 2013

Digital radios for preppers

When I got my Kirisun S780s a few days ago, I was messing about with all the settings as I usually do with new gadgets, and turned on encryption in the programming software. This got me thinking about preppers. Preppers usually like to have communications equipment prepared for possible times of disaster.
In a WROL situation, where someone could loot you for all your preparations if they knew about them, I'm sure preppers would like to have encrypted communications, so that anyone with a scanner can't find out where they keep their food stores or secret stash of fuel.
These Kirisun radios provide inherent security, in that not many people will have radios that use the same vocoder, and it is unlikely anyone around you will have one. This could be called "security through obscurity". That is even if you don't turn on the encryption. To a scanner listening in analog, these radios just sound like a load of noise. Now, if someone were to buy a radio the same as you, and program it up to the same frequency, they would be able to listen in to any unencrypted comms. Thats where the encryption comes in handy. Switch over to an encrypted channel, and they will not be able to understand it at all. All you hear when listening to an encrypted channel on a radio without encryption, is a few funny digital noises. But at the same time, you can understand anyone without encryption on their radio.

Friday, 12 July 2013

Kirisun S780 photos

Just a few photos of the kirisun s780. For more info, have a look at my YouTube playlist with the best videos of the Kirisun S780.

Friday, 5 July 2013

Home made repeaters

I have been experimenting with building a repeater at home with parts I already have. Not buying any duplexers or cavities or anything. I've tried 3 different types: A cross band, a simplex, and a erm same band repeater.
The repeater with both input and output in the same band seemed to work okay, until I got a friend who lives about 2 miles away to try and get in to it. When he keyed up his radio, it completely desensitized the receiver which lost the signal straight away. The effect of this, heard on the repeater output, was just a load of noise. I would hear noise, then the repeater would close the squelch, then it would stop transmitting, and the receiver would be able to hear the signal again, and it would start all over again.

This might have been to blame on my use of a scanner as the receiver, but as I said, it was a simple design using only parts I already had. All I used was a PMR446 radio as the transmitting side, and a Uniden USC230-E scanner as the receiver. When the scanner heard a signal, it would send the audio through a standard 3.5mm audio cable, to the Binatone Action 950, via a 3.5mm to 2.5mm converted. The Binatone would then key up using vox. I told you it was simple!
 Someone told me afterwards that the scanner probably has a very wide front end, meaning that it would be desensitized very easily. I should try it with another radio, such as one of my Chinese PMRs, but I need to buy another 2.5 to 3.5mm adapter to do that, since the audio out on the Chinese radios I have is 2.5mm. With a large split, and a better suited reciever, I think the same band repeater should work a lot better.

The other type of repeater I tried was the cross band type. I used 446 as the output, and one of the UK simple business channels and the input, on VHF. I know this is not strictly within the rules of the bands, but it is only for experimentation, not permanent use, and I set it up in a way that would cause minimal disruption.
This setup did not have any problems with desensitization, but it did have problems with signal propogation being different on VHF and UHF. I asked the same friend again to try and talk through this repeater, but this time, he could not get in at all, even though he could hear it perfectly fine. His VHF signal just did not reach the repeater.
I suspect this may have been down to the antenna he was using. It was the stock antenna that came with a dualbander. These stock antennas are usually good on UHF, but awful on VHF, since they are just too short. I think if he had used a longer antenna, like a dual band whip made for amateur use, he might have been able to access the repeater fine.
I also tried this repeater out from slightly closer, but still not a location where the signal would be very strong, and it worked fine from there.
So I think the fix for this repeater would just be to use extendable antennas on the radios, so that they could be extended to transmit effectively on VHF.

After these two problems, I decided I would try a simplex repeater, using the scanner again, and the Binatone radio on vox. This seemed to work pretty well for range, but it did have a bit of a problem of cutting off the first second or two of audio, so you would have to repeat messages a lot. It's also quite tedious having to wait for your message to be played back again after you send it.

I think the cross band repeater is the most effective. Maybe if I were to switch the output and input, and use a VHF radio to transmit, instead of the 446 radio, it might work better. Although I would then have to use a computer and a com port keyer to key up the radio, since all of the radios I have don't key up the vox when you use an audio cable plugged in to them.

Tuesday, 2 July 2013

Kirisun S780

I ordered the S780 today, so will be doing a very detailed review as soon as it arrives! Look out for it.

Update: Just checked the postage tracker, it has left hong kong today, 06/07/13
 A few people on the group have been complaining about them ordering 2 radios and one of them not having working audio. I'll be pretty annoyed if that happens with mine! I'm really hoping at the moment that it doesn't.

Okay the radios came today (10/07/13) and they do not have the audio problem (yet!).
I have already done a range test and have to edit it, along with an unboxing video showing what the digital audio sounds like, and the analog.
I must comment, that the analog sounds awfully muffled on transmit.
Will be uploading the videos either tomorrow or the day after.

Another update: there are now lots of videos about this radio on my youtube channel.
One of the radios has developed the audio fault and I am having to send it back to Hong Kong to be repaired/replaced.

More updates:
here is the unboxing and digital audio test

Monday, 1 July 2013

Super simple guide to setting up DSD on Windows

Here is my new video. I spent a long time making and editing this one so it should be good. It's about DSD and the easiest way to set it up and start decoding.

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