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Wednesday 29 October 2014

RTL-SDR enclosure prepped

I picked up 2 different diameter hole saws today to enable me to cut the hole needed in the lid of the tin for the USB connector for the SDR, the connector was fitted after a suitable hole cut and another hole drilled through for a screw (a second screw will be sourced and used later to finish the job).

A connecting lead for the antenna socket on the stick was sourced from the magnetic mount stick antenna that was supplied with the RTL-SDR stick, it was simply a small amount cut from the lead with the MCX connector intact, the cut off end was simply prepped and soldered to the appropriate points on the BNC connector, with the excess trimmed off, continuity was checked before the lead was connected to the stick.

The stick was then tested with just the antenna socket, I installed the SDR# software to do this, it worked as it should have done, the stick was then connected to the USB socket inside the tin lid and the tin closed up, it still works, the NA-771 antenna is not tuned for everything the RTL-SDR is capable of tuning to, but it seemed to work OK in the broadcast band, it of course worked fine in the 2-meter band and on PMR446 (PMR446 frequencies fall into the 70cm band in the US so to be expected). I tried it on 11-meters including on 27.555 MHz, but no luck, partly due to being indoors and partly due to being the wrong antenna for the band, a final test was to see if broadcast reception was eliminated while inside the tin, it was.

The last stage of this project is to fasten the USB connector down properly with one final screw, silicone seal the inside of the tin to be sure that no leaks can occur, fill it with oil after the silicone sealant has cured, and immerse the operating RTL-SDR into it, the reason I want it operating while I do this is to ensure that the stick continues to work while immersed in oil, SDR for mariners claims that it does.

It has taken me a bit of time but I finally have got the tin fitted out.

73 de 26CT730

Sunday 26 October 2014

DXpedition called off

Due to extremely strong winds, so strong I could not open the car door, I decided against DXing at Tan Hill, and arrived at Emley Moor (my second choice) too late to do anything due to heavy traffic on the motorways.

It is a shame I was unable to DX as Tan Hill is a superb spot for DXing due to it's elevation as is Emley Moor which is why there is a broadcast facility there to cover West Yorkshire and some parts of North and South Yorkshire, of course I'd have found a spot some distance away from the broadcast tower to avoid interference to and from it.

If the wind dies down I will plan to set up the T2LT near to my home address in time for The Big Net in November, I've missed previous UK CB big nets but would like to take part in this one, and as my T2LT is a temporary structure I should, in theory, be able to operate on it then remove it when I am finished, not sure I have sufficient cable though, this I need to deal with before I can go on air from home.

Also I am planning on getting a working PMR446 bazooka antenna on the gateway radio very soon, an antenna of this type is so small and unnoticeable that no one would really care that's it is there, it should improve coverage somewhat after I had a station on the A1 use the gateway a few days ago.

73 de 26CT730

Thursday 23 October 2014

Possible DXpedition this weekend

I am renting a car on Saturday afternoon for a few days (until Tuesday afternoon), this is primarily for me to get somewhere I need to be on Monday afternoon without taking the train, however it has another plus point, getting to a nice high point for a spot of DXing.

My initial plan in August was to go to Tan Hill and do some DXing there, this fell through as I could not find any time to get up there and I was late finishing the T2LT and finding a suitable pole for it, this is now remedied, and I could go to Tan Hill or Emley Moor, the latter being home to a famous broadcast transmitting station, but I'll see which would be best, Sutton Bank on the A170 is another option but the only car park is owned by the North Yorkshire Moors National Park Authority so only useable with a magmount and tank whip, and I don't have the latter and cannot put a magmount onto a rental car as it may damage it, Tan Hill is closer however.

The radio (the President Grant 2) will be powered by my sealed lead-acid battery and not from the car's cigarette lighter to avoid damage and running the car's battery flat, the only antenna I have available is the T2LT, this will happen assuming the weather is better than it has been of late.

If I can do this I will be on air most of the day, and I hope to catch you on air that day if conditions permit.

73 de 26CT730

Sunday 19 October 2014

Digital modes

As it stands, all my radio operations have been using analogue modes of transmission, and due to the prohibitive cost of most existing digital equipment I've obviously not been able to experiment with it, but my radio related browsing has caused me to stumble on yet another Chinese radio that offers functions of a more expensive radio but a cheaper price, the Kirisun S780.

The S780, when operating in digital mode, appears to be compliant with dPMR standards, using  FDMA, 4-level FSK modulation, and in essence works like a mobile telephone but minus the infrastructure so no loss of coverage, it is seemingly compatible with dPMR446 but with a minimum TX power of 1 watt it wouldn't be legal and it isn't type approved for dPMR446, it does analogue transmissions as well.

The S780 appears to be able to send text messages, like SMS but peer to peer rather than through infrastructure, in common with other digital radios like this it can talk directly to another radio without transmitting to them all, it also offers encryption, though this is limited to voice, the text messages can be decoded by anyone listening if sent to all radios in range.

Looking at pictures of the radio the connection does not appear to be Kenwood, as is the case with other Chinese radios such as those by Wouxun and Baofeng for example, it instead appears to be 2-pin Motorola, thus immediately ruling out compatibility with my existing Wouxun accessories, which is a pain as when I do buy one of these radios I will have to order it with a USB lead to actually program it to work on the right frequencies.

So if finances permit a digital radio may join all my analogue gear, and given the quality of Chinese radios now I think it would be worth it.

73 de 26CT730

Friday 17 October 2014

Amateur radio club night - 16th October

Nothing between my last post as I've been a little busy to find any radio time other than casual listening of GB3IR, but last night was indeed the club night again.

The founders of the club brought in a rig that could do HF, VHF, and UHF, but for the purposes of the club it was on 40-meters, and as the club did not have a call sign only those that were licensed could actually use it, the antenna was a G5RV, which I didn't see as it was dark outside, connected into a tuner and then into the rig.

I had a discussion about the foundation training and useful resources with the tutor, some of which I will have a look at tonight when things settle down.

Despite not having the same mishap as last week I still arrived earlier than I expected to, but because there is resurfacing works overnight at my road-end I didn't want to risk being stuck so had to leave the house earlier than normal.

It wasn't a busy night last night unlike most nights but we had two newcomers, also unlicensed like myself, bringing the total of those that would be doing the foundation up to about 5 or 6.

Next club meeting is in two weeks time, I need to get some airtime hours on 11-meters and PMR446 logged in the mean time and also a bit more revision on the old Foundation license, as my course starts on the 4th November.

73 de 26CT730

Thursday 2 October 2014

Amateur radio club evening - 2nd October

Tonight was the local Amateur radio club meeting, pretty much almost everyone who was there last week was, topics of discussion included discussion of a neighbouring club's delivery of a modern repeater and a chat between the founder and the 3 (later 4) of us that would be doing the foundation exam, myself included, we were each given a CD which I will have a look at tomorrow when I am less tired and have my jobs I need to do out of the way.

I arrived there a shade earlier than expected tonight owing to some unforeseen and unfortunate issues earlier in the day, but it was still a good night, with the licensed members trying out the neighbouring club's repeater which was connected up to a dummy load to keep it all above board, and it was a very clever looking piece of kit but I did not have a closer look.

So, next meeting is in 2 weeks, and I also hope to begin my training in November, so forwards we go.

73 de 26CT730