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MB7UBP QRT for now

9/20/2010

2 Comments

 
I have been having some problems with my virgin media broadband connection over the last few days and it looks like the whole thing has finally fallen over completely. This means that MB7UBP is not gating to the internet until I can fix this!

Hopefully it will be back on soon
2 Comments

New Igate hardware?

9/8/2010

1 Comment

 
One interesting thing to come out of the discussion with M0RXW was his work with the omnima embedded controller for APRS. I have blogged before about using APRS4R running on an Asus router flashed with Openwrt here at MB7UBP to reduce the cost and environmental impact of the Igate and this has been running for about 2 years now. Whilst APRS4R works many folks, including me, find it a bit clunky to use. Furthermore the Asus routers are now out of production so the aprs4r development team are looking at other hardware platforms.

In the meantime Reuben, M0RXW, has got Openwrt and APRX running on the Omnima (which with box and programming cable costs about £50 or $75). The flashing process looks a bit more involved and there is no GUI for settings, but these are both problems for me with APRS4R so I am not worried about that. How long will I be able to hold out before I splash the cash to play with one? I suspect it won’t be long…..
1 Comment

APRS gating woes

9/8/2010

2 Comments

 
I have been on holiday for a week, so had to turn of the MB7UBP APRS I-gate to meet the shut down terms of its licence. M3SXA provides such good coverage of North London that I am not sure it was missed too much.
  
I used aprs.fi to look at my track after driving home (up the M20 from the Channel Tunnel and round the M25). I was surprised to see that there were some serious problems with the paths. This was backed up when a Kent I-gate owner, M0RXW enquired on the aprsig email list to solve the problem. |he group came up with an interesting solution – it seems that Alan, G3RJI’s new bi-directional I-gate, MB7UUE, is translating local internet packets to RF. I have no problem with this (*if* it is limited to very local packets) but, Alan has a great location and a high gain antenna giving him a large RF footprint and therefore high channel occupancy. This meant that timing of packets was being disrupted as the I-gate had to wait for a free slot on the air to TX a packet queued from the internet. As we have reasonable I-gate density around the perimeter of London the overall effect was to cause my position to jump around on the map.
For example
 Time 1; M0BPQ-9 heard by M0RXW and gated to the internet at position X. Time 1: The channel at MB7UUE is busy so the position X received via the internet packet is stored until the freq is clear

Time 2: M0BPQ-9 Heard by M0RXW and at position Y and gated to the internet

Time 2: Channel clears at MB7UUE and the stored packets (including M0BPQ-9’s the out of date position X) are sent to RF

Time 3: The MB7UUE packets are gated back to the internet by M0RXW.
 
The overall effect on the internet map is the M0BPQ-9 travels from X to Y and then back again!  
 
What is there to learn form this? The main issue is to set your “ignore dupes received with n seconds” setting at the correct level if you are gating Internet to RF. Perhaps this needs to be longer for Internet sourced spots than it is for ones generated on RF? Secondly, perhaps I beacon too frequently when mobile? I will revisit my smart beacon settings to look at this.
   

This is certainly not a criticism of Alan and his efforts to get more activity back onto RF (which I applaud), but an interesting example of the pitfalls faced by this system. I am happy to report that once Alan realised what was going on the resolved the problem quickly, so well done that man.
2 Comments

MB7UBP coverage

3/10/2010

0 Comments

 
MB7UBP coverage plot - compare to M3SXA-10!
Picture
0 Comments

M3SXA-10 is live

3/9/2010

0 Comments

 
I finally got my act together and sorted out the gear for Steve M3SXA to run an APRS I-gate from his QTH in North West London so I popped over there at the weekend and helped him get everything set up. For once things went smoothly and Steve is now gating items from all over west London and even to the southern stretch of the M25, which is a real step forwards in coverage.  The plots from aprs.fi below look great, the darker red the square the more packet have been received from it:

Picture
Steve’s station runs a tri-band collinear on the chimney which has about 3db more gain than the antenna at MB7UBP, so I am wondering whether I should change things around here to get better coverage..... or maybe I have loaned out one of my best radios!
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APRS coverage

2/22/2010

1 Comment

 
The MB7UBP I-gate continues to give good service using APRS4R, but I always knew that my location would limit my coverage quite dramatically due to rising ground to the North east and South west. I spent a little time using the DB0ANF web server to analyse my actual coverage and the picture shows that I really don’t cover west London at all. 
Picture
A few minutes more using Radio Mobile shows exactly which bits I don’t cover - West London really is a blank spot!
Picture
But looking on the APRS.fi site, there are several stations who are regularly active only via the internet in this area, but not RF. I decided to write to one of those, M3SXA, asking him if he would consider becoming active as an RX only I-gate. A full two way gate would be preferable, but as a foundation licence holder Steve is unable to hold an NoV  so working on the “something is better than nothing” basis this would be a real step forwards. Steve got back to me straight away and said yes – what a nice bloke!  I am very grateful to Steve for offering his location for the good of the wider amateur community.

Steve has a nice radio set up, most of which will be wasted on APRS. I have therefore agreed to loan him a TNC, PMR set and PSU to get things going. Radio Mobile suggests that coverage will be a real improvement! 
Picture
I’d better get on with sorting all the bits out…..
1 Comment

MB7UBP back on

1/20/2010

0 Comments

 
I have been running an IGate in North London for some time, with the call sign MB7UBP using APRS4R running under OpenWRT on an Asus router. All has been fine and the system has needed little attention, until this weekend when the gate stopped reporting to the Internet.

I have logged into APRS4R and everything is running OK, but I couldn’t get the router to ping the WWW. I run a wired LAN to my radio shack (loft!) and the cables were firmly seated at both my ADSL router and the APRS box. This had stumped me for a while, until I realised that I was forced to cheat when wiring the APRS LAN cable. During installation I didn’t have a long enough cable to do the whole lot in a single run, so I made up two shorter cables, connected with a female back to back joiner.  This joiner happens to be quite close to the main electrical switch to the shack and it seems that I managed to dislodge one Ethernet cable when I reached across to throw the switch on my way out. Doh! Anyhow, all is now fixed and I am back on the air. 

That has taken me three days to work out, so my apologies to users who may have missed some functionality. The only good news is that the system was still active on RF and other local gates such as 2E0RNT and M0XDC probably picked up traffic for me in, albeit with an extra hop inserted.
0 Comments

UIDIGI

8/5/2008

4 Comments

 

Still very busy with work at the moment, but I was trying to get my APRS digi up an running at home again to see if I can fill in some of the holes left by the demise of GB2GP.

The rising cost of electricity means that I don’t want to run a PC all day just to perform the digipeater duties (I calculated the cost as 50p for 24 hours) as there are already three good I-gates in 2E0RNT, M0TEC and MB7UFF already.

I have been looking at using UIDIGI for some time and fortunately I got a prom blown by N1VG at Argent Data systems – the man who makes the open trackers. I finally got around to putting up a low co-linear in the garden last night and inserting a UIDIGI prom into my tiny 2.  I had to reconfigure this a few times to get things going, but I think everything is now OK and I am now acting as a fill in digipeater again for North London. The antenna needs to go on the roof, to be really effective, but I have been saying that for months!

4 Comments

APRS on holiday in France

7/30/2008

0 Comments

 

I shot off after VHF FD for two weeks on holiday in France. The first week was split between the North (near Calais) and a city break in Toulouse. The second week we had a gite near Pau and a hire car so I threw in my FT-60E, Opentracker+, puck GPS and a ¼ wave mini mag mount to see if things worked out there.

There were several issues learnt: the standard HT battery only lasts about 2 days , but I had two, so I covered most of our trips out and about (I didn’t take a charger to reduce the amount I was carrying). The 1300MAH lithium cells that I used to power the tracker and GPS also had a surprising short life but a recharge half way through covered that off. A final issue was setting up the transceiver/tracker. If I set the squelch to an appropriate level at the gite , out in the sticks, it was useless in town where the noise levels were higher. This meant the tracker thought the channel was busy and didn’t tx for long periods of time. Once I had worked this out and adjusted the squelch in town things were much better. Perhaps I also need to play with the software DCD on the tracker as well to avoid this in the future.

I checked aprs.fi on my mobile a couple of times and was surprised about the level of coverage I received. If you look for M0BPQ-12 on the db0anf site you will see some great tracks.

I see that this is all down to the efforts of the F5ZVO digi at La Pierre St-Martin, which is a ski resort in the mountains. There is no wonder it does such a good job when it is at 1700M ASL.

Looking at the data afterwards, I was also amazed to see that I was logged by EC1H-12 at a remarkable 464Km, also when I was up in the mountains. Not bad for a data mode, 5W and a ¼ wave whip on 2m..... Location, location, location!


0 Comments

Gilwell shut down and VHF FD prep

7/2/2008

0 Comments

 

Again a big gap between posts.

The radio scouting team dismantled the GB2GP shack last weekend and I have ended up with yet more kit to hide in the loft. Everything went smoothly, but there will be no radio activity from Gilwell until the LID is back running in March 2009. 

The group has been offered a time step wx sat receiver and antenna though and we are investigating ways to put this up as a permanent demonstration station, perhaps coupled with a weather station. There are obvious possibilities for publishing data on the web or tying it in with a formal APRS Igate. I find the RSGB packet radio licensing forms baffling, so I may look for some help on how to move that forwards. 

It is region1 VHF FD this weekend and the weather forecast is terrible! I am providing the computer network running n1MM and 3G cluster along with the 6/4m and 2m station for the Clifton ARS.  

The 6/4m station will be my FT-847 running 100W on 6m and 25W on 4m to a dual band yagi at 10m agl (4 el on 6m – restricted section, 5 el on 4m low power section). 

The 2m station will be my IC-756Pro, DEM transverter, linear amp, sequencer, preamp and 9 el DK7ZB at 10m AGL for the restricted section. 

I might chuck in the Gilwell TS-200 to run on 70cm if we have enough operators!

That doesn’t look like much gear, but add in tents, poles, ropes, ac distribution, computers, networking, heliax, rotators and all the interconnecting cables it will fill the hire van. Never mind all the effort that goes into making it all fit together in the first place.  This will probably be the last time I get so involved as it is becoming expensive and an awful lot of work! Anyone need a seasoned operator for VHF FD next year?

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    A few notes on recent radio activity by Steve, M0BPQ.

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