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Tuesday 24 November 2015

The previous Sunday local net on GB3IR

I don't often post about the regular local net on GB3IR unless there is something of note, and, although this is a couple of days late coming, there was something noteworthy the previous Sunday.

First off, the Sunday evening net on GB3IR is open to anyone who can access the repeater either direct on RF or over Echolink, it's not strictly local and it's nice to hear new voices on the air.

So, how is it noteworthy, by use of the Leixen VV-898 and my homebrew yet unfinished dipole of course, it was still hung up and I thought to save the batteries on my handhelds (of which I have reprogrammed to include all 2-meter analogue and System Fusion voice repeaters in the UK), performance wise the antenna was getting into the repeater fine (though I could just as easily use a very leaky dummy load or a piece of wet string though of course I'd not recommend that given that I am very close to the repeater).

This has been the first time the VV-898 has been used for a Sunday net on IR since removal from my previous car, it has not been fitted to the new car as it would be much easier for me to fit a radio with a detachable front, hence my interest in the Yaesu FTM-100DE (which I think is an after-Christmas purchase though I am seeing this rig in the flesh soon to see what it is like), though I am also interested in this rig for the benefit of System Fusion, the ability to turn up the TX power once I have my intermediate, and the APRS side of things as well as I'd like to get a bit more into that, all of these things are beyond the VV-898 (except the APRS with a little bit of extra hardware), hence why it has been now demoted to home radio, and it only puts out 10-watts anyway

The VV-898 seems to be performing well as a home rig on the homebrew dipole, the next thing to do is put the antenna outside and see what it can really do, but first there is waterproofing to do, as for the VV-898, it will be taking place in most Sunday nets on GB3IR and perhaps any simplex nets once I get the antenna outside the window, I just need to waterproof the coax join, I was initially going to use black Sugru but I may use blue Sugru instead as it matches the blue on the dipole elements..

As for the Sunday net itself, nothing of note to mention really apart from the antenna and rig I used, just leaves me to finish it off, roll on payday and a trip to somewhere I can get blue Sugru from

73 de M6RSQ

Sunday 22 November 2015

How to get a Leixen VV-898 to transmit and recieve on APRS

Just exactly how do you get a Leixen VV-898 to transmit and receive on APRS? This is how it is done.

Firstly you need to find the pinout for the mic, a Google search will bring it up in no time, using my method you may also need to find an Ethernet pinout as well, but be aware that the pin numbering may be opposite to that of the VV-898 mic plug diagram, it remains for you to match and note the colours.

Next you need an interface, I already had one lying around but my shack computer has no physical COM port onboard so a USB to Serial adaptor had to be used, the one I have is a Prolific type, be aware that these may need older drivers as newer drivers reject some cheap programming cables that are allegedly based on a Prolific chip but it is in fact a non-genuine chip, and the Serial adaptors may have one of these rather than a genuine Prolific chip, my serial adaptor appears to have a genuine chip in it unlike my mass of programming cables and TTL lead, my interface is wired up to pin 7 on the serial plug (RTS) though you can wire it to pin 4 (DTR).

On your computer you need to install a sound card TNC, I use UZ7HO's Soundmodem, there is a high speed version as well but we do not want this for APRS, it needs no installation, just extract from the zip file to a convenient folder (desktop on my shack computer with the icon pinned to the taskbar), set up the modem as required (APRS is 1200 baud AFSK), then set it up for the PTT on your COM port, in my case this was COM 7 but yours may differ, unless you have a physical COM port which is always COM 1 (modern computers rarely have more than 1 onboard COM port)

Next you need to set up your APRS client, I use APRSIS32, this client can be used without a radio to connect to the Internet, and also as an iGate or digipeater, but we don't need that functionality and it would require the appropriate NoV and a full license from what I understand, it needs to be able to talk to sound card TNC, this is found on localhost (unless the machine you're running the client on is on your network separately from sound card TNC), if you have a second sound card in your computer (I do) then ensure that is set up in the sound card TNC first so your main sound card can be used for other things like Echolink for example, plug a lead into the back of the VV-898, I placed a ground-loop isolator on this line to eliminate unwanted noise, power it up, and tune to the APRS frequency (in the UK this is 144.800 MHz, in other European countries it should be the same, but check first before you transmit), ensure you have disabled the APRS-IS side of APRSIS32, and it is not set up as an iGate or digipeater (turn off options for RF to IS and IS to RF and if you wish disable Internet access entirely), if the soundmodem is working and APRSIS32 is talking to it you should see a list of callsigns and other items scrolling on the top left of the window.

Now you can test your interface, tune the rig to a clear frequency or connect it to a dummy load, and connect the circuit to the mic socket, the rig should do nothing, if the red light comes on and it has gone into transmit this indicates a problem with the interface wiring, if not you're good to go.

At this stage don't plug the audio feed into the computer, if you are doing this into a dummy load there should be no need to identify, you should still be able to listen on a handheld placed close to the dummy load and tuned to the same frequency, you will also need to get the volume set up correctly, you can use existing APRS transmissions as a reference, if your interface is built with a potentiometer, as mine is, you may need to adjust this, too quiet the iGate and other stations won't receive the transmissions properly, too loud is just as bad and may cause interference, once you have it right, connect your rig back to the antenna and send a packet to APRS, if it is heard by an iGate you should appear on, if not your packet was not received properly by the iGate if at all, in this case check all your settings carefully.

Once it all works give yourself a pat on the back, you've got a radio with no TNC port to transmit APRS packets successfully.

Though if you are in my situation and want to use the same rig for voice, just disconnect the leads and reconnect the mic, job done.

73 de M6RSQ

(note that this isn't an exact guide, the full ins and outs are a lot more detailed)

Saturday 21 November 2015

Another APRS update

After soldering an offcut of Ethernet cable into the auto-key interface I originally built for the CB gateway (including removal of the relay as the Leixen VV-898 can RX without a mic connected), I managed, after some trial and error, to successfully transmit an APRS packet which was  received by MB7USD, the antenna was still indoors and power was my max allowed 10 watts (though cable losses and SWR may have caused it to be reduced some at the antenna itself, before actually transmitting a packet I located a clear frequency to check the key circuit was working, it was working just fine.

After this test I removed the interface line from the mic socket, I then moved the rig so it is now located on top of my Grant II to make sure I had some desk space, this then amounted to a recheck of the SWR to make sure it was the same, it is, and all I need to do is finish the antenna (I was thinking Sugru for the centre) and hang it up outside, I may also cut the coax shorter as it is RG58 and on 2-meters it is a bit lossy for my liking.

So, I can now transmit on the APRS frequency from home, just need to do that for the car but as I mentioned in my previous post I can use my mobile phone as a stop-gap

Another day and another success in Amateur radio

73 de M6RSQ

APRS update

I have got APRS working on both the laptop and my phone, the latter will be used in the car until I obtain the Yaesu FTM100DE which has this on board anyway, and both report position to APRS-IS no problem, I have yet to get the Leixen VV-898 to transmit on the frequency as I've not had chance yet today to remove the relay and old CB related cabling from the auto-key unit and wire in an Ethernet cable.

What does this mean? It means that anyone, licensed or not, can see my current location on or similar, just need to search for my callsign, which will have a - then a number after it, mobile use (in the car) is -9, my laptop currently is -10 (internet only as my laptop rarely if ever leaves the house) and my shack should show as either -0 or no number after my callsign.

I'll post a bit more later once I have the VV-898 operational on APRS, time to grab a cup of tea and a hot soldering iron.

73 de M6RSQ

A bit more time dedicated to radio

Firstly with my Leixen VV-898 on the bench rather than in the car (I had replaced the fuse holder for a mini-blade type after the regular one fell apart) and connected to the power supply I thought maybe it is a good idea to play with antennas so I dug out my 2-meter slim-Jim that I had built at the club some time ago, only to find it was not working as it should (the SWR was a bit high so I figured it was kaput as it had been on the floor in the hallway for some time), a T2LT cut to the right length was my next attempt, again this did not work, then finally I relented and assembled a dipole, this too, despite being cut to about the right length, was not working with a high VSWR, though it was lower on 70cm, what gave? Turns out the choke I had wound was too far from the feedpoint, so I cut the excess coax between the choke and antenna out (I did this so I did not have to redo the choke), after resoldering the antenna elements (two pieces of the neutral conductor from high-current twin and earth cable) to the coax at their new position and rehanging the antenna from my winter washing line in the living room and reconnecting it to the rig, the SWR had dropped though still read between 1.5 and 1.7 on the meter, better than it was but could still be better however it handles the 10 watts the radio gives it fine, all I now have to do is finish it off and hang it up outside the window.

I have also had a look into APRS, as there appears to be transmissions on the APRS frequency in the locality, which I believe is coming from MB7USD as aprs,fi isn't really showing a lot otherwise, I have been working to get the VV-898 to be able to TX on APRS but thus far have only got it to receive into my shack computer, and I don't yet have a passcode to do Internet-only operations as yet, as I have decided to decommission both my FRN gateways indefinitely some time ago as I want to focus a bit more on the Amateur side of things I plan to modify the auto-key circuit I built for the CB gateway to use it with the VV-898 for APRS as it sounds like something that might be worth playing with and the Yaesu FTM-100DE has this onboard as well and as I plan to get one of these for the car (as the box can live under the seat or in the boot out of the way) I may as well use the APRS feature on it, I'll hopefully be looking at one of these up close and personal at the next club meeting intermediate training pending.

I also have the APRS software installed on my laptop computer, of course not having a passcode as yet means I cannot transmit onto the APRS system but that should change soon, with a crude but working antenna up I should have no problems transmitting all being well, so let's see what APRS is all about

73 de M6RSQ

Sunday 8 November 2015

A catch up after a busy few weeks

I have had a lot on over the last few weeks, but I have some good news, I made it to the Newark Hamfest after going to a local Toyota dealership and obtaining a 2009 Toyota Aygo Platinum, which at the moment lacks rigs but does have a Parrot handsfree and an aftermarket SD/USB MP3 virtual CD changer, and the only Amateur radio activity I have done from this car is by means of Echolink on my phone.

The hamfest was what I imagined it to be, a couple of the other club members were also in attendance, I went down in the hope to get a 2-meter rig for home that was SSB capable that I could run off a slim jim or a homebrew 1/4 wave groundplane antenna, though I am going to put this on hold at this time because I'm having the windows replaced in the not too distant future and I did not get a rig anyway as there were no suitable used rigs in my price range, perhaps after Christmas which will also be when my motor insurance should go down as I've had no claims (touch wood)

I have also begun my Intermediate training, which I have been eagerly looking forward to, it's going to be a while before I can get that 2x0 call but it will be a great day when I do, and hopefully as soon as I pass I will progress onto the full license, which is my ultimate goal, the more I progress in the hobby the more I am interested in it.

I haven't been as active on the air as I would have liked of late and need to get back into the habit of going on air, I believe that after the disaster of an MOT that my old car went through only to ultimately be scrapped I feel that I lack a bit of motivation, I should be happy as I have another car now but perhaps I still miss my old car.

Anyway, I should be on air more frequently soon

73 de M6RSQ/26CT730