Work on the future Catterick Garrison igate underway

I have been working on getting the radio hardware working for the future APRS igate that I intend to run from the home QTH, the radio is my Leixen VV-898 as it's sat doing little, the rest is done via a Raspberry Pi with a keying circuit and a USB sound card.

The setup is currently into a dummy load and is powered from my bench power supply for the radio and the Pi is running off my phone charger.

The next jobs to do for this is to get the shelves in the shed and to get the antenna built (which I plan to make resonant on 144.800), then of course batteries and solar panels to get power to the shed.

So far the tests show promise, the transmissions are received by my Yaesu FT2D and it is used to test receive on the igate which seems fine.

I have two You Tube videos on the subject and they are attached below.

73 de M0WNU

Testing the Leixen VV-898 on APRS receive and the hopeful igate plans

I've set up the Leixen VV-898 on a power supply and connected the antenna from the NooElec NESDR SMArt to it, using a creative method to adapt it and left it on RX on the APRS channel, so far it sounds like it is working fine on RX however I'd like to test it out both ways at some point.

This did indicate that APRS activity around here is next to non-existent though I did hear the odd packet come through over the course of this, and there is, of course, a blackspot in the area as far as APRS is concerned, with there no longer being an igate in the locality which is inspiring me to apply for the NoV to run an igate from home, the radio is capable of 10 watts though can be dropped to 5 watts if needs be, the radio has already been configured to make it a little difficult for anyone casually going near it to press buttons and change settings as well as to turn off the backlight if no buttons are pressed to save energy.

I have alluded to looking to purchase the Yaesu FT2D now it has come down in price and with APRS on board it makes sense to have an igate in the locality, and it would be of benefit to other local hams, at present the closest igates are MB7UMB at about 13 miles LOS and MB7UVU which is a little further than that in the opposite direction, not ideal on a handheld right down in a built up area.

I am now looking at a TNC and have my eye on the TNC-Pi from the US, sadly I cannot find any local sellers of this unit and would have to import it from America then build a custom loom for the VV-898 to work with it and do various bench tests with the radio and the Pi to get everything just so, it may also require a ground loop isolator though I can get these cheaply off Amazon or ebay.

As I plan to run this unit off a battery and solar charging I will need to fit a fusebox to the output of the charge controller then an output with Anderson PowerPole connectors to take the radio connection, this way should someone unplug the radio it can be reconnected without causing a reverse-polarity incident, I also intend to fit a stop button to the same circuit and a heavy current relay to kill the radio instantly if requested to do so by Ofcom or in an emergency, a light will be added to the shed as well ahead of time all being well.

The antenna, well I have a clever plan for that one to disguise it from the local residents.

73 de 2E0EIJ

An APRS black hole to fill?

Perhaps, looking on ukrepeater.net shows that MB7USD is no longer licenced, so as soon as I have my full licence this may be an opportunity to fill in a gap in APRS coverage and packet access to and from the APRS-IS.

My plan is to run an igate or digipeater, whichever, to cover the area once covered by MB7USD, using a self-contained setup of a Raspberry Pi 3 B+ (or whatever will be the highest performing Pi by that time), with solar power, a reasonably high capacity battery (probably a leisure battery), and my Leixen VV-898 for an output of about 10 watts, hopefully linked to my home WiFi and kept in my shed to start with until I can find a suitable place elsewhere.

The VV-898 being a 10 watt radio should more than suffice for this job, and being a cheap radio to get hold of should it fail I can swap it out for another one, and being low power draw it is suited to this ultra green setup.

I need to fit a shelf in the rear of my shed which means moving some of my antenna mounting hardware up to the shack, there are already mounting points to do this and a convenient air vent at the rear, though I suspect I ought to tread carefully as I did see a wasp nest near the vent and therefore there could be wasps but the nest may be derelict or all wasps in it dead due to this very cold snap we've had lately, the air vent is convenient as that will serve as a path for coaxial cable to feed through, RG8-mini preferred as that is small enough in diameter and low loss compared to RG58, the vent will also serve as access to solar panel power cables.

The need for GPS is not required for this setup as it is fixed, it's precise location will, for its and my security, be off slightly (appearing on the map on the roads near to my home QTH.

As a temporary antenna I could use an off-the-shelf mobile antenna on a magmount on top of a suitable piece of metal, I have an old magmount that I got with the Team RoadCom-FS that I don't plan to put on a vehicle, I just need to change the coax (with RG8-mini) as it needs a coax change anyway

I've not even started my training for my M0 call and I am already planning on what NoV to get when I am able to, and when this is done I hope to restore local APRS-IS access in the local area.

73 de 2E0EIJ

Portable ops... ruined by pagers

Yesterday I went out to do some portable ops on 2-meters (FM only considering my equipment though I could have done DMR had I took an adaptor with me for the Anytone which I did not do), I took my Leixen VV-898 as the radio simply because I could go as low as 5 watts (which is QRP in my opinion) if I wanted though I stuck with 10, however no matter what channel I went on in the FM simplex range or any of the repeaters, the radio was wiped out by intermod from pagers in the 155-158MHz range, and though pagers are not as common as they were because of the SMS facility on mobile phones, they are still in use as they work almost anywhere a mobile phone does not as they use high power transmissions from their base stations.

I will of course be doing a test with my QYT KT-8900D to see if it has better rejection of the paging traffic or not in the same location, and will also make a point to promote the hobby at that time and also the local club to try and get some more numbers there, after all it makes some sense.

I have a video of how the VV-898 was swamped by the pager noise in the pipeline, a short one but it gives you an idea of what the problem was, and I will do some footage of the KT-8900D when I go up next to the location to show if the KT-8900D is a better radio or not.

I am also looking at fitting a notch filter to the VV-898 to see if that helps get rid of the pager intermod as that seems to be the worst problem for it.

The pager issue itself will not go away, but there are means to help prevent it interfering with Amateur radio operations.

The video should appear on YouTube and here in the next day or two, and an update regarding if the KT-8900D is also suffering intermod from pagers will be posted as and when.

73 de 2E0EIJ

Edit: the video is live on YouTube and is also available here, comment on YouTube if you have one of these radios and have suffered the same intermod problems

homebrew dipole working

Last night I got my homebrew 2-meter dipole antenna tuned and working while the rain held off, to use it I clamped the upright to an open window and the boom with the antenna on the end was outside the window, GB3CD was able to be accessed but it seemed to be below my squelch and a little in the noise, as were a couple of the stations on the S12 net I discovered, one in Darlington could hear me as I could hear him just fine, from the location given the station in Darlington was on the other side of Darlington to myself up near the retail park and car dealers, this was enough confirmation the antenna was in fact doing its job satisfactory, GB3HG and GB3IR obviously were not going to prove a challenge for the antenna given their locations.

Tomorrow if the rain holds off and the weather is good I may set up a portable station on Richmond's old racecourse with this antenna, the radio I will take I have yet to decide, also undecided is if I will go QRP or not, my VV898 can go as low as 5 watts (QRP levels) however the KT-8900D can only go to 10 watts at its lowest settings, after all this antenna is meant to be a portable design requiring nothing more than a screwdriver to disassemble the support from the boom, the VV898 may of course need reprogramming depending on how it is currently configured.

The next antenna I'd like to make is an antenna to work the FM satellites as I have still yet to do that, this dipole is my third successful antenna, the first being the T2LT for CB work and the groundplane antenna for 2-meters that was my original homebase antenna.

The coax on the antenna itself is a short run of RG58 to a BNC, this meant I have had to use a BNC-PL259 adaptor and a SO239 coupler to connect the feedline, which is the repaired feeder that was from the groundplane antenna after it was cut and it works great and is fitted with a crimp on PL259.

I shall see what happens tomorrow and see what stations I can work simplex if I go portable.

73 de 2E0EIJ

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

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 aprs.fi, 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)

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 aprs.fi 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