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Sunday 27 January 2019

An APRS black hole to fill?

Perhaps, looking on 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

Thursday 24 January 2019

The dilemma of my soldering iron

Almost every Amateur will have a soldering iron in their shack, given that Amateur radio operators are more often than not building their own gear, some have a basic cheap soldering iron, some have a temperature controlled soldering station, I have the latter, and the one I have is a unit sold by Maplin under their Precision Gold label, trouble is now that Maplin have gone bust getting new tips and irons may prove a challenge.

The same unit is sold by Rapid Electronics under the Atten brand (which appears to be what it actually is), the iron is rated at 28V AC rather than the 24V AC some other generic Chinese soldering stations are rated at (though the measurement I got with my multimeter suggests the voltage out of the transformer is in fact around 30V (I put a voltmeter across the two yellow wires inside the base rather than across the connector), I also discovered construction of the unit is similar in fashion to units disassembed by Clive on his 'bigclivedotcom' YouTube channel, however the wires are connected onto the board using connectors rather than solder)).

The fact the transformer put out 30V did puzzle me at first, though I suspect this is because I am supplying the transformer with 240V on the primary, and it is labelled for 220V on the primary, though I have no means to test my incoming mains supply, the only sure fire thing I know about the iron is that earth is connected straight from the iron to the earth pin on the plug, thus backing up the ESD safe claim and meaning I can replace sensitive components without risk of ESD damage, modern radios do use a lot of solid state components so this is critical.

So Rapid sell a replacement iron for the pricely sum of £10.90 exclusive of VAT, add the VAT (at current rate this is 20%) it is more like £13, all the irons I found from China are in fact for the 24V stations and presumably are not compatible. the iron I have is the third for this unit and the final Maplin sourced one, so new irons would have to be sourced from Rapid or CPC Farnell as I suspect they are the only other supplier and sell this same station though under the Tenma brand, new bits can come from China as they fit a number of irons

So as long as the station is being sold I should be good for a new iron should I need one as they'll always be available separate to the station (though the last two were destroyed while being used at the same time as my former PMR446 gateway was in transmit, though when I say destroyed it is more likely they need a new heater element).

Naturally this only occurred to me while the iron was being used for component salvaging in the shack, and I don't want to be without my soldering iron, as it is the most useful tool any Amateur could have and I certainly plan to use mine for as long as possible, and also so I can actually turn the temperature down a bit I plan to switch back to leaded solder, a lot of the hams I know that solder prefer it.

not too much radio related but it does go with our hobby, and with that I could see if it is possible to repair the Intek DRS-5070 as I suspect the finals have failed inside it.

73 de 2E0EIJ

Tuesday 22 January 2019

The beginning of my journey to my full licence, and a few bits of electronic salvaging in the shack (with some interesting discoveries)

As you will recall, at the back end of last year, I enrolled on Steve Hartley's Bath Based Advanced Distance Learning Course, which will take me to the Advanced licence all being well.

The course starts properly a week on Friday, so I hope to get some revision in before then, bearing in mind I have work and will be busy, I have already signed up for the system the course is using though have not had a chance to look at it properly, though that will be something I can do after work tonight (I start 40 minutes or so from time of writing).

I already have the book, a scientific calculator, and the RSGB radio communications handbook, I may benefit of course by getting some other books, I look forward to completing this course, and ultimately getting my full licence before the syllabus change in August of this year and also before the National Hamfest.

So the journey now begins, and I look forward to the challenges I will face, as I love a good challenge, keeps the mind active and healthy.

I also spent the last few days salvaging useful electronic components, I have an old power supply that I have spent years stripping down slowly, some of the electrolytic capacitors on it appear to have failed and show some bulging on the bottom which makes me think if they failed the time the supply itself went pop and a cloud of smoke emitted from it, the actual failed capacitor was removed a long time ago, the resistors, other capacitors and diodes seem fine.

I also cut the connectors off a load of old computer fans that I'd not likely be reinstalling into computers, which run happily of 13.8V DC (they are rated 12V DC and an extra 1.8V should not harm them considerably), the wires then stripped and tinned, and the fans retested on the bench supply, all seem happy and I do plan to put them into service at some point later on, preferably with a thermostatic controller to stop them from running all the time, I also salvaged components from my Internet Radio project including the speaker still inside the box, the amplifier is  still in situ, I removed its regulator and the 5V regulator I used to run the latter of the two Pis, this regulator is a 7805 and puts out around 4.98V DC when fed from a supply greater than it, I might use this as a USB outlet regulator and have a handy charge point in my shack, of course I do need to provide adequate filtering and tie the data lines to tell the phone what it can pull, though that information should be readily available on the Internet as a lot of phone chargers should now be reverse-engineered (the regulator is 1A though is fitted with a heatsink so may at a push work higher).

So tomorrow I may tinker a bit more if I have time and start extra revision on my Advanced tonight again if I have time.

73 de 2E0EIJ

Sunday 20 January 2019

Adding some 'retro' to the shack

I love old tech, which is one reason why I enjoy radio so much as you can still get radios that are very old yet still work very well, and near enough all antenna designs are getting on a bit now and if it isn't broken why fix it?

So in my collection of random bits of electronics I had lying around I had a moving coil DC voltmeter that looks quite old, and works fine, all it needed was a resistor on the positive line (I used the resistor that was originally used on it retrieved from the wiring loom of the equipment I'd salvaged it from, which I measured at about 30k), two wires, and the meter readjusting to read zero when no voltage was applied, I then promptly wired this into my Maplin 13.8V DC 7A power supply and it read about 13.8V (which tallies with my multimeter), the meter will find a new home when I custom build a new supply for the radios, as the 7A supplied by the Maplin supply is not adequate for some of my higher power radios, such as my CRT SS9900, which is capable of 50 watt transmit, though interestingly when I tested the K-po EA35 linear this was well within spec of the power supply though I have not tested current draw fully as yet.

The idea is that I build this meter into the housing of the new power supply because it's so retro, it mounts using a couple of threaded studs on the back so hole cutting into panels is not an issue, and when I go to the next rally I go to I'm going to look for some of these as well as ammeter versions because they have this retro charm, so when this new custom supply is built I can see how much current is being pulled as well as what the output voltage is.

I even took a photograph of it on the operating power supply, the supply is a big heavy linear one, which I have owned for years initially for CB use, then it got used for my VV898 and then my KT-8900D, the latter being a 25 watt radio and does not draw a lot of current despite this high transmission power, wondering how they've done that.

The reason the wire to positive is pink and not red is because this was the wire the resistor was already soldered to, I used a black wire for negative to make it pretty clear how this wired up as the meter is polarised, and wiring it in reverse would cause the needle to go the opposite way and potentially break the meter, and it looks the part with the power supply, sadly though Maplin went out of business last year and the XM21X bench power supply can only be had second hand, however regulated supplies like that aren't popular anymore due to modern switch mode supplies being much cleaner from an RF standpoint due to much better filtering than older designs, and their output currents significantly better and of course switch mode supplies are small and lightweight.

This supply currently drives the blue LEDs inside my homebrew extension speaker and the KT-8900D, and gets occasional use for CB testing as I don't go on 11-meters from home, however I am working to solve that issue in a stealth manner, hopefully it will be solved soon.

These moving coil meters can be picked up at radio rallies and also if you look on eBay you'll often find them, sure digital displays can be a bit more accurate but they just don't have that cool factor.

73 de 2E0EIJ/26CT730

Wednesday 9 January 2019

Beginning the antenna experiments

Today I popped out briefly to get a bite to eat, I rewarded myself from fighting the cold I've had the last few days and completing the tidy up of my living room after the slowest progress on Earth by getting something to eat from the pizza shop I work at, where I will be going this evening, while I was out I called in at a discount store at the local shopping park and picked up a roll of steel wire, I know copper wire works, as it is logical, though most commercial antennas are made of steel or aluminium as it generally is cheaper, the wire I bought is galvanised so should not rust though corrosion around dissimilar metals may pose a problem.

I still have a square SO239, the last one I ever bought from Maplin since it disappeared last year, and this could be used, the band? 11-meters, I already have a T2LT for that band but it is so narrow banded it will not work at all on 10-meters and I am keen to experiment to see if the trusted T2LT can be beat on 11 with anything else and if a good antenna can be made to work on 11 and 10, though lacking an antenna analyser this means testing will take place in the FM portion of 10-meters for that band, 11-meter tests can take place on any of the 80 channels at present though I avoid testing on channel 9 on both sets of channels, the other part of 10-meter testing will reveal just how much power I'd be able to run through the antenna (up to legal limits) before it would fail, though on 10 I can legally run 50 watts and 11 it is 4 watts or 12 watts PEP on SSB.

So let the antenna experiments begin

73 de 2E0EIJ/26CT730

Tuesday 8 January 2019

examining the other accessories sold with the RoadCom-FS

So after my last post I returned to the shack and had a proper look at the other bits I got, the magmount needs a new cable but that is not a big problem as I will look into this at a later date anyway, the mount converter to convert an SO239 mount to 3/8" fitting seemed fine and my orbitor screwed into it without a problem, the switch had some corrosion on some of the SO239 connectors so I had a quick peek inside, the switch was very simple, in being only a switch and some stiff wire connecting the SO239s to the switch and presumably the chassis connecting them all to ground, it functions fine, I did a test of it into both the Zetagi dummy load and the saltwater dummy load, though the saltwater load needs a little calibration though it still works, the switch worked with RF through it no problem, that also allowed me to test a couple of patch leads that were included, they were functioning fine.

The RoadCom-FS itself has been put back into the car for tests, I still have the Grant II and the SS9900 in the car as well, and as I have a long list of things to tidy up, and the car is one of them, they will probably make it back up to the house at the point I tidy the car out, though as part of the big tidy up I am doing I will more than likely have to do some tip runs before the car can be cleaned out so it may not be for a while just yet.

With all the tests done it's time to do the big test, putting the RoadCom-FS on the road, and advertising the benefits of two-way radio communications as I go of course, and as some hobbyists move up to Amateur radio from CB, much like I did in a sense, it could encourage more people to get on the air and hopefully we'll have some more M7 calls out there soon.

73 de 2E0EIJ/26CT730

Monday 7 January 2019

Team RoadCom-FS UK in the shack (and a stint on the road too)

The Team RoadCom-FS UK and other bits (a switch, a K-po linear amplifier and a combi SWR meter along with some very used antenna mounts and cables) arrived today and after visual inspection tests were then carried out on the radio and amplifier, the radio had an intact fuse, however the amplifier had a blown under rated fuse covered over with foil, a big no-no for electrical safety so a trip to the local auto parts store for a replacement fuse and a safe test could be carried out, the fuse did not blow, and the amp has only been tested for FM operation, not AM and SSB as yet, these tests, along with the radio on its own, were done into the dummy load, running the rig with the amp off though still in line gives the rig's legal output, so all is good.

The rig was put onto the antenna on the car for the run out to the auto parts place, and an opportunity was taken to test the SWR meter which is working just fine as well so now I once again have 3 SWR meters for CB/11 meters, though I will continue to use the Zetagi one as that can cover most of HF, but it is nice to have extras.

The rest of it, the antenna switch, cables and mounts will be given a proper once over at some point today, as noted above the coax cables were very used, some having been removed from vehicles, the magmount is indeed a Sirio magmount and appears to be an older one, there is a fixed body mount of PL259 type and an adaptor to 3/8" along with another 3/8" type mount (my orbitor is a 3/8" mounting antenna), the biggest surprise was a cable with two PL259s crimped on it and the cable marked as "low loss", but without knowing the specifics of this cable I would not know if it truly was low loss, the cable was intact for it's run, it's short but that shouldn't be a major issue.

So with the RF generating components tested, the SWR meter also tested that leaves me to test all these cables and recycle what I can.

73 de 2E0EIJ/26CT730

Thursday 3 January 2019

The successful testing of my TTI TCB-550, concluding my CB tests

As another radio that had stood idle for some time, though it did power on when I did the CB/Amateur differences video, was my TTI TCB-550, so it was reunited with its microphone which was connected to the computer interface, and connected it to a speaker, as it had the speaker removed, and the mic to run it as normal as with it being a CB the audio turns off should the mic (or properly wired PC interface) be removed.

The radio receives and transmits fine, only indication of receive is "RX" on the screen (the TCB-565 which uses the same fundamental electronics has an S-meter on the front), the TX indication is simply "TX" on the screen, the radio's finals are operating as they ought to be putting out the 4 watts legal power.

This radio was used for my rarely active and since closed 27MHz FRN gateway, the antenna was the excalibur antenna with SWR at unusable levels (though I had and still have a matcher), this is why the speaker was removed and a semi-permanent operating fan was fitted though I have since took the fan off, I plan to use this radio for range tests on stealth CB antennas from the home QTH, as these antennas are to be stealth I of course won't be saying where they will be mounted, of course they will be temporarily mounted and removable in less than 10 minutes, all antennas I use will be temporarily mounted.

To make this run as an antenna range testing radio, it needs interfacing to a PC, the interface I used for it originally had been repurposed for use with the likes of my Leixen VV-898, thus meaning I'd need to build a simple interface, should be able to get away with a simple circuit and an automotive relay so that TX and RX are properly controlled, a Raspberry Pi to run the test transmissions, the radio to generate the RF on any available CB channel, and I want to set it up to transmit the test transmissions every few minutes but not constant carrier RF as this, even at 4 watts, may warm them up and shorten the life of them.

I did a little test of my desk mic as the plug has been changed back to a Uniden pinout 4-way which the TCB-550 has, the audio levels in it are poor, the gain pot is in dire need of replacement and the tone pot is not a million miles behind it, so a complete refurb sounds good for it, the TCB-550's mic will be returned to the computer interface in due course.

The test set (dummy load and Zetagi SWR/power meter) will remain in situ until the arrival and complete test of the Team RoadCom-FS and the linear it supposedly comes with (though the linear will be subject to further tests to find out if it is clean or not, and as it only operates 26-30 MHz the input radio has to be in that range), I have done a brief compare of how my Midland 42 truly performs on batteries over its car kit, the car kit does allow the radio to run the full 4 watts, the power is no more than 2 watts on the batteries, and I did do a video showing just how dire, over a short distance, handheld CB radios actually are between one another, the contributing factors being voltage drop on the batteries and exceptionally inefficient antennas (a 1/4 wave is 2.75m long or thereabouts and an antenna that long on a handheld radio is not ideal or practical), the car kit was connected to my 7A supply using a cigarette lighter socket which I had fitted ring terminals to, rather than mess about removing the plug, which I had somewhat water sealed for my planned but otherwise not started scooter CB project.

The only niggle the TCB-550 appears to have is a slightly crackly volume control pot but it's otherwise ok.

73 de 2E0EIJ/26CT730

Team RoadCom-FS-UK hopefully coming to my shack real soon

Been scouring eBay at CB sets recently seeing if I could find a bargain or two, no Audioline 341s sadly as I am still after one of these to this day, however another radio I've been after for a while did show up, the Team RoadCom-FS, the UK variant of this radio, it fits a car stereo spaced hole (DIN mount) though can be mounted on a standard rig bracket, the radio I found was advertised with a K-PO linear amplifier, which I'd never use on CB other than into a dummy load, an SWR meter with power measurement, useful to have, a magmount that appeared to be a Sirio Mag 145 PL, a through body mount, and what appeared to be an antenna switch, so some testing to do, winning bid of £49! Yes it really was £49, add in shipping it comes to £57, so a bargain even for just the radio that retailed, when new, for £100+ (£135 as listed on, though of course they report it out of stock as it was new in 2008, making the radio at most 11 years old, my oldest CB is 13 years old this year).

The radio is one of the few that have CTCSS on board that are type approved for the 11-meter band, the original RoadCom,the TTI TCB-1100 and at least one or two Albrecht radios have this as well but it is very rare to find it on a CB radio, "export" radios (those meant for 10-meters) have it due to the fact that 10-meters is an Amateur band and occasionally you will find repeaters there that would require CTCSS to access them, there are no repeaters on 11-meters but FRN gateways do sometimes operate there with CTCSS on board, though this is rare (the gateway in Clacton-on-Sea, for instance, is open on UK29).

The radio started a trend of DIN size radios with front speakers, the Albrecht AE6491 and its rebadged cousins being an example of this, the TTI TCB-1100 is also similar in this regard, both these radios are still available new however.

Naturally on arrival I will inspect the radio and anything that comes with it and test as appropriate, RF generators into dummy loads, cables for continuity, mic audio on the radio's TX during tests, my Maplin linear supply would happily run the radio, however current draw from the linear may require me to use a slightly higher current rated supply, I have an old ATX supply under the desk I was using to power the SS9900 with.

I'll update on this when the items arrive

73 de 2E0EIJ/26CT730

Tuesday 1 January 2019

Testing my Moonraker FA5000

My first CB I bought with my own money, a Moonraker FA5000, has been stood unpowered for a few years, I believe it was last used in about 2013 on an on-glass antenna, since then I've used the Midland Alan 78 Plus Multi B and President Grant II on 11-meters.

Today, the first bit of radio I did was to power up the FA5000 and see if it would receive, it appears to do this just fine, however as all my patch leads, the 50 watt rated dummy load and the SWR and power meter were all still in the car from testing the SS9900 on 10-meters (and the Grant II on 11-meters on the same antenna) I was not able to to a transmit test until this evening and it was then the quirks showed up.

Firstly the transmit power was reading not quite at 4 watts though the meter is not totally accurate, though it seemed a little lower on some of the EU channels over the UK channels, though not a big deal as still on the correct side of Ofcom regulations, the microphone however did not appear to work, so I checked the plug, full of dry joints so I will have to repair or replace it later, the inside of the mic I did not check as I don't have a screwdriver immediately to hand to open it, however I remembered this radio does have a mic gain control, and turning this up to max seemed to work, though the mic still has to be close, so I don't know if it is a fault with the radio, poor design, or just a dodgy mic, which I will replace for a powered mic should I recommission this radio for any reason, as it is still useful in this age of AM and SSB on the CEPT channels.

I will be doing a transmit test of my TTI TCB-550 as I have something in mind for it considering I did remove the speaker, though I will do a receive test of it as well with an external speaker plugged into it, and I have the mic to hand for this radio as all I need to do is unplug it from the PC interface box, or I could use my desk mic though that won't be a good judge of audio as the audio from that mic is terrible.

I'll keep you posted, but as it stands the FA5000 appears to be working and should be fit to air

73 de 2E0EIJ/26CT730

Happy New Year

May I take this opportunity to wish all my regular readers a very happy and prosperous new year, I hope to work many of you on the air very soon and hope to also hear some new voices on the air too.

Normal service should be resumed later on today or this evening

73 de 2E0EIJ/26CT730