Wednesday, 5 December 2007

Pole Position

Today i had to do some shopping. A trip to the post office to collect the pressure sleeve UHF connectors i had ordered (finally got fed up of poor connections due to trying to solder braid to normal plugs) and to get animal feeds.

Now, i get my animal feed from a place called Hillam Feeds, a few miles away. So, with the car loaded up with sacks of feed, plastic containers etc, i headed back. As i passed a small building site, where some nice looking houses were going up, i noticed a young lad loading short scaffolding sections on a wagon. I slammed on the brakes, reversed back, and went over and asked who the scaffolder was. After explaining why i wanted scaffold poles, he went to talk to his gaffer. The gaffer then phoned the boss, and about five minutes later, told me "a tenner each", so with the help of the young lad i roped two 21ft galvanised scaffold poles onto the roofbars of my Fiesta, handed over £20 and started the careful drive home. Its only when carrying such a load that you realise how bumpy the roads are, and i had to go at 20mph to avoid the poles starting to bounce about. Luckily, the whole journey is over lightly used rural roads. So now im sorted for mast poles! All i need to do now is decide on the actual method of mounting and get the job done, and my 6m and 2m beams will be up in the air.

To that end, getting the pole attached to the house, i had a chat with the chaps at Brymar. Brymar are a satellite TV company, and i had to visit them anyway for a splitter and some sat coax and F connectors, for the wifes small works project of getting DTV into the kitchen. I had to get some self amalgamating tape as well as mines nearly run out, blimey thats expensive stuff, but its a real must have, its either that or Denso, and i dont think the XYL would like me using that! Im now wondering wether to go with the T & K brackets, which i think are a bit too far a stand off, or get some A frame brackets, that spread the load further out, and i think would be less pulled by the wind loading. If it can hold a 1m solid dish up in the wind, i think it can handle a couple of VHF beams!

Sunday, 2 December 2007

Theres a hole in my sealant

I finally got around to resizing the doublet from 102ft, as was for G5RV, to 88ft top section. I took the opertunity whilst scared stiff up the ladder to extend the lanyard considerably, taking the end of the antenna well clear of the buildings, and hopefully putting an end to any RFI problems triggering the neighbours security light.

As soon as i had it back in the air and went to test, disaster! nothing would tune right, and 20m (my favourite band) wouldnt work, giving an SWR greater than 6:1 if i ran high power. So, i thought, the line lengths are now wrong, so i went through the calculations and added 6ft of feeder to ensure no band was an odd quarterwave. No change. Hmm, strange. So i inspected all the joints and found one that was corroded. This being the point where the original G5RV matching section line joins the ladder line back to the balun. So, i cut the bad joint out. Still no better. Closer inspection showed one side of the ladder to have black copper oxide on it, hmm, its been wet. I cut it back, and back, and back. I cut out 4ft of line and it was still oxidized. Now, i had assumed that the water had got in at the bad joint, but now the oxidation was on a section that went vertical. So i lowered the whole antenna and had a look at the feedpoint. Nasty. Theres a little hole, right above the end on one of the lines, where the water can get in. And guess what - yes, thats the side thats corroded. All the way down the line.

So it looks like the poor tuning and performance is down to this water ingress. So i have to replace that section of line. Unfortunately i only have 13ft of line left, and the section if much longer, so unless i come up with a better way of routing the feeder, i'll have to buy another roll of ladderline.

All this has come at an awkward time, just as my friend Andy G7PZL is finally equiped for HF and wanted to do on air tests. I couldnt hear him at all, and hes only 25miles away or so. Im considering a Cobwebb antenna for the higher bands, this at least is coax fed. It all depends on what the XYL will let me have. Shes already not happy with me wanting to put two VHF beams up. It would still mean i would need antennas for 40m & 80m, maybe even topband 160m, but i could perhaps get away with a fan dipole for these and coax feed.

Either way, i need to finalise the antenna system before spring, for both HF and VHF, after which no further work can go into them except normal maintenance, likewise the shack. It has to become operational only, no engineering.

Monday, 26 November 2007


Typical, isnt it. I have only one scaffold pole, and its 12ft long. I need at least 6ft between the stand off brackets, and theres a 2m 9el tonna and a 6m 3el yagi to go on it. So this pole is nowhere near long enough. I need 20ft at least, and none of the local scaffolders will sell me poles. Like it would hurt their business to sell one or two poles. Ive got everything else i need except a rotator, but then i cant afford one. Ive even got a 100m drum of RG213 coax at the ready.

So, how do i get a pole? of course i could always look further afield, but then how do i get it back here? i dont have a truck! Ive put another request on the freecycle group, but i dont expect to get anywhere. So im stuck, i cant get the yagis up without it, neither can i work on the doublet, which needs it as one end support, or put up a new TV antenna for the missus.

oh where oh where can i get a pole?

Thursday, 27 September 2007

Corned Beef Hash

I had corned beef sandwiches for breakfast yesterday, and whilst pondering that corned beef is the chipboard of cooked meats, i worked into Oman on 17m. That was followed up by working the ARRL club station in Connecticut, W1AW. I could hear Isreal as if they were next door, but as always they were only calling stateside. Whats with this obsession with the Isrealis and Europeans for wanting to work the states? I can get the states most days on 17m, im much more interested in Africa and Asia, and the Pacific, or South America. Theres, someone told me, 600,000 hams in the US, so its hardly going to be rare to find one on whatever band.

All in all a good couple of days on the radio, not gone flat out, but worked some interesting calls. However, im now, inevitably i suppose, on the trail of RFI! I first noted that 7MHz wipes out my ADSL router, but thats not surprising as its totally unsheilded, cheap BT rubbish. But these past few evenings ive noticed that my neighbours new PIR halogen lamp, is triggered on by my operating on 20m. If i keep to 10W its fine, but 100W and it lights up. So i made a note to myself to operate low power on 20m in the evenings. When i mentioned this to my neighbour, Mick, he told me that their touch controlled bedroom lights also react, seemingly dependent of frequency, and flicker with my signal. Oh Dear! He told me he wasnt bothered, and that it was actually a bit amusing, but that really isnt the point, its RFI and i need to sort it.

I have been intending recutting the doublet down to 88ft anyway, so i have bumped that up in my priority list. Im going to keep the feedpoint in the same position, which will mean extending the lanyard cord at the house end by some 7ft. Hopefully that increased seperation will negate the RFI problem. Im also, with Micks help, going to carry out a suite of on-air tests, on all the bands i use and at all power levels, to see which cause problems. If nothing else it will give me a guide of frequencies or powers to avoid when the interference would be likely to be troublesome. Theres no evidence of TVI, so a LPF wont help here, it looks to be direct pickup.

Oh, and the receive longwire has come down again. This time snapped at the mast end. I really must put a proper insulator on it this time...

Saturday, 22 September 2007

All quiet at the BBC

Ive just spent a week at the BBC training center Wood Norton. Pleasent enough place, excellent restuarents in Evesham, and very good training, learning about TV signals. But as far as radio goes, the place is dead! I only took the 2m handheld, but i thought i would get something. Even with the stonking great 7/8ths whip i could only get two repeaters, nothing on simplex at all. And of those two repeaters, only one would respond to 1750Hz toneburst. As i dont yet have CTCSS in this radio, it pretty much limited my options.

It was however fairly academic anyway, as it turned out the 12v EBP-18N battery pack i had chosen to take has a bad cell, so i could only transmit with a decent power level if plugged into the charger. Hardly practical with an antenna attached that reached the hotel room ceiling. Even the telly in the hotel was badly tuned, although the one in the bar was probably more due to having a half dozen telly techs, engineers, production people or whoever retuning and adjusting it every five minutes!

So, i now need to recell that battery pack, and maybe even the 7.2v pack as well, although ive not tested that one properly yet. I do however have the EJ-12U CTCSS unit for the handheld on order from R&L in the states, so hopefully that should be here soon.

The DR-130 is now fully installed in my car, along with its huge whip antenna. Supposedly a 50W set, ive adjusted it to run at 25w, which im more comfortable with. Even so, using its low power setting of 4w i can hit the Hull repeater from my driveway, a good 30miles or so, and i can hold the Flockton repeater, close to my works at Emley Moor, all the way home from work, another 30miles. As it stands, this radio has only 20memories, but i found a chap in Italy on ebay selling various Alinco modules (sadly not the EJ-12U), and bought the EJ-19U 80ch memory module from him. This my son Sam and myself installed into the radio this morning, Sam passing me the tools from the passenger seat. He knew exactly what we were doing and how to do it, not bad considering he's only 3 and a half. So now the radio has 100 memories, plus the calling channel. My intention is to program them up with all the repeaters and their CTCSS tones that i am ever likely to be within range of in that car.

Sam helped me repair and reinstall the receive only longwire today. It had been down for over a week after the feed connection broke. Unfortunately the insulator got stuck on a newly grown branch in the tree, so could onlu be brought down by wrapping a carrier bag around it to smooth its passage. If i had taken it down the other way i would have needed to rethrow it into the tree, doing it this way left me able to pull it back up, as i had put an extra length of rope on its fixing line. Once back up, and its counterweight (a house brick) attached, we tested it. For around an hour at about six o'clock we had solid copy on 12MHz of Kyodo news FAX, so its definately working fine. At least, that was after we had solved the QRM problem that was covering the bands in S9+ hash. This turned out to be the portable telephone on my radio desk, but only when the phone is charging. Ferrites on the power lead make no difference, so the trick it to turn off the charger when using the radios.

Theres still plenty of VHF QRM, from the broadband router, but thats something to deal with another time. Im now looking for a AKD/NASA HF-3 radio for Sam, these radios are very simple to operate and Sam would enjoy tuning around, on a radio he cant break!

Tuesday, 14 August 2007

antenna height

Now, this is something i freely admit - ladders terrify me. Its not the height, its the ladders. I love being up high, i can stand on the edge of a roof and look down without a care. But actually going up ladders i hate. Yet its unavoidable if i want decent antennas. So, ive bought a new ladder, practically the biggest they had, and certainly more than enough to reach to and beyond the apex of the roof to work on the turnstyle antenna and the met instruments. Ive also bought a stay bracket that gives the ladder between 1-2ft clearance from the wall, so i'll have space to work. There was no point getting a smaller set of ladders that would 'just' reach. Even if i dont use these fully extended, that will just add to the stability and my safety.

So, next job then is to repair the vhf turnstyle antenna for the weather satellites. This needs a whole new coax run. I can check and test the anemometer in situ as well and recable that if required. I may rig a rooftop receive only random wire as well for the FRG-100 to replace the wire that goes down to the tree.

I also need to improve the support for the doublet. This im going to do by building a 25ft wooden mast. Built from tanalized 2x4, it should do a good job and be aethetically pleasing (or at least not too ugly). The difficult part, is that for it to be freestanding will require a foundation some 6ft deep. So i need to invest in, or borrow, some post hole diggers. I may replace the 1" allow tube mast at the roof apex with something a little stronger as well.

Thursday, 2 August 2007


yesterday, i spent some 5hours, on and off, through the afternoon and evening, chasing DX. Well, chasing anything! I could hear so much - colombia, madiera, egypt, thailand, USA, isreal, couldnt work anyone! it seemed all my power was vanishing before it hit the ether. Only at midnight did i make my one and only QSO, into Nova Scotia!

Today i changed from the ATUs internal 4:1 toroidal balun, to the Collins coaxial i have built -

now, whether the conditions are better, which i dont think is the case, or whether the coax balun really is so much better, i cant say yet. What i do know is this morning ive worked Belarus, Sweden, and now Morocco, on the first call each (well, ok, CN8ZG was second call), all with this balun in line. The ATU is letting me tune up at maximum capacitance settings ( zeros on the dial) just as the manual says i should, and ive even been able to get tuned up on 17m and 15m. Shame both bands appear to be closed at the moment. So it certainly seems to be doing well. My first couple of QSOs using it quickly faded away, leaving me thinking the balun had saturated and lost all signal, but listening to comments from others on 20m revealed that this morning the band was suffering badly with QSB anyway.

I still think some feeder adjustment is needed, but i now have the feeling im on the way to a good all round antenna.

I also worked GB4IPY on 20m, but as that station is in Wakefield, about half an hours drive away, i could have worked him on the dummy load! I think the 100W i was using was a bit much, that said i didnt bother to tune up!

Tuesday, 31 July 2007


Once again ive had the lid of the ATU. I did so a couple of days ago when my curiosity got the better of me and i decided to take a look inside, and im glad i did. The connection from the capacitors to the inductor was dry joint and loose, and the inductor itself was slightly deformed. I resoldered the joint and repositioned and straightened the inductor.

Today, whilst messing trying to calibrate the antenna, i decided to switch to the dummy load and check the rig in straight through 50 ohm unbalanced load. Hmmm, SWR 1.1:1? should be perfect? wait a minute! 30W? im running 10W?!

so, out came the bird meter and the 25W load. Ive only got a 25-1000MHz element for the bird, so set the alinco on 24.990 and low power - perfect 10W, so, the old MFJ is out of cal.

Ive now calibrated the low power (30W range) of the ATU both forward and reversed in bypass mode to the dummy load at 10W. Ive also calibrated the high power (300W) forward reading, this being done on 3.8MHz at 100W to aerial, as ive no suitable load for this power, and the antenna can tune a 1:1 SWR on 80m.

It just shows, its worth taking the time to check 2nd hand gear carefully! The antenna is still no better, but at least any readings i take from the MFJs SWR bridge are meaningfull now.

Antenna Work

The coax originally connecting the antenna (in its G5RV form) was removed long ago in favour of all balanced line. But, this unfortunatly puts the feeder/element combined lengths at a rather unfortunate multiple of 1/4wavelengths for my main bands, and so getting the thing to tune up well isnt easy, and on 40m the low SWR point is very sharp. Im going to add another 13ft of feed to hopefully bring the length away from the current wavelenth multiples that are creating the high impedance problems. The new feedline arrived today, and so hopefully i can get it patched in soon. Ive also constructed a coaxial balun that i will try in place of the ATUs internal toroid, which i dont have great faith in.

Sunday, 22 July 2007


ok, so the shack in the bedroom was to be moved, as can be seen it was pretty cramped
so the sunroom cupboards came out, and it moved in there, after re-using as much material as i could, the result is a custom shack, neatly built in one corner.
top shelf - RX-2cc weather satellite APT receiver; MVT-7100 scanner; 2m 30W linear; Ft-290mk1; vase of artificial flowers.

main shelf/desk - FRG-100; DX-70TH; ATU; phone. Logbook and a pair of coasters. Underneath - dustbin; boxfile of manuals; cables etc; 30A PSU (not visible cos on floor)

Sunday, 27 May 2007


ok, were in business!

after a couple of hours of sheer terror up Micks rickety ladders, and 20mins or so explaining to my little boy what i was doing whilst wedged in a tree, the G5RV is up. Ive had to use the coax that was feeding 2m, so im now QRT on 2. But the MFJ tuner and the Alinco DX-70TH, G5RV combo is working fine, already getting me several special events and IOTAs in the log. Im still calibrating the G5RVs tuner settings, and this ive only completed on 80m, 40m and 20m, so these are the bands im active on. Conditions on 80m are abysmal, the QRN is very strong, so 20m is prefered.

It doesnt help, whilst trying to work a special call (in this case GB100TT) to have more than the usual number of lids who insist on tuning up on the frequency (like a 3kHz QSY is really going to affect the SWR!) or those who insist on calling the station even though they are already in QSO. Its not difficult to tell when a station is in QSO or when ready for a call, if the last thing from them wasnt QRZ or CQ, then DONT call!!! Its just pure ignorance, and spoils it for those without 3el triband beams on 100ft towers and who cant run a 1kW amp. I at least can command 100W, but i do feel sorry for QRPers trying to work against such ungentlemanly conduct.

Tuesday, 15 May 2007

Wood, Sweat & Tears

The shack move is coming along nicely. This is how it looked in the spare bedroom

quite a shambles as you can see. Being that close to the computer wasnt good for my signal to noise ratio, and even a mild 10W on HF would knock the ADSL modem off-line.
And this is where im moving to -

There was a tall narrow cupboard in the corner, but thats now providing material for me to build a custom desk with

the main desktop is 24" deep, enough for equipment and writing space, so long as theres nothing jutting out the back. To accomodate wiring etc, the desk is mounted forward from the wall with a 2" gap. The same gap is to be maintained for the shelf above the desk (the VHF/UHF shelf). Eventually, the whole of the under side will be shelved (again with a cable gap), and a cupboard door fitted, apart from a 9" space next to the wall. This will be open and will house the high current PSU and battery chargers.
For now the shack is temporarily squashed up even more-

My new logbook, and the G5RV have arrived. Im now working on getting hold of a couple of scaffold poles for use as masts for the yagis for 6m and 2m.

Thursday, 10 May 2007

Shack Movin'

At present, the shack is one half of the spare bedroom. It is also a computer room, and an office. This is not ideal, and if we decide to have another child, then it will become a nursury, and i would be forced to vacate.

So, thinking ahead, ive decided to relocate the shack to the downstairs backroom. When i think about it, this makes perfect sense -

It shortens all the feeder runs considerably (except for the cable to the WX sat crossed dipoles);
It drastically shortens the ground connection;
It puts me, when operating at night, diametrically as far from the missus as possible, so i wont disturb her sleep;
It means that i can use the radios and still be near my family in the front room;
It also means i can customise the shack furniture

It involves some quite serious woodwork, and rearranging the room, but i can make it neat and tidy.

On more directly radio related notes, Ive got a G5RV on order, which should be more effective than the random wire, and a logbook is on its way. Ive also secured an exchange of FT-290s, giving me a unit with a MuTek front end (and working backlight!). This and the 30W linear are going to be mounted on a wooden carrier, so i can rapidly move them for mobile or portable use, as well as base. Im also in the process of ordering the aluminium stock to build a 3 elelment 50MHz yagi.

Wednesday, 25 April 2007

coming up

ok then, since the first post on here, some wheeling and dealing have aquired me -

25A variable PSU (to run everything)
MFJ -948 Antenna Matching Unit
Alinco DX-70TH HF + 50MHz transceiver

the first thing done to the alinco was to lock out the Tx! this is a safety measure until i have got the antenna working properly, and to stop my lad from keying it up.

A new RF ground gets installed tomorrow, hopefully then the wire antenna will load up satifactorily.

So far the DX-70 seems just as sensitive on Rx as my FRG-100. The only gripes are - A, there is no REC output, so in order to feed audio to the PC i have to lose the speaker output. B, the filters are not as sharp. But these are minor compared with the generally increased capabilities, not to mention the reduction in size.

Friday, 23 March 2007


I'm Martin G7MRV, this blog is more a sort of diary for me really, just an occasional ramble about what im up to radiowise,

anyway, a bit of background is in order to start with - aged 31, interested in radio since age 13, licensed radio ham since age 15. Recently reactivated my callsign after a few years break. Slowly getting back into it all.

Equipment - Yaesu FT-290Rmk1 2m multimode; Microwave Modules 144/30-LS linear amplifier; Yaesu FRG-100 HF comms receiver; RX-2cc weather satellite receiver; various homebrew/commercial items (handhelds/ testgear etc)

ok, the story so far...

Not got around to much operating on 2m yet despite having had the 290 for some weeks. I have yet to install the muTek front end board, as i cant seem to get any installation details. The linears preamp seems to be working, at least the noise gets louder! cant really run it at full whack yet as its only on the 12v 7Ahr solar power system intended for the weather sat and the meteorological instruments. Hopefully will get the mutek in soon, and a high current PSU that will run the linear and whatever HF rig i end up with. I would prefer a solar/wind solution to the high current requirements, but im not sure i can afford it.

Im watching out for a HF + 6m rig, probably an Alinco DX-70TH if i can, as i think they receive better on low bands than the other rigs on the market.

Heres the general wish list to get my station back up and fully operational =

2m Multimode - got, FT-290Rmk1
2m Linear Amp - got, MML 144/30-LS
general rx/airband - got, MVT-7100
Primary HF receiver - got, FRG-100
Secondary HF receiver Target HF-3/4 or DX-394 maybe
HF + 6m Transceiver DX-70TH or IC-706mkIIG
25-30A 12v supply
Auto ATU
2m Beam
6m Beam
small 2m FM mobile Icom IC-229 prefered