Sunday, June 1, 2014

Hustler 6BTV Installation completed

Well at last the Hustler is up and running but it took a little while. 
I completed my tilt over plate, not the exact quality of DX Engineering but near enough and it does the job which made life easier when I was doing my tuning. 

The tilt plate works with the one bolt at the bottom left, all others are removed and it's hinged so that the antenna just swings over. Finished off with a little bit of a rockery to keep the XYL happy!

As soon as I started testing the antenna with the MFJ 259 I realised whoever had the Hustler previously either had it raised on a mast or used it as a ground base but with limited radials. The readings were all at the low end of the bands if not below, especially the 30 meter trap which was reading 700 kHz down which was way out. Because I have an extensive ground radial system in place I guessed this was why the readings were so low.

So I went through the instruction sheet and followed the process of tuning by adjusting all the tubes but with little effect, obviously this was for minor tuning and not large adjustments which was clearly required. 

Further reading on QRZ and other websites pointed me towards the DX engineering website where there were full instructions on what to do if band readings were all low. The answer is to adjust each trap so that they are placed in to the correct frequency and then finer adjustments are completed by moving the tubes. Evidently this is not unusual and can be due to either due to good soil conditions, near water or a very good radial system. 

So I followed the instructions and adjusted all the traps. Moving each trap is a fairly easy process provided you don’t get too ham fisted and do small adjustments. Initially I thought this might be a little tricky especially if these traps are reasonably new (this is meant to be a 3 month old antenna)!

So imagine my surprise (not!) that all the traps were fairly loose and it was obvious that these had been moved a number of times before. There is absolutely no way this antenna is 3 months old, not even 6, I would guess certainly around a couple of years minimum! 
Anyway after a couple of tries I got the hang of it and suffice to say the bands are back up to their correct frequencies including the 30 meter trap. 

In the shot above there are some guy attachments in place but they are not tightened so everything looks a bit loose, the old 30 meter fibre glass mast is to one side ready to be stored away.

So far I've done some initial testing having had a couple of QSO’s with some local European stations and received good signal reports. Testing against the Cobweb the Hustler is slightly down by a few S points but that’s to be expected as the cobweb is high up and situated in a good position so there’s no real surprise there. It’s early days yet but I shall give the antenna a good work out this week and see how it goes.

Thursday, May 29, 2014

Hustler 6BTV Installation and Alterations

I feel I am becoming the original grumpy old man but sometimes I do feel justified.

The Hustler was delivered yesterday and without going in to too many details, I had questioned the seller about how old the antenna was (a claimed 3 months) but on arrival and inspection it was obvious it was much older. 

There was corrosion and rust and some connections looked very worn, added to the fact that the seller had mysteriously sold a hustler antenna the week before with the exactly the same pictures and description except that one was highlighted as 6 months old, I was naturally suspicious
He assured me it was a different antenna and that a friend of his on seeing he was selling a hustler asked him to sell his, (yeah right)! 

Anyway, grump over and after a thorough inspection check, all parts were duly ticked off and I knew I could work with the antenna. I would however have to give it a good clean and at the same time add a few of my own minor accessories.

Thankfully having a motorbike I have all the metal cleaners you could wish for and I spent most of the day cleaning up each segment and traps, it’s by no means perfect but looks a lot better, I now just need to spray on some Krylon coating to keep it protected.

I also looked in to buying the DX engineering direct coax feed connector and tilt base plate which is supplied via a dealer here in the UK. The coax feeder £27.98 plus postage, the tilt over base plate (are you sitting down) £79.94 plus postage! 
I'm sorry but someone is taking the mick here how does it cost nearly £80 for a metal plate with a few holes in? 

Anyway the coax feeder looked pretty straightforward to build and I'd fabricated one within the morning. The tilt over base plate will take a little longer as I've had to order some aluminium plate but for the price of £6.50 I'm quite happy to wait, as it really doesn't take too long to drill a few holes and cut out some small slots.

This plate for the coax connector was cut from an old aluminium roofing slot I needed to shape one side of the plate to fit round the antenna, drill some holes for the attachment nuts and also drill a hole and fit the actual connector.

The antenna core wire was then soldered to the connector core and the other end will then attach to the antenna centre screw

I cleaned up the base then added the completed connector and finally added the ground wire which will be connected up to my radial base. The antenna will be separate from the ground radial plate, hence the ground wire.

The completed item doesn't look too bad and cost me nothing but a mornings work. The base has come up quite well so if I can get the rest of the antenna looking as good I shall be rather pleased.

There's not much else I can do now except carrying on with the clean up and wait for the aluminium plate to arrive to build the tilt over base.
More to follow when I get the ali plate.

Tuesday, May 20, 2014

Tidying Up, Refurbishing the Ground Radials and Thoughts Turn to a Hustler 6BTV

Looking over the garden I have a number of antennas dotted around various points and it’s definitely beginning to look rather scruffy and the XYL has started to make some comments! 
This time though I actually agree with her and I really ought to do something about it. Although I love my hobby I don’t want antennas to take over my garden, after all I am very lucky to live in a wonderful location and I don’t want passers-by to think who’s that messy individual ruining this wonderful countryside! 

At the moment In one corner of the garden hanging some 30ft up in the silver birch is my home brew experimental G5RV, it’s in the inverted vee position and has various bits of cord hanging down off the ends and does look very scruffy. 

In the opposite corner is the 30 meter vertical and the old Hygain 18vs, now a 20 meter mono bander, both placed there simply because that’s where I have all the ground radials centred, the 30 meter vertical is a simple wire thread through a fibre glass pole but works very well, the pole is some 25ft high and is white so stands out against the spring foliage which is rather obvious and not exactly stealthy! 

It actually looks quite picturesque but believe me it is a bit of a mess, especially when you go up close and see all the wires hanging everywhere.

Then to the side of the house I have the 40ft mast which has the Cobweb and the W3DZZ. Obviously I cannot use the antennas all at once and really I think the time has come to reduce the number and just concentrate on one particular area of the garden. So I'm going to remove the G5RV, the 30 meter vertical and Hygain and replace with one smaller multiband vertical.  

The Cobweb will stay as it’s my pride and joy and I doubt for the size if any other antenna besides a small Yagi (what's one of them?) would beat it and since the mast and Cobweb are staying I might as well keep the W3DZZ as it's an excellent antenna for the lower bands, this way I will eventually just have 3 antennas that will be used for the all the transceivers. 

While mulling over my antenna dilemma I did a check on the ground radials and the plate needs a good tidy as some of the bolts are looking very rusty and grass and mud is beginning to cover the plate which is not good for the connections, so I've gone ahead and dismantled it and given it a good clean ready for mounting the new multi band antenna. 

Where is the ground radial plate?

So once I had unbolted all the 30 odd wires and cleared away the muck I managed to prise it off the ground and give it a good inspection. Considering it's a home made job it has lasted pretty well and providing I maintain it every few years it should go on for many years to come.

The wires are a bit of a mish mash, some connected together others are separate, I guess because I've added extra as I've gone along. I will add some more as I'm short for 80 meters so whilst they are free of the plate I get busy adding a few extra.

After a good clean the actual plate doesn't look too bad but there are some bolts that will need replacing and I'll need to re-coat them with some protective grease. Then its just a matter of adding a few more radials and putting back in the ground.

All cleaned up and reconnected plus a few extra wires for 80 meters.

.........So what vertical multi band antenna should I get or make? 
To be honest I'm rather tempted with something commercial like a Cushcraft or a Hustler, normally I like to build my own antennas but quite honestly I just fancy a change. 

My Brother in law has a Hustler 6BTV and reckons it’s an excellent vertical, I've had a play on his FT1000D (wonderful radio) and the antenna does bring in some good signals and transmits pretty well especially considering he’s surrounded by telephone and electrical cables and has minimum ground radials. With my location, nearly 1000 ASL plus my ground radials I should see a definite improvement to his set up. Also the Eham reviews are very good for the Hustler but, there is no way I'm paying out over £200 for a new one. 

By chance I happened to be looking in Ebay last night and there as if fate was telling me something was a 6BTV for sale, 3 months old but going for £150. A little high on price but I have to admit I was bitten and so purchased it there and then, (oh Lord what have I done, don't tell the XLY!!)

Wednesday, April 30, 2014

Catapult Antenna Launcher

My latest toy to hang antennas up in the tree is a catapult with an old fishing rod, a fishing reel and heavy lead weight attached. The rod splits in two so I have just used the base with the catapult attached via two jubilee clips. 

The idea is to fire the catapult over the targeted tree branch thus releasing the fishing line. Once happy with the positioning of the line over a branch, you attach a stronger piece of cord to the weighted end of the fishing line and reel in back over the tree branch. Tie the two cord ends together so that you have a long loop then you can add the antenna to the loop and pull up and down to your hearts content. 

I've seen the idea on a couple of web sites and thought I'd give it a go as I wanted to raise the Windom up in my silver birch tree to the maximum height possible, thereby raising it a further 15 odd feet to about 35 feet in total, hopefully this will improve the transmit/receive. 

I've done some testing with the catapult in a local field and it seems to work reasonably well getting a distance of roughly 100 feet without really trying. I'll put it to the real test (excuse the pun) over the weekend and we'll see what happens.

Tuesday, April 22, 2014

Rebuilding a Carolina Windom 80 from Radio Works

A long time ago I bought a Radio Works Carolina Windom 80 Special from an amateur who had been using it for experimentation. I think he was using it for a write up he was doing for some radio magazine, I forget which but either way he was selling it on Ebay and I got a bit of a bargain. 

The trouble was the antenna was so long (133 feet total, 50ft and 83ft with a 22ft vertical radial) I had it wrapped round the house and all over the garden, so I never really did get it working properly. 

In the end I put it away in my shed and forgot about until I came up with the idea of making it a CW 40 by reducing the wire to 66 feet total (25’ and 41’) with the vertical radial shortened to 10ft. I figured rightly or wrongly that the “matching transformer/balun” and “Line Isolator/choke” were exactly the same for the 80 as was the 40. There was nothing to contradict that on the Radio Works website so I went ahead and reduced. 

The antenna worked reasonably well and I got some good contacts, but I never really felt that I'd got the best out of it and with various wires hanging all over the garden (I had other antennas up at the time) the XYL was none too pleased. So under orders I removed the Windom and a few other antennas and instead constructed my first cobweb as a single replacement.

The Windom got put away and I used the wire for other antenna projects, the balun and choke which remained attached got stored away in my shed. 

With the recent work on the G5RV and whether I add a 1:1 balun reminded me that I had these items somewhere in the shed, so I dug them out to take a fresh look and see if a) I could use the 1:1 balun/choke for the G5RV, or b) perhaps have another go at the “Windom” project. In the end I chose the latter since it would be a shame to waste the balun and choke while they were still attached and also I had just ordered guanella 1:1 balun kit for the G5RV.

After taking a good look there is no problem with the 4:1 balun and I can certainly remove the old remaining wire and re-solder some new, so I think it’s just a case of getting the correct wire measurements and seeing how I get on. 

My only concern is that the balun is the same for a 40 windom as it would be for the 80, (had Radio Works altered it in anyway?) But in all honesty I cannot see what would change, it should still be a 4:1 balun? 

Re-checking the website I still cannot find anything to doubt my theory,(if anything I just think it's a better constructed balun), so I'm going to go ahead and re-attach the wiring and see how it performs. 

The other major factor which will now help me is that I have my own MFJ 259b before I had to borrow my brother in laws with limited time to use it and I had little knowledge in using it. So now hopefully things should be a little easier and clearer with plenty of time to get things right.

As a further update as I have now virtually completed the rebuild. Both lengths of wires have been re-soldered to the balun, theses have been cut to an approximate length of 46' and 25', the balun to choke coax remains at 10'.

All neat and tidy ready to be tested and trimmed.

This then give me room to manoeuvre as once again too much reading on the web starts to do serious brain damage. I've seen and read there are various possibilities as to the correct lengths
From 14% from the centre, to 43'-23' or 46'-20' and the list goes on! Its all to do with finding that sweet resonant spot and I guess different lengths will favour different surrounds, I just have to find the correct one for my location. 
It should prove rather interesting!  

Well today it’s pouring with rain but being somewhat keen in getting the Windom back up in the air to do some testing I've braved the weather and hung the antenna up. It’s hanging at about 30ft in the inverted V position with the wire trimmed to 41.3’ and 25.1’ respectively; this is the best trim I could get at the time with the antenna analyser, but when its pouring with rain it’s not the most ideal conditions to try and get the best out of the antenna. 

It’s by no means perfect and I will continue with the trimming with the MFJ 259 once the weather clears up a bit, but so far I can use the auto tuner on the FT1000 MP V for all the bands so I must be doing something right!

Monday, April 21, 2014

Half Size G5RV

The first antenna I ever bought after gaining my licence was a G5RV. I think it cost me around £30 and it used to hang in my garden, squeezed in some tiny area at the back of my house! But I couldn't complain I got a signal out and had contacts all over Europe and the east coast of the States. It suddenly dawned on me last week that I had never actually built one and it was about time I put that right. 

If you trawl the websites you’ll find plenty of examples and I decided upon a half size build, this purely because I had my old Mystery antenna sitting in the shed doing nothing and I could cannibalise that and use the wire for the half size G5RV. 

The W5GI Mystery antenna is similar to a G5RV but W5GI (now SK) used coax stubs to give what he called “a coaxial colinear array on 20m”. It consists of a half wave length (at 20m) of 300 Ohm ribbon that feeds a dipole centre. I made one many moons ago as an experiment (see previous posts) and it worked very well. 

The measurements for a half size are listed below and with having the mystery antenna already made up it was a quick case of re measuring and then trimming wire where necessary. I noticed some measurement do vary especially the matching section, (look at the picture (above) which states 17' and the table (below) that lists 15.6'), which is correct - take your pick?

So by the end of an afternoon I had the antenna made up and ready for hanging in my silver birch at approximately 25ft. As a change I decided on an inverted vee and after a quick double check of all connections and making sure the angles were good I connected up via manual ATU to the FT 1000 MP. 

Band Coverage
3.5 - 28 MHz
1.8 - 28 MHz
7 - 28 MHz
Length of Antenna
102 ft ( 31.1 m )
204 ft ( 62.2 m )
51 ft ( 15.55 m )
Matching section :

- Open wire
33.7 ft ( 10.28 m )
67.5 ft ( 20.56 m )
16.9 ft ( 5.14 m )
- Ladder line
31.3 ft ( 9.54 m )
62.6 ft ( 19.08 m )
15.6 ft ( 4.77 m )
- "TV" twin lead
28.5 ft ( 8.69 m )
57 ft ( 17.38 m )
14.3 ft ( 4.35 m )

Normally I would put any home brew antenna through the MFJ 259 for checking, but the SWR readings on the G5RV would not be 1:1 and would certainly have me scratching my head trying to get all the bands to an acceptable level. In the case of a G5RV you use the tuner to do most of the work.

So initial results are I have to admit, surprisingly good! 
I manage a couple of QSO’s on 20 meters and on 30. Interestingly 40 meters proved more difficult to tune up, but eventually I got there with some gentle adjusting. I also tried all the bands with the auto tuner on the FT, all was OK except 40. I then brought out the MFJ 259 and SWR on 40m was way up compared to other bands. 

Checking on the web I looked for any mistakes I may have made but the only conclusion I could come to was it maybe an issue with the height as 25ft is not that high and at 40 meters virtually the whole of the antenna is used to radiate. 

Also as a precaution I added a choke balun at the base of the 300 ohm part of the antenna. Of course this where the 300 ohm feeder is attached to the 50 ohm coax (or to be absolutely correct the 75 ohm). You'd think you'd have a 4:1 balun, but then I've never really been an antenna theorist, I just build them!

Further reading from the web I came across the W2DU balun which looked to suit my purpose nicely. It states, "The W2DU bead balun consists of 50 FB-73-2401 ferrite beads over a length of 1ft coax. 


Sadly not having the correct beads I added what spare ferrite rings I had to the coax, which for the moment hopefully may have done the trick but I will find some proper ferrite beads at a later date. Unfortunately the W2DU balun looks to be only available in the US and although fairly cheap the shipping costs to the UK are not! So I will either have to replicate with a home brew or find some other 1:1 Balun. 

A mish mash of ferrite rings but it seems to work!

Now manually adjusting the tuner for 40 meters is a little easier but in theory it should be the easiest band to tune up, so I think something is still not right, (probably the balun) but for the moment I'm just happy to get out and  have fun with my new antenna!

As a Further update I have been reading up on baluns for G5RV's and what a can of worms you can open with the statement " to have or to have not"! 

It looks like my home made necklace of ferrite cores will not do the trick, so today After reading G3TXQ's interesting article on the G5RV I have taken his advice and bought a simple 1:1 Guanella balun. 

The Guanella balun fits nicely in to an old plastic screw container, it's now a matter of just connecting up to the G5RV and see if the performance will improve.

Steve Hunt, G3TXQ is a bit of a guru to me, he has a wonderful website all about Amateur radio with a lot of very useful information on antennas and antenna theory, well worth a look especially if you are in to HexBeams or Cobweb antennas.

Thursday, April 10, 2014

LDG Z100 Plus Autotuner

I've been getting a little tired of manually tuning up the K2 with my Tokyo HC-400L tuner. I know it’s me being lazy and I should know better, but hey when there’s an auto tuner out there that will do the job for you well, what the heck! 

Having my three transceivers connected up at one time means that my set up is a little different. I have three antennas, the cobweb, my 30 meter vertical and my W3DZZ trap for 40 and 80, so I have all three connected up to my Tokyo ATU and then to a homebuilt connector box which switches over to each individual transceiver I want to use. 

When operating with the Yaesu FT1000MP MkV I can bypass through the Tokyo and use the auto ATU from the FT or when using the K2 or OHR100A I can use the manual override and manually adjust the ATU for each radio. Complicated? No once you get used to the idea it works fine! 

The LDG Z100 will be set it up through the K2, so it will be K2/LDG/ with the bypass set on the Tokyo, and then through to the connector box on out to the antenna. To be honest I wasn't sure it would work, but it does and I'm getting out OK. I’ve only tried QRP as I don’t want to tempt fate just yet but the ATU is tuning up nicely against the K2 and so far so good. 

In the UK the LDG Z100 retails for around £140 which is a fair sum, but I've been meaning to purchase one for some time and I thought I’d probably have to go down the 2nd hand route. Luckily I found a site on Ebay, a Greek radio dealer who was selling the ATU for under £120, a fair bit cheaper than the UK, so I bought one. 

It arrived well packaged and only 5 days from ordering, so first impressions on opening the packet are pretty good. Nice clear instructions are provided and it’s dead easy to connect up with the usual TX and RX coax inputs, a ground and a power connection for 7–18 VDC 100ma. I’ve connected power via my PSU for the K2 and it works fine. 

Initial tuning is pretty easy, you have to select the required band, transmit a carrier and hold the tune button whilst the ATU does its business, all very quick and efficient. I've done a couple of QSO's and all is behaving as it should so touch wood I'm very pleased with this little ATU. Now I’m looking forward to having a real play and thankfully no more trying to remember the settings for each band and adjusting the manual controls on the old Tokyo.

Wednesday, April 9, 2014

MFJ 259b Antenna Analyzer - An Update

Going over some previous post I see that a lot of people have read my little summary of the MFJ 259b. This is what I originally said: 

"The MJF 259b has finally arrived, it’s a fiddle though, you would have thought you’d get the power supply with it, but no, that has to be ordered separately, typical! So now I'm busily checking around the local hardware stores for an AC DC adapter with the right connector, it never comes easy does it? 

On surfing the web I came across a UK Amateur dealer who wanted £68 for the MFJ 99x accessory pack which includes the dip meter coil, carrying case and you guessed it the power adapter! Having checked out the web I can get a power adapter for £6.50, makes you wonder doesn't it? 

The other pain is that I knew it took rechargeable batteries, but I was rather taken back when I realised it needed 10! Removing the front cover to install the batteries requires the removal of 8 screws; you'd think MFJ would have come up with a simpler design? 

However I digress, last night I popped round to my next door neighbour and asked if by any chance he had a 12v power adapter, he did and blow me it fitted! So I was able to do a quick test to make sure all was working as it should, interestingly enough all my antennas were slightly out on the SWR readings, most likely from the recent storms, but over the weekend as a simple experiment I will borrow my Brother in Laws MFJ that I originally used to set them up to see how good the SWR matches are on both units, that could prove very interesting!!" 

I never did complete the last bit until much later, well it turned out that my MFJ wasn't too far off my brother in laws, I must admit I was expecting it to be way out.

Now that I've owned this piece of kit for some time and am a regular user I am probably now able to give a better report. The analyzer is actually a very useful especially if you are in to or going to make any sort of HF VHF antenna system. It's fairly easy to use with simple instructions, but if you get stuck just "google" and there are plenty of users out there who will help you.

However, in my humble my opinion it's not that well made, it's rather tinny, it doesn't feel very solid and to be frank feels rather cheap, but of course we owners know it don't come cheap; £300 plus I believe is the present asking price for a new one, so spare your blushes go 2nd hand if you can, believe me they are fairly easy to fix!

Mine does have some drawbacks, somewhere within the area of the coax connector there is an intermittent short, so whenever I connect up my coax cable to the connector I have to fiddle about to make sure I have a good connection otherwise I get a reading or +25 on the SWR. 

I've tried to find this short but it still is escaping me at the moment and it very annoying. More to the point it’s been there since new which doesn't exactly give me any comfort with MFJ products especially since they all seem very expensive! 

As a footnote I eventually found the issue and this is precisely the sort of thing I'm talking about when I say "cheap". The problem was a simple soldering connection of the inner (live) coax connector. The soldering looks and is quite frankly rubbish and once I'd done the fix correctly all was working how it should.

Something had obviously gone wrong when this analyzer was made up at the factory, look at the actual connection, the soldering is that bad the connection has failed.

I have extra bits I've made for the analyzer, I'm not going to purchase any bits of kit if a) I can make them and b) they are always far too expensive!

The loop coupler I use for measuring my homebrew traps; It’s dead easy to build and I strongly suggest you build rather than buy otherwise you may find yourself spending a large amount of money for what can be made in a jiffy at very little expense. 

If you have a good soldering gun you just take was some reasonably thick copper wire (about 6” in length) bend in a circle but keep ½” of each end straight. Take a male to male 259 connector and it’s a simple case of soldering one end of the wire to the centre pin and the other to the outside ring. So you finish up with a circle of Copper wire attached to the male to male 259.

The other piece of kit I made was a frequency counter lead out of some coax and with a PL259 connector at one end and the probe on the other. I used this for working out the frequency measurements on my K2, very useful and very cheap!

Overall, an essential piece of kit for the shack. 
Sometimes you'll get lucky and have one that has no issues and when they work correctly they are very good, but there are other analyzers out there at a cheaper price that do the exactly the same thing. 
In other words, "you pays yer money and takes yer choice!...Hope this helps.

Revisiting the 60 Meter Band

Having been somewhat dismayed when I first listened in on 60 meters I thought I’d better give it another go and see if the awful abuse I heard before was just a one off incident. 

So I put the old inverted vee back up and had another listen to see what was about. There were a few amateurs on sideband and some interesting conversations, but quite honestly I am still surprised how quiet the band is, I didn't hear any CW at all. 

For the past week I've listened most mornings, afternoon and evenings but I can probably count the number of amateurs I've heard on one hand. Admittedly the band is used on a secondary basis but it is very quiet. 

Then finally on Monday afternoon whilst sweeping across the band I crossed over 5.325 heard some voices, so I fine-tuned and there they were, back again, swearing and cursing with the most obscene language and believe me I'm no prude! 
I appreciate that not all users of 60m are licensed amateurs and 5.325 is not in one of the UK 60m frequency blocks but listening to that language does put me off. By the sound of their accents they were from the South West, possibly Gloucestershire or Bristolian and they seemed to be talking a lot about fish, so one can only guess these are local fishermen. 

It’s a shame really because 60 meters can be a great band, I remember back during my military days being stationed for a while in Belize and having to set up a radio station to contact our main base which was at Bruggen in Germany. 

I worked with a Royal Signals chap who was very knowledgeable and together we set up a nice little radio station by the main runway of Belize airport with a massive dipole system and over a period of weeks we had some great contacts with other military establishments all over the States. 

We actually had some success with Europe contacting the base at Bruggen on a number of occasions and I specifically remember using 5 MHz for a few attempts and managing some reasonable contacts!

Tuesday, April 8, 2014

Playing with a HyGain 18-VS

The other month we had our local radio club junk sale, everyone brings in something to sell and we have a good natter and lots of items get exchanged. It’s normally a very good event and gives all the members a chance to catch up and see what we are all up to. 

I brought in a tired looking 2m collinear and my home brew 2m yagi to be redistributed, both items had been sitting in the shack doing nothing and I needed the room for other projects plus they could be put to good use by another amateur instead of sitting there doing nothing. 

Whilst rummaging around looking at what other people had brought in to sell I noticed a chap with an old Hy Gain 18-VS vertical multi-band antenna. I vaguely remember my brother-in- law having one but always being a little frustrated because on each band change you had to go out to the antenna and manually alter the connection to the coil. To add to his frustration he always forgot the exact position he should set the connection and always ended up digging out the antenna analyser and resetting the SWR! 

This particular antenna in the sale looked like it was all there, but it certainly needed a good clean, the owner only wanted £10 and considering that a new one was over a £100 I thought I’d buy it and have a play to see if I could do something with it. 

After giving it a good clean and checking the manual I immediately realised that the antenna had been altered. Instead of the usual tatty coax connection above the coil, a previous owner had put in an SO 239 socket at the bottom of the antenna to make things a bit tidier, however, with that connection in place the coil was being bypassed therefore was useless. 

Investigating further I realised that the antenna had been set up as purely a mono bander, the previous owner had obviously given up on the state of the coil and from notes in the manual they mentioned about removing 12” of tubing, or he must have been like my bother-in-law and got fed up with changing the coil every time he wanted to alter bands! 

The two coils after a quick clean up, no doubt in the future I will put them to use.

With the antenna originally at 18ft in length I rightly guessed it had been reset as a mono for 20 meters but in its present state it wasn't going to transmit or receive anything. So I took it all to bits, and started from scratch, the coil looked in a sorry state, it had been glued together at some stage and so I removed it altogether since in its present condition it was certainly not going to work. 

After a good clean and checking the rest of the connections I reset the antenna length to roughly 16½ ft and connected it up to my analyser, all now seemed much better with an SWR of 1:1. 

So then I planted the refurnished antenna next to my 30 meter vertical via an old piece of scaffold pole hammered in to the ground. Using the 30 meter ground wires I attached some thick copper wire to the ground plate and I was now all ready to connect to the radio and have a listen on 20 meters. 

You wouldn't believe there are 30 odd ground wire connected to that plate!

Sure enough signals were coming in and after double checking everything was correctly connected I did a quick transmit through the dummy load, everything worked perfectly. Calling CQ I immediately got a reply with a signal report 599 from another QRP station in Italy. 

The HyGain planted next to my 30 meter vertical

Very pleased with the outcome I did some further testing against the 20 meter portion of the cobweb; however the cobweb was definitely stronger no doubt because its thirty odd feet up in the air and clear of all surrounding objects. But never the less it was great to get hold of an old Hy-Gain and bring it back to life!

Sunday, March 30, 2014

Swapping Over the Cobwebs

Last Friday evening in a bit of madness during a bout of boredom, I decided to dig out the dismantled G3TXQ cobweb from the attic and set it up outside in the garden. I’d wanted to re test it against the present G3TPW cobweb I'm using, just to go over the pros and cons and possibly replace the G3TPW. 

With the G3TXQ quickly set up on a piece of 6ft scaffold pole and after doing an approximate tune I couldn't believe my luck when wondering over the 21Mhz band that I managed to have a qso with a Russian station who gave me a 599 which made me think maybe it was time to swap the cobwebs over. 

Saturday morning I set to work and I did the full tuning with the MFJ 259 which took an age as the G3TXQ definitely has much finer tuning points, it dips very quickly and the freq range is literally a few hundred kilohertz, a noticeable difference to the much wider freq of the G3TPW. 

Because I was tuning/trimming the antenna with the MFJ 259 at only 6ft above the ground I had to take the risk of setting each of the elements to tune a little lower than the freq I wanted to operate on, the theory being that once raised the SWR would rise slightly from the tuning at ground level.

By Saturday evening I had adjusted all the tuning, secured the ties and finally waterproofed the junction box, I hadn't needed to do this before because this antenna had only been set up in my attic, So by Sunday morning the G3TXQ was ready for mounting

I grabbed the ladder, lowered the 40ft mast and removed the old G3TPW cobweb, I’d forgotten just how heavy the antenna is and it took a while to gently bring it down the ladder back to mother earth.

Placing the two antennas side by side it was interesting to see the physical difference. The G3TXQ is so much lighter; certainly the single wire and smaller aluminium central clamps make all the difference. 

The G3TPW has a much heavier clamp and is beginning to look very worn!

The G3TXQ is a much neater and lighter clamp, a definite improvement.

I also needed to do a few adjustments to the mast, add some more kevlar cord guides and do some general maintenance. Once that had been completed I grabbed the G3TXQ and hoisted it up the ladder and clamped it to the top of the mast, I have to admit it was so much easier than with the G3TPW and just looked a lot tidier! 

The final result and there was a definite improvement in performance.

By the afternoon it was all finished and after a quick SWR check I called a CQ and got another Russian Station (Alex R3ZK in Belgorod) who gave me a another 599, I was very pleased with the final results. 

There’s a few little bits I need to do, (like add the top mast clamp cover which I forgot.....doh!) But everything went pretty well according to plan and I shall now dismantled the G3TPW and store it away in the attic until I have another mad moment!

Final SWR results for the G3TXQ:

20 meters   1:2:1
17 meters   1:1
15 meters   1:1
12 meters   1:1
10 meters   1:1

Monday, February 17, 2014

Simple Magnectic Loop Antenna

A while back I mentioned my interest in mag loops and proposed at some stage to build an experimental antenna. 
After much searching I finally found and purchased a variable capacitor from my local radio club, I’m not sure of the exact tuning range but I figure it’s got to be approximately 20 -115pf, this should cover me for QRP work, but it obviously limits my power output. 

So now having the copper piping and the variable capacitor I’ve been able to begin building the antenna. As this is purely an experimental project I wasn’t going to make it as neat and tidy as some of the examples I’ve seen on the web. The idea was to build a simple loop connect it all up and see what happens. 

The first issue I had to work out was how to build it, as I had no experience with mag loops what so ever! But after hunting around on the internet I found plenty of examples and a handy calculator tool  to work out dimensions etc.

Getting round bending 9ft x3/4” of copper tubing was a bit of a problem, I had no plumbing tools so I had to have a think as to what I could substitute and eventually used my circular garden water butt which at roughly 3ft in diameter and set against a wall allowed me to squeeze the copper tubing in between the butt and the wall and gently pull the tubing in to a rough circle. It’s by no means perfect but as long as it circular I wasn’t too bothered. 

 It's not exactly round but it will do the job for this experiment!

For the smaller loop (Primary coupling), I used some thinner copper tubing measured length at 1/5th of the size of the larger loop and ¼” width, I could have used the same width tubing but as I had some of the ¼” handy and it was far easier to bend, I didn’t think that for this particular project it would cause any problems. 

The smaller loop threaded through the PVC tubing and ready to be connected to the coax.

Next I mounted both loops on an old piece of 7ft x 1 1/2” plastic tube.  Both copper loops were fed through holes I drilled midway along the length of the plastic piping so that they were held in place. The top ends of the larger loop were then attached with two pieces of thick copper wire and then soldered to the two connections of the variable capacitor. 

 The Variable capacitor connected up to each end of the main tubing

The smaller loop with both loose ends hanging down were also connected by thick copper wire and then via a choc block connected up to the coax cable which in turn is connected to the receiver or transmitter. 

Basically the whole set up is as simple as possible and took all of one day to complete. 

So, results – well I have to say I haven’t transmitted yet but I connected the mag loop up to my OHR100A and had the antenna sitting next to me as I tuned around 20 meters. No question about it as I tuned and peaked the variable capacitor the signals started coming in, it was working! 

Obviously I've got to do some more testing especially having a go at transmitting but so far considering I've never built a mag loop before I'm very pleased.

Tuesday, January 7, 2014

Heavy Weight K2 Tuning Knob

I recently bought the heavyweight tuning knob for the K2 off Ebay from a Bulgarian supplier. I’ve seen these tuning knobs before either on Ebay or via other Internet suppliers and have been staggered by the price, as much as £60.00. 

This Bulgarian supplier had the dial priced at £36.00 with free postage which I thought wasn’t too bad and so went ahead and purchased. The knob duly arrived well packaged and protected by a foam surround and a thoughtful inclusion of the required allen key. 

First impression of the knob was a well-constructed nice weighty item and I was keen to mount it on the K2 as quickly as possible, but imagine my disappointment when I offered up the dial and no matter how much I pushed it didn’t fit. 

I checked the dimensions, specifically the width which was 6mm but on checking the shaft width on my K2 it was more like 6.2mm!  I checked for any dirt etc within the knob or on the shaft but all was clean; there was clearly a measurement issue somewhere.   
Had I missed something in the small print?   

However the difference was so small all that was required was a 6.5mm drill and a steady hand and I gently removed some excess metal and hey presto the knob fitted neatly over the shaft. A little extra bonus was that the old K2 knob fitted perfectly on to my OHR 100A!

Anyway, I wrote to the supplier asking him if he knew that maybe Elecraft later versions of the K2 had possibly changed the shaft size. "Boris" kindly wrote back and indeed Elecraft had changed the shaft size somewhere along the 7xxx version, he had mentioned it in the small print but of course I had missed it, Doh! 
Never mind all is now well and Boris will make the small print a little larger for dumb people like me!