Wednesday, February 20, 2013

K2 Ordered

The money has been handed over and the K2 order is in, now it's the wait .......possibly a whole 2 weeks! 

To think it was only back in June last year that I started my QRP quest with the little old Rockmites then the OHR100 A,  now I'm ordering the kit I've always wanted. I've feel I've come a long way since June 2012 and am quite ready for the challenge, in fact I'm really looking forward to it. 

All the Elecraft reviews I've read point towards how good the kits are and the great support the company provides. Fingers crossed I wont need too much support but it's nice to know its there should I need it.

In the next few days I'm going to join the K2 build forums and have a good read, naturally once the kit has arrived I will publish how I get on, so obviously watch this space.

Sunday, February 17, 2013

60 meter Band Big Disappointment

I’d built my 60 meter antenna and had hung it up in the silver birch at the end of the garden, all connected up ready to start listening full of anticipation. 

Over the past week I have listened and heard the odd ham but quite honestly I was disappointed, I was hoping for more, no CW at all, nothing all week. As for side band there were a few but enough to count on one hand. 

Then this morning as there was a big competition going on and most of the bands were busy I’d thought I try 5MHz to see what was about, 5.325.00 to be precise. What I heard really astounded me and believe me I’m no saint, the language was colourful to say the least, whoever these two muppets were they were local boys from around Gloucestershire, it wasn’t hard to tell by their extremely thick Gloster accents. 

No call signs naturally, just happy to gossip about various people in their neighbourhood whom obviously they didn’t like and in doing so swear as much as they could. As I said I’m no saint but you don’t swear on the radio, certainly not the language they were using its common sense, something that these idiots were obviously lacking. 

In the end after listening for about 10 minutes in case they gave anything away I gave up and turned the rig off. I’m taking the antenna down, I don’t want to be a part of that, its part of the reason I hardly do side band, give me CW any day. No doubt there will be operators out there saying if you don’t use the band you will lose it, well sorry I won’t be a part of that particular band when there are idiots like that around. Enough said and back I go to CW! 

On a different note I’m almost ready to buy the K2, I rang the UK distributor and at the moment they are waiting for new stock, so I will ring back next week and put my order in. I must admit I was tempted by the Kenwood TS 590 but after serious investigations (mainly through Eham and You Tube) I decided on the K2. Overall the impression is that the RX quality of the K2 is marginally better but of course the winner for me was that you have the pleasure of building the transceiver. 

I’m going for the basic 15 watts first and see how it goes, I’m really looking forward to building this rig, after all it’s taken 3 RockMites and one OHR 100A to get to this point. More updates will follow once I have the kit.

Friday, February 8, 2013

W3DZZ Trap Service and 5MHZ Dipole

Since I’ve serviced the G3TPW Cobweb and completed the G3TXQ, I decided I might as well check the traps on the W3DZZ antenna and re-tune if necessary. Also I’ve successfully applied for the 5Mhz so I need to make up an antenna for that band. 

The W3DZZ has been up for a number of years and is a really good antenna for 40 and 80 meters. The 40m was originally set for the CW portion of the band and 80m set to 3.700MHz for some listening and the odd rag chew. 

The antenna was made from instructions I found off the web, a piece written by GM0ONX. I was that impressed I actually contacted him to say what a great antenna it was and how easy to build. He very kindly replied and informed me that it was literally built in a day and by chance he managed to get it published in Practical Wireless!

My particular W3DZZ uses the coax traps which were very easy to build and seem to work really well. GM0ONX's design is very easy to follow and simple to construct and if you're starting out this is an excellent way to get in to trap antennas.

You will require an antenna analyzer to tune up the traps

Recently I've noticed that the SWR has been reading quite high and I've been repeatedly having to tune up. So it was definitely time for a service; I removed both traps and did a quick check with the MFJ 259, the SWR was showing 1:1 at around 6.800MHz and it also looked like the coax on the tubing had slipped slightly and just needed some re-adjusting. 

It was just a matter of removing the electrical tape and adjusting the coax, then gently trimming the 40 meter portion until I got a good reading of 1:1 at 7.0030MHz, I also lengthened the 80 meter portion by 6" each end to drop the peak to around the CW part of the band. Once both bands were set with the correct trim it was just a case of re-taping the coax traps up and making sure everything was waterproof.

 Multi coloured trap (adds a bit of colour to the garden)!

Now SWR readings are good at 1:0 for 7.030 and 1:1 for 3.0550, it's funny how once all connected back up you'd swear the receive signals sound much better!

The 60 meters antenna will be an inverted Vee and I’m using the 1:1 ugly balun I made some weeks ago, (see previous posts), I’ve roughly trimmed it up and once I have it raised up in the silver birch at the end of the garden will do the final trim with the MFJ 259b.

The 5MHZ dipole complete with 1:1 ugly balun ready to be mounted in the silver birch tree, the red tag reminds me which is the positive end!

Having the MFJ 259b for measuring my home brew antennas does make building a lot easier. Another accessory you can buy (for some stupid sum of money) is the loop coupler for measuring traps and coils, my Brother in law has one which I borrowed when I first built the W3DZZ. 

 However, as he was away this week I realised I’d be stuck for doing the trap measuring. There was no way I was going to buy one , so I decided to have ago at making it, after all it couldn't be too difficult.

 Thankfully I had a 100 watt soldering gun and all it took was some reasonably thick copper wire and a male to male 259 connector and a simple case of soldering one end of the wire to the centre pin and the other to the outside ring. I've probably made the ring a bit too big, but hey the traps fitted fine for testing so it works and cost me nothing!

Sunday, February 3, 2013

Both Cobwebs Now Up and Running

Well after much playing about with tuning and trimming, I finally got the G3TPW Cobweb back up on the mast yesterday evening.
After my initial tuning the other day I had to dismantle the antenna as the weather was proving very bad, so yesterday by the time I had re-assembled and started up the tuning process the morning had passed quickly by. Finally with a bit more trimming completed, I climbed the ladder with antenna in hand and clamped it in to place.
I switched on the MFJ 259 and did some checks, the SWR was all over the place, I had a problem, something was definitely not right and after a quick check of all the coax cables, I had to make the decision to bring the antenna back down, and so I clambered back up the ladder and removed the antenna.
I spent most of the afternoon with the terminal box open trying to figure out what the problem was, I knew it was shorting somewhere but in the end I had to go through each connection to find the short. Eventually I found the problem, it turned out to be one of the 12 meter elements had split at the join to the choc block causing one of the U connections to short and all it needed was re-stripping. Then it was just a case of re waterproofing the box, sealing up and mounting back on the mast.
Dusk was fast approaching when I clambered back up the ladder and attached the cobweb back on the mast, I quickly said a prayer and did my checks on the MFJ and thankfully all proved OK. 

Finally back on the mast!

The SWR measurements are now pretty good, they are all set for CW except for 10 meters which I set for 28.500 as I like an occasional rag chew on 10.
14.000 - 1:4
18.070 - 1:0
21.050 - 1:0
24890 - 1:2
28.500 - 1:1
With the G3TXQ cobweb now set up in the attic I am at last ready to do a bit of testing with both cobwebs. Obviously as this antenna is in an enclosed space there is bound to be a difference. The most noticeable being the background noise but that cannot be helped as the attic naturally has bricks and mortar and electrical wiring.
Here is the final SWR reading for the G3TXQ:
14.075 1:5
18.080 1:4
21.073 1:3
24.890 1:1                        
28.015 1:1    
As suspected there is not a lot of difference, but the SWR is slightly higher on the G3TXQ on a couple of bands (most likely because of the attic positioning). I could trim to match the frequency of the G3TPW, but to be honest I couldn't be bothered to get it exactly the same. 

Physically the G3TXQ is far lighter and easier to handle also the tuning is much quicker because you only have one wire for each element. But that said, I do like my G3TPW, it is heavier and chunkier with my larger home made plates and it definitely feels more solid especially with the windy condition we have round here.

It was very apparent when lifting back on to the mast how much heavier it was compared to the G3TXQ, you feel the lighter cobweb would literally blow away in the wind, although that said it's exactly the same build just lighter materials.
The main difference on receiving is of course the background noise but if the G3TXQ was raised outside on my mast I doubt you would know the difference when listening. On transmit I've now used both cobwebs on 20 meters and reports from both are good with the G3TPW showing  slightly stronger RSTs, again no doubt due to due location.

So all in all as suspected there is very little difference, for me I'd go for the G3TPW simply because it feels stronger, but that personal choice from QTH circumstances. It's been fun servicing the old cobweb and building a new one and I hope you have enjoyed the entertainment as I've struggled along. I'm not a technical antenna geek so all this is very basic but hopefully gives you a rough guide to both types of the antenna.

I'll probably remove most of the posts I have regarding the Cobweb antenna and place them on a separate page so that potential builders have all the information together.

I'm not sure what I'm going to do with the G3TXQ cobweb now, so for the moment it's sitting snugly up in the attic out the way. Currently I'm saving up for either a K2 or a TS590 so I'm tempted to keep the G3TXQ and connect to the new radio, then I'll be spoilt for choice with two cobwebs!