Tuesday, October 30, 2012

Another QRP Kit

Well I’ve gone an ordered another kit, this time it’s the Oak Hills Research OHR100A
I suppose once I’d seen it I knew it was the next sensible step up from the RockMites, I’ve chosen the 20 meter version, I did think about the 30 meter but quite honestly the last RM I built was for 30 meters and its working so well that I really don't need another rig for that particular band at the moment.
This rig has a bit more power 5 watts, so I should get a lot more first time contacts, thats the one thing about RMs, you have to be patient when calling CQ!
I'm really looking forward to it's arrival I think I'm definitely addicted to QRP building and this should be fun. Not sure how long it takes to dispatch but also I will need to take into consideration all the problems that hurricane Sandy may bring so I need to be patient.
I’ve also ordered the extra 10 turn VFO tuning pot and the LED kit, I thought I might as well get everything straight away.

This build will really be the prototype for the main event the K2, so I hope I find it fairly straight forward in construction and also put in to practise all that I have learned when building the RockMites.
Providing all goes well I will add photos and descriptions as I go along, might prove interesting for some budding home builders. If it’s all successful then I will certainly start looking at the K2 but I doubt I will get that until sometime next year.

Wednesday, October 17, 2012

The Higher Bands Open Up

I have just been skimming across the bands and this morning 28MHz is wide open, I’ve heard VKs VUs and ZLs and it’s a refreshing change to the normal quiet hiss of the band!
Interestingly there never seem to be any slow operators in the early morning, whenever I switch on first thing you always hear the diehard Dxers tapping away, mostly at speeds that I find difficult to keep up with.
Always first thing in the morning when I fire up I'm too keen and I have the typical CW operator’s problem I find I can send faster than I can receive. I call it BNC (Brain Not Correlated).
Sometimes when I hear a distant station and dive in giving a quick reply they come back at me like a machine gun because I’ve gone in at such a quick speed.  I then have to put my brain in to gear and concentrate very hard to translate the reply.
If it’s a standard reply such as “gm es tnx fer ur call ur rst 599 etc”, then I’m ok but if the conversation alters then I really need to buckle down and think! Its classic mistake that operators can make, but it’s not the end of the world, after all it’s your hobby so enjoy the challenge and it's a great way to speed up your code!
I’m still at a loss at what kit to build next, I’ve been looking at my ultimate build, the Elecraft K2, I just love that transceiver and a real challenge to build, but like all things it comes at a price which is something I just cannot afford at the moment, but one day I am going to buy it, it’s just a matter of time.
I’d also love to have the K3 the ultimate CW operators rig, but its a lot more money (nearly £2k) and I already have my super rig, the FT1000 MkV which is a very good radio. So if I ever did buy the K3 the MkV would certainly have to go to part finance the K3, which I'm not sure I could do.
In the meantime while I dream for my super kits I now want something to fill the gap of the RMs, basically it must be a challenge above the build of RockMites so more than likely its going to be a Hendricks or Oak Hills Research kit.
It must be a minimum of 5 watts with CW only and definitely have a VFO as I’m not too keen on being limited to a small section of the chosen bands.
Certainly with the RockMites it can be a pain when you switch on and the band is swamped within your particular frequency, you have little or no ability to move away. I know you can mod the RockMites but I feel I want to keep them as they are and move on to something new.
In the meantime I’ll carry on tapping away at the key especially whilst the higher bands are open.

Thursday, October 11, 2012

A Simple Manual Antenna/Radio Switch

Now that I have three RockMites and one FT 1000MPV to play with I wanted to make it easier to switch from each radio, the simple solution was a basic antenna/radio switch.  
I had an old 3 way Altai switch from years ago but quite honestly it was a cheap bit of kit and anything above 50 watts it would probably burn out. So I decided to build my own using various bits of junk I had in the shack.  
I pinched the four SO239s from the Altai which were fine but interestingly on further inspection the Altai was definitely on its last legs, the plastic switches on it were virtually worn away. After rummaging further in the shack I managed to find another SO239 to make 5 connectors in all.
I also had a small aluminium/aluminum enclosure which would do nicely for the case and being metal would take care of the groundings and any stray RFI. I found a one pot 4 way rotary switch, but it was plastic job, fine for a guitar or something similar but I doubt would have lasted very long for what I wanted.
So I decided to buy something heavy duty and after trawling around the web I found a UK company that sold 1960s rotary switches and I spotted a good solid 1 pot 4 way switch that would be just the job.

It cost me £6 but when it arrived I knew I’d bought the right switch, it was a good solid bit of kit, nice and heavy with a break before make connection.
I soldered some 14 gauge wire to the SO239s and fitted them to the enclosure, after cleaning up the switch I drilled another 16mm hole in the top of the enclosure and fitted it in to place. 

Finally I connected up all the 14 gauge wire from the SO239s to the switch and gave it a smoke test. The SWR was good on all five connections and another useful bit of kit was completed. 

The nicely thing now is that I'm not chopping and changing antenna connections to different radios all the time, with a simple twist and satisfying "clunk" of the heavy duty switch I can connect to each radio with ease.

Sunday, October 7, 2012

Oner Stockton Wattmeter

To get an idea of QRP power and SWR for the RockMites I bought the "Oner" Stockton Wattmeter from Kanga Products

It comes in kit form and is a simple circuit and fairly easy to put together. I suspect many QRPers will know of it and what a useful bit of kit it can be. It only took me half a day to put together and now at least I have a more accurate means of measurement. 

I had an old enclosure that was able to use to fit the kit, the hole for the meter was a bit too large, but a bit of tape fixed the problem otherwise all the other connectors and parts fitted in nicely!

I'm at a bit of a loss now, no more RockMites to build and although I'm having fun operating them I need some kits to build, I've obviously become an addict! I think I've said before I've got my eye on the 5 watt CW kit from Oak Hills Research or possibly the similar CW kit from Hendricks.
We'll just have to wait and see and to be more precise what I can afford!

Thursday, October 4, 2012

RockMite 30 Update

Well some good news, I’ve had my first QSO with the RM30 but there have been some minor issues along the way.  
After completing the build and doing some further testing  it became obvious that the transmit was not working as it should, I was using the 2N3053 transistor with the 2 ohm resistor in R18 and of course the bifilar toroid filter mod in L1, but I was only getting about 400Mw out when I should have been getting around 700Mw.
On further investigation/checking and through chatting on the Yahoo Rock-mite forum it eventually came apparent that I was using the wrong toroid FT37-6 as opposed to T37-43.
 Unfortunately I did not have that particular toroid so after having a good think realised the best way forward was to revert back to legacy and remove the T37-6 and pop L1 back in and use some jumps to bypass the trace cuttings.
Actually surprisingly enough it did not prove too difficult and I soon had the RM back up and running pushing out approximately 600Mw of juice.
At the same time I had a play with various transistors I have, the standard 2N2222 and the 2N3053 plus another, the 2SC799 which in theory can give you up to 2 watts of power. Sadly with my RM30 it hardly gave me any power, so either it’s broken or my set up is incorrect for that transistor.
So I reverted back to the 2N2222 and after a couple of attempts Calling CQ this morning I got DL6FAX, Konrad in Korbach a distance of 670 miles , not bad for my first attempt and Konrad was kind enough to give me a 569!
I’ve now ordered the correct toroid which should arrive later this week and then I will do some further experiments and we’ll see how we go from there.
The main thing is all my RM’s are now built and thankfully working correctly, something I would not have dreamed of if you had told me at the beginning of the year. 

Some further news regarding batteries, at present I have been using standard 9v batteries, which are fine but obviously not rechargeable. A member of the Yahoo RockMite forum announced last week that he had purchased a re-chargeable 12v battery from China which by all accounts seemed to fit the bill for RockMites really well.

So I took the risk and also bought one, it arrived the other day and I’m really pleased with it. It comes complete with charger and 3 pin plug (for UK users) and seems to hold the charge pretty well. It’s excellent for when I want to get out and about, not bad for £8.00!