Thursday 27 February 2014

Rockmite ][ 30 conclusion

Just a quick photo of the Roackmite board sockets and switching hardware inside the Hammond box.
The Box measures 111X60X30 mm (outside dimensions) and is the perfect size for this project. It is extremely robust and should be more than adequate for my needs.


If you are contemplating building a Rockmite please be aware that there are several modifications that various operators have made which are easy to incorporate just as long as you know about them before you install all of the components.
  • There is a power modification that just involves changing the 2N2222 for a 2N3866
  • There is a volume control that involves removing 1 resistor and installing a 1 Meg pot.
Both of these modifications are much easier to do if you know about them before you start.

I am not a great constructor with only average ability in this area. I found the screen printed board easy to follow and just large enough to build comfortably. There are no surface mount components to worry about or coils to wind.In fact the hardest part for me was wiring the coaxial cable to the board itself without causing a short. 

I bought the Rockmite from Kanga Products whose service I thought was excellent. The only part that is not included in the kit is the box to finish it off with.
The Hammond Box came from Bitsbox who also provide a very rapid and efficient service.

The board was built over 2 days but could easily be finished in 1 if you are not as over cautious as me. The box was easy to drill to install the sockets and switches. So in conclusion I am very pleased with kit and I definitely got a great sense of achievement in completing it successfully.

73 de Jim G0HGH

Wednesday 26 February 2014

Rockmite ][ 30 update


It survived the smoke test.

Thanks to G8NWC and M0CVO for offers of Altoids tins to complete the Rockmite in true QRP style but in the end I decided on a rugged Hammond box from Bitsbox to finish it off.
The box is 111X60X30 mm and the board is a perfect fit. It leaves just enough room for me to get my fingers in to fit the rest of the hardware switching.


I  powered up with a dummy load attached but, not being a true QRPer, I do not have a meter that goes down that low, so tuned to the frequency with my FT897 and there it was with a very nice received tone. I must confess that I breathed a sigh of relief.

Next step is to work out how to lable the box and build an antenna.
Hope to be on the air soon.

73 de Jim G0HGH

Tuesday 25 February 2014

Rockmite ][ 30 TRX Kit

Much as I love modern Radio Equipment, with all of its whistles and bells, I often find myself yearning for simpler days, especially when technology bites back and things go wrong. I am also very much a fair weather /P operator and, much as I enjoy our Club's annual Fun Field Day, the thought of dismantling my radio shack for expeditions does not fill me with joy. 

My longing for simpler equipment that was easily portable recently tempted me to look at some radio kits that are on the market. Once you start looking, the temptation is to start at the cheap end and then convince yourself that, for just a few more pounds, you can get various extras that would be very nice to have. Before you know it, you are spending serious money and you might just as well buy a "proper" rig. As I am very prone to getting carried away like that, I narrowed my choice down to either The Foxx-3 or the Rockmite transceiver. For just a few pounds more than the Foxx-3, the Rockmite offered a built in keyer and the ability to use 2 frequencies so the choice was made.

These transceivers are all single band, CW only, so my next decision was which band to go for. Most of my HF operating tends to be on 80 or 40 meters CW, both crowded bands at the best of times and for QRP, maybe a little too challenging for me. Chatting to keen QRPer at SDARS, Graham, G8NWC, I  decided to go for the 30 meter version and promptly placed my order with Kanga Products. I was extremely surprised to be disturbed by the Postman the very next day with a package that needed signing for. Top marks to Kanga Products for their rapid service.

                             Rockmite 30m

There was not a lot to unpack, but, what there was came in half a dozen envelopes and all components looked nice and shiny and good quality. Keen QRP operators will be pleased to know that the finished TRX will fit inside the obligatory Altoids mint tin so it was bound to be small. However, I did not want a project that was so small it was impossible to build or operate.


The board itself is very nicely printed and, I am pleased to say, does not use any surface mount components. It is quite densely populated so a magnifying glass is  definitely going to be needed, but that is more due to my aging eyes rather than anything else. The component layout is screen printed on the board and looks cramped but workable. So far so good. 
   

It was quite reassuring to recognize most of the components but one little strip has got me puzzled. It is only 18 mm wide but I have no idea what it is as yet.














The first step is to visit Kanga Products web site and download the instructions and builders help PDF's.
These appear to be detailed and I think that I will actually take the time to read them before starting work.




Twenty four hours later I have a populated board - well almost.
The build was quite straight forward although the instructions were very minimal. I started with the IC Sockets and then sorted the capacitors and resistors into groups according to their value. This way I was able to keep track of the components as they went on the board. Snag one was when I found that I was 2 capacitors short. They were both from the band specific batch of items so assume it was a bit of finger trouble when packing. A quick email has sorted that out. Kanga Products certainly cannot be criticized when it comes to speedy service .

Although the board is crowded, I found no difficulty in fitting any of the components. The design appears excellent from this point of view.

The unidentified component/s continued to be a mystery, they have not been mentioned in the instructions and there is nothing remotely similar indicated on the board. It or they are the only bits that I have left over after populating the board so that is a small area of concern.
Update; Just had an email from Kanga Products and the mystery item is part of a mounting kit for an LED accessory.

I have noticed that the kit has been upgraded with a volume pot added. In the instructions this was referred to as an optional extra so I will now have to remove 1 fixed resistor from the board and wire in the 1 meg potentiometer supplied. I hope this will not be too much of a problem as I usually find removing components much more difficult than fitting them. 

Next step, once the capacitors have arrived, will be testing prior to sorting out the hardware and boxing up. From experience this is my weak area and I have made some pretty shabby projects in the past. I am determined to make a better job of this kit as I think I will be using it quite a lot.

It is my hope that I will end up with a radio that is compact enough to be carried on my bike or taken on walks. The easier it is to pack, the more likely that I am to use it.

I have been playing with a variety of vertical antenna just lately and they work very well in quiet locations over a good ground but I do like resonant aerials and I do think that a single band QRP rig just has to have a mono band dipole. No losses from Baluns or traps when you are only starting with half a watt!



Based on a glass fibre fishing pole support 7 meters high should give me an easily handled antenna with the ends 2 meters agl for safety. As an inverted "V" it should be good for DX as well.

73 de Jim G0HGH