Portable 40 Meter Antenna Ideas

I need to have a portable antenna for the Rock-Mite 40.

Somewhere hidden away I have an old 30 meter loop that I was experimenting with and I remember finding it very easy to set up and dismantle. I’m just wondering if I could build a 40 meter loop and try having a play with that, obviously a 40 meter loop is a little bigger than 30.

 Alternatively I could build a vertical but hanging 60 odd feet could have some problems. A way round it might be to do some sort of helical or coil, the only limitation maybe the band width but that really doesn’t matter for the Rock-Mite.  

I don’t want to do anything complex, I want to make it as simple as possible and easy to set up, I’ve had a quick look on the web and found a few ideas, notably KH6JRM who has come up with a fairly simple idea which might fit in with what I’m after.

It’s ridiculous really I have various antennas dotted around my shed which include a Mystery antenna, a radio works Carolina Windom for 40 meters, a standard homebrew Windom complete with 4:1 balun set up for 40 and loads of 14 gauge wire, I’m sure I can manage to make something suitable for portable use!

Still awaiting the arrival of my stereo key connector for the RM40 and the freshly ordered RM20, I’m quite happy to wait though as I’m having fun just listening on the RM40 and playing QRP with the FT1000MP V.

The Completed Rock-Mite 40

The completed Rock-Mite 40 in its enclosure

Just some decals to add.

Not bad for my first transceiver build, even though I say it myself !

Rock-Mite Update

After wiring up different mini jacks with various combinations I was beginning to think that I had totally lost the plot and that the Rock-Mite was going to become a little receiver, never to be able to transmit in anger.

I could not understand what I was doing wrong; I had followed the instructions from the manual and taken all the advice from the Rock-Mite forums yet still when pressing the key I got dits only.

Finally when once more reverting back to the Yahoo forum a message appeared from Dave Benson of Wonder labs to say he’d realised a mistake had been made in recent orders and that the jack plugs that had been sent out were mono instead of stereo, hence the reason for my problem.

So I was not going mad after all there was a simple explanation. Dave naturally apologised and is in the process of sending out the correct item which hopefully will arrive this week.

In the meantime I think I mentioned before that I have been doing some QRP with the FT1000 MP V and had a great success last night when I got an Italian station with 0.5 watts, although he replied with an RST of 569 but then sent “I do no QRP” and promptly wished me 73s and signed off!

Ah well at least I knew that I could get out with the home made W3DZZ on half a watt.

If all goes well with the RM 40 I am already planning the sequel..................the RM20; watch this space!

The Rock-Mite Comes Alive

Eureka! After changing over U2 and U3 to their correct positions I fired up the Rock-Mite and heard some sounds in the earphones.

What a relief, I honestly thought I wouldn’t get it working, so it was wonderful to hear some CW chatter and what clarity I was very surprised how clear the signals were.

Although I now have another problem which maybe a very simple issue or might well be due to the damage I may have caused by my embarrassing slip up.

When wiring up my straight key I seem to get dits only, no dahs! From talking with the Yahoo Rock-Mite group they think it’s just a wiring issue, but having tried different groundings and set ups I’m now not so sure and it maybe that when I inadvertently had the chips in the wrong sockets I may have damaged one.

As a precaution I have ordered a new 12C508A PIC microprocessor which hopefully will arrive soon and I can swap out and check. I can't wait to have my first QSO so it’s very frustrating hearing all those CQs and not being able to reply!

Changing the subject somewhat, yesterday whilst in the local Maplins store collecting parts for kit building, a voice from behind me asked "what are you building"? We got in to conversation and it turned out that Giles was from up the road and also a radio amateur.

From speaking with him his voice sounded familiar and then it suddenly dawned on me that this was the chap I hear most mornings in conversation on 80!

How strange to meet someone you feel you know but only heard on the radio, you find you have developed a mental picture of them and of course they look nothing like your image.

Anyway we had a nice chat and agreed to meet up on the bands in the future. It's always nice to meet a fellow ham in the flesh and exchange conversation face to face!

Oops... I think I May Have Found the Problem

Well I’ve been looking over the Rock-Mite kit for the past few days wracking my brains trying to figure out what’s wrong with it.

After two days of searching/checking each part I finally noticed that R6 had blown, there were burn marks all over the base, difficult to see without a magnifying glass but it would correspond to the smoke I saw when first firing the rig up. So I have removed it and am currently purchasing a new 10 ohm resistor.

After joining the Yahoo Rock-Mite discussion group and informing them of my problem, they were extremely helpful and various suggestions and tests were carried out as advised by some of the experts. Nothing was found and after doing numerous searches for shorts and bad connections I have to be honest here I was on the point of giving up.

Then this morning before going to work I was reading up on the manual to see if I had missed anything and there in front of me was a photo of the PCB with the two IC’s U2 and U3 seated in the board, I looked at the numbers on the chips in the photo and then looked at the numbers on my circuit board……… they were the wrong way round!

How could I have missed that? Well I did and what an embarrassment, but it just goes to show that you need to check everything and never assume the obvious because guaranteed it will be the culprit.

Tonight after reinstalling a new resistor I will attempt another smoke test and I’m guessing even being a novice builder that should sort the problem. I will obviously update this post once I have the result.

I am very embarrassed with such a stupid mistake but at the same time enormously relieved that at least I have possibly found the issue and I am not going nuts! More updates to follow soon.

Rock-Mite

The Rock-Mite arrived last week and I eagerly opened up the package and as soon as I could began work on the kit.

I followed the very useful instructions written by NE1RD as well as Dave Benson’s and after neatly placing out all parts, I checked them over to make sure everything was there.

NE1RD’s notes do have a few minor errors, there one large one re the check list (a mix up on Capacitors), but it is quite obvious and after checking the web I noted that other builders had also warned about this.

So with all parts accounted for I set to work and had the circuit board built by Saturday evening. Sunday morning I did a thorough check of my soldering to make sure there were no dry joints, I had also ordered the controls so by Sunday midday I was wired up and ready for the smoke test.

 Things then started to rapidly go downhill, connecting the circuit board to an antenna and applying power via a 9v battery I listened out for signals, nothing, it was dead. I replaced the headphones, (just in case) and tried again, nothing, not a whisper.

So I checked I was getting power in to the board it was quite low, 4v, I checked the battery and got 6volts, not a lot of power, so I looked around to see what I had available. I found my small adjustable DC power unit and set it to 12 volts and re-applied the power.

This time I got a puff of smoke by R6 and C103, C7, so I quickly switched off. Was it a small amount of flux burning or was it a problem? I persevered and re read the instructions, checking the wiring etc.

Resetting the power to 9v I fired up again, no smoke this time but still dead, not a sound. So the conclusion is I’ve either mounted a wrong part somewhere or there is dry joint/join or the worst case a part is damaged.

Power is definitely there and I have thoroughly checked for bad connections/dry joints, so at some stage I will have to a check of each part to make sure it is in the correct place and providing the correct resistance and voltage.

Interestingly on the Yahoo Rock-Mite support group there is a ham with a similar problem M6CLL, only he was getting signals off 9v but moved on to his PSU and something smoked. I may well contact him to compare notes. The investigations will continue and I will update as I go along, wish me luck…

……..Ah the joys of home building!

The completed Rock-Mite but sadly not working!

Quiet Bands and Cobweb Service

The bands seem to be particularly bad this week, normally first thing in the morning I can tune around 30 or 20 meters and find some interesting stations, but for whatever reason everything seems very quiet, except for white noise!  

Even 40 meters is suffering with white noise and I have heard only a few stations, perhaps it’s sympathising with the weather which at the moment is damp and miserable.

I am still awaiting the arrival of the Rock-Mite, I can only think that Dave Benson K1SWL is awaiting parts before sending the kit out or that it could be stuck with customs here in the UK. These things happen and you just have to be patient but it’s always annoying when you’re raring to go and have everything in place to build the kit.

Whilst waiting for the arrival of the Rock-Mite I have been practising QRP work firing out CQs on 5 watts with the FT1000 MP V, which seems rather amusing as normally I'm using a minimum of 50 watts. You can almost hear the strange comments from the stations you work when you tell them you're rig is an FT 1000 MP V at 5 watts!

At the end of the month I have managed to get a week off from work so providing the weather picks up I will take down the cobweb and give it a good clean and service.

It’s been up for two years now and has suffered the rain and winter storms so I suspect the connectors within the box will need a good clean up and re grease.

The wires are beginning to droop either from stretching in the wind or the string that pulls them together has become slack through time. The 20 meter wire certainly needs adjusting as the SWR now reads 1:5 and I will have to re treat the wooden poles with some preserver.

I have some spare speaker wire and poles should the need arise to replace but I’m hoping that shouldn’t be necessary. Hopefully by then I will have got round to buying a new camera and I will take some pictures to post.