Tuesday, November 29, 2011

A long-standing RF feedback problem solved

For a long time now my Yaesu FT-1000MP has been suffering from a problem where the radio does an automatic factory reset when I am on 10 metres (28 Mhz). This doesn't happen every time. Sometimes I can run 100 watts for ages without a problem. At other times, the radio resets once I go above 80 watts.

So I spoke to a couple of ham friends about the problem, determined to fix it. It seemed that some RF was getting back into the radio somehow and that this was causing the CPU to reset. It was only happening on 10 metres. One time I mistakenly called CQ on my Icom 746 through the Antron 99 with the FT-1000MP switched on and the MP reset!! The problem was a puzzle for me, but clearly it was related to RF feedback or a problem we hams know as "RF in the shack".

One ham friend said that as 10 metres was the shortest wavelength, it was highly likely that at least one of the cables running into the radio was of such a length that it was picking up RF from a harmonic of 28Mhz and feeding it back into the radio.

So I set about transmitting on 10 metres with various cables removed, or choked. Obviously the AC cord cannot be disconnected, so I choked it with a couple of ferrite beads. No improvement. I disconnected the coax from the Butternut vertical which feeds into antenna socket B (I was using the MA5B minibeam on socket A to transmit). No improvement. The radio was still resetting.

The I disconnected the earth wire from the back of the radio. I have a station ground, a copper rod, sunk into the ground just outside the shack. Disconnecting the ground wire did not make any difference. The radio was still resetting.

At this stage I decided to try to disconnect leads that were running into the front of the radio. I plugged out the desk mic and keyed up on CW. Radio still reset. I disconnected the lead from my Signalink USB. Still resetting.

There was only one cable running into the radio which I hadn't tried. And that was the cable running from my Kent morse paddle into the CW Key socket on the front of the radio. So I disconnected that and keyed up on 100 watts in FM and . . . . . . no reset!!!

I started to get excited. I powered up the Acom 1000 linear and decided to put more power out to see if the radio would reset. I plugged in a homebrew CW paddle which has a much shorter lead and keyed up in CW. No reset. I put the power up to 400 watts. Still no reset!! Oh boy was I happy.

Given that it was Sunday and the CQWW CW contest was on and Irish hams are now allowed to run 1.5kW in contests I decided to put out even more power. I managed 1 kW without a reset.

The solution, given that the Kent key cable seemed to be causing the issue, was to shorten the cable to the same length as the homebrew paddle. A couple of snips with wire cutters and a bit of soldering later, problem solved!! I was able to run 600 watts on 10 metres Sunday evening without any problem.

Hopefully this might provide some assistance to anyone who may be experiencing a similar problem.

I have to put ferrite beads on the cables running into my laptop. Certain peripheral devices, such as the external keyboard, mouse etc, are malfunctioning because of RF in the shack. I will let you know how that goes when I acquire some ferrites in the coming week.

Sunday, November 27, 2011

CQ WW CW . . . anyone for morse?

I didn't have much time for the bands today until it was getting dark. I collected my new (second hand actually but new for me) Acom 1000 linear today and needless to say it has been put to good use in the CQWW CW contest which is on this weekend.

Just dipping in and out on 20m and 40m I have worked 75 countries and 29 zones with just 120 QSOs. I nabbed at least six new ones on 40m so from that point of view it has been a great night. The highlight perhaps was EL2A, Liberia, but others included 8P, PJ4 and ZF.

With increased power limits in certain contests, EI ops are now allowed to run 1.5 kW in the CQWW contests. I was able to push the Acom to 1250 watts on 40m into the inverted V but only very briefly as I do not want to be working it to the max. Generally QSOs are being made at anywhere between 400 watts and 1 kilowatt.

As someone who has always used a maximum of 100 watts at this station I have to say the extra power has been a revelation. It certainly is easier to break the piles. I worked a number of VKs on 20m in the late afternoon. Most were easy to work. I can see the Acom coming in useful . . .

Tuesday, November 22, 2011

One day's work gives a good snapshot of conditions

Right, before I start, I have to give you a health warning. This blog may contain traces of HF DX!!! There you have it. Conditions have been nothing short of fantastic this past few months, as you might have gathered from reading my enthusiastic musings on this site.

The 9N7MD Nepal team - worked a few times, thanks!
Today might, as a snapshot, give you some idea of just how good things are. This morning at 8.13am I worked 9N7MD (Nepal) on 10m CW for a new band slot, having worked them on 17m CW yesterday as a new band and 10m SSB as a new one. That was followed by BA5HAM in China on 10m CW at 8.21am. It's great how early ten metres is open in the mornings. I have worked DX at 7.30am, before sunrise!!

V31QS in Belize was a new country on 12m when I worked him at 5.41pm on that band. I used 400 watts from the Acom 1000 linear which I have a loan of currently and it didn't take long to break the pile.

E51MAN (Bill N7UO) on Manihiki, North Cook Islands, was put into the EI2KC log for the second time, this time on 12m CW. I had to give him 400 watts and it took a while, and he was very light on the MA5B which is a rotary trap dipole on 12m, but I made it through. He had both Europeans and North Americans calling him. Yesterday evening I worked him on 10m CW at 17.58 with 150 watts. It was a brand new DXCC for me yesterday and now I have him on two bands.

This was followed shortly afterwards by E51CG on South Cook Islands on 10 metres SSB. This time I was running just 90 watts. I heard him working MI6CWC and figured he must be hearing Ireland so gave him a call and I was next in the log. South Cook Islands was a new one for me last month (Oct 23rd) when I worked Bill N7OU who was at that stage E51NOU on Raratonga. A month ago I had never worked E51-S. Now I have South Cook on four band slots.

PZ5T in Suriname was a new country on 12m when I worked him at 19.18 this evening with 300 watts.

VP2MWT in Montserrat was worked on 15m CW with just 100 watts as a new band slot at 19.50.

VP8LP, Bob in the Falklands, was a new DXCC on 20m when I nabbed him with 220 watts at 20.13.

And this was followed by XW3DT in Laos on 30m CW at 20.24, using 400 watts.  A week ago I worked XW3DT on 20m CW as a brand new DXCC so two band slots is nice.

Sunday, November 13, 2011

It's November, but it feels like summer on the bands!

You might be puzzled as to the heading above, but let me be clear. This time last year there was no action to be had on 10 metres or 12 metres. 15 would close at sunset, and 17m might just stay open a while longer. Guys like me would arrive home from work - after dark - and find everything from 20m up closed.  Not so this year!

10 metres has been open as early as 8am. One morning this week I worked China on 10m CW at 8am. Nice. But the liveliness of the bands, and the wealth of DX available, shows just how much conditions have changed in recent months. This weekend has been no exception, with great openings around the world on 10 and 12.

This morning I called CQ DX on 10m SSB using 200 watts. I got a couple of VKs coming back, solid 5 and 9, like European stations. Then I ran a pile on 12m for the afternoon, mostly into the States, but also snagging a couple of new DXCC, like V51B in Namibia and 3A2MG in Monaco. The USA was bombing in on 12m SSB, where, with the help of a borrowed Acom 1000 linear amp, I was able to run 400 watts for the afternoon. There were many states worked during the session, including: WA, CA, UT, NH, SC, LA, PA, MO, MN, ID, CT, TX, WV, IL, NC, OH, FL, NM, GA, VA, AZ, AR, WI, NY, ME, MT, CO, NE . . . the list goes on and on.

To top it all off, I nabbed E51NOU, South Cook Islands, on 15m CW, a new one on that band, followed by ZK2V (Nieu) as an all-time new DXCC on 10m. I worked him with 75 watts on 10 m, and about 40 minutes later I got him on 15m CW with just 100 watts.

Thursday, November 3, 2011

Now this is one I am very proud of!

I just received Logbook of the World QSL confirmation of a QSO I made on September 15th this year with VK9OL, Lord Howe Island. Celebrating his 75th birthday (and 60th year in ham radio) Merv N6NO was active from Lord Howe island as VK9OL between September 10-18, 2011. I was absolutely thrilled to get him into the log on September 15th on 30m CW. What particularly impressed me was that there wasn't a huge pile calling him, which gave me a better chance with my 100 watts and homebrew inverted V. I have also sent a direct QSL card to Merv and am looking forward to getting his card in return for this rare one. That brings to 183 my total number of DXCC confirmed via LoTW.

UPDATE: I just received a paper QSL from VK9OL with a note attached, saying that, out of 882 QSOs with Europe during his operation on Lord Howe Island, only two EIs made it into the log, and I was one of them!! Chuffed . . .