ad: Radclub22-1
ad: L-HROutlet
ad: l-rl
ad: Subscribe
ad: l-assoc
M0DHO England flag England

Login is required for additional detail.

Email: Login required to view

Ham Member Lookups: 41070


Thanks for looking up my details. If you have just had a QSO with me, I appreciate the contact and hope we can meet again especially on other bands. My main interest is working DX on HF, mostly on CW and data modes, but you might catch me on SSB.

Please respect what CQ DX means.

On CW, if I am calling CQ DX and you are in Europe, then please wait for several calls before replying. That allows me to work any DX first. If there is a lot of DX, I will focus on the DX first taking advantage of what might be limited openings.

On data modes, if I am calling CQ DX and you are in Europe, please do not reply!
CQ DX means outside of Europe. Calls from EU stations cover weak DX signals and hinder me trying to work DX. I will politely send "DX ONLY PSE" or "DX OUTSIDE EU" as a hint that I will not answer an EU station at that time. Please be considerate and respectful of this. Thanks for your cooperation.

Please don't call on my TX frequency while a data mode QSO is in progress. It usually results in me having to ask for repeats and delays the other station and me from completing the QSO. If you want to call me during a QSO, please use a different frequency and I will reply to you after the QSO completes. If I don't respond after a couple of calls, try split either up or down. I may send "SPREAD OUT" if I can see reasonable strength signals on the waterfall but get no decode. FT8 seems to be very intolerant of multiple callers on the same frequency.

I used to be an electronics engineer before moving into computer software in my mid-twenties, and a keen SWL. However, I only got licensed in September 2002, initially as a foundation licensee, M3DHO. Passed the RAE and morse test Dec 2002, and became a full licensee, M0DHO, in January 2003. Better late than never.

My rigs are an Elecraft K3 (S/N #4986, main station rig) with P3 panadapter, Elecraft K2/100 (S/N #4030) and an FT847 (mostly used on 6m and up). I built the bare K2 in Jan 2004 and had great fun operating QRP CW using simple dipoles from my earlier QTH. In March 2005, I built the KPA100 option and the K2 was my main HF station rig up until Xmas 2010 when I got the K3. I also have an Ascom converted for 4m, and some QRP rigs constructed from kits or home-brewed, mostly for 80m. I also have an Acom 1000 linear.

I moved to my current QTH in Crookham Village near Fleet in August 2004, prompted by neighbours at my previous QTH being intolerant and hostile towards the hobby. The new QTH has a lot more space and tall trees. If you look at Google maps you might just be able to see the tower.

QSL via the RSGB bureau, direct (please enclose SAE and IRC or green stamps), or LOTW. Usually my day's QSOs are uploaded to LOTW at the end of that day. If you do not have an account set-up for LOTW, I would encourage you to do-so. It's free and saves a lot of effort and money for QSLing. I also upload data to eQSL and Clublog as a service to those of you who use it. However, since these do not count for DXCC, please also send a QSL card or submit to LOTW. I reply 100% to all QSL cards received if they are in my log and if they can be returned via the bureau or enclose SAE and postage. Note: Unless there are exceptional reasons, if you send me a QSL card direct without an IRC or green stamps, I will reply via the RSGB bureau. Sorry, but it becomes too expensive to pay £1 postage a time to reply to cards that in most cases are not new countries for me for all the direct cards I receive.

Thanks again for the contact. I look forward to meeting you on the air.

vy 73 de David, M0DHO.


Some details of my station, projects past and present...

Current antennas are:

  • 4 element SteppIR with 30/40m dipole option at 18m (60ft), (upgraded from a 3 element in July 2008)
  • Inverted L for topband fed against more than 400m of ground radials
  • Dipole for 80m and 60m, only up 12m but great for short skip contacts
  • Monoband vertical for 80m, fed against 34 ground radials
  • Slim-jim for 4m up about 15m (50ft)
  • 7 element LFA monobander for 6m on the tower at 19m (63ft)
  • 9 element Tonna for 2m on the tower at 20m (65ft)
  • 13 element Tonna for 70cm on the tower at 20m (65ft)
  • K9AY receive antenna

Replaced vertical for 80m after a storm brought down a limb of a nearby tree through the guys and smashed the fibreglass telescopic pole into three sections.

Put up a dipole for 60m. I have a NOV for 5MHz.

Changed the rx transformer in the K9AY loop to use Amidon type 73 binocular core. Response frequency range better and lower common mode coupling. Looking forward to better RX on 80m and 160m.

I completed the rebuild and resiting of my K9AY receive loop. I built a new remote switching box using a PCB of my own design and manufacture. As well as the loop switching, it allows for remote setting of 8 termination resistances, and can switch out the loop during TX. I built a new controller, again using a PCB of my own design and manufacture. Since research had shown that reducing common mode currents along the antenna feed and control line, put plenty of ferrites long both over the 25m of cable run. Seems to be working much better now.

Completed a project to put up an 18m vertical for 80m. Most of the effort was putting down 34 ground radials totalling about 600m equipment wire. The vertical is linearly loaded by winding wire helically down an 18m fibre-glass mast.

Earlier in 2010, I put up a 7 element loop fed array (LFA) monobander for 6m. This was completed at the end of March ready for the Es season. This helped to boost my country totals on 6m, but sadly the multiple-hop Es season ended earlier than normal. I hope to give this another serious go next year.

II had the 3 element SteppIR for about two and a half years and have been very pleased with it. In 2007, I decided to upgrade the tower and antennas and starting planning how to do this. I finally completed this project in June 2008.

In September 2007 I bought a second hand Westover HD3 that was in need of some TLC but was otherwise physically sound. The first job was to strip the tower of all bolts and pulleys and straighten some bent struts with a mallet. All the welding looked in good condition and the tower sections themselves were straight and true. I then cleaned the sections with steel wool and treated them with Galvafroid, a zinc-based galavanising treatment. Three of the large pulleys had standard metric bearings that I replaced with new ones. The remaining pulleys did not have proper bearings or bushes so did not run very well. Paul Cullen, G4KTZ, helped to machine out three of the pulleys to accept standard metric Oilite bushes. Other pulleys could accept Oilite bushes without too much adjustment. Paul also welded up a frame out of 50mm angle iron that I bought to form the anchor for 6 M20 x 500 threaded studs that would be encased in concrete for the tower base. Thanks Paul! The main pivot bar was in poor shape. It was supplied as an engineering stud but the non-threaded part was too short and the tower had worn down some of the thread. I made a new one out of some one inch stainless steel bar I bought. I tapered one end with an angle grinder and then drilled out to take a Cotter pin at each end. I also managed to get some marine grade washers to fit over the bar. I bought two Fulton K2550 winches, one for luffing and one for raising the tower. I made a heavy duty bracket for the luffing winch out of 10mm thick angle iron I scrounged free from a local scrap metal place.

The hardest work was doing the base for the tower. I dug out the soil by hand and dumped the soil elsewhere in the garden. The hole was too far away for ready-mixed concrete. So I barrowed 5 metric tons of ballast and 800kg of cement in a day to right by the hole. On a later day, it took about 9 hours to mix the two and a half cubic metres of concrete in my cement mixer. A very tiring day! Left the concrete to cure for 3 weeks.

Assembling the tower and getting it cabled up was a little tricky. My son was there to help me lift the bottom section over the top of the base to get the pivot bar in place. However, he wasn't available to help with the other sections. Lifting the middle section (90kg) and top section (85kg) in and sliding them in single handed was possible but not easy! Put on the refurbished rotator cage with a Prosistel PST61 rotator in.

The final job was to assemble the 4 element Steppir. It's a big antenna. I left off the fibreglass housing elements and built the boom and truss assembly. With two people, it wasn't too bad getting the stub mast through the thrust bearing and rotator clamp. Thanks Graham, G3XYX, for the steel scaffold pole! Then added the 30/40m dipole and other elements. Space was very tight with neighbouring trees but it just fit. Last job was to tidy up the cabling from the top of the tower to the shack. The satisfying completion of a long project.

8554512 Last modified: 2018-01-02 20:24:07, 9644 bytes

Login Required

Login is required for additional detail.

You must be logged in to file a report on this page

Please login now...

Public Logbook data is temporarily not available for this user
ad: giga-db
Copyright © 2018 by QRZ.COM
Tue Feb 20 23:50:39 2018 UTC
CPU: 0.049 sec 65714 bytes mp