Operator: Enno J. Korma, PF5X

Previous news
  • Back in The Netherlands again ...

    My last QSO as 9V1CW was on June 16th, 2006 on 15:01 utc with UA4FRL. I am now active again from our temporaty house in Malden with a 30m delta loop.
    Japan and Brazil were logged the first two evenings of my activity (Aug. 15/16th). So quite encouraging after the difficult condition in Singapore ... The delta loop even tuned on 6m, and I had a nice opening to the Balkan and Montenegro (new one !) on Aug. 19th.
    We will move to our own house sometime mid-September. I will be without antennas for a while until I build the station again. This time a 3-el SteppIR will be the main HF antenna. If the 4 el 6m home brew survived the 2 years of storage it will go on top again. I will build a combi-dipole for 30 and 40m to complete the stack.

  • Combi dipole for 30 ∓mp;mp; 40m ready and up !

    Monday October 16. Having moved into my own house again it's time to start building the station again. Beautiful weather and the urge to be able to work serious DX led to taking a day off. After some preparatory work in the morning I could finish all the mechanical and electrical details of this antenna in the early afternoon. So after cranking the mast down and tilt it, the 14m tip-to-tip monster could be mounted. Here are some pictures of it with some details.

    Caphat-trap assembly
    Capacity hat and 30m trap assembly with coil on 40mm PVC tube and coaxial capacitor
    Coaxial capacitor
    Principle of coaxial capacitor: 10mm OD alu rod with RG213 inner conductor/insulation
    Guying contruction
    Guying construction: vert. 1 m of angle alu (40x40x3mm) and hor. 1m, 32 mm OD PVC rod
    Antenna-to-mast clamp
    Antenna-to-mast clamp: 250x500x3mm Al plate, 40x20x2mm angle Al and muffler clamps
    Antenna at full height in sunrise light
    Antenna at full height in morning sun
    30/40m combi dipole
    Zooming in on the 30/40m combi dipole ...
  • Combi dipole did not hold against gust of 7 Bft ...

    Alas, the fishing poles are not strong enough to withstand the Dutch weather. The antenna broke on Wednesday November 1.
  • 3 elements SteppIR up and runnning !

    Today, Nov 12, the 3 ele SteppIR went into the mast with the help of Frank, PA7F (big thanks !).
    Transporting the antenna out of the garden to the top of the fold-over crank-up tower was the most difficult task. Once in the right position against the pole, it was easy to fasten the boom-to-mast clamp, securing the coax and control cable. After putting the mast upright and cranking it up, the great moment was there. SWR appeared to be almost spot-on on all bands. Some small pile-ups were quickly broken and reception was great ! The coming days more testing will be done and of course during CQWWcw I hope to test the antenna more extensively.
    I also strung out a simple 1/4 wave combi sloper for 30 and 40m. Not as good as dipole, but it puts out some sort of signal ...

    Assembled boom
    Boom as assembled in the workshop
    Cable tube
    The cable tube mounted slightly turned away from mast plate to make room for a wrench when tightening the bolts
    Assembled EHTs
    The glassfiber element housing tubes (EHTs): 5.30m each
    EHT joints
    Close-up of the joints: 1 layer of PVC tape covered with self molding silicone tape
    6m element (own material/home brew)
    6m element (own material/home brew): each half element = 1m x 13mm + 41.7cm x 10mm
    6m element-to-mast clamp
    6m element-to-mast clamp using PVC brackets
    Penetrox graphite grease
    With Penetrox graphite grease aluminium joints will last longer
    Oops, damaged EHU
    One of the EHUs did not survive the typical transportation shocks, due to absence of foam packing chips (peanuts). It resulted in a broken shaft of the CuBe spools.
    Joint with tierap
    To avoid "flagging" of tape, the tape wrap is secured with a tierap.
    Rubber boot with tape/tierap
    The rubber boots have a UV blocking wrap of silicone tape, with a tierap to avoid "flagging".
    3ele up with low tower
    The antenna in the mast just before cranking it up.
    3ele at full height
    3ele SteppIR at full height !!
  • 30/40m combi dipole V2 in the tower !

    10-Dec-2006 - 06-Jan-2007
    As a follow-up of my earlier experiments with a combi dipole for 30 and 40m (see Previous news), I have bought a second-hand Cushcraft D40 dipole. This antenna features a 13m tip-to-tip, shortened 40m dipole. It has coils and capacitor hats in order to shorten the antenna. After modelling this antenna with the described dimensions in the manual, it appears that the inductance is in the range of 10.9 µH, on 7 MHz.
    After some experiments I could dip the trap around 10 MHz with a coax capacitor (17cm of RG214) of 17pF. So the coil at 10 MHz has an inductance of 14.7 µH at 10 MHz. This is consistent with literature stating a fairly strong frequency dependance of the permeability of glass (note that the coils are wound on glassfiber tubing).
    The new combi dipole is slighty longer than the original D40: 13.68m tip-to-tip and will have a larger capacitor hat (144 cm tip-to-tip) on the inside of the coil (the original capitor hat - 87.5 cm tip-to-tip - was on the outside of the coil).
    See below for pictures of the various parts as the project progresses.
    The antenna is ready and has been tuned at 6m height. Some final adjustments were necessary to adapt for the stronger than expected dependence of the inductance upon frequency. When actual values are put into NEC2 again the inductance at 7 MHz is 10.9 µH. At full height the resonance frequencies are at 7.02 and 10.4 MHz. So, after modelling effective capacity hat spoke length is 62cm instead of the physical length of 72cm. However at 10 MHz this antenna is rather broad-band and its SWR is still 1.5 at 10.1 MHz, so I am not going to re-tune it for the time being.
    Here is the NEC2 file of the eventual antenna (save to disk and open with Notepad).
    The antenna went into the tower on 6th of January.

    D40 trap
    D40 coil modified to a 10MHz trap with a 17pF coax cap (15-dec-2006).
    D40 truss support
    Truss support (1.5m high) made of scrap alu angle stock, attached under bolts of one of the element clamps. Using this construction the antenna is self-contained including its truss (30-dec-2006).
    Combi dipole assembled along the house
    The new 30/40m combi dipole along the house; 13.80m tip-to-tip (30-dec-2006).
    Close-up of cap hat
    Close-up of a capacity hat. The original small alu bracket holds the hat. Not very rugged, so I added thin nylon guy-wires to the spokes to off-load windforce (31-dec-2006).
    CLose-up of the feed point. A current-choke type balun is used. Antenna impedance ~50 ohm on both 7 and 10 MHz (30-dec-2006).
    D40/30m in the tower
    The new 30/40m antenna in the mast just before cranking it up (06-jan-2007).
    D40/30m in the tower, fully cranked up
    D40/30m in the tower, fully cranked up
  • Storm Kyrill on 18-Jan-2007 and its consequences ...

    On Thursday January 18th we had a mean little storm in North-Western Europe. Though the average wind force was not that strong (9 Bft), the wind was very gusty with peaks of 130 km/h. This puts extra strain on the antennas. I had limited damage with only the 30/40m dipole bend. However I found out later that my rotator, a Create RC5-3, was also out of order. It acted weird in that it did not turn correctly having some dead points. Harry, PA3CWQ, sponsored me with loaning his spare RC5-3 so I could do a quick one-on-one swap. When disassembling the damaged rotator it soon became clear that one of the cast aluminium gearwheels was damaged ... The rotator will be replaced by an RC5A-3 which has steel gearwheels.
    The bend part of the dipole has been replaced by a new piece of alumimium tubing.

    Dipole bend by storm
    Bend dipole after storm Kyrill on 18-Jan-2007.
    Rotator damage
    Create RC5-3 rotator with broken gearwheel.
  • CQ contest ... (PACC & ARRL CW)

    On 10 and 11 Feb 2007 we had our very own contest hosted by VERON, the Dutch amateur radio league. It is a 24hr type of contest, but in view of the current state of the solar cycle that is long enough. Because it coincides with the WPX RTTY contest there is not that much of interest in this contest by foreign stations. In particular CW operators seemed to be dragged away by the internationally oriented WPX.
    I participated in the CW, low power (< 100 W) section as in previous years. Around Saturday midnight there were already about 700 QSOs in the log. But then activity got less and less ... With great difficulty I ended up with 1153 QSOs, with the last hours runrates of only 30Qs/hr. Many nice mults were spotted on 15m/RTTY, if they only would have taken the time to give us Dutchmen a call ...
    Anyway, my station seems to run fine with the SteppIR, 40/30m rotary dipole (40m was GREAT !!) and an inverted vee for 80m. Only 160m is a bit of a pain antenna wise. My property does not allow to string out sufficiently long radials in all necessary direction. So I had to deal with an inverted L and 2 folded radials. Good enough for some EU mults.

    I entered the ARRL CW contest (17/18 feb) for about 10 hours and had fun S&P-ing a bit. On Saturday I could raise a decent run on 20m, whereas on Sunday a late opening on 15m yielded a good run until after local sunset. Sunday evening late, after 506 QSOs I was reasonably satisfied and called it a day.