Create CB-3F/2K Balun

Yesterday I have problem with my three element yagi - Create 318jr that intermittent of high SWR occur. I dismantled the balun and checked that the colour of the wire changed, may be the result of handling high power all the time. I need to replace another balun or repairing the balun this weekend.

Volta RTTY contest Award

Recently recieved this nice certificate through mail.

JARL 2008 ALL ASIA DX CONTEST - PHONE

JARL ‘All Asia DX Contest’ is one of my favor contests. The contest period is Sept. 6-7, 2008.
During the contest, stations exchange RS report plus operators' age. I have decided to enter the category as SO20HP, but finally moved to SOABHP. As a result, made 844 QSOs and have the score 82343 points.
The eldest operator age logged is 89 and youngest is 15

VR10XMT RTTY Award

Here are two RTTY contest awards for the Prefix "VR10".

4X4DK QSL Card

Ami, 4X4DK sent me the QSL card for our six meter QSO. Many thanks.

AP2DKH QSL Card

W2FB Steve, QSL Manager of AP2DKH sent me the QSL card to confirm the great six meter QSO with Dr. Khalid.

Many thanks.

50Mhz opening to AP and 4X

Good six meter opening to AP and 4X on 26 Jul 08.

Worked:

AP2DKH 0627z 50.163
4X4DK 0638 50.168

Look forward to have more opening soon.

Digital Terrestrial TV Reception

Since the launch of DTT services on 31 December 2007, the first phase of DTT services covers the northern part of the Hong Kong Island, the Kowloon peninsula, part of Shatin and the eastern part of the Lautau Island, amounting to around 50% of population in Hong Kong. My home is located in northern part of New Territories, so need to wait until mid of July, 08.

Last week, I purchased one decoder and connect it to my old "Sony" TV and test the reception before making any decision to but new HD TV set. The decoder start to search TV program when power on and finally all 13 channels were shown up. Signal strength is in between 57-60 % , not bad.

The next step is searching around a suitable HD TV .

3-500z flash over

One of the 3-500z experienced with "flash over" problem recently. I am not sure if the tube already damaged or it can re-condition with burn-in procedure apply.

I plug in the tubes (both V1 and V2) into an empty chassis, with only heater voltage connected, no HV. I have observed the V2 (flash over tube) heater not light up correctly, compare with V1.

I have no idea why it is, need to check later.

2008 IARU Contest

Over the contest weekend, the band condition was really terrible. It also happened that thunder storm during the Sunday afternoon time, I need to switch off the radio and unplug all antennas.

Of course, the scores was very poor ...

FT-2000 Remote Keypad

FT-2000 has 4 voice memories, which is a convenient feature for me during contest. However, I find it inconvenient to hit the F1 - F4 function keys with my big fingers. The alternative is to buy the remote keypad FH-2, but consider it is very expensive.

Information from the net that the keypad is a combination of push button and resistors, which make it as voltage divider and it is the same as the previous model FH-1, see attached circuit diagram and resistor values.

The original FH-2 keypad has 12 buttons, which are for other functions. My application is for F1-F4, so I decided to make the keypad as simple as possible by using a plastic box, with 4 push buttons. It works fine and ready for the IARU contest.

RDXC 2007 Award

I am happy to receive the RDXC 2007 Award.

13th Place - World and of course Country Winner, because no other VR2 participate in this Category.

I3VHF - Baby Loop Antenna

Recently I got the I3VHF Baby loop antenna from Horst, VR2BT. He is going to move QTH and no more room for this antenna. The loop antenna is quite heavy and well designed. Control open and close to the variable capacitor by using a mouse connected to the controller.
I have installed it today. It works fine from 10M to 40M, performance close to the dipole.

Six Meter Open to EU

At 0659z , six meter open into EU.
SP8AWL replied to my CQ call on 50.115 Mhz. Then followed with SP7CDG at 0702z.
At 0723z, SV2DCD coming up.
This is the first time EU QSO in Cycle 24.

FT-2000 FSK connection

Last week, I connected the FT-2000 with my homebrew interface, which use the opto coupler 4N32, for RTTY FSK keying. Calling CQ for quite some time without any reply and finally find out thatI wasn't getting any shift.

I've used this interface on other radios over the years with no problem, including FT-920, IC756pro and FT-990. Finally I solved the problem, by the help / information from one of the member in the FT-2000 newsgroup .

The 4N32 opto coupler has a 0.50 volt plus collector "on" voltage which is OK under the usual TTL "low" state and has keyed all my other radios with no problem.

The FT-2000 requires the low or "ON" state to be less than 0.4 volts in order to key the FSK line.

I replaced the 4N32 by a 4N37, which has 0.3 saturated voltage (VCE sat) and it works perfect now.

I believe the FT-2000 is the first of the Yaesu radios that makes extensive use of 3.3 volt (low power) CMOS logic. The "low" requirements of the low power CMOS devices is considerably less than the old CMOS and TTL (most of which worked below about .65 volts). The standard for low power CMOS is down around .3 volts

C52C - The Gambia 2007 DXpedition

I am one of the lucky station in Hong Kong worked C52C on 40M in the Gambia 2007 DXpedition operated by the OM0C contest team. On 24 Oct 2007, by chance I can stay a little bit longer at home early in the morning, normally I need to leave home at 2200z. I made the contact with several calls, two many competitors (JAs).

Today I received the nice QSL card.

CQ World Wide WPX Contest - 2008

Over the weekend, participate in the CQ World Wide WPX Contest, 15M High Power category. The propagation on the first day was terrible, no signal heard from EU, but JAs are workable. The score on the first day was very low and only achieved approx. 300,000

In the morning of second day , the situation was almost the same, and could only work JA, YB, BY, UA9 and with several station from Pacific.

In the afternoon, start from 0700z, EU signal going up and maintained good condition until 11:00z. I am very lucky to catch this opening and boot up my score just over my last year record. Final at 865,686

The equipment used during the contest are:

Yaesu FT-2000

Create 318jr

Heathkit SB-220

2006 UK RTTY Contest Award

The award finally arrived on today. I need to wait more than two years for this nice colourful award issue by GM4FDM.

Russian DX Contest 2008

Over the weekend, participate in the Russian DX contest all band-phone.
I have been in this contest started from 2005 and have fun with it.
With the low solar activity, band condition was poor. My score not as good compare to last year.

TX5C

With a simple trap dipole,which is only two meters high on the roof, I was lucky to catch TX5C on 40M at 1428z on 9 March. It is very difficult becasue of JA wall. I need to call almost for an hour to get it, new one for me on 40M.

I hope to have them in the log on 20M and 17M. Watch and wait for good propagation ...

Palestine E4/OM2DX

The QSL card arrived yesterday.

Band condition was poor lately, only worked them on 20M.

Porsche and Jade with RED PACKETS

As promised, Martin and Anni gave Porsche and Jade the "RED PACKETS" for the year of RAT. They like it very much but Jade walk away when taking photos !

Six Meter SB-220 Rebuild

Steve, VR2XMQ gave me the SB-220 when the time he moved QTH. The amplifier was modified to six meter by one of the ham in the United States. However, the amplifier experienced with problem since it arrived. In the first instance, the HV meter was damaged in shipping and flash over when switch on, which finally proved one of the 3-500z have problem. The outlook of the amplifier was bad, most of the screws are rusted and internal wiring is in a mess, overall it is not a professional workmanship.
The amplifier was sit there for sometime and few weeks ago, I decided to re-build the amplifier and make it ready for cycle 24 for some DX in the magic band.
Here below are the major improvements:
1) repainted the power and filament transformer and inside chassis
2) replace most of the rusted screws
3) replaced all eight HV filter capacitors to 270uf 450V 105 degree C
4) replace the HV rectifier board completed with eight 1N4007, which used as the 5.1V bias zener diode
5) replace two panel meters
6) replace the load capacitor
7) add soft-start and soft-key
8) replace the burnt safety choke (8 mm Teflon rod with approx. 60 turn of SWG 22 wire.)
9) replace one 3-500z
10) refine the input SWR
11) tidy up all internal wiring

With AC mains supply at 207V, it gave out 900W with 100W drive. It can be more if AC voltage up a little bit. Now it is a 100 percent working amplifier and ready to go.

WPX Phone Contest 2007

Another achievement for WPX Phone contest 2007. I am very surprised to be no.1 in Asia for 21 MHz . I will participate in this year contest again, still not decide which band to go, may be 14 MHz?

Contest Award

Very happy received ARRL International DX contest Award 2007 on today.

Power-on delay PCB

I made a new power-on delay relay circuit (soft-start) PCB yesterday. The zener diode which create a high turn on voltage for the Darlington connected transistor pair. The delay is approx. 3 seconds using 47K resistor and 100 uF capacitor. Longer delays can be obtained with a large capacitor.

GI7B Six Meter Amplifier Project - Update 9

It is connected to a BIRD Dummy Load (Model 8401) and 43 Watt Meter and easy tune to approx. 700W output. End of the project. Look forward to hear you on the magic band.

GI7B Six Meter Amplifier Project - Update 8

First RF test and found the tune variable capacitor totally meshed out, then I removed few plates and measured the capacitance is in between 4.5 to 10 pF. The tank coil also cut one Turn, now is 3 turns. The load capacitor is half-meshed, just fine.

After that, test Starting with 5 W of drive from a TS-600, gave 85W on the output first time, which equal to about 12.3 db gain.

Increasing the drive up to 10W brought 150W output, equal to 12.07 db gain.

I stopped at this point because the 150W dummy load already very hot, will test later with a high power one.

I also installed the top cover with ventilation holes.

GI7B Six Meter Amplifier Project - Update 7

Last evening round up all connections and perform initial test at the input SWR. At firs, the SWR is quite high with 1:3 , modified the coil to 4 turn 13 mm dia. with good result at 1:1.2.

After that, connect plate voltage and measured the plate idle current at 80mA, which indicated it is correct.

Now the amplifier is ready to go for load test.

GI7B Six Meter Amplifier Project - Update 6

Logan (VR2XRW) gave me a 10mm ferrite rod for the filament choke, it is in place all together with the input tune, consists of two Arco variable capacitors and 15mm dia. coil.

The GI7B tubes are in place. They were supplied with the filament votlage for few hours.

Front Panel

Plate Voltage and Amperes meter installed on front panel, it fit well and look good.

The meter at right hand side showing 2050 V DC, scale need to calibrate later.

GI7B Six Meter Amplifier Project - Update 5

The high voltage supply was wired up.
AC 220V input to primary winding (240V) and secondary measured at 800V tapping is 730V. After rectifier and voltage doublers, measured at 2050V DC. It meets with the plate voltage of the GI7B.
The soft key and bias board PCB is mounted at the bottom, nearby the T/R relay.

Plate Choke

The plate choke is made from 50-turns, 22swg(purchased from UK), close wound on a 80mm length of 20mm PTFE rod(purchased from Apliu Street)

It is tapped hole in one end for support.

GI7B Six Meter Amplifier Project - Update 4

Last evening I have completed the high voltage board as well as placing the high voltage transformer into the chassis. The high volatge PORCELAIN insulator and safety resistor (47 ohm 50W) are also in place.

GI7B Six Meter Amplifier Project - Update 3

In the past couple of day, the six meter amplifier project moving very slow.

1) I have made the PCB Board Fabrication for High Voltage and Soft Start. This weekend, will go for the Software Key and Bias PCB.
2) I also drill two big holes for the front panel meter High Voltage and Plate Current meter. Although it is a tough work, which took me an hour to complete, it looks very nice.
3) I cut 80mm Telfon Rod of 20mm Diameter for the plate choke. SWG 22 wire expect arrive from UK within this week.
4) I bought one 12V 10A contact rating Omron relay from Apliu Street, which is for the T/R switching.

From the photo, you can see the soft start PCB mounted on the bottom of the chassis.

GI7B Six Meter Amplifier Project - Update 2

If is quite difficult to get small diameter of copper tubing. It needs to buy at least a roll of several meter of quantity. So I give up this kind of material. Looking around and thinking of using surplus short length of hard line cable, center conductor is 5mm diameter. Wound 4 turn, inner diameter 40mm.
Doorknob capacitor is 1000pf 15KV purchased from Mainland China.

GI7B Six Meter Amplifier Project - Update 1

Yesterday went to Canton road to cut the aluminum sheets for the front panel and partition for the chassis. Six pieces cost of $215. I also locate one winding transformer company and ask for the quote for a 1000VA transformer at a reasonable cost. Size is approx. 6”x6”x6” and delivery time is one week. I told the shop will prepare the specification and order next week. What a surprise that they have transformer oil (for my HN-31 Heathkit dummy load) in stock, which is very rare and difficult to find here.

The major component is ready and has tried to place them on the chassis and it looks fine.