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Friday, 31 December 2010

QRP2004 Build day 1

Here starts the log for the build today easy first day.

I'm creating the PCB and my process is to use press and peel film (Maplin AB15Rso I use the REVERSED images of the CU layer you can obtain either from the qrp2004 project team website ( the yahoo group ( Printer is a laser doesn't work with an inkjet printer, Samsung ML-2240 and I am printing 1200x1200 dpi and as DARK as I can get it.
Make sure you check the print size is right. I used a 40pin DIL socket and couple 8 pin DIL sockets to check the sizes. Mine I had to print at 107% size. Print to normal paper until you get the size right.

Anyway I have 7 nice pieces of blue film ready to use.

It is still cold out so doing the rest of this in doors.... (except the etching)

1. Cut out 7 pieces of PCB sized to fit. Mine are slightly oversized.
2. Clean them of all grease and finger prints (I use Acetone and then fine wire wool and emery paper in a circular pattern). You end up with 7 shinny pieces of PCB. Now clean all the wire wool or emery paper remnants away
3. Iron on or feed the sheets and PCB through a laminator (I will be testing the later option on another build).
4. Allow to cool, peel off the film.
5. I use black marker (permanent) on the top ground plane side, you can use close fitting tape etc... your choice.

Outside now in shack...

6. Etch. You do not need a tank but I home-brewed one from a fish tank heater and aerator pump. I use either Ferric Chloride or some clear etchant. The home-brew tank I set the solution to 35degrees C and let it bubble away for about 35 mins and the boards are usually fine. Wash the boards with water and allow to dry.
7. You have a choice: either remove the etch resist pattern off the boards now or wait until after drilling the boards. I will tin mine (you do not need to) so will remove the etch resist and the tape or pen from the other side and I use a dip solution, you can tin too by chasing a bead of solder around the board (hint this is much easier when NOT drilled!). If not tinning and if you remove the resist the copper will tarnish quickly so you might want to use a flux spray like KS10.

Now the boring bit... drilling c900 holes! This might take a while.
I use a Dremel in a stand (the task is hopeless if not in a stand) with 0.7mm drill bit. Note some holes will need to be enlarged will cover those in later posts.
Drill all the 3mm holes for the mounting and the other 4-5mm holes for the TO220 and other transistors.

I think the drilling holes is why so many home-brewers have moved over to SMD...

I'll post some photos later.

You can use a photo resist and print the CU layer images to sheets and expose and develop etc... but I have not done it that way but many other homebrewers do.

Thursday, 30 December 2010

How to make a CW QSO

The original site at has disappeared so I post that page here for reference for those trying to get started in CW.

A search for zs6ez on QRZ:
Born 1964, licenced 1980 as ZS6BCR. I've basically been inactive since 2000, due to other commitments. I hope to resume some ham radio one day. My main interest was in contesting, where I held several world and continental records in the single band category of CW, RTTY and Phone contests. I attended WRTC three times, as W6O, OJ1W and S572L. I ran a series of DXpeditions in the Eighties and Nineties, emphasising low band, WARC band and RTTY activity. You may have worked me from 7P, 3DA, A2, IH9, V5, ZS0 or ZS9. I also once did a bit of DXing, with 10BDXCC, 5BWAZ, 5BWAS and Top of the DXCC Honor Roll. I've slipped down a bit with the most recent additions, but maybe I'll get up there again one day. In the mean time, I'm working on my DXFC score (see while flying business jets as a South African Air Force volunteer, playing with my daughter, holding down a real job, working on my PhD, managing a small group in our local church and running a flying school.

How to make a Morse Code contact...

The original is back up on a new site, here is email from Chris about it.
----- Original Message ----
> From: Chris R. Burger ZS6EZ <chris@********>
> To: Dominic Baines <dombaines@********>
> Sent: Fri, 31 December, 2010 1:02:57
> Subject: Re: Fw: [GQRP] Re: OT? Morse procedures...

> > Other emails used all bounced...
> To this address,or did you use an  obsolete address? I'm not aware of a
> problem with this address。

> >  Please let me know if this is a problem.
> I would prefer if you linked to the  actual article:

> That way,if I  make changes they will show up。Also,Google is more likely
> to pick up the new  address if you link to it。

> The original domain name disappeared,so I  suddenly had to establish a new
> one。 All the original content is  there。

> Regards

> Chris

Tuesday, 14 December 2010

QRP2004 Build

I have had a few questions about this project ( for details) so I will start a build from scratch and blog it here starting in the new year (i.e. 2011).

This is the designed polyphase network for the QRP2004

Copyright © 2004 - 2005 by QRP2004 Design Team

The project design team include details of the design and method where you can look at options using different components (depending on what you have to hand), using different components the results are:
(RED) C=33nF, R (Kohm) 12,10,6.8,3.9,2.7,1.8,1
(BLUE) C=10nF R (Kohm) 47,33,22,15,10,6.8,5.6

See the project docs for details.

QRP2004 Web Site:

Sunday, 5 December 2010

Mag Loop

Just posting this as not QRT.

The WX here in Mechelen (Belgium) had been snowing for the last week. So I have taken a mag loop antenna built by Clive (M5CHH) (from G4TPH design) I have put it up suspended in the open door way out to the patio.

I determined that the door was 100% uPVC not metal framed and there does not appear to be any chnage in coupling with the door closed or open. The sealed windows are some metal looking but doesn't seem to effect the loop.

Just thought you might like to see these:

This is the loop on 40m :-)

This is the loop on 30m :-)

This is the loop on 20m :-)

I am about to go out to find a place were I can get some AA batteries for The 30m QRSS beacon I obtained from Han (G0UPL) and Steve (G0XAR). So hopefully ON/M1KTA should be QRV on 30m shortly.

The land lord still will not allow an external antenna so this looks like a good option.

BTW the pictures grabbed from MiniVNA Java software. Putting it on a contunous loop makes tuning dead easy.

Not tried a different balun that will give me 10m yet. I used 10 x 400mm legs to make up the loop. I'll post a photo soon.

I'll run it with the FT817 later.

Saturday, 30 October 2010

Quick and cheap dummy load for QRSS/QRP TX

In Belgium and don't have the rest of the homebrew shack with me but needed a dummy load and ability to measure the RF levels so knocked this one together.

I grabbed a tiny strip of veroboard and 20 1k 1/4 resistors, 15nF capacitor and a 1N5711 diode.
It is 2 sets of 10 x 1K resistors in parallel so 50 ohms. The diode and capacitor follow the dummy load so can use a cheap typical DVM to measure the RF voltage.

The 1N5711 limits the power to about 15W but the resistors would frankly pop well before then.

The circuit is not original, neither is the idea and I do not claim any ownership in any way.... I built the excellent NorCal SMT dumy load a while back.

The basic design can use larger wattage resistors but if you want to do this for something that might last a while then ideally you use identical resistors. This would mean 2 x 100, 4 x 200 etc... A cheap 10Wdummy load is 44 x 2K2 resistors.

Back at QTH I have 4 x 200ohm 25W chip resistors in TO220 packages bolted to a heatsink using insulated TO220 washers and a little heat sink paste. There are others that use these suspended in mineral or olive oil for QRO use (check out . I planned to bolt an old CPU fan to the heatsink to increase run time but mine never gets that hot.

Monday, 11 October 2010


Was sent this image of a QRSS homebrew build.
I then did a double take... it's from ET "Phone Home"



just melted solder on this

Tuesday, 14 September 2010

Another K1 Build - this one will be mine this time.

Various shots going through the RF Part I build.

The Front panel and filter board already built.

The extensive home brew bench.

Sunday, 12 September 2010

FtTuthill80 Build

Kits components as sent.

Following the pdf instructions of Dan Tayloe, N7VE

These are the build images from the kit I just started to build.
Up to the power test (used a 9V battery) and the blue LED lighting.

Blue LED


Sorting the 0.1uF caps

0.1uF caps

More caps

And more



More resistors

More resistors

Applying 9V.

The LED lights blue.

Elecraft T1

Was recently given an Elecraft T1 auto tuner kit and as now working in Belgium thought I'd make it up. First started in hotel room.


The portable 'homebrew' bench is perfectly adequate. Note I have brought a 12" square of PCB to build on.

Initial components going in.
Relays fitted.
Fitted the underside capacitor.
Fitted the sockets and headers.
Built up the control interface.
First fitting. Looks good so far however, visual check of all the components against the build list and couldn't work out why had extra FT37-43 torroid. Then remembered there is an errata...

Oops... errata clearly state use 2 FT37-43 cores for T2 not 1.
No harm done, removed T2 and added the new T2 fitted easily.

Removed the PIC, added battery, checked the voltage through the 2N3906 when tune/pwr switch depressed and onto the regulator says 6V.

Added PIC and tested the power on, seems to be fine. Will test again once have working TX with me in Belgium.

Thursday, 5 August 2010

dBm Meters using the AD8307 logarithic amplifier

I'm having a go at building a couple of dBm RF Power Meter from AD8307

The first is W7ZOI design having found a nice 500uA meter at w/e there is a nice construction website here. Also note W&ZOI own notes on callibration here. There are plenty of variations on this design and the daa sheet and application notes from Analogue Devces are worth a read. Some like this one use an AF amp to provide an audible feedback too

Part of the circuit from the design from N2PON (QST August 2008) uses temperature compensation. Basically he divides the pin 4 output of the AD8307 that is fed to a DVM through a resistor network containing a 10K pot that adjusts the GAIN to achive c1mV/dB with an NTC temperature compensating thermistor (c1K at 25'C) connected to ground so if there is any temperature changes the instrument retains a level of thermal callibration.

In many places this is not necessary but I know from experience my own shack does vary from -10'C in deep winter to +30'C in summer if it is unheated. Any meter is likely to be built into a die-cast box that will take a while to equilibrate too... so I am trying to use a thermistor salvaged from a PC motherboard (as had a few) with a 2k7 value at 25'C and c4K close to freezing and 500ohms when about 100'C (basically put it in boiling water and into ice water and measured). So I think could use it but would adjust the value of by placing resistors in parallel and series with to obtain 1K at 25'C.

Friday, 23 July 2010

Just back from Rhine trip

Some interesting post whilst away...

Seems I came 2nd in IOTA qrp category in EU005 during 2009 as I have a certificate!

Lots of QSl cards some go back as far as 2006, lots more 3B8/M1KTA.

An FPGA development board.

Anyway I'll be preping for the RSGB IOTA contest later and making a 12 our entry again then back to melting solder on the MOBO builds.

Monday, 14 June 2010

MOBO V4.3.4 SR V6.3 (Original) preparation

I just build a new SR V6.3 from scratch and added the headers for RX and TX IQ and beefed up the power.
I didn't have a 1N5422 but I have a 1N5408 instead and after a quick test then extended the diode PCB pads a little so not as 'tidy' as the little DO41 drop in replacement.

I did a scratch rebuild as the previous build had a LDVS version not a CMOS Si570 in place as a sample chip and could go to >260MHz and as this is for SDR-Radio development I will keep the build to 'vanilla' only.

I noted the MOBO kit seems to have plenty of jumper connectors so will make some up.

I will use a length of RG174 or similar for the RF and I will use some shielded audio cables for the RX & TX IQ.

Sunday, 13 June 2010


Images of the build.

I used a length of RG58 as the single turns through the binocular core.

I will also homebrew one of these using 1N5711 and discrete components.

MOBO V4.3.4 Mini Filter A Set

PCB made up and installed.

Quick test on a VNA shows the filters frequencies are about right.