Spreader drilled and tapped

I had some issues drilling the spreader, I thought the drill would go through the copper like butter, that is partially true, but as this is a very thick piece I’m drilling, it grabbed the drill and twisted it. I had two 2.5mm drills twist to bits and I could not get them out of the hole. This actually happened on the first hole I drilled, so I ended up moving the whole PC board 2mm to the side. Now I marked the MRF150’s and I think it’s very important to mark them first, drill and solder afterwards so there will be no forcing of the pcb when they are clamped tight. Unfortunatly I broke on drill in one of the mrf150’s mounting hole, but I could drill the hole and tap it. I hope I did not damage the tapping drill, as a bit of the old drill was wedged in the hole!. secondary plan was to widen this one hole to M4.

Here is a picture, this was surprisingly badly drilled – I blame not having a proper tool to mark with ;P

here is a picture of the “handywork” – put some lines over to see how it really went, it’s still withing tolerance and the mrf’s are clear of the PCB, and no forcing when taped down. I used M3 screws – and for that I think you have some room for “mistakes”

600w update – pdf’s

Here are some excellent pdf’s from the father of the EB104



Motorola-600 Watts RF Power FETs EB104

And here are some of the best links I have found:

crazy italians (must stop this music!): http://i5uxj-2.cln.it/amp/amphf150/amp150.html

This is a good page, if not the best.. : http://www.g4apvweb.pwp.blueyonder.co.uk

One more: http://oh8jep.kotinet.com/eb104.html

This is perhaps not to par, don’t understand how this was posted in QST: http://www.w6kan.com/ssamp.html

Here are EXCELLENT pictures of the EB104 assembled: http://www.k6if.com/gallery2/main.php?g2_itemId=1768 This is the project page: http://www.k6if.com/ssamp/

Update Nov 20.

So, day7 in the H1N1 swine flue s***… just starting to gain consciousness

Got my way to expensive Mouser order today – happy that the FedEx charge was 0.00 usd… so they just smeared that on the rest of the components. Only reason I used Mouser was the selection of 1000v silver-dipped-mica capacitors, they seem to carry the best stock of these very expensive components.

So, now I have the following:

  • Amidon toroids + some nice high quality wire
  • PIC + LCD + some thermistors.
  • Filter capacitors
  • PSU filter/ripple capacitors
  • power transistors for the regulator
  • EB104 “kit” – now built – will blog specially about that
  • Copper spreader – Old friend works at workshop that produces switches and other high power stuff for the local power companies, they have ton’s of VERY nice copper stuff, was very happy to remeber this old friend.

here is a gallery link: 

As you can see I have started construction of the chassis. As I don’t have any good “sheet” bending machines I opted to build the chassis from 10mmX10mm aluminum square axles.. don’t have the English word here 😉 I tried using some aluminum “brazing” tech called durafix. My impression was this was like these products on TV market, look good but are really shitty…. and unfortunately the latter was true, so I ended up going to a shop with a TIG AC machine to point-weld this.

Now my brother, who happens to be the secretary of the Icelandic Radio Amateurs has asked me to give a short lecture on this amplifier business next Thursday, so that forces me to put something down on paper, and design this properly. So some Viso/power point drawings will be made. I was just thinking how good It would have been to have a proper block diagram with good checklists.

I started work on the PIC control circuitry, hooked up the LCD and testing out some A/D -> LCD. I asked my wife if I could select my xmas present, and she said YES… so I ordered an ICD3 PIC programmer. I have been wanting to build or buy a ICSP programmer so I can fully apply my trial and error method of programming

WordPress problems…

This is a new version of the site…

after having very strange stalling issues with WordPress,  when loading the page, it would just wait 10-15s before anything would be transferred out of the server. Tried disabling all addons, etc.. In the end, I just downloaded newest version of WP, theme and some plugins.. seems to work now. Manually transferred over – so I would not carry over some shit from the previous install…

600W process report

This is based on the Motorola EB104 bulletin:


  • EB104 amplifier board ordered from Communications Concepts, including 4x MRF150
  • Omron 12V Relays ordered from Ebay – used for TR switching and filter selection
  • Toroids and accessories orderd from Amidon
  • Large heatsink gotten from my father, TF3T
  • 1200VA toroid transformer was bought in my trip to Shanghai – loong story there!
  • Going to order some silver-dipped MICA capacitors and PIC MCU + filter capacitors from www.mouser.com

Still need:

  • Copper spreader
  • 12v cooling fans
  • Hardware
  • Heatsink for the PSU – asking locally

Next thing is to build the case

Going to build it from Aluminium parts available locally, have made some sketches in AutoCad, but it’s hard to draw it exactly as I don’t have all the components in hand, and don’t know the exact dimensions of some of the components.

Project start – 600W 1.8 – 30 Mhz Linear Amplifier

I have been planning to build a 600w linear amplifier to use on the HF bands.

Why homebuilt??

I have been asking my that question many times. If I have to order a commercial built amplifier I have to give out at least $1500-2000 USD. That will put a dent in the home budget and my XYL will notice big spending’s like that. Homebuilt projects usually consists of many many small orders! 😉

But I really like to undertake a project like this, there are many aspects to this project. Mechanical design, DC power supply design, RF deck, Filters and control circuitry . I have been playing around with programming PIC MCU’s and have decided to use one of those buggers for control and protection circuit.

Why use Transistors. Why not go for the ever so simple, reliable, tolerant Vaacum tube design?

I don’t like working with HV circuits. Don’t understand the theory behind the tube amplifiers. And the challenge is mostly mechanical !

Availability of parts here in Iceland is very poor, so I have to order most components online.

Design principles:

  • Single chassis for now – can be modified later on if I decide to double the power output
  • 600W Output.
  • Manual and remote bandswitching – using the BCD interface from my Kenwood / Yaesu
  • Protection: Over voltage, Over current, Over drive, High reflected power. Over Temp on PSU and RF stage. ALC back to Exciter.
  • LCD display – showing vital amplifier stats. (just me playing around with the PIC)

Project timeframe is from now to the finished project. I really hope to test the amplifier around Xmas 2009…  now the component collection phase starts.

Fyrstu loftnetspælingarnar!

Jæja, þá lánaði Pabbi mér TS-570S, fínasta stöð

Þá er málið, hvernig skal maður koma sér í loftið. Ég bý á jarðhæð í blokk í Grafarholtinu, svo það er nokkuð snúið að koma sér í loftið.

Ég ákvað að byrja að koma mér í loftið í skjóli næturs, þ.e. setja upp loftnet þegar rökkva tekur og krakkarnir hættir að leika sér í “garðinum”. (það er allt hverfið þarna).


Hér má sjá mjög aumingjalegan vertical, með hustler 20m spólu sem TF3T lánaði mér.. smá radíalar og stög.

Fyrsta kvöldið heyrði ég bara ekkert nema surg og læti, rétt náði QSO við TF3SG á 20m. Nú í kvöld prófaði ég að skipta út switch-mode PSU sem ég nota yfirleitt til að hlaða stór LiPO batterí í RC sportinu, setti hefðbundið supply sem notast við spennubreyti – og vola! ekkert suð, en aðeins 50W possible! Nú vantar mig almennilegt supply

Ég er nú byrjaður á næsta projecti

það verður Inverted-V, verður sett upp með 5m mastri …í skjóli næturs ;P

ég byrjaði að búa til 1:1 balún…

13 vöf af 14awg vír, …hvernig lýst ykkur á ?


Komið í kassa.. ég náttúrlega tóks að klúðra þessu, stytti vírana of mikið…


Þá koma nokkrar spurningar.

1. Er svona rúst-frítt / ryðfrítt efni eins og ég notaði í úttökin í lagi ?

2. er í lagi að lóða svona víra saman ? ekkert issue með leiðni?

3. hvernig lýst ykkur á ? ;P meikar þetta sense til að hafa í toppinum á inv. V?