Hi All,

I received one of these for Xmas to build.

Has anyone else on here built one as I have a few questions.

Firstly, is the orientation of the Potentiometer important, as the doctmentation conflicts with itself? Is the picture below correct? In the instructions downlodable from the website (in Dutch BTW) it shows them in both orientations and unfortunatley i'm not clever enough to read the schematic and am just following the pictures and components location list.

Also someone mentioned the RD06HVF1 transistor could be replaced with a 15w version
RD15HVF1. Is this correct and if so do any other components need to be changed?



Thanks in advance.

Lazy.

A nice piece of kit which I plan to get my hands on in the very near future. RF-Head is probably the man to answer any of your questions. From what I remember the 15 will go straight in place where the 06 goes but RFH will be able to confirm this....

RD06 and RD15 are interchangable but RD15 will need more input to give full 15W. Regarding trimmer pots, doesn't matter how they are oriented if you put them in the right pins.

Thanks guys. When you say more input, do you mean adjusting the Bias trimmer or giving it more voltage?
I should have it finished at the weeknd with the RD06 installed, I can look at chaging for the RD15 later or maybe look at ordering one of their amp kits and give that a try. I'll post up some pic of the finished product when i'm done.

Lazy.

Here's what it looks like so far.

Nice piece of kit that, and it's a good price as well.

Hope you get it up and running first time.

LAZY wrote:Thanks guys. When you say more input, do you mean adjusting the Bias trimmer or giving it more voltage?
I should have it finished at the weeknd with the RD06 installed, I can look at chaging for the RD15 later or maybe look at ordering one of their amp kits and give that a try. I'll post up some pic of the finished product when i'm done.

Lazy.

No, more input power from previous stage. You will need at least 300mW to get 15W output with RD15. 500mW wouold be even better. You must set bias carefully because it affects current through RD15. Best practice would be to set trimmer to minimum, and then slowly raise it while measuring voltage at the gate of RD16 (RD06 in your case). This voltage should be 2.3 - 2.8 volts DC. DO NOT EXCEED 3V! You will burn fet...
A bit of theory: Gate voltage above 3V will enable too much current through fet. This is not a big problem when you have enough drive power and large heatsink. But if your rf drive is too low and cooling is quite bad, fet will overheat from current flowing through source-drain and it will burn...

Pjeva knows his stuff and theres some good advice there! i would say experiment! mount the output device on a healthy large heatsink and start small! Monitor the temperature, output power and PLL voltage stability! Datasheets for each component will give a good guide to thier limitations!

Thanks for the comments guys. Not quite at that point yet but a little update with progress so far. Just the coils and the final to finish.





The SGA6489Z and MSA0886 were tricky little buggers, although not very pretty I managed to get them soldered in place.

Quick question before I get to testing the PLL. It directly translates as "We are now so far that we can test the oscillator and PLL . This may be connected with or without display. Turn the power potentiometer fully counterclockwise . Verify that the middle leg of the power potentiometer to ground (-) is . If there is an external potentiometer is used for the power control than the center pin to connect temporarily to ground. Connect a supply voltage of 12,5Volt to the plus and minus ."

My power potentiometer isn't connected to ground. Have I made an error, or do I need to solder a connection from ground to the power potentiometer middle pin to test?

All comments greatly apreciated.

Lazy.

You need to turn it until it is short circuit between middle leg and ground (probably counter clockwise)

Think i have soldered it the wrong way round.

It doesn't matter. Trimmer can be used either way

This transmitter is designed by me and my brother so not RFhead

You cannot replace the RD06 for a RD15 to get 15 Watt because the drive power from the SGA is to low.

teckniqs wrote:A nice piece of kit which I plan to get my hands on in the very near future. RF-Head is probably the man to answer any of your questions. From what I remember the 15 will go straight in place where the 06 goes but RFH will be able to confirm this....

That's the right answer

pjeva wrote:It doesn't matter. Trimmer can be used either way

Nice to see someone building our transmitter
Because many people has problems soldering the small msa and sga smd devices i decided to pre solder them with reflow to avoid problems.
So i will place this two parts already on the pcb in the future.
Hope you enjoy the kit.

LAZY wrote:Thanks for the comments guys. Not quite at that point yet but a little update with progress so far. Just the coils and the final to finish.





The SGA6489Z and MSA0886 were tricky little buggers, although not very pretty I managed to get them soldered in place.

Quick question before I get to testing the PLL. It directly translates as "We are now so far that we can test the oscillator and PLL . This may be connected with or without display. Turn the power potentiometer fully counterclockwise . Verify that the middle leg of the power potentiometer to ground (-) is . If there is an external potentiometer is used for the power control than the center pin to connect temporarily to ground. Connect a supply voltage of 12,5Volt to the plus and minus ."

My power potentiometer isn't connected to ground. Have I made an error, or do I need to solder a connection from ground to the power potentiometer middle pin to test?

All comments greatly apreciated.

Lazy.

mauri wrote: You cannot replace the RD06 for a RD15 to get 15 Watt because the drive power from the SGA is to low.

This is what I said few posts ago. Mauri, are you new here on the forum? And are you owner of shop in NL?

Hi Pjeva, yes i'm new here.
I was a member from the old website but it's gone...
And yes, i'm the owner from the shop

pjeva wrote:

mauri wrote: You cannot replace the RD06 for a RD15 to get 15 Watt because the drive power from the SGA is to low.

This is what I said few posts ago. Mauri, are you new here on the forum? And are you owner of shop in NL?

So mauri welcome back! And if it is dutchrfshop, you are my supplier of components

So mauri welcome back! And if it is dutchrfshop, you are my supplier of components

Hi Pjeva

Aaah, that's nice to hear.

Thanks