Opinions on this driver.

thewisepranker · Post by **thewisepranker** » Tue Oct 20, 2015 8:30 am

sinus trouble wrote: pilot is stable but is square in waveform rather than sinus a little noisey?

Your username makes sense now. I thought you had hay fever.

sinus trouble · Post by **sinus trouble** » Tue Oct 20, 2015 10:27 pm

Loool Mr pranker!! your detective skills are 1st class!!

You dont happen to work for ofcom do ya??

thewisepranker · Post by **thewisepranker** » Wed Oct 21, 2015 8:04 am

Now you mention it...

sinus trouble · Post by **sinus trouble** » Wed Oct 21, 2015 9:56 pm

LOL!! Errmm? Did i mention that i think ofcom are a cracking bunch of guys! ive always admired thier great work!!

MiXiN · Post by **MiXiN** » Fri Oct 23, 2015 4:21 pm

radio-berlin wrote:Its another exciter by PCB Wizard guy on ebay, but on another account.

There was another he did on here a while ago, im guessing this is the newer once since. Hopefully it has some regulation as the last one didnt. Looks Ok from what I can see, however the big inductor placed by oscillator looks a bit suspect ? why would you place an inductor there? hopefully its not powering osciallator in replace of a regulator or being used as a PLL filter but I cant see why else it would be for placed right where it is.

I can also only see one varicap, so hopefully its not being used for modulaton and PLL like th elast version he made. There may be a varicap hidden behind the tuning coil but cannot tell in the photo but looks like a volume pot. One Varicap means that modulation level will be affected by PLL tuning voltage

Look at ebay item no 301766561286 , this was the last design by him

My friend ended up buying this, so as we're off out for a few beers either tonight or tomorrow I'll get some images of the board and post them up.

Is there anywhere specific you'd like to see as to whether the design is flawed?

MiXiN · Post by **MiXiN** » Sat Oct 24, 2015 6:22 pm

Here are the images...

Can anyone spot any inherent flaws?

I notice a slug is missing from both the Toko transformer and a PA variable inductor, the final appears to be a 2n3866 so will this even do 1w at 15v?

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Gigahertz · Post by **Gigahertz** » Sat Oct 24, 2015 11:11 pm

Well that logo on the underneath of your board seems to be the same as the one on my board but two different builders!
That logo seems to be getting a battering "Radio-Berlin"

radio-berlin · Post by **radio-berlin** » Sun Oct 25, 2015 12:25 am

That logo was drawn by me, it was on all my stuff

Then rf-head copied it off me about 2 years ago and started printed it on his stuff which at the time I was unhappy about, we are cool now I must add haha.

Now whoever this guy is building these exciters claiming 1watt from a 3866 with a similar logo.... Unbelievable

radio-berlin · Post by **radio-berlin** » Sun Oct 25, 2015 12:28 am

And the flaws are there looks to be an inadequate pll filter, but I can't be sure ... Only 1 vari cap used for pll tuning and audio modulation, very bad practice.... However apart from the 3866 it doesn't look to bad, looks ok compared to some.

I also try and keep the tuning coil as close to the osc transistor and general layout neat, I personally would have laid it out slightly better but that's just my opinion, it is probably fine

MiXiN · Post by **MiXiN** » Sun Oct 25, 2015 1:31 am

Thanks Gigahertz and Radio Berlin!

My friend had plans to run a 20w amp off this driver, and the amp requires 1w of drive - so based on the fact the 3866 won't deliver this, would it be possible to substitute a 4427 in place of it without altering any other components?

My friend doesn't have a power meter just now, and I won't be seeing him for a little while - so realistically off the 15v supply what sort of power do you think this driver will probably do?

In other words, could it half heatedly drive his amp that needs a 1 watt input or will it be far too low power for it?

teckniqs · Post by **teckniqs** » Sun Oct 25, 2015 2:01 am

If you haven't got access to a power meter may I strongly suggest you wait until you have for obvious reasons.

....Yes a 4427 will go in where the 3866 was but the equipment will need to be properly tested before attempting any kind of use.

MiXiN · Post by **MiXiN** » Sun Oct 25, 2015 2:18 am

teckniqs wrote:If you haven't got access to a power meter may I strongly suggest you wait until you have for obvious reasons.

....Yes a 4427 will go in where the 3866 was but the equipment will need to be properly tested before attempting any kind of use.

I have a power meter, it's just that my friend doesn't and I probably won't be seeing him for a couple of weeks otherwise I'd allow him use of my meter.

Just trying to work out roughly what that driver of his will produce in its current state off 15v?

If it goes nowhere near the specified 1w I'll get him to get someone to put a 4427 in place of the 3866 that's in use.

Analyser · Post by **Analyser** » Sun Oct 25, 2015 11:30 am

radio-berlin wrote:That logo was drawn by me, it was on all my stuff

Then rf-head copied it off me about 2 years ago and started printed it on his stuff which at the time I was unhappy about, we are cool now I must add haha.

Now whoever this guy is building these exciters claiming 1 watt from a 3866 with a similar logo.... Unbelievable

...and that logo with the guy sticking his middle finger up was first used by Broadcast Warehouse many many years ago! Unbelievable.

...oh wait, so was that whole driver design (RF bit, anyway).

teckniqs · Post by **teckniqs** » Sun Oct 25, 2015 2:32 pm

MiXiN wrote:
Just trying to work out roughly what that driver of his will produce in its current state off 15v?

At a guess around 500mW.

teckniqs · Post by **teckniqs** » Sun Oct 25, 2015 2:32 pm

Analyser wrote:
radio-berlin wrote:That logo was drawn by me, it was on all my stuff

Then rf-head copied it off me about 2 years ago and started printed it on his stuff which at the time I was unhappy about, we are cool now I must add haha.

Now whoever this guy is building these exciters claiming 1 watt from a 3866 with a similar logo.... Unbelievable
...and that logo with the guy sticking his middle finger up was first used by Broadcast Warehouse many many years ago! Unbelievable.

...oh wait, so was that whole driver design (RF bit, anyway).

Haha, rumbled!

pjeva · Post by **pjeva** » Sun Oct 25, 2015 2:40 pm

Hahaha, I think Mr. Colpitts can claim design of most our drivers

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sinus trouble · Post by **sinus trouble** » Mon Oct 26, 2015 12:11 am

Edwin_Henry_Colpitts_(1872-1949).jpg

teckniqs · Post by **teckniqs** » Wed Oct 28, 2015 9:20 pm

PCB Wizard has loads of them up for sale now.

http://www.ebay.co.uk/itm/111805559480

radio-berlin · Post by **radio-berlin** » Wed Oct 28, 2015 11:07 pm

Listing says Harmonic filter on output.......................................... where? lol
Harmonics -60db

MiXiN · Post by **MiXiN** » Wed Oct 28, 2015 11:32 pm

My friend bought himself a SWR/Power meter and claims he's had 1.2w out down at 87.5Mhz and around 900mW up at 108Mhz, this apparently on an Avair meter (not sure if these meters are any good) - but I'm also not convinced.

Will see him either this weekend or next and see for myself and take some images, but I too aren't convinced about the guys claim.

Would harmonics and spurii show up as extra power on a power meter?

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