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 70Mhz Transverter 
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Post 70Mhz Transverter
Just finished putting together my Ukrainian 4m transverter.

Gives a comfortable 10W out.

Don't know why I made it, just liked the idea of having 4m from the 817.

Was it worth it?

$85 for the transverter board, plus sockets, heatsink, relays, attenuator parts, case, so it comes to over £75 in parts, and still time to put it together, so probably not!


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Sun Jun 14, 2015 11:05 am
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 70Mhz Transverter 
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Post Re: 70Mhz Transverter
What the PA device it uses Steve?
And what IF?

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Sun Jun 14, 2015 11:09 am
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 70Mhz Transverter 
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Post Re: 70Mhz Transverter
G0BHD wrote:
What the PA device it uses Steve?
And what IF?



28MHz IF and RD16HHF1 PA

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Sun Jun 14, 2015 11:13 am
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 70Mhz Transverter 
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Post Re: 70Mhz Transverter
Sangoma wrote:
G0BHD wrote:
What the PA device it uses Steve?
And what IF?



28MHz IF and RD16HHF1 PA

Neat little well assembled project I have to say! :good:
Might be worth it to someone with the skills, as oposed to say a build it yourself spectrum or whatever!

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Sun Jun 14, 2015 11:21 am
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 70Mhz Transverter 
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Post Re: 70Mhz Transverter
G0BHD wrote:
Sangoma wrote:
G0BHD wrote:
What the PA device it uses Steve?
And what IF?



28MHz IF and RD16HHF1 PA

Neat little well assembled project I have to say! :good:
Might be worth it to someone with the skills, as oposed to say a build it yourself spectrum or whatever!



Yes, true, it does at least give a reasonable output without an add on PA, as the Spectrum one I built needed (the one with the PA was too expensive).

And it can be made quite small.

I used a beefy heatsink to avoid the need for any other cooling, which almost doubles its size.

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Sun Jun 14, 2015 11:29 am
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 70Mhz Transverter 
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Post Re: 70Mhz Transverter
Looks nice that.
I must dig mine out one day and have a blast on 4.
I even thought about adding 4m to my kx3.

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Sun Jun 14, 2015 4:43 pm
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 70Mhz Transverter 
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Post Re: 70Mhz Transverter
What does it look like on a spectrum analyser?
There have been some interesting observations, from some amateurs.

Cheers

Tony

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Sun Jun 14, 2015 8:58 pm
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 70Mhz Transverter 
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Post Re: 70Mhz Transverter
gw8asd wrote:
What does it look like on a spectrum analyser?
There have been some interesting observations, from some amateurs.

Cheers

Tony



As long as you don't drive it to the max, unwanted at least 50dB down.

It takes a lot more drive to get the last couple of watts out, but then it is around half that.

After setting, changing the 817 from battery to external power makes no difference, it takes a much bigger change in drive to make any difference once you get to a certain point.

Mine would give 13W max, I turned it down to 10W.

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Mon Jun 15, 2015 3:09 am
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 70Mhz Transverter 
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Post Re: 70Mhz Transverter
Sangoma wrote:
gw8asd wrote:
What does it look like on a spectrum analyser?
There have been some interesting observations, from some amateurs.

Cheers

Tony


As long as you don't drive it to the max, unwanted at least 50dB down.

It takes a lot more drive to get the last couple of watts out, but then it is around half that.

After setting, changing the 817 from battery to external power makes no difference, it takes a much bigger change in drive to make any difference once you get to a certain point.

Mine would give 13W max, I turned it down to 10W.

That's OK.
There are, apparently, several versions.
Some had harmonic problems, some close in noise and some power issues.
Looks like you got a good one. :thumbsup:

Have you checked on the spec of the output device?

Cheers

Tony

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Mon Jun 15, 2015 10:31 am
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 70Mhz Transverter 
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Post Re: 70Mhz Transverter
No, haven't looked it up.

There are several versions, mine is not the original, it is one of the improved ones with canned inductors, and better output device.

I will check the third harmonic sometime. The output filter looks reasonable, looks a bit small, but doesn't get warm.

I did read about the power problems, but I think that was with the previous output device. I'm happy with 10W for its size.

Still don't know if it is value for money or not.

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Mon Jun 15, 2015 10:44 am
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