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Re: Transverter/converter saviour?



Howard,

One thing that I have done in the past that seems to work good it to put two
diodes back to back at the IF output followed by the thinnest wire you can
find followed by a small chip cap. It looks totally transparent at
everything below 1GHz and if you transmit, the diodes conduct and the little
wire fuses. I have transmitted 100 watts into a similar circuit with no
problems. You just have to replace the fuse.

Pieter

----- Original Message -----
From: "Howard Long" <howard@howardlong.com>
To: <amsat-bb@AMSAT.Org>
Sent: Sunday, April 01, 2001 18:54
Subject: [amsat-bb] Transverter/converter saviour?


> Whilst at a local ham shop a week ago in London I saw the following on the
> 2nd hand shelf:
>
> Microwave Modules Transverter Interface Unit.
>
> It was GBP50, but they let me have it for GBP40 ($60) as there were no
> manuals available.
>
> I was unsure as to its exact function, but I purchased it anyway.
>
> Externally it's got an HF rig SO239 and a Transverter SO239, and a DIN
plug
> for power & PTT.
>
> I had the lid off and inside it's got not only external PTT, but also an
RF
> VOX sniffer.
>
> When switched off, nothing is let through at all.
>
> When switched on with no RF, it acts as a pass through.
>
> When switched on with RF (or PTT), it dumps a large percentage, if not all
> of the load (adjustable) into a big juicy heatsink: maybe enough for 50W,
> more if you put a fan on it.
>
> Although designed for HF, I've tried it on 2m and the SWR's <1.5:1, and on
> UHF it's 2.5:1. As you're hopefully not TX'ing too much power anyway, one
> would hope this is not such a big deal.
>
> On question I have: assuming that the relays take a finite time to switch
> over, I'd hope that the rise time of the transmitter is slow enough to
avoid
> catastrophe if you hadn't used the hard wired PTT option.
>
> So I recommend picking one of these units up if you see them at a good
> price. It may well save you a lot more than its purchase price.
>
> 73 Howard G6LVB
>
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