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Saturday, 25 June 2016

New Amplifiermabob


I've been thinking for a while about upgrading the amplifiers I have here for 4/6M and also 2M. Here's the result of my investment:

The 950 deliveres 1KW on 6M (500W on 4M) and the 1000 is 1KW on 2M. Both solid state amplifiers from Beko in Germany.

Given the termoil on the currency markets as a result of Brexit - I might have just timed this right.

Local conditions.

Sunday, 19 June 2016

I've made another one!


You may recall the recent Frequency Reference that I made, I've just finished building another one for someone else! This one is almost identical except I have included a 1MHz low pass filter as this one will be configured to have a 1MHz fixed output.

Here's the 1MHz output:

Good, egh?

Friday, 3 June 2016

RTL on HF? no way!


I read with interest an article in Practical Wireless from June 2016 describing a neat looking receive converter to be placed up front of an RTL dongle type receiver.

These RTL devices are easy to find for a few GBP:

Here's the schematic of the converter:

And its built on a PCB from OHS Park which cost a staggering $5 USD for 3 including postage to the UK. They were delivered in a very timely manner too! 

You will see that I have actually built two - but basically we have a 50MHz oscillator and a mixer, so in the example below my SDR would be tuned to 70MHz and I would be listening to my signal generator on 20MHz. The output contains what you would expect from a mixer in that we have the input frequency, the on board oscillator frequency, their sum, their difference and all the other harmonics from this mixing process:

More to follow once I have it up and running with the RTL dongle, but so far so good!

Local conditions.