Sunday, December 7, 2014

14318kc , ra3aae dc receiver

I had made the linear (25w) using the IRF510 for pumping the radio waves into the ethers. At present only 20 meter antenna was known to work. The 40 meter dipole has the possible coax problem. I have long wire also. But I thought to test this linear on 20 meter due to constant traffic on that band.

I had the ra3aae receiver prototype receiver to test tx on the 40 meter but nothin on the 20. I also wanted to  modified original PA2OHH design for the INDIAN conditions. So made this receiver for the 14318kc cw/dsb tx using the 7159kc crystal.
Will house it in a neat sleek box so look like a walkey talkey.

Hope to monitor it for long range.

building blo
RA3AAE, Poliakov sub-harmonics mixer. by VU3INJ, Indrajit sinh 04dec2014

Diode mixer for amateur :: At the first glance we thing that how the lowly doiode will help us ? But, fact is that they are easily available, very simple to make, gives a very good result, they have high dynamic ranges... can process small signal as strong signals.

In this particular detector, i have made atleast 3 prototypes on the three different frequencies. Now, it is safe to say that its a reproduceable design.

Block diagram:::

First stage is the BPF + RF amp, Detector, AF Preamp, AF Amp. Xtal VXO, ( power supply, antenna and speaker switching, casing etc Hardware).

List of components:::

Ckt Diagram of the first version as derived from the PA2OHH.

This latest Working Version. :::

Tips for building it on copper boards. :::

Problems and solutions.:::

I did not encounter the problems. As most of the problems were solved at the first prototype. Be symmetrical and dont hesitate to use liberal adhesive to solder the copper pads on the copper boards. You will need crocodile clips to hold the components and pads togather. Use wood for giving support during cutting. Please cut the copper carefully so that its straight & clear. Carefull during toroid making so wire does not get shorted.

From this where ?

Its a serious toy. Can impress with childrens. As a gift to new local swl for listeing your signals or as a single frequency local net receiver. field-fone... 

This receiver is  housed in the metal box but i think you should place it in a plastic box. works okey in monitoring my own tx signal i.e 14316.04kc beep beep beep.........


 14318kc receiver

1 comment:

  1. It is working nice. I am running from 8volt (two 4volt sealed lead acid ) battery. Gives good signal test....