Homebrewed on 70MHz

This is my homebrew Six & Four Metre transceiver. Here working a station during a Four Metre, 70MHz contest. The rig has an SDR output. which can be seen driving #SDR. It has an output of 2 Watts which is enough to drive the homebrew amplifier to 125Watts. Power out on Six is 10Watts which drives 150Watts out of the Six Metre amp.

Inside and tuned to a Six Metre beacon

How I tapped into the first IF and connected my IC706 to an SDRpanadaptor

Lifted from a post I made on my local club website.

Useful search terms for more infomation; Powersdr-if, Ham radio deluxe, homebrew sdr, etc

Below is a video of my home-brewed transceiver for two metres which also has a wide ranging receiver. I recently decided to add an SDR output with a small unit that I developed over a long period of time. It is a fairly straight forward SDR tapped into the IF, which in this case is 10.7MHz.
The unit consists of two diode ring mixers, a twisted wire hybrid directional coupler, which provides both phase shifting and splitter, slightly off tune 10.7Mhz oscillator and a low noise op-amp. If any one is interested I can provide more details at the club. To build should cost less than £10.00 especially if you can find a suitable crystal. The unit is on the right of the rig, slightly raised and can be seen at the end of the video. You could of course buy something like this or a Softrock will do the job.



I don’t have a circuit diagram, I’m afraid it's mostly in the old gray matter!

Next video will be a IC706 with TV dongle connected to the IF, it works very well.

It's quite easy to pick up the 69MHz intermediate frequency in an Icom 706 mk1. There are two plated holes in the track which carry the IF signal so just by inserting the inner of the coax into one of these it can be picked up by the dongle.

The TV dongle accepts this signal and if it is then tuned to 69MHz you are then able to see the IF on the spectrum display and waterfall. The waterfall is not shown here . With the dongle I have here I am able 1.8MHz of spectrum but I can also zoom-in. There are lots of features in the software most impressive is the filtering.

Software used here is SDR#, another that works with the dongle is HDSDR.

So why would you do this? Well it adds a whole new dimension to an otherwise boring black box.

Try it and find out.

There is no reason, of course, why this set-up can not be applied to other rigs with an IF over 60MHz (dongle doesn’t go lower).

UPDATE 04/2014: "SEARCH "RTL DONGLE HF MOD" for info on how to tune it to HF

Hope you find this of interest.

Sorry video's not up to much.

If you want more info ask me at the Club.

 Powersdr-IF and CAT control of the IC706.

I think that this set-up is the most likely to appeal to members.

Here I am using my IC 706 Mk1, the intermediate frequency of which is feed to a home-brewed SDR which I mostly use on Six and Four Metres, so it's ideal to receive the 69MHz IF from the 706.

The software in use here is Ham Radio Deluxe, PowerSDR-IF and Rocky.

HRD is used for the CAT control of the 706. PowerSDR-IF then connects to HRD.

The waterfall display of Rocky is used to view CW, it is not connected to the 706 or the other software, using the sound card output only.

In the video I'm just tuning around the bands mostly using the mouse to click on the spectrum display/pan-adaptor of PowerSDR-IF but also using both the slider and DX-spots of HRD. Of course it's also possible to use the 706 tuning knob but this seems a bit “old hat”.

The pan-adaptor reveals some pretty wide signals, some very clean ones, some with poor carrier suppression, sweepers, odd QRM sources and more. There is no CW filter in the 706 so the SDR output is the only way to receive CW properly.

Hope this is of interest.

If you want more info ask me at the club or post here.

I have been asked by a Club member for infomation on the 1st IF tap point that I used to feed the
RTL TV dongle from my IC706 Mk1.

You should also consider using a buffer amplifier between the rig and the SDR something like a J310 FET should do.

The photos below should help with the tap point.

"It's quite easy to pick up the 69MHz intermediate frequency in an Icom 706 mk1. There are two plated holes in the track which carry the IF signal so just by inserting the inner of the coax into one of these it can be picked up by the dongle."

Use the hole towards the front panel. BE CAREFUL AND TRY IT BEFORE SOLDERING.

Tropo S meter recording of GB3VHF

Here is a recording I made yesterday morning of the signal strength of the GB3VHF beacon which is located in Kent JO01eh as received here near Chippenham IO81wm.  It usually hovers around S6-7 here but there was a clear enhancement yesterday morning. Doubtless more distant repeaters and stations than normal where heard on FM.
The line on the graph is the signal strength of the beacon (-60dBm is S9+10db approx)  time goes right to left so the recording starts at 1140 ends at 1211.
Weather at first was fog with rain arriving round-about 1145 and then getting more persistent.
I think that the drop in conditions is very apparent.

GB3VHF S METER LEVEL

Towards the end of the recording signal strength is bumping along at S5-6 (-90dBm). It's also a lot less stable than earlier.

The regular dips in the trace at the beginning are the WSJT tones sent by the beacon which produce a slightly lower average S meter reading.

SIGNAL INCREASING

This image shows the beacon increasing in signal strength.

Here is the link to the GB3VHF website and more info on this propagation report.
http://www.gb3vhf.co.uk/GB3VHFusingthebeacon.html

Hardware homebrew 144Mhz SDR - Software SDR-Radio by HB9DRV

Azores beacon CU8DUB

If you'd checked the Hepburn VHF Tropo forecast on the 15th May you would have seen the extended ducting from the UK out into the Atlantic.
This enabled the reception of the Azores beacon CU8DUB on 144.420MHz here in North Wiltshire at a distance of 2600km which is half way to North America.

Distance between IO81WM & HM49KL is 2601.68 km (1616.684 miles)

CU8DUB RECEIVED IN IO81WM

The signal is not strong but I'm some way inland in that direction unlike the people in Cornwall  and on the south coast that also reported it and had contacts.

The other beacons are GB3VHF (Kent) at the top, just beneath CU8DUB is a faint trace from ON0VHF and a stronger French one at the bottom.  The vertical lines are the farmers electric fence!

October Two Metre Opening Log Extract

Here is an extract from my log of contacts made during this wonderful opening.
-----   Date   ---      Station |   Locator | Distance km
13 12/10/2010 08:49 OR0A JO20 492.06 2m USB 57 53
14 11/10/2010 18:08 PA3EWP JO21 461.40 2m USB 57 57
15 11/10/2010 18:08 PA0GSM JO22 560.42 2m USB 57 57
16 10/10/2010 18:48 PE1ODY JO23 500.98 2m USB 57 57
17 12/10/2010 09:12 DO1KRT JO30 674.82 2m USB 55 53
18 12/10/2010 09:04 DL1EJG JO31 637.37 2m USB 57 55
19 11/10/2010 06:47 PE1BIW JO32 580.99 2m USB 57 57
20 11/10/2010 18:08 DF0WD JO42 730.67 2m USB 57 57
21 10/10/2010 18:25 DG3XA JO44 864.63 2m USB 57 55
22 10/10/2010 19:25 OZ6TY JO55 1,018.53 2m USB 53 53
23 10/10/2010 19:19 DF1AN JO63 1,088.00 2m USB 55 53
24 10/10/2010 18:30 SM7OVK JO65 1,118.86 2m USB 57 59
25 10/10/2010 18:52 OZ1HTB JO75 1,184.92 2m USB 55 53
26 10/10/2010 19:01 SP2IPT JO94 1,416.39 2m USB 54 53

All these contacts where made using homebrewed 144MHz Software Defined Radio if you are one of the stations I worked thank you very much. (Not all contacts are listed).

73

Dave

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