GB3VHF - Loud and Proud

Well,

I've been fiddling a little this morning with my 2M VHF setup; I have been using my TS-990 with a G4DDK transverter along with a DG8 masthead preamp.

It works extremely well; I use this set of "macros" to put the TS-990 into transverter mode and set things the way I like them:

$COMMAND OM0D;$ Mode USB-D
$COMMAND FA00028370000;$ 28MHz VFO Frequency
$COMMAND FB00028375000;$ 28MHz VFO Frequency
$COMMAND XO000116000000;$ offset 116MHz +ve
$COMMAND XV1;$ transvert on
$COMMAND AN00911;$ DRV on and RX ANT On
$COMMAND PA00;$ main preamp off
$COMMAND PA10;$ sub preamp off
$COMMAND EQT00;$ TX Equaliser off
$COMMAND EQR000;$ RX Equaliser off
$COMMAND BS01;$ Scope on
$COMMAND PC200;$ Power control to 10 (70W in non transvert mode)
$COMMAND BSC020;$ Scope Ref -10dB

And just for completeness:

Good egh?

Transverting - Complete!

Well,

The 4M Transverter I started back here:

http://g0mgx.blogspot.co.uk/2015/04/transverting-even-more.html

Is now **nearly** complete.I say nearly as I am still waiting for a ZLPLL board from here.

The interior has been completed and all wiring completed, here's a shot mid way though that process:

Now, you may remember that I have a Gemini 4M & 6M amplifier. Well, this was configured for a 25W drive level when I bought it, so I needed to modify it for the lower drive level of this transverter. The amplifier includes an attenuator which needed to be replaced. Here's a view of the Gemini with the covers removed:

In the photo above I have highlighted with a red circle the component that needed to be replaced. You can hopefully see that I have also had to remove the internal covers from the RF board screened enclosure to access the part.

Here's the RF board with the new attenuator installed:

This is working beautifully from the transverter now and giving me full power out from the transverter drive levels.

Good, egh?

Transverting - Even More More!

So,

Following from the start of the 4M Transverter project I posted about last time:

http://g0mgx.blogspot.co.uk/2015/04/transverting-even-more.html

I've done some more today.

The power amp module is built and mounted on the rear of the enclosure with an aluminium heat spreader:

The rest of the enclosure is prepared:

The internal wiring is almost complete, I've just run out of SMA cables - which is a bit of a bummer! I'm also waiting for the ZLPLL from here to complete the project properly.

Not a bad start though, egh?

Transverting - Even More!

Well,

Following the success of my 2M transverter project back here:

http://g0mgx.blogspot.co.uk/2014/10/transverting-some-more-some-more.html

which I showed off working here:

http://g0mgx.blogspot.co.uk/2015/03/ts-990-on-2m-144mhz-no-way.html

I decided that I would like to have a bash at making one of these transverters for 4M. Sam, G4DDK agreed to supply me with a kit of parts for a 4M variant of the Anglian. There are about 40 or so component changes. This meant that the board needed the SMD soldering to complete the unit - the 2M version required no SMD soldering!

So here is the project in it's infancy:

And here with quite a few more components in place:

and here with it complete and in the tin screening box:

I've run all the basic tests and both the RX converter and TX converter are working fine. There is a 42MHz local oscillator (70 - 42 = 28) - as with the 2M variant, I have ordered a ZLPLL board from here:

http://zl2bkc.com/projects/zlpll/

to provide an external frequency reference to stabilise the on board LO.

I've started the PA board to go with the unit; it should deliver about 7W output.

I've decided that to avoid any switching between transverters I will leave the 2M box interfaced to the TS-990 and use this 4M variant with the FT-DX5000. That has a transverter output which is -10dBm rather than the 0dBm I require. I may have to experiment a little with the levels but I should be able to drive the 4M Gemini amplifier perfectly with this combination.

Let's see.

Freddy cat has been doing a fine job of being almost completely in the way throughout.

Local conditions.

How can something so Simple be so Tricky?

Well,

What a couple of days! I dropped the antennas down yesterday, the idea being to fit a Masthead preamp for the 2M antenna.

The preamp has been homebrewed, but I am sworn to secrecy as to it's design and origin. Needless to say, keeping an eye out here:

http://g4ddk.com/

May prove to be a most excellent idea if you happened to want one of these.

This is the basic board populated but still under test inside the house:

The board  gave me about 17.5dB of gain right across the 144-147 MHz range. This is a close up of the top of the amplification peak on the Spectrum analyser:

So I took the antennas down (which involves taking the closest element to the ground off the HF beam):

and I fitted the pre-amp. Now, this involved replacing the direct feeder to the beam and introducing a joint in the coax (so I can remove the amp if needed in the future).

So the preamp in in the waterproof box you see above, after many iterations I have the set-up working perfectly. I have, during the process, proved how completely incompetent I am at fitting N-Type connectors!  I've got there in the end though - only about a day and a half elapsed time!

All told though, a most excellent result.

Freddie has become exceptionally clingy to me since I returned from the Middle East earlier this week, hasn't helped much today though:

Local conditions.

Good, egh?

I think we made it

Well,

Following on from all my transverting conundrums, I have finally finished the configuration today.

Here's how the setup is now configured:

It's been the PTT switching that's caused me the most confusion. I've ended up making a switch box containing a 4 way rotary switch that allows me to select 2, 4, 6 or HF. In the 4M selection position the PTT drives both the 4M transverter and the 4/6M linear, in the 6M position it's just the 4/6 Linear that's enabled.

I've written a load of Macros for transverter control that I issue using the Logger32 Radio Control Panel. Here's an example of the macro that takes the TS-990 into 144MHz transvert mode:

$COMMAND OM0D;$ Mode USB-D
$COMMAND FA00028370000;$ 28MHz VFO Frequency
$COMMAND XO000116000000;$ offset 116MHz +ve
$COMMAND XV1;$ transvert on
$COMMAND AN00911;$ DRV on and RX ANT On

My only disappointment is that the radio isn't including the transverter offset in the results returned from the "IF;" command. That's the command that the Logger32 software repeatedly issues to the radio to determine the operating frequency.

For example, when the radio is configured like this:

You can see that the Transvert option is enabled as is the external DRV socket (that is the 0dBm output signal to drive the transverter) plus the RX antenna is enabled.

When the "IF;" command is issued to the radio, unfortunately it returns 28.370.00MHz as the frequency.

That's a real shame.

Local conditions.