Monthly Archives: March 2012 - Page 2

Electronic progress

Last week I managed to finish the input filters for the amplifier. I did test them a bit and it seem to be working fine on 160-15m. I am not sure that I will be able to get it running well on 10m but we will see. Not that it will matter much since we don’t have any propagation on that band anymore.

Today I did some work attaching some cards and power supplies into the 19″ box which will be used to control the amplifier. Its got a control card, power meter and stepper driver card. The power supplies are switched ones for 24,12 and 5v. The last one is used for the stepper motors. There are a lot of D-SUB connectors, I added a few extra just in case for future improvements.

The idea is that the amplifier will be controlled from the openASC system. So when we change band in the shack the amplifier will tune itself automatically. At the beginning we will just have it preset-tuned but I might consider making it fully automatic in the future. The new power meter boards improved frequency counter makes it possible to automate the in-band tuning while I will use band data to control the band.

Buy PCBs

I’ve built a lot of different antenna switches and spent time and money to develop PCBs for these. Since the interest seem to be quite high I decided to sell boards and use the small profit to finance parts of the SJ2W project which usually also includes more electronic projects.

All boards have 140 um copper thickness and they easily handle OM3500 type of power levels.

I am working on getting all details on the website. Info right now added for 6×1, 6×2 and stacker.

6×1 Regular six port antenna switch 40 euro
6×2 Six antennas can be routed to two radios 50 euro
Stacker Three antenna stackbox 40 euro
4-SQ 4-SQ board 45 euro
VHP 6×2 Six antennas can be routed to two radios, 7/16″ connectors 80 euro
VHP Stacker Three antenna stackbox to two radios, 7/16″ connectors 70 euro

To order, just drop me an email with the board(s) you wish to have and I can give you details regarding payment options plus also the shipping cost. And please note that I only sell boards, no other parts are sold.

Amplifier control box front

I did mill the front panel for the control amplifier electronics as well today. It was a pretty quick task and the front has got room for 13 pcs of 9-pole D-SUB connectors which will be used for various electronics and 3-4 of them has got no intended function but just added as extra in case of future modifications. I also added 2 BNC for the openASC bus, 2 BNC for the power meter and a BNC for the PTT input.

Now I need to buy some D-SUB connectors and start making cables to the controller card. I will begin with making the control box I built previously to be hooked up to the device and also add the power supplies that will be needed (24v, 12v, 5v).

The whole idea of making it all in a 19″ rack casing is to make it easy to just unplug everything from the amplifier and take it with me up here if I need to do some work on it. Instead of needing to take the electronics out of the amp and have no easy way of testing it on the bench.

Input filter progress

I’ve gotten some progress made on the input filter for the amp project. I’ve got some problems with the neutralization causing some problems on 21 MHz but hopefully I can solve that. I am not 100% sure it will even be needing the neutralization, and without it I have no problems at all to get a proper input SWR on all bands. I’ve simulated the tube input capacitance with a couple of silver mica capacitors.