Desoldering tweezers for SMD removal

After a recent post on the GQRP Yahoo group I have been asked by several people about the desoldering tweezers I use for removing SMDs. They plug into a Xytronic LF 1000 solder station. I have several different bit sizes as follows:2mm,3mm 5mm,10mm,20mm and 30mm. There are more available but these [...]

Band pass filter diode switching

The DC receiver project is progressing slowly. Yesterday I lashed up another band pass filter,BPF,using 10mm coils from Spectrum Communications. With a bit of fiddling it worked well. The PCB design is almost done and for the first time for me the BPFs will use all SMD components to keep the size and [...]

Easy filters

A few months back I bought a VNWA from SDR-Kits. Now this was a big purchase,equal to a new rig or well on the way to one. So what can it do? The answer to that is that I am still finding out and learning how to use it.

Today is a cold,wet [...]

High performance direct conversion receivers

I have always liked using DC,direct conversion receivers. Their sheer simplicity makes them attractive but the drawbacks can be irritating. They often suffer from breakthrough from broadcast,BC,stations and rarely have very good selectivity. I have heard of designs for high quality receivers but have been sceptical of the claims,until now!

The [...]

SCAF demo files

I have had a few discussions recently about SCA filters, switched capacitive audio filters,and how effective they are. The best way to demonstrate is by listening to recordings made with a variety of receivers.

The first is a Small Wonder Lab Rockmite on 30m. The clicks/clunks are the sound of switching the filter in/out. This [...]

The DX code of conduct

I will listen,and listen,and then listen again before calling. I will only call if I can copy the DX station properly. I will not trust the DX cluster and will be sure of the DX station’s call sign before calling. I will not interfere with the DX station nor anyone calling and [...]

Eight band homebrew CW QRP transceiver

At last the rig is complete,in its box and working. Not saying it is completely finished,there will always be improvements to make but it is working well on all bands. The Rx seems very good,better than I expected. The TX is good with adequate power on all bands. The PA stage is [...]

Contesters win again?

Some Yahoo groups have been buzzing this week after news filtered out that the latest International Amateur Radio Union,  IARU,  meeting had recommended that the 40m QRP centre of activity be moved from 7030Khz.

There was some confusion as to what was really happening and it turned out a move was discussed but not recommended. [...]

SCAF filters

Testing the RX section of the eight band cw-transceiver produced the following MP3 recording.(Just click on the link and it should play.)

20M SCAF demo

The clicks and thumps show when the filter was switched in and out –the effect is quite obvious! The recording made was using an Idiom Press SCAF-1 which I [...]

Homebrew BuddistickHomebrew Buddistick

A recent /P trip convinced me that I needed a quick deployment multiband vertical antenna. The 20M ‘squid pole’end fed half wave worked well but I wanted to use other bands.

Searching the web produced plans from W3FF for a homebrew Buddistick. (Clicking the the link will download a PDF file.) A trip to [...]

/home/m5fraorg/