Designed by Ian White, GM3SEK, and based on the front end of the Anglian Transverter by Sam Jewell, G4DDK, the DG8 2 metre masthead mounting preamplifier delivers a high standard of performance and environmental protection. With no exposed metal parts to the pre-amp package, it offers an extremely high degree of corrosion resistance.
Download Technical Article (kept updated by GM3SEK)
Download Technical Manual
Further Information on GM3SEK Website
This short kit contains the basic parts for assembly of the DG8 Masthead Pre -Amp by Ian White GM3SEK.
To complete the unit you will need to purchase the remaining parts yourself, as described in the Technical Manual.
Component references are given as well as stock codes for Farnell and CPC as the main suppliers.
Short Kit contains:
- 1pc Printed Circuit Board GM3SEK
- 1pc Coilcraft 330nH 5% 0.31A
- 4 pcs Coilcraft Tunable inductor Shielded for 144 MHz
- 1pc Coilcraft Tuning Wand
- 1pc Integrated Circuit SPF5043
- 4pcs solder tag brass
- 30cm enamelled wire 1mm dia to wind RFC2
This product requires you to terminate your antenna and shack coaxes onto the PCB. The holes in the PCB for the coax inner are sized for UR67/RG213 size cables. Some users have experienced difficulties and reliability issues when forcing slightly larger cables, such as Ecoflex 10 through the via hole. This is because the larger size of inner damages the via between the two sides of the PCB, and they become disconnected. If you want to use a low-loss cable such as Ecoflex 10, then the following recommendations should be followed:
do not tin the inner before passing it through the PCB – this will cause it to expand in diameter.
make sure that the inner does not need to be forced through the hole in the PCB.
it may also be a good idea to leave the dielectric of the coax clear of the PCB on the underside of the PCB by about 5mm, to allow access with a soldering iron – the inner can then also be soldered on the bottom side of the board, which will provide a signal path even if the via does become damaged.