RUSSIAN GI 7B Valve AMPLIFIER

-


I finally decided to try my luck with a proper amplifier and managed to get hold of a second hand Russian GI7B amplifier which covers 80m through to 10m. I picked the amplifier up earlier this evening off of a radio amateur that was in the same county - Yorkshire, to the south about 35 miles away. On returning home, I installed the new Russian kit and with 20 watts in I had 400 watts out. I am feeling very pleased with my new investment and this year's CQWW DX Contest should be even better than last year with a bit more coal on the fire. 73  I'll be back soon with more on the new amp.

Comments

Post a Comment

Popular posts from this blog

Full Size Delta Loop for 20M

-
Image
I came across a simple delta loop design courtesy of dxzone found on the net some time ago and have been planning to give it a go for a while. This weekend I had a couple of hours spare, so I decided to give it a go using some 2mm multi strand wire cable, a dipole centre and a mixture of 75 ohm and 50 ohm coaxial cable. The delta loop is supposed to be resonant on 20 meters but I found it to be a little high so at present I am tuning the Loop with my mfj-969 which copes extremely well. The resonant frequency is 13.2 MHz at the moment so the next chance I get, I shall shorten the overall length making sure that each of the three sides are still equal in length, and hopefully adjusting the antenna for maximum performance ATU free for 14.2 MHz. I believe the miscalculation in the resonant length is probably down to the fact that my wire is covered in the plastic sleeving from the manufacturer which always effects the swr as I have noticed in past experiments with dipoles you always get sl...
Read more

Homebrew 40/80 Trap Dipole Design

-
Image
This Antenna design was one that I used about 4 years ago, it worked exceptionally well on 80m and 40m. The size of the antenna makes a Half wave length on 80 meters, and with the traps a half wave on 40m with a SWR (standing wave ratio) of 1:1-1.5 across both bands. It worked well also on 20m with the use of an A.T.U (antenna tuning unit). I made my version of this antenna using 3mm multi strand copper cable which I left covered by the PVC insulation. The traps can either be home brewed using some 40mm diameter plastic drain pipe and winding wire around the pipe approximately 10 turns, then connected in line after the 10 metre lengths. Or the alternative is to purchase some commercially made 7.1 MHz traps, and fit them in line the same way. The antenna can be fed with 50 ohm coax with a home brew balan or again a commercially purchased balan. The wire lengths of the dipole are 2x 10 metres and 2x 6.7 metres as shown on the diagram above. This antenna can be mounted quite low to the gr...
Read more

YAESU G - 5500 Elevation Rotator Repair

-
Image
After 10 years of careful use my G-5500 eventually developed a couple of faults on the elevation rotator side.  Fault 1. For the past year I have had to guess the elevation as the readout was no longer working on the controller unit. I suspected the position switch which was located inside the rotator up above the house roof which was a pain in the butt to say the least. Fault 2. Over the winter the gearbox on the elevation rotor seized up solid. I plucked up some courage and erected my ladder and which with the aid of a rope to lower the mast it all worked out quite straight forward. Once down out with the impact driver and away I went. Once I split the case with the impact driver which was easy, I found lots of sandy grit and dried out remains of what should have or once was gearbox/bearing grease. The next step was to inspect the seized gearbox and then remove the main shaft which can only be carried out by first removing the entire gear housing u...
Read more