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G8JVM England flag England

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If heard on CW please send slowly, very slowly

I was first licenced in 1974, my hobbies have always included electronics since the age of 14. Which progressed in to RF engineering.

My RF preferences have always been VHF to microwave, HF has never really bitten me, although I have the capability.

Transceivers:- Homebrew multimode multiband 50,70,144 & 432 MHz.

TS-530S For HF.: The antennas for HF are a  mutiple half wave dipoles for 7,14,18,21,38 MHz spaced 50 mm mtrs aprt with a common feed, a bit like a sleeve dipole.



For all the microwave bands another homebrew multimode 144 MHz IF, all the transverters are controlled from this new transceiver.

Which is built in 2011.

The antenna farm was completely rehashed and GRP is now used for the cross boom on 2 mtrs and the top 3 mtrs of the stub mast.,

However, the weight of the 67 ele 23 cms antenna caused the GRP stub to bend, so the 70 cms 2x 19 ele have been moved to vertically stacked

I do have problems with my hearing, I only have one partly functional ear, so unfortunately weak signals can be difficult

Bands active:-

HF + 6mtrs 200W, 4 mtrs 150 W, 2mtrs 400W, 70 cms 200W, 23 cms 150W, 13 cms 100W, 6 cms 10W, 3cms 5 W.

e-mail richardATg8jvm.com

replace the AT with @

Status:- December 2014

70 MHz SSPA rebuilt 180W

2320 MHz Masthead transverter has been repaired after water damage.and the power output increase slightly

5760 MHz masthead transverter being repaired due to water damage, both caused by condensation.. NOT GOOD !

(April 2014: still down cant get more than 6W out of it !, so still in the shack.)

I've now removed all antennas above 1296 MHz from the tower, and the the 5 ele Vargada on 50MHz and 5 ele on 70MHz have been removed and replaced with a single YU7EF Duoband 7ele on 4 nd 6 ele on 6 mtrs. the removal of dishes and masthead transverters has more than compensated for the larger antenna.

A single 80 cms offset dish is used for 13 cms and 6 cms to be mounted on the side of the house

Anyone desparate for a QSL card, send direct, My address is correct QTHR. I do QSL: via the bureau , but I have a backlog


Below are views to the East and SE from this QTH, visible horizon is about 40 miles


In 2012 our cat we had for 16 years died, and in the fall we gave a little black rescue cat a home, Hector follows me everywhere and

below he is discovering how to stop the cooling fan on the DDS VFO on the microwave IF rig.

Unfortunately in June 2014 he was hit by a car and is no more :(

Our new cat a little black female is not so technically inclined.

Further work has been done to improve this tranceiver, with the refernce clock incresed to 1 GHz and the o/p from the DDS increased to +20dBm

to drive a high level mixer , that has improved the Rx dynamic range, which on 23 cms is important due to the high level radar QRM from a nearby site. As well as high level qrm from the nearby DVB-T transmitter 5 miles away LOS.

This transceiver controls all the transverter switching from the from panel.

The software for this transceiver and the main VHF/UHF rig has been written by my very good friend Buck KD8RRI



Projects for 2013 are:-

Replace the LO chain in the 23 cms transverter, at the moment the LO chain is from a SSB electronic receive converter about 30 years old now

Done !

The new one will be based on the DDK2001 LO board, but using a very low noise VCXO at 96 MHz, that will be locked to a 10MHz referenece.

Done !

The another project which must be completed is the 9MHz FM modulator and source for the main HB rig which since changing the VFO to DDS has has no FM Tx capability. It will just be a Si571 with the freq set by a smal PIC and the pre-emphasis audio stage.

Done !

The next in line is the FM IF Rx & TX for the little microwave HB 2 mtr rig above.

Then either rebuild the 6 cms masthead transverter, now I have all the parts needed, or finish the 1 GHz clock for the DDS VFO in the main HB rig.

This should provide me with a low phase noise clock loosely locked to a 10MHz reference. I have been told my method of locking up a SAW ocillator at 1 GHz by controlling the temperature of the SAW module cant be done, so I'll proceed on and show it can be done. My target is to hold the SAW oscillator to within 5 Hz of its nominal 1 GHz.

May 2016:-

I never got the chance to try temperature locking as I lost the SAW oscillator I purchase for the job somewhere in the shack.

Another 1 GHz SAW oscillator was purchased with the facility to adjust the frequency, this is now controlled with a LMX2470 PLL and locked to a 10 MHz ovened oscillator, checked against the Rb standard in the shack.

July 2016:-

Changed the 144 MHz antenna from a pait of 9 ele vargardas bayed to a single 13 ele long yagi from Dual in Serbia, very well built on a 8mtr boom of 40mm section

The IF board in the main transceiver is in the proceess of redesign with an addition 500Hz filter and a keyer has been added as well, after 40 years I decided to improve my morse. !

done !

Below shows the shack, it is not just a clean desk with a rig on top !


Piccy a bit out of date , the RHS is now used by a model railway.

Projects for 2015

rebuild the 70 MHz stage on the main rig, its old through hole and uses a lot of space. Done !

Get all the microwave bands up and running again.

Build a new FM IF and modulator for the microwave IF rig.

Build the HF stages of the main rig to cover 450 KHz up to 30 MHz,

this may involve reprogramming the DDS vfo to use serial expansion as I'm already using every port availble on the PIC, 18F2550, controlling the DDS ect.















7471294 Last modified: 2016-07-28 16:08:51, 6993 bytes

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