logo
Most Viewed Last 7 Days
(7)
(7)
(7)
(7)
(7)
(7)


Cluster Activity

Spots per uW band today:
UK spotter or spotted only.

Solar data:
SFI
77
A-Index
14
K-Index
3
Exp.K
0
Sunspots
34
Activity
qui
GMF
qui
Aurora?
no

My Weather

Date:01/01/70 Time:01:00
Temp:C
Wind Speed:0mph
Wind Dir:deg
Pressure:0mB
Humidity:%
Dew Point:-20C
UKHASnet

Amplifier RD06HVF1 & RD15HVF1

I found these devices give very good results for low cost when getting started on 2m DATV, and so simple to construct!

They have about 20dB gain each stage, so -10dBm input from the DATV Express gives +30dBm of output power using both devices in series.
There is reasonably good harmonic attenuation, approx -55dBc at 1W output.

The RD06 is capable of just over 7w saturated power output.
The RD15 is capable of just over 20w saturated power output.

I built two amplifiers using the circuit below, one for the RD06 and one for the RD15 device and used them in series.
This allowed me to get the DATV Express output level up to 1W cleanly, when using one device I had to drive the DATV Express very hard and the output spectrum was far from ideal.

The input and output match of these devices is very similar so the layout is the same for both.
The bias is around 4V, 2k2 pot from a 5v6 zener reference supply to keep the bias stable vs supply voltage.

All coils are 8mm inside diameter and 0.9mm wire.
Input and output series caps are 100pf.

RD06 device seems best at a bias level to get 0.4A drain current with no RF.
RD15 device seems best at a bias level to get 1.4A drain current with no RF.
These were found when the power is set to 1W.


Other caps can be variable or fixed, i got good results with the fixed values shown, 20W saturated from the RD15 device and about 7W saturated from the RD06 device.
Tuning each amp by adjusting trimmers or coils for best power at or near saturation usually gives the best linearity, tuning at low power levels for best gain will give much poorer results.

My current setup is using the DATV Express driving an RD06 device then into a RD70 device (RD70 Amp)


RD06/RD15 Amp Drawing


<** 100pf cap in series with the output is missing from the drawing!

Here was the test setup:
146MHz Amps
















Last page added:25/03/00 18:32
M0DTS.co.uk