- HF Linear Amplifier SOMMERKAMP SLA-300 -
Trying to find an Affordable and simple to use Linear amplifier for my station. I'm not into hunting in any DXpedition pileup's - so my need for lots of power is not that 'urgent' - The ide´a is simple usage and maybe an s-units or sow of extra signal in the other end...
Now testing the SolidState HF-Linear amplifier 'SOMMERKAMP SLA-300' - It's actualy the same as RM-Italy HLA-300plus - In the text on this page i try to describe my efforts and problems when using this device.
SLA-300 Frontpanel CloseUp
- First look -
I previous been using RM-Italy equipment when active on 11-Meter band (1990-2002) - The overall quality of the 'CB-Brand' from this manufacturer was not 100% good - The first impression of the SLA-300 unit is that the quality is better. The data stated from the factory is a bit more accurate than the data given for the 'CB-Brand' amplifier models, but still not adequate in real usage.
2009.11.06 The amplifier tend to miss on selecting band in AUT mode. First i thought the error came from over-load on input. But there is now problem when running same input when selecting band with the band-switch manualy. Now using the amplifier with my new ICOM IC-7200 - Also using an Automatic antenna tuner LDG AT-1000pro
2009.09.30 Now testing output with propper test equipment. The Amplifier is hocked up to a dry dummy load, using 2x BIRD Thruline Wattmeters to monitor input and output. Here are the results.
Left: BIRD Wattmeter + 1000H Element (Reading 220W output)
Right: BIRD Wattmeter + 250H Element (Reading 15 Watt input)
- Test Conditions -
# Input meter used ................... BIRD 43 Thruline Wattmeter + BIRD 1000H Element slug # Input SWR used ..................... Tranceiver meter # Output meter used .................. BIRD 43 Thruline Wattmeter + BIRD 250H Element slug # Tranceiver internal antenna tuner .. OFF # Amplifier internal attenuator ...... ON (-3dB) # Amplifier auto band selector ....... ON (AUTO mode) # Amplifier SSB delay ................ OFF # Dry Dummy load ..................... ZETAGI DL61
2009.09.28 TVI problem solved! - It's not any amplifier problem. The problem eminated from the balanced feed-line. I previously only used coaxial cables so this problem is new to me.
2009.09.26 During the SAC this weekend i got problems with TVI into my digital TV-Box. This has not been a problem before. Trying to eliminate the problems with 'SnapOn' RFC Ferrite's on power supply line and a Kenwood LF-30A LowPass filter connected directly on the output on the amplifier.
SLA-300 Backpanel with RFC Ferrite core and RF-Ground connention
 RFC Ferrite core on DC-Power cable |
 RFC Ferrite core on PTT-Line |
2009.09.20 Done some 'Real-Life' testing with the SLA-300 on the 40 and 80 meter band today,- in average the signal drops 6-10db (1-1,5 S-Units**) when turning of the amplifier and running barefoot with tranceiver output only (100W PEP/SSB) - My estimation is that the output from the amplifier is about 350-450W PEP Using the meter on my PALSTAR AT1KP tuner and the 'PEAK-HOLD' function turned ON.
**PreAmp on receiver station OFF
2009.09.19 First look @ the 'SOMMERKAMP SLA-300' HF-Linear Amplifier.
Some functions s.a. the automatic band selection and SWR protection is controled by a microcomputer, these functions is self tested when the amplifier is turned on. When ready to use the amplifier gives a audio 'beep' signal and the Band selection LED lits or 10-12/Auto LED lits if in auto-mode.
When i auto-band selection mode the amplifier doesn't remember last operation frequency, it always start up on 10-12M Band, an built in frequency counter read actual frequency from input signal an select proper band, if it fails to do so a warning audio 'beep' is heard and the Protection Warning LED lits up.
The unit is also protected against overheating and overload. There is allow wrong polarization protection (Diode-Crowbar fuse burner)
The amplifier have a built-in attenuator on the input, the attenuator is enabled / disabled with a switch on the front panel, I didn't understand anything about it's function when trying to read the enclosed manual. The manual (English part) is actualy quite confusing.
From testing i understood that the switch should be ON and the LED '-3dB' should be lit when the attenuator is enabled.
SLA-300 Amplifier with PALSTAR AT1KP Antenna Tuner
I hooked up the amplifier with a dry-dummy load to determine correct input drive power level for every amateur band. The chart shows input and obtained output during test. Measurements is read from the power meter** on my PALSTAR AT1KP antenna tuner.
**Previously compared in parallel with a Bird 43 watt meter and quite accurate.
- Test Conditions -
# Input meter used ................... Tranceiver meter # Input SWR used ..................... Tranceiver meter # Output meter used .................. PALSTAR AT1KP # Tranceiver internal antenna tuner .. OFF # Amplifier internal attenuator ...... ON (-3dB) # Amplifier auto band selector ....... ON (AUTO mode) # Amplifier SSB delay ................ OFF # Dry Dummy load ..................... ZETAGI DL61
Read more...
Some nice pictures and data from testing the RM-Italy HLA-300 by: PA0FRI
- Data -
This 'Solid State' HF-Amplifier utilizes a matched quad of the Bipolar HF(UHF) Power Transistor SD1446 manufactured by ST Microelectronics Group. Theoretically the SD1446 is capable of max 183W Power Dissipation (4 x 183W = 732W) but this is in an ideal situation with no loss in the surrounding components s.a. power splitter/combinder a.s.o.
In real use (With transistor manufacturers recommended safety margins) a commercial Class C application using SD1446 transistors should not exceed 12,5 Volt** DC supply and 10Amp current drain. This equals 125W power dissipation for one transistor (4 x 125W = 500W)
**16 Volt Maximum according to amplifier owners manual (Tension must not exeed 16 Volt)
The amplifier manufacturer state the maximum output RF-Power to 300W AM/CW and 550W SSB
Given the transistor data above and practical tests a closer assumtion of actual output RF-Power is 220-240W AM/CW and 400-460W SSB depending on band and DC-Supply situation (13,8V - Voltage drop)
BIPLOAR POWER Transistor SD1446
- Technical data -
FACTORY SPECIFICATIONS
========================================
Frequency ............ HF 1.8 - 30 MHz All-Band
Supply ............... 12-14 Vcc
Input energy/power ... 40 A
Input power .......... 1-15 W
Input power SSB ...... 2-20 W
Output power ......... 300 W AM Carrier
Output power SSB ..... 550 W pep
Mode ................. All-Mode
Fuse ................. 4x12 A
Input power levels ... Direct / attenuator -3db
Size ................. 191x450x66
Weight ............... 3.0 Kg
Electronic switch
PTT input
Watt Meter
6 Low-pass filter manual or automatic selected
Manufactory .......... RM ITALY Costruzioni Elettroniche Snc
Via IV Novembre 42
40045 Ponte della venturina (BO) - Italy
Phone: 0534/60460 Fax: 0534/60463
http://www.rmitaly.com
- Documentation -Previously i also owned and used: DENTRON MLA-2500 - DENTRON GLA-1000 - KENWOOD TL-922 - HEATKIT SB-200 - YAESU FL-2100B and some others.
- Power supply -
With the linear amplifier i'm using a switched power supply from RM-Italy. The model SPS 1050 gives up to 55 Ampere peek current and 50 Ampere continuos load.
Power sypply - RM-Italy SPS 1050
- Technical data -
FACTORY SPECIFICATIONS
========================================
Supply ............... 230/240 or 110 Vca
Input energy/power ... 980 VA
Fuse ................. (230V) 5 A
Output Voltage ....... 13,5 ± 0,5 V
Max load ............. 55 A
Continuos load ....... 50 A
Ripple ............... 50 mV
Size ................. 185x113x274
Weight ............... 2,85 Kg
protection ........... Output short circuit
Over output voltage
Automatic forced ventilation
Manufactory .......... RM ITALY Costruzioni Elettroniche Snc
Via IV Novembre 42
40045 Ponte della venturina (BO) - Italy
Phone: 0534/60460 Fax: 0534/60463
http://www.rmitaly.com
- Documentation -<-- Go Back!
©1999/2000/2001/2002 SM2YER Goran