- for HF NPR linearity testing I usually use either my modified Wandel Goltermann RS-5 White Noise Generator or modified Hewlett Packard 3708A Noise and Interference Test Set (07.022018)
- on HF I often use WG crystal notch filters as per ITU-T G.228 or homebrew, specific notch filters per demand (07.02.2018)
- as an example, a 11700 kHz: narrow span, wide notch filter (insuffient measurement points in the wide span plot for correct response of the notch depth) (07.02.2018)
- here is an S-band test setup I put together for demonstrating Noise Power Ratio linearity testing of power amplifiers (27.10.2014)
- for NPR measurements at microwave frequencies I typically use purpose made waveguide notch filters (27.10.2014)
- listed here some demonstration videos of various RF phenomena:
- notes on passive interference cancelling from my home TV network (in Finnish, updated 25.10.2015)
- article on noise (temperature) measurement (with practical and concrete examples) - to come (16.05.2010)
- in the meantime, some photos: of cold sky, a blooming birch, the hot ground and boiling water, with an article in Finnish
- put together a couple of measurement preamps for field testing, here (142k) is a more robustly packaged amp
- the frequency response/gain curve (27k) of the prototype model, using two Mini-Circuits GAL-21 MMIC's
- a photo of my DVB-T(2) Gap Filler Echo Canceller test box (second delay line is external)
- prototyping a 10.7 -> 30 MHz converter for microwave noise temperature measurements
- pulled together (professional job) a local control box for a special DVB-H dual amplifier, dual antenna transmitter configuration - box under lab tests and in operation
- some notes on an 11 GHz linear, low noise SatCom Esaki Tunnel Diode preamplifier, in Finnish (12.03.2007). The unit sports 40 dB gain and a NF of approx. 6 dB
- test results (professional job) for our SRAL national meeting DVB-T TX after aligment (in Finnish)
- developed a nifty method for calibration and alignment of high stability frequency references using a Vector Network Analyser
- some notes on microwave scattering (21.08.2005)
- this is a link to the RATS Frequency Measurement Competition technical details page (in Finnish)
- found some serious tin whiskers (64k) in the N(m) type connector of a small RF load in my hamshack
- a closer zoom to one of the longer whiskers tin whiskers (51k) and one very long one outside (86k) the outer coax shield
- another photo under different illumination brightness temperature and angle tin whiskers (104k) - pretty scary stuff...
- some notes on my first UWB experiments - dissipating all RF in a 50 ohm termination of course
- a few notes on Passive Intermodulation and the importance of torquing connectors, the 7/16 in particular - also with a VNA RL screenshot
- a 2.4 - 2.5 GHz selective & active multicoupler
- ever wondered what the practical difference between rectangular and gaussian filtering is ?
- Spread Spectrum experiments with a demo box.
- A pulsed microwave source. Here is a time domain image of the RF pulse as seen on an MS2668C spectrum analyser
- an demo AMPS masthead amp simulator ( photo, 43k, measurement results, 15k, on an Anritsu Two Port SiteMaster )
- prototype test port extender for MT8801B tester ( photo here, 101k )
- a demo box for measuring power device S-parameters with an Anritsu Scorpion VNA during TDMA pulsed conditions
- the demo TDMA (GSM) pulse modulation drive box from the front (56k) and from the rear (56k)
- a constant group delay, flat response DVB upconverter (16-QAM, 256-QAM), measurements: Anritsu MS2665C analyser
