HM5005 spectrum analyzer
The Hameg HM5005 spectrum analyzer is probably one of the most basic spectrum analyzers one can built. It is clearly built down to a price, and its input frequency range from 0.15 MHz up to only 500 MHz is pretty small for a comercial product. On the plus side I was able to get my HM5005 for approx. 280 USD used on ebay. Taking into account that I will most likely never use a frequency as high as 500 MHz during my hobbiest use this offer was perfect for me. Especially when most other spectrum analyzers on ebay often start at a minimum price tag of 800 USD or far more. The spectrum shown below belongs to the FM radio band.
Opening the unit revails much less electronics than I have expected before. Most likely no custom parts with the advantage of high repairability. The whole power supply is located in the closed metal housing at the back of the unit. All RF input circuitry is located in the fully shielded and closed metal box shown at the top right picture above.
Drawback of course is the lack of functions like Max Hold, only two settings for the resolution bandwidth, and also otherwise very limited performance for a spectrum analyzer. The CRT does not offer a readout function itself, but a frequency marker function is implemented in the form of a 7-segment display. Unfortunetly the resolution of the frequency marker is pretty limited. I want to note that Hameg sold an extra option for this spectrum analyzer (HO500-2) in form of an additional board which allows to readout the spectrum from a computer. Despite of all this limitations I still wanted to introduce this unit here because I like the idea behind this product.
