HamSCI Link Budget: Observations and Modeling the Signal Strength of HF Radio Links from WWV to W2NAF

This work explores the ionospheric High Frequency (HF) absorptions, specifically at 5 and 10 MHz. We investigate the HF absorption levels for the radio links from the two National Institute of Standards and Technology (NIST) dedicated Radio transmitting Stations, WWV Colorado and WWV Hawaii, to the Personal Space Weather Station (PSWS) receiver W2NAF. W2NAF, located near Scranton, Pennsylvania, is equipped with the GPS-disciplined Great Radio Amateur Propagation Experiment (GRAPE) receiver. Our work utilizes the International Reference Ionosphere (IRI-2020) model and PHaRLAP ray tracer to calculate the absorptions of the HF rays from the two WWV transmitters to W2NAF connected by 1, 2, or 3 hop links. For the modeled rays, we also calculate the percentage of successful rays connecting WWV and W2NAF. Our results show that the modeled absorptions are consistent with the signal strength observations for some of the quiet days, albeit with divergences at others. We will present these results on the data-model comparison of the Ham Radio Science Citizen Investigation (HamSCI) link budget.