We discuss new Hubble Space Telescope spectroscopy of the radio-loud quasar , 3C 288.1 .
The data cover \sim 590 Å to \sim 1610 Å in the quasar rest frame .
They reveal a wealth of associated absorption lines ( AALs ) with no accompanying Lyman-limit absorption .
The metallic AALs range in ionization from \ion C3 and \ion N3 to \ion Ne8 and \ion Mg10 .
We use these data and photoionization models to derive the following properties of the AAL gas : 1 ) There are multiple ionization zones within the AAL region , spanning a factor of at least \sim 50 in ionization parameter .
2 ) The overall ionization is consistent with the “ warm ” X-ray continuum absorbers measured in Seyfert 1 nuclei and other QSOs .
However , 3 ) the column densities implied by the AALs in 3C 288.1 are too low to produce significant bound-free absorption at any UV–X-ray wavelengths .
Substantial X-ray absorption would require yet another zone , having a much higher ionization or a much lower velocity dispersion than the main AAL region .
4 ) The total hydrogen column density in the AAL gas is \log N _ { H } ( { cm } ^ { -2 } ) \approx 20.2 .
5 ) The metallicity is roughly half solar .
6 ) The AALs have deconvolved widths of \sim 900 km s ^ { -1 } and their centroids are consistent with no shift from the quasar systemic velocity ( conservatively within \pm 1000 km s ^ { -1 } ) .
7 ) There are no direct indicators of the absorber ’ s location in our data , but the high ionization and high metallicity both suggest a close physical relationship to the quasar/host galaxy environment .

Finally , the UV continuum shape gives no indication of a “ blue bump ” at higher energies .
There is a distinct break of unknown origin at \sim 1030 Å , and the decline toward higher energies ( with spectral index \alpha \approx - 1.73 , for f _ { \nu } \propto \nu ^ { \alpha } ) is even steeper than a single power-law interpolation from 1030 Å to soft X-rays .