Pith. sign in

REVIEW 3 major objections 5 minor 1 cited by

Understanding the HERA Phase I receiver system with simulations and its impact on the detectability of the EoR delay power spectrum

T0 review · 3 major / 5 minor · reviewed 2026-08-14 · deepseek-v4-flash

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗ Review JSON

Pith's one-line read HERA Phase I's own cables and dish-to-dish coupling delay the 100,000-fold suppression of the system response to 1400 ns, so foreground avoidance leaves line-of-sight wavenumbers below 0.7 h/Mpc contaminated.

desk verdict The qualitative result—mutual coupling dominates HERA Phase I system response at high delays—is solid and important, but the headline 0.7 h/Mpc threshold is an unvalidated extrapolation from a half-length strip; the paper still deserves serious peer review. read the letter →

arxiv 1908.02383 v2 pith:C6IHJX3S submitted 2019-08-06 astro-ph.IM

Nicolas Fagnoni , Eloy de Lera Acedo , David R. DeBoer , Zara Abdurashidova , James E. Aguirre , Paul Alexander , Zaki S. Ali , Yanga Balfour
show 62 more authors
Adam P. Beardsley Gianni Bernardi Tashalee S. Billings Judd D. Bowman Richard F. Bradley Phil Bull Jacob Burba Chris L. Carilli Carina Cheng Matt Dexter Joshua S. Dillon Aaron Ewall-Wice Randall Fritz Steve R. Furlanetto Kingsley Gale-Sides Brian Glendenning Deepthi Gorthi Bradley Greig Jasper Grobbelaar Ziyaad Halday Bryna J. Hazelton Jacqueline N. Hewitt Jack Hickish Daniel C. Jacobs Alec Josaitis Austin Julius Nicholas S. Kern Joshua Kerrigan Honggeun Kim Piyanat Kittiwisit Saul A. Kohn Matthew Kolopanis Adam Lanman Paul La Plante Telalo Lekalake Adrian Liu David MacMahon Lourence Malan Cresshim Malgas Matthys Maree Zachary E. Martinot Eunice Matsetela Juan Mena Parra Andrei Mesinger Mathakane Molewa Miguel F. Morales Tshegofalang Mosiane Abraham R. Neben Bojan Nikolic Aaron R. Parsons Nipanjana Patra Samantha Pieterse Jonathan C. Pober Nima Razavi-Ghods James Robnett Kathryn Rosie Peter Sims Craig Smith Angelo Syce Nithyanandan Thyagarajan Peter K. G. Williams Haoxuan Zheng (the HERA Collaboration)
This is my paper · ORCID
classification astro-ph.IM
keywords EpochofReionization21cmcosmologydelaypowerspectrumforegroundavoidancemutualcouplingreceiverchromaticityHERAradiointerferometry
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

The paper asks whether HERA Phase I can detect the Epoch of Reionization 21-cm signal with a pure foreground-avoidance strategy, and answers that the telescope's own hardware shrinks the usable delay window. Combining full electromagnetic simulations of the antenna array with circuit models of the receiver, the 150-m cable, and the mutual coupling between dishes, it computes the system's voltage time response. The response is not attenuated by a factor of $10^{-5}$ until 1400 ns, which maps to line-of-sight wavenumbers below about $0.7\,h\,\mathrm{Mpc}^{-1}$ at 150 MHz being contaminated by foreground leakage. Earlier single-antenna estimates placed the boundary near $0.2\,h\,\mathrm{Mpc}^{-1}$. The result matters because it changes which Fourier modes of the EoR power spectrum HERA Phase I can actually measure without foreground subtraction.

What carries the argument

The load-bearing object is the system voltage time response $h(\tau)$, obtained by Fourier transforming $H(f)=V_2/E_{\mathrm{in}}$, where $V_2$ is computed from the antenna effective length and the receiver's two-port impedance matrix. Mutual coupling is included by terminating the $2N$-port array $Z$-matrix with the receiver impedance and solving for the input impedance seen by each antenna. A Blackman-Harris window over the 100-200 MHz band sets the $10^{-5}$ noise floor against which reflection levels are judged. The delay-to-wavenumber relation $k_\parallel = 2\pi f_{21} H_p(z)\,\tau/[c(1+z)^2]$ converts the 1400 ns delay into the $0.7\,h\,\mathrm{Mpc}^{-1}$ boundary at 150 MHz.

What would settle it

Take the autocorrelation visibility of an edge antenna in the deployed HERA core, Fourier transform to delay, and compare the envelope with the simulated response: if the normalized response falls below $10^{-5}$ before roughly 1000 ns, the extrapolated boundary is too pessimistic, and if it stays above $10^{-5}$ past 1400 ns, the boundary is too optimistic. A complementary check is to run the same electromagnetic simulation on a longer array and see whether the ~50 ns dish-to-dish echoes persist with the same decay slope.

Watch

Extended reading notes

Core claim

The central discovery is a four-regime system time response. At low delays, reflections between the feed cage and dish vertex dominate; in the mid-delay range, mutual coupling dominates, with echoes arriving roughly every 50 ns as waves hop from one 14.6-m dish to the next with little attenuation; then micro-reflections in the 150-m cable add a quasi-continuous floor; and finally the cable-end reflection produces a factor-300 bump around 1200-1300 ns. Extrapolating the mutual-coupling decay from the simulated 11-column strip to the 300-m core implies the overall response reaches $10^{-5}$ only near 1400 ns, corresponding to $k_\parallel\sim0.7\,h\,\mathrm{Mpc}^{-1}$ at 150 MHz, with edge antennas worse than central ones. The paper further establishes that the dominant coupling path is feed-dish scattering rather than direct feed-feed interaction, and that a source near the horizon can spread the response across a delay equal to twice the array crossing time.

Load-bearing premise

The simulation covers an 11-column strip about 150 m long and extrapolates the mutual-coupling decay slope to the full 300-m core; if echoes in the longer array die out faster or scatter differently, the 1400 ns / $0.7\,h\,\mathrm{Mpc}^{-1}$ boundary moves.

Editorial extensions

If this is right

  • Under a strict foreground-avoidance analysis, HERA Phase I can only claim EoR delay power spectrum measurements at line-of-sight wavenumbers above about $0.7\,h\,\mathrm{Mpc}^{-1}$ at 150 MHz; modes below that are foreground-leakage contaminated.
  • The usable wavenumber range is roughly a factor of 3.5 narrower than the earlier $0.2\,h\,\mathrm{Mpc}^{-1}$ threshold, cutting the number of clean line-of-sight modes available for the EoR measurement.
  • Mutual coupling makes the system response depend on antenna position and array size, so edge antennas are more chromatic and the set of truly redundant baselines shrinks, complicating redundant-baseline calibration.
  • Strong sources near the horizon are especially damaging: their geometric delay spread can reach twice the array crossing time, so horizon radio emission leaks into higher delays.
  • Replacing the coaxial cable with optical links, as planned for Phase II, would remove the 1200-1300 ns cable-end reflection and the micro-reflection floor, leaving mutual coupling as the limiting chromatic effect.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • Inference: if the paper is right, the same coupled-array chromaticity will affect any close-packed 21-cm array whose dish spacing is comparable to a wavelength, so other EoR experiments should recheck their line-of-sight cutoffs with full-array mutual-coupling simulations rather than single-antenna responses.
  • Inference: the array-size dependence implies a sensitivity-versus-chromaticity trade-off: bigger cores buy collecting area but push the foreground wall to larger delays; damping dish-rim scattering could recover some of that delay space.
  • Inference: a direct test of the extrapolation is within reach: a long-duration autocorrelation measurement on the deployed array out to 1400 ns, or a simulation of the full core, would confirm or correct the 0.7 h/Mpc boundary before Phase I data are mined for cosmology.
  • Inference: if the 1400 ns floor holds, Phase I's low line-of-sight modes will likely require calibration-based foreground subtraction or inverse-covariance weighting rather than avoidance, with avoidance reserved for the high-delay end.
Share X Bluesky LinkedIn Reddit HN

Signed reviews

No signed human review yet.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

3 major / 5 minor

Summary. The paper presents co-simulations of the HERA Phase I receiver system, combining electromagnetic models of the antenna array with circuit models of the receiver and cables, to quantify the instrument's chromatic response in the delay domain. It models internal reflections, cable micro-reflections, the 150-m cable end reflection, and mutual coupling in a reduced 11-column strip array. The central result is that the system voltage response is attenuated by only 10^5 after a delay of about 1400 ns, which the authors translate to a limiting k_parallel of about 0.7 h/Mpc at 150 MHz, implying that foreground avoidance with HERA Phase I is more challenging than previously estimated (which had suggested ~0.2 h/Mpc).

Significance. If the central claim holds, the paper is important: it directly affects the forecast sensitivity and data analysis strategy of HERA Phase I, a major 21-cm EoR experiment. The paper's strengths include validation of component models against VNA measurements, in-situ beam comparisons (to -20 dB), and receiver noise measurements; a clear separation of the contributions of different chromatic terms; and an explicit acknowledgement, in Section 5.3, that the full-core conclusion relies on an extrapolation of the decay slope from a reduced strip. The companion data paper (Kern et al. 2020a) provides partial empirical support to delay ~500 ns. The headline 1400 ns / 0.7 h/Mpc number, however, is not directly validated or simulated for the full core, so the quantitative significance is conditional on the validity of that extrapolation.

major comments (3)
  1. [Sec. 5.3 and Sec. 6] The headline quantitative claim that the system response is attenuated by 10^5 only after 1400 ns, and the resulting statement that k_parallel modes below 0.7 h/Mpc are affected, is not a direct simulation result for the full HERA core. Section 5.3 explicitly states that the simulated strip is 'half of the final length of the core' and that the 10^5 crossing at about 1000 ns is obtained by extrapolating the slope of the system response, with the 1400 ns figure then adding the 150-m cable reflection. The full core is a two-dimensional 300 m by 250 m array, not a doubled one-dimensional strip. Because this quantity is load-bearing for the paper's main conclusion, the extrapolation must be either validated (e.g., by a larger or full-core simulation, or by extending the empirical comparison to the relevant delay range) or presented with a quantitative uncertainty budget and clearly marked as an extrapolated estimate in the abstract and conclusions. Currently Section 6 states the 1400 ns and 0.7 h/Mpc values without this caveat.
  2. [Sec. 4.4 and Fig. 13] The mutual-coupling simulation is a one-dimensional 11-column strip with a specific edge termination. The conclusion that 'any antenna could significantly interact with the dishes at the edges' depends on the assumption that the dominant propagation path is along a single row and that the decay slope in the strip is representative of the full two-dimensional core. Equation (17) shows that the coupling delay depends on Dmax, which in a 2-D core would vary with direction and antenna position, and corner geometries or diagonal paths could modify the tail of the response. This assumption is not tested, yet it directly sets the time constant of the 10^-4 and 10^-5 crossings used in the paper. Please provide additional justification or a test of this strip-to-core extrapolation, or soften the full-core claims accordingly.
  3. [Sec. 6, last paragraph] The comparison with the 46-antenna data from Kern et al. (2020a) is described as 'consistent' with the simulations, but the data exhibit a noise floor at about 10^-4 after 500 ns. The decisive quantity for the headline claim is the 10^-5 crossing at about 1400 ns, which is not probed by these data. The paper should state explicitly the range of delays over which the simulations are empirically validated, and identify what evidence (if any) bears on the extrapolated regime. Without this, the statement in the abstract that 'the system response is attenuated by a factor 10^5 after 1400 ns' overstates the current level of validation.
minor comments (5)
  1. [Sec. 4.2, last paragraph] The sentence 'Nunhokee et al. (2020) has measured the HERA radiation pattern...' should use the plural verb 'have measured'.
  2. [Fig. 13 caption] The caption 'for various antenna configurations' is vague; please specify which positions (center, edge) and which configurations (all feeds present, single feed, etc.) are shown so the figure is self-contained.
  3. [Sec. 3.3] The statement 'We verify that the output voltage is attenuated by a factor 10^5 at least' should identify the configuration for which this verification was performed (single antenna versus array), since the later array simulations show a slower decay.
  4. [Eq. (17)] Please define Dmax explicitly as the distance to the farthest aligned antenna in the simulated strip, and note that for the full two-dimensional core this quantity would depend on direction and reference antenna position.
  5. [Sec. 5.3] The conditional sentence beginning 'If the simulated antenna strip were longer, the extrapolation of the slope...' is a key caveat. Consider moving this caveat to the abstract or conclusions, or at least ensuring the numbers quoted in Section 6 are clearly labeled as extrapolated estimates.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the simulated 1400 ns / 0.7 h Mpc^-1 threshold is an output of electromagnetic and circuit simulations whose inputs are external component measurements and a standard delay-to-k_parallel conversion, not a fit or self-referential derivation.

full rationale

The central claim, stated in Section 6 as "The response is attenuated by a factor 10^5 only after 1400 ns, which means that the k_parallel-modes below 0.7 h Mpc^-1 are affected by the foreground leakage," is a simulated output rather than a fitted parameter. The inputs are external component characterizations: CST antenna models, VNA measurements of receiver and cable S/Z parameters, manufacturer transistor data, and a literature-based sky model. No parameter is fitted to the EoR delay power spectrum or to the 10^5 crossing time. The 0.7 h Mpc^-1 value follows from the standard cosmological mapping in Equation (5), which converts delay tau to k_parallel using known redshift and bandwidth relations; it is not an assumption that contains the conclusion. The 10^5 attenuation requirement is stated as a foreground-contrast design goal, not derived from the simulation target. The paper also cites companion papers by collaboration members, notably Kern et al. (2020a) for 46-antenna data consistency and Kern et al. (2020b) for calibration applications, but the central prediction does not reduce to those citations: the measured data are presented as a consistency check with an explicitly acknowledged noise floor at about 10^-4 after 500 ns, and the simulation's delay tail is the primary evidence. The most significant limitation is the explicit extrapolation from the simulated 11-column strip, which is about half the final core length: Section 5.3 states "If the simulated antenna strip were longer, the extrapolation of the slope of the system response suggests..." and Section 6 notes the 46-antenna data were collected "in a larger two-dimensional array with a more complex configuration compared with our simulation." This is a transparent robustness and validation caveat about extrapolation, not a circular step: the conclusion is not equivalent to its inputs by construction, and no fitted input is renamed as a prediction. No uniqueness theorem is invoked, no ansatz is smuggled in via citation, and no known result is merely renamed. The main residual concern is correctness risk from extrapolating the mutual-coupling tail to the full core, not circularity.

Assumptions & free parameters 4 free parameters · 4 assumptions · 0 invented entities

The central prediction depends on several literature inputs (sky temperature law, receiver datasheet, cable measurements) and one explicit extrapolation from a truncated simulated array. No new physical entities are introduced.

free parameters (4)
  • Sky temperature power-law normalization = 180 K at 180 MHz
    Used in Eq. 16 for Tsys; taken from Furlanetto (2016), not derived here.
  • Sky temperature spectral index = -2.6
    Same power law; an input from prior literature.
  • Chromatic cable micro-reflection parameters = Not reported
    The final co-simulation uses 'a chromatic cable' (Sec 5.3) whose local impedance variations produce micro-reflections; the parameters are not given in the paper, so this is an unquantified input fitted to lab cable measurements.
  • Receiver noise parameters = Fmin 1.6-1.8 dB, RN 27 ohm, Zopt 135+30j ohm
    Datasheet values used as inputs to the circuit simulation (Sec 3.2).
assumptions (4)
  • domain assumption The antenna and receiver form a linear, time-invariant system, so the output voltage is a convolution of the incident field with an impulse response (Sec 2.1).
    Standard for RF systems; not proven for this array.
  • domain assumption Far-field approximation for the antenna effective length, neglecting the radial field component (Sec 4.3, Eq. 10).
    Standard for a 14-m dish at 100-200 MHz.
  • domain assumption Uniform sky brightness for the system temperature estimate (Sec 5.1).
    Used to convert receiver temperature into Tsys; a real sky has angular structure.
  • ad hoc to paper The mutual coupling simulation strip is representative of the full HERA core, and the decay slope can be extrapolated to the full 300-m array (Sec 5.3, Fig. 13).
    Load-bearing for the 0.7 h/Mpc threshold; explicitly an extrapolation.

how reviews work

0 comments
Cite this review

Pith. "Pith review of Understanding the HERA Phase I receiver system with simulations and its impact on the detectability of the EoR delay power spectrum." pith.science (2026). https://pith.science/paper/C6IHJX3S

@misc{pith2026190802383,
  author       = {Pith},
  title        = {Pith review of: Understanding the HERA Phase I receiver system with simulations and its impact on the detectability of the EoR delay power spectrum},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/C6IHJX3S}},
  note         = {Machine review of arXiv:1908.02383}
}
abstract

The detection of the Epoch of Reionization (EoR) delay power spectrum using a "foreground avoidance method" highly depends on the instrument chromaticity. The systematic effects induced by the radio-telescope spread the foreground signal in the delay domain, which contaminates the EoR window theoretically observable. Applied to the Hydrogen Epoch of Reionization Array (HERA), this paper combines detailed electromagnetic and electrical simulations in order to model the chromatic effects of the instrument, and quantify its frequency and time responses. In particular, the effects of the analogue receiver, transmission cables, and mutual coupling are included. These simulations are able to accurately predict the intensity of the reflections occurring in the 150-m cable which links the antenna to the back-end. They also show that electromagnetic waves can propagate from one dish to another one through large sections of the array due to mutual coupling. The simulated system time response is attenuated by a factor $10^{4}$ after a characteristic delay which depends on the size of the array and on the antenna position. Ultimately, the system response is attenuated by a factor $10^{5}$ after 1400 ns because of the reflections in the cable, which corresponds to characterizable ${k_\parallel}$-modes above 0.7 $h\;\rm{Mpc}^{-1}$ at 150 MHz. Thus, this new study shows that the detection of the EoR signal with HERA Phase I will be more challenging than expected. On the other hand, it improves our understanding of the telescope, which is essential to mitigate the instrument chromaticity.

Figures

Figures reproduced from arXiv: 1908.02383 by the authors.

Figure 1
Figure 1. [PITH_FULL_IMAGE:figures/full_fig_p004_1.png] view at source ↗
Figure 2
Figure 2. HERA dish and feed modelled with the simulation software CST. the frequency response. The dipoles are terminated by four pins which are directly connected to the ”front-end module” (FEM). Its presence is modelled by a brass tube terminated by two coaxial cables. The feed is surrounded by a cage which tapers the beam radiated by the dipoles. The cage is made up of two elements: a 172-cm backplane and a 36-cm high cyl… view at source ↗
Figure 3
Figure 3. Equivalent electrical circuit of the antenna - RF re￾ceiver system. while taking into account the transmission and reflection effects through the chain. Zrec = Z11 − Z12Z21 ZL + Z22 . (7) 4.2 Validation of the models with measurements A vector network analyzer (VNA) is used to measure the S and Z-parameters of each block of the receiver and of the antenna. The impedances obtained from measurements and simulations ar… view at source ↗
Figures from the paper (11 more)
Figure 4
Figure 4. Figure 4: Differential input impedance of the RF receiver and of the antenna, from measurements (”meas”) and simulations (”simu”) [PITH_FULL_IMAGE:figures/full_fig_p006_4.png]
Figure 5
Figure 5. Figure 5: Amplitude of the voltage reflection coefficient at the interface between the antenna output and the receiver input. 4.3 System voltage response We now include the effects of the antenna beam pattern and its frequency response, in the description of the system. Voc prev…
Figure 6
Figure 6. Figure 6: Array configuration used to simulate the mutual cou￾pling in HERA with CST. The red numbers correspond to the ports associated with the X-polarization, and the blue numbers with the Y-polarization. To compute the response associated with a receiver, this 2N-port networ…
Figure 7
Figure 7. Figure 7: Noise generated by the sky, the radiation losses, and the simulated / measured receivers when terminated by 100 Ω or the measured antenna impedance. Combined together, they define the system noise temperature. 100 Ω, the differential impedance of the measurement de￾vic…
Figure 11
Figure 11. Figure 11: Gain patterns at 150 MHz (amplitude in dB) without and with mutual coupling in the simulated strip configuration, Y￾polarisation [PITH_FULL_IMAGE:figures/full_fig_p009_11.png]
Figure 12
Figure 12. Figure 12: Percentage of difference in the simulated gain at zenith with respect to a system without mutual coupling. on the antenna position, the 3-dB beamwidth varies up to 1 ◦ , and the gain at zenith fluctuates by ± 0.3 dB, which represents a difference of up to 7% (cf [PIT…
Figure 13
Figure 13. Figure 13: System time response at zenith, terminated by a 125-Ω load and including mutual coupling for various antenna configurations. attenuated by a factor 104 between 600 and 700 ns, and by a factor 105 after about 1000 ns. By comparison, the core of the final array is about…
Figure 14
Figure 14. Figure 14: Snapshots of the electric field propagating through the array, when the antennas are excited by a plane wave coming from the zenith, at t = 0 ns, 25 ns, 50 ns, 75 ns, 100 ns, 200 ns, 400 ns, and 600 ns. The intensity of the E-field is expressed in dBV/m. Note how a pa…
Figure 15
Figure 15. Figure 15: System time response at zenith, terminated by the measured receiver, and including mutual coupling for the port 2 (Y-polarization) [PITH_FULL_IMAGE:figures/full_fig_p011_15.png]
Figure 16
Figure 16. Figure 16: Time response of the system terminated by the mea￾sured receiver and including mutual coupling for the port 2 (Y￾polarization), and for a plane wave coming with an incidence angle θ in the H-plane [PITH_FULL_IMAGE:figures/full_fig_p011_16.png]
Figure 17
Figure 17. Figure 17: Maximum delays before the system response is atten￾uated by a certain factor, with the measured receiver, including mutual coupling, for the port 2 (Y-polarization), and for the H￾plane. reference antenna at the edges will receive the main signal approximately at the …

Discussion (0). Continue with ORCID to comment.

Forward citations

Cited by 1 Pith paper

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

  1. Intensity fluctuations of radio halo in galaxy cluster: Insights from power spectrum estimation

    astro-ph.CO 2026-07 conditional novelty 6.0 of 10

    Angular power spectra of 610 MHz radio halos show excess power-law fluctuations only in Abell 2744, requiring multiplicative C_ℓ ∝ ℓ^{-3} structure atop an exponential profile and consistent with ICM turbulence.

Reference graph

Works this paper leans on

57 extracted references · 17 canonical work pages · cited by 1 Pith paper

  1. [1]

    S., et al., 2015, @doi [ApJ] 10.1088/0004-637X/809/1/61 , 809, 61

    Ali Z. S., et al., 2015, @doi [ApJ] 10.1088/0004-637X/809/1/61 , 809, 61

    doi:10.1088/0004-637x/809/1/61 2015

  2. [2]

    D., Morales M

    Bowman J. D., Morales M. F., Hewitt J. N., 2009, @doi [ApJ] 10.1088/0004-637X/695/1/183 , 695, 183

    doi:10.1088/0004-637x/695/1/183 2009

  3. [3]

    Antennas Propag.] 10.1109/TAP.1981.1142671 , 29, 773

    Bucci O., Di Massa G., Savarese C., 1981, @doi [IEEE Trans. Antennas Propag.] 10.1109/TAP.1981.1142671 , 29, 773

    work page arXiv 1981

  4. [4]

    CEL 2012, NE461M02 / 2SC5337 NPN RF transistor data sheet , http://www.cel.com/pdf/datasheets/ne461m02.pdf

    work page 2012

  5. [5]

    Chapman E., et al., 2012, @doi [MNRAS] 10.1111/j.1365-2966.2012.21065.x , 423, 2518

    arXiv 2012

  6. [6]

    B., Dulwich F., Jeli \' c V., Mort B., 2016, @doi [MNRAS] 10.1093/mnras/stw161 , 458, 2928

    Chapman E., Zaroubi S., Abdalla F. B., Dulwich F., Jeli \' c V., Mort B., 2016, @doi [MNRAS] 10.1093/mnras/stw161 , 458, 2928

    doi:10.1093/mnras/stw161 2016

  7. [7]

    Clemens M., Weiland T., 2001, @doi [PIER] 10.2528/PIER00080103 , 32, 65

    doi:10.2528/pier00080103 2001

  8. [8]

    Cortes-Medellin G., 2007, SKA Memo 95: Antenna Noise Temperature Calculation , https://www.skatelescope.org/uploaded/6967_Memo_95.pdf

    work page 2007

Show all 57 references
  1. [9]

    Craeye C., Gonz \' a lez-Ovejero D., 2011, @doi [Radio Sci.] 10.1029/2010RS004518 , 46

    2011 doi

  2. [10]

    R., 2015, HERA Memo 11: HERA Phase I Feed Design, http://reionization.org/wp-content/uploads/2015/01/feedP1.pdf

    DeBoer D. R., 2015, HERA Memo 11: HERA Phase I Feed Design, http://reionization.org/wp-content/uploads/2015/01/feedP1.pdf

    2015

  3. [11]

    R., et al., 2017, @doi [PASP] 10.1088/1538-3873/129/974/045001 , 129, 045001

    DeBoer D. R., et al., 2017, @doi [PASP] 10.1088/1538-3873/129/974/045001 , 129, 045001

    2017 doi

  4. [12]

    S., Parsons A

    Dillon J. S., Parsons A. R., 2016, @doi [ApJ] 10.3847/0004-637X/826/2/181 , 826, 181

    2016 doi

  5. [13]

    S., et al., 2014, @doi [Phys

    Dillon J. S., et al., 2014, @doi [Phys. Rev. D] 10.1103/PhysRevD.89.023002 , 89, 023002

    2014 doi

  6. [14]

    S., et al., 2018, @doi [MNRAS] 10.1093/mnras/sty1060 , 12, 1

    Dillon J. S., et al., 2018, @doi [MNRAS] 10.1093/mnras/sty1060 , 12, 1

    2018 doi

  7. [15]

    Ewall-Wice A., et al., 2016, @doi [ApJ] 10.3847/0004-637X/831/2/196 , 831, 196

    2016 doi

  8. [16]

    S., Liu A., Hewitt J., 2017, @doi [MNRAS] 10.1093/mnras/stx1221 , 470, 1849

    Ewall-Wice A., Dillon J. S., Liu A., Hewitt J., 2017, @doi [MNRAS] 10.1093/mnras/stx1221 , 470, 1849

    2017 doi

  9. [17]

    Fagnoni N., de Lera Acedo E., 2016, in Int. Conf. Electromagn. Adv. Appl. (ICEAA). IEEE, Cairns, Australia, pp 629--632, @doi 10.1109/ICEAA.2016.7731474

    2016

  10. [18]

    R., Riley D., Razavi-Ghods N., Carey S., Parsons A

    Fagnoni N., de Lera Acedo E., Drought N., DeBoer D. R., Riley D., Razavi-Ghods N., Carey S., Parsons A. R., 2020, Design of the New Wideband Vivaldi Feed for the HERA Radio-Telescope Phase II , Submitted to IEEE Trans. Antennas Propag

    2020

  11. [19]

    R., 2016, The 21-cm Line as a Probe of Reionization

    Furlanetto S. R., 2016, The 21-cm Line as a Probe of Reionization . Springer International Publishing, @doi 10.1007/978-3-319-21957-8_9

    2016 doi

  12. [21]

    J., 1978, @doi [Proc

    Harris F. J., 1978, @doi [Proc. IEEE] 10.1109/PROC.1978.10837 , 66, 51

    1978

  13. [22]

    C., et al., 2016, @doi [ApJ] 10.3847/0004-637X/825/2/114 , 825, 114

    Jacobs D. C., et al., 2016, @doi [ApJ] 10.3847/0004-637X/825/2/114 , 825, 114

    2016 doi

  14. [23]

    Antennas Propag.] 10.1109/8.99046 , 39, 1372

    Jenn D., Rusch W., 1991, @doi [IEEE Trans. Antennas Propag.] 10.1109/8.99046 , 39, 1372

    1991 doi

  15. [24]

    S., et al., 2020a, @doi [ApJ] 10.3847/1538-4357/ab5e8a , 888, 70

    Kern N. S., et al., 2020a, @doi [ApJ] 10.3847/1538-4357/ab5e8a , 888, 70

    doi

  16. [25]

    S., et al., 2020b, @doi [ApJ] 10.3847/1538-4357/ab67bc , 890, 122

    Kern N. S., et al., 2020b, @doi [ApJ] 10.3847/1538-4357/ab67bc , 890, 122

    doi

  17. [26]

    Liu A., Tegmark M., Morrison S., Lutomirski A., Zaldarriaga M., 2010, @doi [MNRAS] 10.1111/j.1365-2966.2010.17174.x , 408, 1029

    2010

  18. [27]

    R., Trott C

    Liu A., Parsons A. R., Trott C. M., 2014, @doi [Phys. Rev. D] 10.1103/PhysRevD.90.023018 , 90, 023018

    2014 doi

  19. [28]

    T., Leong M

    Lui H.-S., Hui H. T., Leong M. S., 2009, @doi [IEEE Antennas Propag. Mag.] 10.1109/MAP.2009.5432083 , 51, 171

    2009

  20. [29]

    McQuinn M., Lidz A., Zahn O., Dutta S., Hernquist L., Zaldarriaga M., 2007, @doi [MNRAS] 10.1111/j.1365-2966.2007.11489.x , 377, 1043

    2007

  21. [30]

    Mesinger A., Ewall-Wice A., Hewitt J., 2014, @doi [MNRAS] 10.1093/mnras/stu125 , 439, 3262

    2014 doi

  22. [31]

    F., Wyithe J

    Morales M. F., Wyithe J. S. B., 2010, @doi [Annu. Rev. Astron. Astrophys.] 10.1146/annurev-astro-081309-130936 , 48, 127

    2010 doi

  23. [32]

    D., et al., 2020, @doi [ApJ] 10.3847/1538-4357/ab9634 , 897, 5

    Nunhokee C. D., et al., 2020, @doi [ApJ] 10.3847/1538-4357/ab9634 , 897, 5

    2020 doi

  24. [33]

    J., 2016, Electromagnetic Waves and Antennas

    Orfanidis S. J., 2016, Electromagnetic Waves and Antennas. https://www.ece.rutgers.edu/ orfanidi/ewa

    2016

  25. [34]

    S., Ewall-Wice A., Parsons A

    Orosz N., Dillon J. S., Ewall-Wice A., Parsons A. R., Thyagarajan N., 2019, @doi [MNRAS] 10.1093/mnras/stz1287 , 487, 537

    2019 doi

  26. [35]

    R., Bradley R

    Parashare C. R., Bradley R. F., 2006a, Memo P011: 75 Transmission System , http://eor.berkeley.edu/wp-content/uploads/2011/09/p011.cparashare.pdf

    2011

  27. [36]

    R., Bradley R

    Parashare C. R., Bradley R. F., 2006b, Memo P012: 120-205 MHz Receiver for PAPER: Precision Array to Probe the Epoch of Reionization , http://eor.berkeley.edu/wp-content/uploads/2011/09/p012.cparashare.pdf

    2011

  28. [37]

    R., Bradley R

    Parashare C. R., Bradley R. F., 2007, Memo P013: Instrument Development for PAPER: A Precision Array to Probe the Epoch of Reionization , http://eor.berkeley.edu/wp-content/uploads/2011/09/p013.cparashare.pdf

    2007

  29. [38]

    Parsons A., et al., 2008, @doi [PASP] 10.1086/593053 , 120, 1207

    2008 doi

  30. [39]

    R., et al., 2010, @doi [AJ] 10.1088/0004-6256/139/4/1468 , 139, 1468

    Parsons A. R., et al., 2010, @doi [AJ] 10.1088/0004-6256/139/4/1468 , 139, 1468

    2010 doi

  31. [40]

    Parsons A., Pober J., McQuinn M., Jacobs D., Aguirre J., 2012a, @doi [ApJ] 10.1088/0004-637X/753/1/81 , 753, 81

    doi

  32. [41]

    R., Pober J

    Parsons A. R., Pober J. C., Aguirre J. E., Carilli C. L., Jacobs D. C., Moore D. F., 2012b, @doi [ApJ] 10.1088/0004-637X/756/2/165 , 756, 165

    doi

  33. [42]

    Astron.] 10.1007/s10686-017-9563-0 , 45, 177

    Patra N., et al., 2018, @doi [Exp. Astron.] 10.1007/s10686-017-9563-0 , 45, 177

    2018 doi

  34. [43]

    C., et al., 2014, @doi [ApJ] 10.1088/0004-637X/782/2/66 , 782, 66

    Pober J. C., et al., 2014, @doi [ApJ] 10.1088/0004-637X/782/2/66 , 782, 66

    2014 doi

  35. [44]

    C., et al., 2015, @doi [ApJ] 10.1088/0004-637X/809/1/62 , 809, 62

    Pober J. C., et al., 2015, @doi [ApJ] 10.1088/0004-637X/809/1/62 , 809, 62

    2015 doi

  36. [45]

    M., 2011, Microwave Engineering, 4th edn

    Pozar D. M., 2011, Microwave Engineering, 4th edn. Wiley

    2011

  37. [46]

    R., Loeb A., 2012, @doi [Rep

    Pritchard J. R., Loeb A., 2012, @doi [Rep. Prog. Phys.] 10.1088/0034-4885/75/8/086901 , 75, 086901

    2012 doi

  38. [47]

    Circuits Syst., II, Exp

    Rahola j., 2008, @doi [IEEE Trans. Circuits Syst., II, Exp. Briefs] 10.1109/TCSII.2007.905420 , 55, 92

    2008

  39. [48]

    R., Moran J

    Thompson A. R., Moran J. M., Swenson G. W., 2017, Interferometry and Synthesis in Radio Astronomy , 3rd edn. Springer International Publishing, @doi 10.1007/978-3-319-44431-4

    2017 doi

  40. [49]

    Thyagarajan N., et al., 2013, @doi [ApJ] 10.1088/0004-637X/776/1/6 , 776, 6

    2013 doi

  41. [50]

    Thyagarajan N., et al., 2015a, @doi [ApJ] 10.1088/0004-637X/804/1/14 , 804, 14

    doi

  42. [51]

    Thyagarajan N., et al., 2015b, @doi [ApJ] 10.1088/2041-8205/807/2/L28 , 807, L28

    doi

  43. [52]

    R., DeBoer D

    Thyagarajan N., Parsons A. R., DeBoer D. R., Bowman J. D., Ewall-Wice A. M., Neben A. R., Patra N., 2016, @doi [ApJ] 10.3847/0004-637X/825/1/9 , 825, 9

    2016 doi

  44. [53]

    J., et al., 2013, @doi [Publ

    Tingay S. J., et al., 2013, @doi [Publ. Astron. Soc. Aust.] 10.1017/pasa.2012.007 , 30, e007

    2013 doi

  45. [54]

    P., et al., 2013, @doi [A&A] 10.1051/0004-6361/201220873 , 556, A2

    Van Haarlem M. P., et al., 2013, @doi [A&A] 10.1051/0004-6361/201220873 , 556, A2

    2013 doi

  46. [55]

    J., Seshadri S

    Vernon R. J., Seshadri S. R., 1969, @doi [Proc. IEEE] 10.1109/PROC.1969.6893 , 57, 101

    1969

  47. [56]

    Weiland T., 1977, Electron. Commun. AEU, 31, 116

    1977

  48. [57]

    Zhu C., Zhuang Y., Chen Y., Huang J., 2019, @doi [IEEE Trans. Instrum. Meas.] 10.1109/TIM.2018.2890327 , 68, 4600

    2019

  49. [58]

    write newline

    " write newline "" before.all 'output.state := FUNCTION fin.entry write newline FUNCTION new.block output.state before.all = 'skip after.block 'output.state := if FUNCTION new.sentence output.state after.block = 'skip output.state before.all = 'skip after.sentence 'output.stat...

Pith tools

Reviewed August 14, 2026 · model on record in the stance chip above.