THIS IS A REQUEST FOR INFORMATION (RFI).
The U.S. Dept. of Commerce National Telecommunications and Information Administration (NTIA), Institute for Telecommunication Sciences (ITS) requires technical and pricing information pertaining to RF combiner/multicoupler systems for land mobile radio repeater stations that operate in the UHF range. The particular application for which the product would be used would be to combine a four-channel UHF trunked Project 25 radio repeater station onto a common single dipole antenna, or, optionally, to combine the transmitters of the trunked system onto a single dedicated transmit dipole antenna plus combine its receivers onto a separate single dedicated receive dipole antenna. Information pertaining to technical parameters, technical performance, post-purchase technical support, price, warranty, and delivery ARO is sought for a quantity of one RF combiner/multicoupler system.

The transmit and receive frequencies, in MHz, of the trunked radio repeaters' channels are listed below:

                 Transmit      Receive
Channel 1: 410.2250   419.2250
Channel 2: 410.4250   419.4250
Channel 3: 410.5000   419.5000
Channel 4: 410.8500   419.8500

The maximum possible transmitter power from each repeater is 100 watts continuous duty cycle and all four repeaters could be transmitting simultaneously. Emission designators are 8k10F1D and 8k10F1E (Project 25 Phase 1 narrowband, FDMA, C4FM, 12.5-kHz channel spacing). The minimum discernable signal of each repeater's receiver is -130 dBm.

The Institute requests that technical information for the UHF combiner/multicoupler system:
(1) Include a block diagram of the design identifying the individual components and subassemblies that comprise it,
(2) identify the maximum transmitter power level, up to 500 watts, that the RF combiner/multicoupler system can sustain under long-term continuous duty cycle conditions when all four of its repeaters are simultaneously transmitting,
(3) include tabulated data and, optionally, graphs (minimum size 3" x 5") for each channel, prepared from either computer simulations or actual measured data, for "representative" operation at each channel's transmit and receive frequencies given above, showing:
(a) absolute magnitude of the transmitter bandpass response in dBc for each channel from repeater connection to antenna connection over a range of at least +2 MHz but not more than +5 MHz and also over a range of at least +25 kHz but not more than +100 kHz, of the channel's transmit frequency,
(b) Transmitter bandpass phase response in degrees for each channel from repeater connection to antenna connection over a range of at least +10 kHz but not more than +50 kHz of the channel's transmit frequency,
(c) Isolation in dBc between the transmitter ports, for each channel evaluated at the channel's transmit frequency,
(d) if the design combines the system's transmitters and receivers onto a single antenna, isolation in dBc between each transmitter port and every receiver port, evaluated over a range of at least +10 kHz but not more than +50 kHz of each channel's transmit frequency,
(e) absolute magnitude of the receiver bandpass response in dBc for each channel from antenna connection to repeater connection over a range of at least +2 MHz but not more than +5 MHz, and also over a range of at least +25 kHz but not more than +100 kHz of the channel's receive frequency,
(f) Receiver bandpass phase response in degrees for each channel from antenna connection to repeater connection over a range of at least +10 kHz but not more than +50 kHz of the channel's receive frequency,
(g) For receive multicoupler designs using active components, noise figure contribution of those devices in dB for each channel at the channel's receive frequency, and
(h) isolation/selectivity in dBc between receiver ports, for each channel evaluated at the other channels' receive frequencies,
(4) an analysis and identification of undesired intermodulation products delivered to each channel's repeater receiver, arising from non-linear interactions between Project 25 modulated spectrum at the system's own transmitter frequencies;
It is desired that the analysis identify what power levels in dBm of intermodulation products are delivered to each channel's receiver that exceeds the minimum discernable signal level, the source of each identified intermodulation product, and what mitigating strategies can be employed to eliminate it,
(5) provide for future expansion of up to a minimum of five channels,
(6) for designs that recommend separate transmit and receive antennas, provide explanation as to why a duplexed single antenna solution is not recommended and the level of improvement that can be realized by adopting a two-antenna solution,
(7) 19" rack-mount mechanical design giving the overall package's physical size (HxWxD), number of equipment racks, weight, and form factor description (e.g., floor-standing 19" equipment rack(s), wall-mountable rack(s) that can be attached to unistrut affixed to concrete load-bearing walls (this is preferred), or other), and
(8) Vendor technical point of contact in event that the Institute has questions of a technical nature about the submitted information.

Existing GSA contract number(s), if applicable, and GSA/Federal Government price, warranty, delivery ARO, duration of time and/or number of free technical support contacts/visits after receipt, should be provided as a separate document from the technical document.

This RFI does not constitute an Invitation for Bids, Request for Proposals or Request for Quotes. Information should be submitted as PDF files on compact disk (supporting files and documentation, if any, can be in Microsoft Office format) and mailed to the US Dept of Commerce, ATTN: Kelly Rima, 325 Broadway St. MC3, Boulder, Colorado 80305 at the contractor's own expense.