FTdx-5000 measured performance → Source: RSGB RadCom  June, 2010 by G3SJX – Table 1*
[*Note]: here, only some of the many performances misured – View the RadCom Magazine to read the full review by Peter Hart) – !! IP3, IMD3, and Blocking figures were outstanding with the appropriate Roofing filters selected. !! The only area for concern is the receiver spurious signal rejection….

Sensitivity SSB 10dBs-n:n 7MHz band: IPO-1 →0.7uV (-110dBm) PREAMP-1 →0.18uV (-122dBm) PREAMP-2 →0.09uV (-127dBm)
Intermodulation (Spacing 15kHz) 2400Hz bandwidth 6kH Roofing USB 7MHz band: IPO-1 →IP3 +37.5dBm IMD 105dB PREAMP-1 →IP3 +26dBm IMD 105dB PREAMP-2 →IP3 +18dBm IMD 103dB
Close-in Intermodulation on 7MHz Band 500Hz bandwidth CW IPO-1:
Spacing →2kHz (15kHz Roofing) IP3 -8.5dBm IMD 77dB – (6kHz Roofing) IP3 -4dBm IMD 80dB – (3kHz Roofing) IP3 +33dBm IMD 106dB – (600Hz Roofing) IP3 +37dBm IMD 109dB
Spacing →10kHz (15kHz Roofing) IP3 +38dBm IMD 108dB – (6kHz Roofing) IP3 +39dBm IMD 109dB – (3kHz Roofing) IP3 +38dBm IMD 109dB – (600Hz Roofing) IP3 +38dBm IMD 109dB

The 9MHz IF rejection on most bands was greater than 100dB, but on 10MHz it was only 54dB, and on 7MHz it was 74dB. VRF front-end tuning improved these figures by 20dB. The first mixer image was only down by 55dB to 70dB but VRF improved this to better than 75dB.
Spurs on the synthesiser resulted in a number of unwanted receiver responses, notably at approx +/- 425kHz from the received frequency at only 65dB down on the VFO-A rx and at +/- 40kHz down by 85dB. VRF improves these figures but only marginaly on the higher bands.
Third order intercept (IP3), dynamic range (IMD3) and blocking figures were outstanding with the appropriate Roofing filters selected (See the Table-1*). The VFO-B receiver dynamic range is nont quite as good as the VFO-A receiver but is still very respectable.

Link to: The RSGB webpage – RadCom Magazine

La rejezione IF a 9MHz per la maggior parte delle bande risulta superiore a 100dB, ma sulla banda dei 10MHz scende a soli 54dB, e sulla banda dei 7MHz risulta 74dB.- L’uso del VRF tuning del front-end migliora queste figure di circa 20dB. L’immagine del primo mixer risulta attenuata solo da 55 dB a 70 dB, ma con il VRF si ha un miglioramento al valore di 75dB. Le spurie del sintetizzatore produce una serie di risposte indesiderate al di sotto di soli 65dB  rispetto all frequenza  ricevuta,  in particolare a circa +/- 425kHz dal centro della frequenza  sul VFO-A (main rx), ed ancora a +/- 40kHz sono al di sotto di 85dB. L’inserimento del circuito VRF migliora queste cifre, però solo marginalmente sulle bande più alte di frequenza.
L’intercept point di terzo ordine (IP3), la gamma dinamica  IMD3 e la dinamica di blocco hanno valori che variano in base alla banda passante  del Roofing filter selezionato (Vedere Tabella-1*). Il ricevitore del VFO-B (sub rx) ha a sua volta una dinamica non altrettanto buona come il  ricevitore VFO-A (main rx), ma comunque è  molto rispettabile. – !! Emerge dall’articolo di Peter  Hart una questione che lo preoccupa:  la effettiva capacità di rejezione di segnali spuri del  ricevitore A.
[Note]: RSGB Members Only can now download the June, 2010 RadCom Review  in PDF format.

Yaesy FTdx-5000 The sharp 6/8-pole crystal roofing filter (300 Hz 600 Hz 3 kHz)
The 9 MHz 1st IF Main Receiver: Eight, 3SK294 Dual Gate MOS FETs are employed for the 1st mixer in 2 x 4 configuration to establish the Double Quad Double Balanced Mixer for the FTdx-5000 RX-A  only – See the Board layout and Schematic diagram on the Image depiction by ©www.radiocronache.com (clik to enlarge) – !! Download the Sales Brochures – by Yaesu Inc. – Link below.

The newly designed 9 MHz 1st IF Mixer using MOS FETs have low losses by themselves so than is required at the RF amp, for the Main RF Front End (RX-1 VFO A) – A 15 BPF (8 x Amateur Radio band + 7 x General Coverange Receiver) are  inserted between the VRF UNIT -1 and the IPO/RF amp stage, automatically selected. –

Link to: Download New Sales Brochures (9.51 MB .Pdf)

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The HRDDS (High Resolution Direct Digital Synthesizer) utilizes a direct locking technique a 400 MHz reference signal, resulting in a lock time that approches zero. (Best C/N ratio and BDR)

RF Preselector: New tiny SCR Preselector 1.8MHz to 30MHz Tunable Band Pass Filter Assembled and kit versions. – tiny SCR Preselector (SCR) Software Controlled Radio via USB or I2C Bus (16 bits standard I2C serial bus interface) Made by Heros Technology Ltd in the United Kingdom.
It can be looped between RX OUT and RX IN of the HF Trancseiver, or SDR Receiver.  – A large toroid core T-200-7 is used, the large core offers a non-loaded Q (efficiency) value. A five bands tuneable Band-Pass Filter bank make up the core of the tiny SCR Preselector, and five telecom grade relays for band switching are connected to its corresponding section of the coil through the Band Selector control on the program software

See the Links and  following image – Preselector or not? Icom Digisel, Yaesu VRF ….

tiny SCR Preselector -  Available bands: • A) 1.8 MHz to 3 MHz • B) 3 MHz to 5.5MHz • C) 5 MHz to 10 MHz • D) 10.5 MHz to 21 MHz E) • 16 MHz to 30 MHz. -
A carefully PCB layout design and strong L/C decoupling prevent stages to couple in to each other improving the stop band response and filtering noise from control lines. – The program performs the task of adding or subtracting capacitor values in binary fashion in direct relationship with the tuning control on the program software. Increments or decrements are done in steps of 1pF. – The USB Control Unit is located in a separate module board to avoid introducing noise generated by the microprocessor itself and the noisy USB bus. – The (GUI) software: CD ROM including all software and USB driver for Windows Operate System

Transmission/Return loss of each Band response Plots and other features, and Price:
Link to: Heros Technology co. uk tiny SCR features

Sweep 0 – 30MHz Band and DIGISEL Plotter at 14.1 MHz (click to enlarge image) – The IC-7700 DIGISEL or Yaesu VRF function is similar to outboard tiny SCR Preselector. It has a -6 dB BW of 500 kHz at a centre frequency of 14.1 MHz Ham Band!
IC-7700 DIGI-SEL Insertion Gain & Bandwidth? there is a interesting test on VA7OJ’s website

Link to: IC-7700 DIGI-SEL test by VA7OJ’s

RF Preselector or not?
[Note-1] The outboard tiny SCR Preselector is single-pole, is similar to Icom DIGISEL Preselector or Yaesu VRF Preselector, and have a -6 dB BW of 500 kHz at a centre frequency. These types of preselector (single-pole) provide outstanding protection against OUT-OF-BAND interference, with a bandwidth much narrowe than the standard RF BPF UNIT “fixed bandpass filter networh” – Adding the single-pole preselector can be particulary useful if your station is located near a broadcast station, or if you use Dual Receive a lot in a “multi-trasmitter environment”

[Note-2] Tuned 4-pole preselectors type, typically with motorised air-variable capacitors and air-wound inductors to avoid saturation IMD, have been used in RN shipboard HF installations for yonks, long before the advent of DSP! – See the image HARRIS RF-551A