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TS-590S G3SJX reviews the Kenwood HF/50MHz transceiver RadCom 01/2011

20/12/2010

Kenwood TS-590S Peter Hart reviews the latest HF/50MHz transceiver on ©RadCom January 2011 – The RSGB Radio Society of Great Britain Members’ magazine.
The figures measured of RadCom  are excellent, similar to or better then top-end radios costing two to four times as much!

Here follows a short summary by © www.radiocronache.com taken from ©RadCom 01/2011 – (View the 01/2011 ©RadCom Magazine to read the full review by Peter Hart. A large and very interesting technical work, thanks) –
Link t0: RSGB Abaut RadCom and news web-page (-Members’ only)

The TS-590S is a single receiver tuning 30 kHz to 60MHz, although the performances is specified within the amateur bands. – The menu system is very comprehensive with 88 items, it uses scrolling display annotation. – Menu items allow for both fast and slow linear switching separely for HF and 50MHz but there is only one linear control line. - For use with transverters, the display can be set to indicate the trasverter frequency.  Three digits are available for the MHz segment, eg 144 or 432.

Measurements – Peter evaluates separately two path: RX1 down-conversion and RX2 up-conversion.  ————– (Short summary data)
The rejection of IFs and image for the RX1 down-conversion path was typically 75dB to 90dB (1*) – For the RX2 up-conversion path these figures were typically better than 90dB. – He searched carefully for other spurious responses as DDS circuits tend to be prone to this problem. – RX2 was very clean with no responses less than 80dB down. – RX1 was exceptionally clean with no other responses less than 100dB down (2*).
- (1*) FTdx-5000 the 9MHz IF rejection on 10MHz it was only 54dB, and on 7MHz it was 74dB. - (2*) FTdx-5000 the first mixer image was only down by 55dB to 70dB (>RadCom  June, 2010 review)

IP3 Intercept and IMD3 Dinamic figures for bands (1.8 3.5 7 14 21 MHz) that use RX-1 the measurement was made 2.3kHz bandwidth. By measuring in 2.8kHz  bandwidth all bands (1.3 3.5 7 10 14 18 21 24 28 50 MHz) use  RX2  path.
—– RX1 path USB mode (50kHz Spacing)
7MHz Preamp OFF – Bandwidt 2.3kHz: IP3 +31dBm IMD3 105dB
7MHz Pream ON —  Bandwidt 2.3kHz:   IP3 +22dBm IMD3 105dB

—– RX2 path USB mode (50kHz Spacing)
24MHz  Preamp OFF – Bandwidt 2.8kHz: IP3 +18dBm IMD3 98dB
24MHz Pream ON – Bandwidt 2.8kHz:    IP3 +6.5dBm IMD3 96dB

Close-in IP3 and IMD3 figures were made in 500Hz bandwidth with RX1 on 7MHz and RX2 on 10MHz.

- RX1 uses the 500Hz bandwidth roofing filter. – RX2 the 2.7kHz bandwidth filter at the second IF and 15kHz rofing filter at the first IF. - The results for RX1 path are really excellente, achiving 103dB IMD3 at 2kHz spacing and 90dB at 1kHz! – The results for RX2 path show the efect of the wider roofing filters (15kHz+2.7kHz). Then at 2kHz and below the signal enter the second IF filter passaband and the AGC takes effect.
—- RX1 7MHz Preamp OFF CW mode – DSP Bandwidt 500Hz – IF Roofing 500Hz:
2kHz sapcing IP3 +23dBm IMD3 103dB / 10kHz spacing IP3 +30.5dBm IMD3 108dB

—- RX2 10MHz Preamp OFF CW mode – DSP Bandwidt 500Hz – IF Roofing 15kHz and 2nd IF  2.7kHz:
2kHz spacing IP3 IMD3 see text below / 10kHz spacing IP3 +21dBm IMD3 103dB

A somewhat complex AGC system is used, detecting signal level in three places within the DSP signal path. – The close-in strong signal performance in some cases may be limited  by the AGC  when a strong signal falling inside the filter roofing but still outside  of the final channel filter will result in AGC action. – This can be heard as a quietening of the receiver from a very strong signal  just outside of the channel passaband. - The effect is most noticeable with the wider roofing filters and is not an issue with the 500Hz roofing filter in circuit. – [Note] clik the thumbnails to enlarge!


FTdx-5000 Review from RadCom June 10 by G3SJX – Here only some data and a summary

11/06/2010

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.


IC-7700 RSGB review summary, RadCom July 2008

06/06/2008


RadCom reviews: IC-7700.  Queste le conclusioni di Peter Hart, G3SJX che ha curato la recenzione per la RSGB, in merito all’analisi dell’Icom IC-7700:
“The IC-7700 is without doubt a most impressive radio. Its performance, its features and its ergonomics place it high in the top league. As a general purpose and contest radio it is excellent, but for serious DXing with split frequency operation the lack of a second channel receive capability or dual-watch is a major shortcoming, particularly with a price tag around 4,000 UK Pounds. It all depends where your interests lie as to which features are most important”.

Link to: Radcom RSGB (Radio Society of Great Britain) Home Page


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