IC7800 Rev. 2 - Analysis and News - New version with kHz Roofing Filter and other enhancements

Report as of 08.02.2007 -

QST, March 2007 Product Review: The IC7800 (upgraded) Revisited, by Dave NN1N - 144 dB BDR, 108 dB DR3!

- (click for large table)

Some data drawn from ARRL product reviews are summarized in the table. These reviews are worth reading in their entirety, so as to obtain a systematic comparison between the most recent rigs produced by Icom, Yaesu, Kenwood and Ten-Tec for the amateur radio sector.

Instead, the visible differences between the Rev. 1 and Rev. 2 IC-7800 will be presented below. One can not easily succeed in seeing the inside of an IC-7800, because the Ham who is fortunate enough to have a 7800 in his station is not too keen to open it up to satisfy our curiosity! Thus, I believe that the following images should be of great interest, as they allow us to view and evaluate in detail the differences between the old and new RXPLL-A and RXPLL-B Unit boards, both before and after the board replacement performed in the course of the Rev. 2 upgrade.

Icom is strengthening the already excellent characteristics of its "flagship", the IC-7800. One result is an improvement of at least 10 dB in LO phase noise at 300 Hz to 1 kHz offset from carrier. (See table.)

© - Original images by Marcucci S.p.a . Web page creation by I0GEJ, for informative purposes only. -

 

As well as adding the new 3 kHz roofing filter to the existing 15 and 6 kHz filters, Icom have redesigned many RXPLL circuits, changed the filter-switching IC's, and added various new components and shielding parts. Note the new yellow toroids, and the metallic shields which separate teh PLL/VCO section of the RX-PLL board from the RF/1st IF section. This ensures better isolation between the two compartments when the top cover is closed.

Moreover, each PLL loop filter has been redesigned to improve the spectral purity of the A/B 1st LO. The upgrade program for existing IC-7800 transceivers involves a complete replacement of the RXPLL-A and RXPLL-B Unit boards (Receivers A and B), as well as minor modifications to the Main Unit board.

The new era of technology has dawned! The IC-R9500 has been presented at HamFair 2006.

.

Update 28.10.2006 -

The IC-7800 Rev. 2 upgrade, and performance improvements anticipated by Icom. (Sources: Icom Japan website, CQ Ham Radio Japan)

--(click for large image)

IC7800 version. 2 - Icom, view of new roofing filters, 3 - 6  15 kHz
	Added FL1403 and surrounding circuits, to improve RX blocking dynamic range for main and sub RX circuit. (Roofing filters: FL-396 for main and FL-397 for sub RX - BW 3 kHz). Modified loop filter circuit in PLL for A (Main) and B (Sub) 1st LO - to improve reciprocal mixing noise performance in A (Main) and B (Sub) RX.

Red curve (1st IF 3 kHz roofing filter): New blocking dynamic range 134 dB at 5 kHz spacing!

Here are the new blocking dynamic range (BDR) measurements. These were performed by injecting a fixed 14.100 MHz signal from a crystal oscillator, and tuning the receiver from 1 to 5 kHz offset with respect to the "interfering" test signal (RX in CW mode, preamp off, IF BW = 500 Hz).

Blue curve (1st IF 3 kHz roofing filter): Blocking dynamic range (BDR) was 115 dB max. Thus,in the Rev. 2 (upgraded) version, the resistance to strong adjacent signals is increased with the 3 kHz roofing filter, and also due to the improved LO phase noise in the two PLL's. (Icom Japan data.) As can be seen, IP3 remains at +40 dBm (at 14 MHz).

The curves below appear also in CQ Ham Radio Japan.

Update 26.09.2006 -

On the official website of MARCUCCI, the Italian Icom importer:

The possibility exists for those who acquired an IC-7800 prior to 1 January 2006 to obtain the upgrade, which includes the new 3 kHz roofing-filter feature. We will soon issue instructions for shipping your IC-7800 to the only authorized service center, Davide Tosi in Copparo (Ferrara).

Preliminary news 20.05.2006 -

Icom has submitted to the FCC an application for a change to the IC-7800 authorization (FCC ID AFJ259000) based on the modifications entailed in the Rev. 2 upgrade.

1. Added FL1403 and surrounding circuits, to improve RX blocking dynamic range for main and sub RX circuit. (Roofing filters: FL-396 for main and FL-397 for sub RX - BW 3 kHz).

2. Modified loop filter circuit in PLL for A (Main) and B (Sub) 1st LO - to improve reciprocal mixing noise performance in A (Main) and B (Sub) RX. (RXPLL-A and RXPLL-B redesigned, with many new components.)

In Official Bulletin No 06-58, Icom America announced that the first IC-7800's to be upgraded will be those in dealer inventory, followed by radios already owned by customers. Icom America will charge US IC-7800 owners an upgrade fee of approx. $500. Shipping to Icom America will be at the customer's expense. Customers must make an appointment prior to shipping their radios to Icom; no appointments will be given prior to May 2006.

New firmware (v2.XX) must be installed to enable the basic IC-7800 system to switch in the third roofing filter included in the Rev. 2 upgrade. (Rev. 2 roofing filter selections will be 15 - 6 - 3 kHz).

Here are some comments by Adam VA7OJ/AB4OJ, on local-oscillator phase noise:

A noisy local oscillator can also compromise weak-signal reception. If the synthesiser phase noise is sufficiently high, it can bury a close-in weak signal in the presence of a strong undesired signal.

Here is a link to additional interesting information.

The news appearing in CQ Ham Radio Japan No. 2/2006 is surprising; as of mid-February, the new version of the IC-7800 transceiver will be ready. It will include architectural modifications which will improve the IC-7800's already excellent performance. A third (3 kHz) roofing filter will be added, to complement the existing 6 and 15 kHz filters. Furthermore, the RXPLL-A and RXPLL-B boards will be redesigned; there will most likely be an improvement to the DDS for greater spectral purity. It is said that this will increase the BDR (blocking dynamic range) from 115 dB to 134 dB at 5 kHz offset.

RX PLL units (main & sub) are replaced to correct elevated LO phase noise.

• Firmware is updated

• 3 kHz roofing filter is added to improve the close-in dynamic range (typical data in 14.1 MHz, 5kHz spacing, 115 dB -> 134 dB)

There is more information on Oba-san JA7UDE's site.

The report assures existing IC-7800 owners that their radios will be upgraded. The cost in Japan will be 50 000 Yen (approx. 480 €). In Europe, it is not yet known what the upgrade will cost, or where radios must be shipped for the upgrade.

The February 2006 issue of the splendid Japanese magazine "CQ Ham Radio" includes photos of the new IC-7800 implementation, with the three roofing filters (3, 6 and 15 kHz). They state that this, together with the new DDS design, will improve the local oscillator still further, and will ensure an improvement in third-order intercept point (IP3) in the presence of very close interfering signals (5 or 2 kHz offset), as tested in the ARRL Lab IC-7800 test suite last January.

The photo of the first IC7800 introduced in Italy by Marcucci S.p.a, taken by I0GEJ at the Novegro - Milan Fair in January 2004. A moment of great emotion, and the start of a dream for many here!

I0GEJ in discussions with a manager of Marcucci S.p.a., examining of the specs of the Transceiver and the first manual available in anticipation of teh start of delivery.

New rigs