S53MV Notune SSB giga radio set

Description: This article is a local and enduring copy derived from replica sites. It appears to have undergone significant revisions in 2006, leading to the disappearance of the original version. When considering SSB transceivers, the primary question is whether it is worthwhile to develop and manufacture new SSB radios. Currently, SSB transceivers are mass-produced for frequencies below 30 MHz. However, options are limited for 144 MHz or 432 MHz SSB transceivers, with only a few products available for 1296 MHz or higher frequencies. Most radio amateurs utilize a base SSB transceiver (typically a commercial product) that operates on lower frequencies, complemented by suitable receive and transmit converters or transverters for operation at 1296 MHz or higher. The IC202 is the most popular base transceiver. Most narrow-band (SSB/CW) microwave activity is concentrated in the first 200 kHz of amateur microwave segments, such as 1296.000-1296.200 and 2304.000-2304.200, due to the limited frequency coverage of the IC202. Transverters are often regarded as a suboptimal technical solution for several reasons. Receive converters can degrade the dynamic range of the receiver, while transmit converters often dissipate much of the RF power generated by the base SSB transceiver. Additionally, both types of converters produce spurious mixing products that are challenging to filter out due to the harmonic relationships among amateur frequency bands (144/432/1296). The most significant issue with many transverters is the breakthrough of strong signals within or outside the base transceiver's intermediate-frequency band, particularly problematic when using a 144 MHz first IF. Strong 144 MHz stations with substantial antenna arrays may interfere with the first IF even at distances of 50 or 100 km. This reciprocal issue can allow a careless microwave operator to establish two-way contacts on 144 MHz while using a transverter and antenna designed for 1296 MHz or higher frequencies. Some microwave operators have addressed this problem by installing a different crystal in the transverter, converting, for example, 1296.000 MHz to a less utilized segment around 144.700 MHz. Serious microwave contest operators often use transverters with a first IF of 28 MHz, 50 MHz, or even 70 MHz to circumvent the aforementioned issues. However, neither of these solutions is inexpensive. A significant challenge is transporting a large 144 MHz or HF all-mode transceiver along with a suitable power supply to a mountaintop. The IC202 itself has its own issues, as it has not been manufactured for over a decade. New radios are unavailable, and maintaining older units is increasingly difficult. Second-hand radios are often found in poor condition due to numerous modifications and "improvements" made by previous owners. In conclusion, it remains relevant to develop and construct SSB radios for 1296 MHz and higher frequencies. The known challenges associated with transverters have prompted various designers to consider numerous technical solutions, though most were rejected due to complexity, cost, and construction difficulty, especially when compared to the already intricate combination of a base RTX and transverter. Most commercial SSB transceivers incorporate a modulator and demodulator operating at a high IF, as illustrated in the referenced figure. The resulting SSB signal is converted to the RF operating frequency in the transmitter and reverted to the IF in the receiver. Both the transmitter and receiver utilize costly components, including crystal filters. In addition to crystal filters, further filtering is necessary in the RF section to suppress image responses and spurious products from both receiving and transmitting mixers. The design of conventional (high-IF) SSB transceivers has its roots in vacuum tube technology.

The development of SSB (Single Sideband) transceivers has evolved significantly, particularly in the context of amateur radio frequencies. The current landscape indicates a predominance of mass-produced SSB transceivers for frequencies below 30 MHz, while options for higher frequencies, such as 144 MHz, 432 MHz, and 1296 MHz, remain limited. This scarcity necessitates the use of base transceivers, which are often commercial products designed for lower frequencies, paired with converters or transverters to facilitate operation at higher frequencies.

The IC202 model stands out as a widely used base transceiver, although its limited frequency coverage restricts the operational bandwidth for amateur microwave activities. This limitation results in the concentration of narrow-band microwave activity within the first 200 kHz of segments like 1296.000-1296.200. Transverters, while providing a means to access these higher frequencies, introduce various technical challenges, including degradation of dynamic range, power dissipation issues, and the generation of spurious signals that complicate filtering processes.

One of the critical challenges faced by operators using transverters is the breakthrough of strong signals from nearby stations, particularly when utilizing a 144 MHz first intermediate frequency (IF). This can lead to interference that complicates communication, even at considerable distances. Solutions to mitigate these challenges have been explored, including the alteration of crystal frequencies within transverters to avoid congested segments. Additionally, using a higher first IF, such as 28 MHz or 50 MHz, has been proposed to minimize interference issues, although these approaches can be costly and complex.

Despite the challenges associated with older models like the IC202, which is no longer in production and often found in suboptimal condition due to prior modifications, the development of new SSB radios for higher frequencies remains a relevant pursuit. The technical solutions proposed by various designers reflect an ongoing effort to address the inherent limitations of existing equipment and enhance performance in the amateur radio spectrum.

Modern SSB transceivers typically incorporate sophisticated modulators and demodulators operating at high intermediate frequencies, facilitating the conversion of SSB signals to the desired RF frequencies and vice versa. The inclusion of high-quality components, such as crystal filters, is essential to ensure signal integrity and minimize unwanted artifacts. The design principles of these transceivers have evolved from earlier vacuum tube technologies, reflecting advancements in both componentry and circuit design methodologies.This article is copied from replica sites to here in order to have a local and long living copy at hand. It seems like had radical rework done to it sometime in 2006 and original copy of this article disappeared.

When discussing SSB transceivers, the first question to be answered is probably the following: does it make sense to develop and build new SSB radios Today SSB transceivers are mass-produced items for frequencies below 30MHz. There is much less choice on the market for 144MHz or 432MHz SSB transceivers and there are just a few products available for 1296MHz or even higher frequencies. Most radio-amateurs are therefore using a base SSB transceiver (usually a commercial product) operating on a lower frequency and suitable receive and transmit converters or transverters to operate on 1296MHz or higher frequencies.

The most popular base transceiver is certainly the good old IC202. All narrow-band (SSB/CW) microwave activity is therefore concentrated in the first 200kHz of amateur microwave segments like 1296. 000-1296. 200, 2304. 000-2304. 200 etc due to the limited frequency coverage of the IC202. Transverters should always be considered a poor technical solution for many reasons. Receive converters usually degrade the dynamic range of the receiver while transmit converters dissipate most of the RF power generated in the base SSB transceiver.

Both receive and transmit converters generate a number of spurious mixing products that are very difficult to filter out due to the harmonic relationships among the amateur frequency bands 144/432/1296. However, the worst problem of most transverters is the breakthrough of strong signals in or out of the base-transceiver intermediate-frequency band.

This problem seems to be worst when using a 144MHz first IF. Strong 144MHz stations with big antenna arrays may break in the first IF even at distances of 50 or 100km. Since the problem is reciprocal, a careless microwave operator may even establish two-way contacts on 144MHz although using a transverter and antenna for 1296MHz or higher frequencies.

Some microwave operators solved the above problem by installing a different crystal in the transverter, so that for example 1296. 000MHz is converted to a less used segment around 144. 700MHz. Serious microwave contestmen use transverters with a first IF of 28MHz, 50MHz or even 70MHz to avoid the abovementioned problem.

Neither solution is cheap. The biggest problem is to carry a large 144MHz or HF all-mode transceiver together with a suitable power supply on a mountaintop. Even the good old IC202 has its own problems. This radio is no longer being manufactured for more than a decade. New radios can not be purchased while the maintenance of the old ones is becoming difficult. Second-hand radios are usually found in very poor conditions due to the many "modifications" and "improvements" made by their previous owners.

As a conclusion, today it still makes sense to develop and build SSB radios for 1296MHz and higher frequencies. Since the abovementioned problems of the transverters are well known and are not really new, many technical solutions were considered by different designers.

Most solutions were discarded simply because too complex, too expensive and too difficult to build, even when compared to the already complex combination of a base RTX and transverter. Most commercial SSB transceivers include a modulator and a demodulator operating on a high IF, as shown on Fig.

1. . The resulting SSB signal is converted to the RF operating frequency in the transmitter and back to the IF in the receiver. Both the transmitter and the receiver use expensive components like crystal filters. Besides crystal filters, additional filtering is required in the RF section to attenuate image responses and spurious products of both receiving and transmitting mixers.

The design of conventional (high-IF) SSB transceivers dates back to the vacuum-tubm