Raytheon Ray 152 HF Marine transceiver
The Ray 152 is a 150 watt SSB/AME HF radio, targeted for the marine user. It lends itself very well for ham use. These radios pop up on the surplus market now and then for acceptable prices, if you are lucky a nice one can be had for less than $500.
In the US, The radio is marketed by Raytheon under private label as the Ray-152. However it was designed and manufactured by JRC, in the rest of the world this radio is sold as the JRC JSB-176
The radio covers 1.6 to 30 MHz TX/RX, in 100 Hz steps. Receive capability goes even lower, all the way to 100 kHz (later more about this). It runs off 13.8V DC and draws 30 amps at peak power.
All controls are on the front through a silicone-rubber keypad which feel very well, and are brightly backlit by an electro-luminescent foil. There are no "moving parts" used for the controls like potentiometers, mechanical switches and the like; all controls go through the pushbuttons. This concept lends itself well for remote computerized control of the radio, but for this feature the optional RS-232 interface needs to be installed.
The backlighting adapts itself for ambient light through a photocell; if there is sufficient light the backlight (and the S-meter light) will throttle down automatically.
The radio derives all internal frequencies from a single master oscillator which is ovenized for maximum stability. This OCXO can be calibrated for maximum accuracy, but you need to lift the hood for doing so. I have found that my particular radio has stayed accurate within 2 Hz for an extended period of time, so the stability of this OCXO is very good.
All electronics are on FR-4 glass-epoxy plug-in boards held in a card cage on a motherboard, with the exception of the PA and the front panel electronics. The cards use real connectors which mate with connectors on the motherboard, no PCB edge connectors are used. Very professional.
Last but not least, the radio is equipped with balanced 600 ohm inputs/outputs which make it the ideal radio for Pactor-III or other digital modes.
The general concept of this radio is of the dual-conversion type, with the first IF in the 70 MHz range, and the second IF at 455 kHz. There is a third IF of 97 kHz, but this is a rudiment once needed for an optional auto-tracking notch feature by JRC, not used in this particular model. It does not play a role in the over-all concept as the selectivity is created through the 455 kHz IF, by a Collins mechanical filter.
To mix down this low in frequency from the 70 MHz first-IF without introducing an intermediate IF of lets say 9MHz is possible for this radio because of the sharp mechanical filter used in combination with the continuously variable RF preselector; without it, it would be much harder to reject the 70 MHz image frequency spaced at twice the second IF (spaced away 910 kHz)that otherwise might have been a problem with such a low second IF frequency.
To elaborate on this: in general, the less mixing for a radio, the better. It is a misconception to think many stages in the superheterodyne chain are a plus, it is not. The high-performance Icom transceivers IC-7800 and IC-7700 (as well as the Hilberlink PT-8000) prove this point; they use an image-reject concept for the first mixer to suppress the receiver image product, which then mixes straight down to a very low IF. The Flex-5000 does it even better, it has no IF, the IF is the baseband....
Back to the Ray 152. The synthesizer allows for 10 Hz steps, but for frequency "tuning" it steps in 100 Hz increments, the 10 Hz only comes in play for the clarifier function, when needed.
The synthesizer deploys two DDS units. One DDS drives the necessary synthesizer PLL loops, the other creates the SSB injection frequencies. As a result, phase noise behavior is excellent, and tuning is smooth.
The radio has no spinning tuning knob, only up-down buttons which allow tuning from a previously set frequency. So let’s say you want to listen on 3.850 MHz (as an example), you would first key in 3-8-5-0-0- which sets the radio on this frequency in a 100Hz accuracy. Then, by pushing either the UP or DOWN button you can tune away from this in 100 Hz steps. The tuning is smooth and fast enough to not make this a painfully slow experience, but slow enough not to miss a signal of interest. The radio does not "blank" audio between the steps (thanks to the DDS) like so many other marine radios actually do, so this makes it much easier to pick up a signal when fast-tuning.
The radio also is pre-programmed with all ITU HF marine frequencies, which is nice if you like to listen to marine traffic. It can show the ITU frequencies as channels or as the actual frequencies. Needless to say the radio also allows for TX frequency offsets (semi-duplex) as required for all marine radios.
The radio also features 200 programmable memory positionsies which allows you to program any frequency of your own in non-volatile memory. The memories store mode as well.
The radio can be freely tuned (and memory-programmed) anywhere across the 100 kHz to 30 Mhz range, there are no lock-outs (TX starts from 1.6 MHz though). It also goes all the way to 30 MHz including TX (many other marine radios only go to 25 MHz). Internal jumpers can be set to limit a user from this free-programming capability. (so if your newly purchased radio does not allow direct-frequency entry you need to change the jumpers)
The radio delivers quite some power, 150 watt continuous made possible by an effective forced cooling system. The fan is thermostatically controlled so it does not run all the time. Fan noise is acceptable, I have heard much worse on professional radios.
The radio also has a reduced power mode of 50 watts, selectable from the keypad. So this makes the radio the ideal radio for the 60-meter band; you just program the allowed five channels in 5 memory locations, reduce the power to 50 watts and off you go!
Let’s talk about the receiver performance. Over-all, I give this a big thumbs-up. Tuning across the bands, I have found very few birdies, even at the VLF frequencies. In fact, it shines on the band 100 kHz to 500 kHz – where most ham radios have such LF coverage as an afterthought, the Ray-152 performs very well there: There are no internally generated spurious noticeable on that band and sensitivity is very good, something that usually is a problem with other radios that can receive this band.
The fact that this is a marine radio must have something to do with that; until recently LF beacons in this band were an important navigational tool for the boating community.
Also in the higher frequencies the radio performs well. As mentioned earlier, the receiver deploys a continuously adjusted RF bandpass filter (a pre-post selector) that also is used in the TX path to filter out transmitter composite noise. (not even the IC-7800 does this for TX) So within a selected RF filter (dependent on frequency choice), the filter is automatically peaked to the particular frequency for an even better out-of-band rejection.
As mentioned before, the receiver uses a high quality Collins mechanical filter so selectivity and sound quality is excellent, you won’t suffer "listening fatigue" on this one.
Two more optional filters can be installed for FSK and CW work, but these modes can be selected nevertheless without the filters installed, it then uses the SSB filter but with the necessary shift in the SSB carrier point.
The third order dual-tone dynamic range for this radio is 95 dB, an excellent number. I base this number on the QST test of the JRC JST-135 because the Ray-152 shares a lot of DNA with the JST-135, it uses the exact same RF card for the receiver.
Now you will also understand my earlier remark about the "rudimental" third IF of 97 kHz, this feature is used in the JST-135 for the optional tracking notch filter circuit, as the Ray-152 uses the same circuits, albeit without the optional tracking board.
(As a matter of fact, because of the similarities with the JST-135, also all the circuits are present in the Ray-152 for the FM mode, but the CPU firmware does not allow for selection of this mode. A simple firmware change might therefore make FM possible on the Ray-152, but impossible to do without source code)
As mentioned earlier, the receiver has a digital clarifier (10 Hz-stepped) which allows coming to within 5 Hz or better of a desired frequency.
The transmitter is pretty straightforward, there appears to be a compressor present which is always on (judging the high average power when talking) but I am not 100% sure of this. Modulation sounds well, no complaints here.
The radio allows for a microphone having a second element to do electronic noise cancellation, which can be useful in a noisy environment like on a ship. I do not have the original mike to test this feature but the radio works well with a standard ham mike; just leave the pin for the second mike open.
One transmitter feature that is different from your run-of-the-mill radio is the fact that the transmitter deploys the RF preselector also for the transmit path. This is very helpful when multiple radios are operating in near-vicinity (both physical spacing as well as frequency spacing). In such situations it is not necessary the receiver that causes problems, it is the fact that the transmitter for the neighboring radio produces wideband noise which then drowns out the weak signals that the receiver for the first radio is trying to pick up.
In that respect, if you look at the QST test for the high-end Icom IC-7700, you will see that transmitted composite noise extends to wide levels for that radio, not a good thing. In the same issue of QST, also the Rohde&Schwarz XK2100L was tested, a professional high-end transceiver used by the government, very comparable in specs to the IC-7700 except for this point. For the R&S, you see the composite noise roll off like it should, because the radio deploys the auto-tuned receiver preselector also for transmit. Just like what the Ray-152 does!
(In this respect, I always have found it silly that such a high emphasis is placed on the dynamic receiver range for a ham radio (without paying attention to the transmitted noise phenomenon), so that you can "receive that weak station in the vicinity of very strong signals" – Believe me, when your neighbor fires up his radio while you are listening to that rare DX, you will not be able to pull it out, because the transmitted noise from your neighbor drowns it. No matter how good your own receiver is.)
To summarize the Ray-152: An excellent HF radio with a superb price-performance ratio on the surplus market. Look for one on the ham flea markets, a great radio for field days or as standby transceiver in your shack!
Luke, AC5XP
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