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Watkins Johnson HF-1000


Watkins Johnson was an American manufacturer of professional communication technology. It produced communication equipment for the military and other agencies with special tasks. NASA and NSA were among its customers. The predecessor of the HF-1000, the WJ -8711, was built around 1991 based on a project award by the NSA.  Because other civil agencies also showed interest in the receiver , the HF-1000 was introduced to the market around 1994.

The Watkins Johnson HF-1000 is a DSP- short wave receiver constructed similar to the Ten-Tec RX340. Both radios show the same development.  Like many other professional radios, the HF 1000 can seldom be found on the market. Sometimes such receivers show up on E-bay and change owners at high prices.

Basic data:
Frequency range: 5KHz - 30 MHz
Tuning steps:  freely selectable
Filter Width: 58 digital filters (DSP) 56 Hz - 8KHz
AGC: Fast, Medium, Slow , Manual (decay rates are selectable)
100 Memories with Scan-function
BITE Test (Self-Test Function)
Good large signal immunity
Large Tuning Knob
19" construction
Weight: 6Kg

When a colleague of mine brought me the HF-100 I was rather excited. In the previous tests it said that this radio is addictive. Well, then let's try this drug. Around evening I started to operate the receiver. Obviously, I had to familiarize myself with it and turn the knobs a little bit. During the first half hour I noticed that the ventilators of the radio were humming quite loudly.  I put my hand on the receiver to check the temperature. The HF-1000 was not even lukewarm. I bent over the HF-1000 and looked for the ventilator but I did not find one.  To my surprise, I noticed  that the humming came from the loudspeaker of the receiver. I thought that perhaps the cable was not plugged in correctly and opened the radio. Wrong! Everything was plugged in the way it should be.  Due to the awkward design of the printed circuit board,  there was digital humming in the NF audio. The headphone output was also affected. There was quite a strong hum, even when the volume was not  raised. I contacted a specialist in the USA and he confirmed the audio problems of the first HF-1000s. Later models were said  to be without this problem. This humming could be suppressed with an equalizer. In the case of very weak stations and when you turned down the RF-Gain,  the humming was still audible in the background,  though.

That was the first damper, the next one was around the corner.

Now that the hum was not audible anymore,  something else was noticed: The miserable AGC! There was an awful scratching noise. This shortcoming could only be overcome by using the manual gain control. I thought to myself: "That can't be true! This is supposed to be the legendary HF-1000." And so I was looking for answers. And I found one really fast: This HF-1000 had the old firmware installed! From a specialist in the USA I got the latest firmware for the HF-1000. I then had itput onto two Eproms. Luckily, this only cost some research and shipping costs (48USD)

Finally, after two weeks I could start reception tests. The new firmware resulted in a considerably improved AGC and 4KHz bandwidth for SSB. Mainly, I compared the HF-1000 with the Reuter RDR50C2 and the JRC NRD 525 with the Kiwa-modification.

The HF-100 has a wonderfully broad audio output. It has a nice bass range and sounds very clear. The clarity is enormous. The radio sounds almost like the RDR50C2 but is a tiny bit better with very weak signals. Despite the Kiwa-Modification, the NRD 525 sounds a little bit muffled. The sensitivity of the HF-1000 is same as for the other two receivers. Except for the upper frequencies (11m - 10m),  the sensitivity decreases a little.  The other two receivers are somewhat better in this respect. The switchable pre-amplifier is  actually of no use, it only creates some noise. The lack of Passband Tuning (PBT) in the SSB mode was disappointing, it only works in CW. The noise blanker worked very well and filtered out the noise created by a nearby pasture fence. The notch filter is excellent, it  practically gets rid of any interference. One of the best notch filters that I have encountered with table top receivers. The reception of broadcasting stations in AM synchronous (SAM) was a delight.  The synchrone detector hardly ever lost synchronization and received weak stations in very good quality. Unfortunately, the sidebands cannot be switched to avoid interference.

The operation of the HF-1000 is rather simple. You only need the manual for seldom used features. One thing, though, gave me a headache: The mechanical quality of the HF-1000. It simply is bad! I have seldom encountered such a cheaply made tin can. Also the front is not worthy of a professional receiver.  It simply is a self- adhesive film . It comes off easily when conditions are adverse. In short:  They really saved on the mechanics.

It is not easy to judge this receiver which  I tested because it was one of the first ones to reach the market, subsequent models improved quite a bit. In this version, the radio does not offer its full scope of functions.  A few important functions were missing, e.g., Pass Band Tuning in SSB and the selectable side bands in SAM. Apart from that and the digital hum in the audio channels, this DSP-receiver offers a wonderful reception with excellent selectivity and intelligibility. It can be operated very easily and you can handle it right away. The mechanical quality is not good, however.  It simply is cheap.

Despite some shortcomings you can call the HF-1000 a top receiver.  Seldom have I heard such a clear and intelligable rendition of the signals.

When buying a HF-1000 you should make sure that
--the preselector  is built in
--that the firmware is at least version 04.01.03
--the BITE-test is without flaws
--the audio is free of digital humming.
Written at 30.11.2014


HD Video from HF-1000


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