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Reviews For: HAMMARLUND SP-600 SUPER-PRO RCVR

Category: Receivers: General Coverage

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Review Summary For : HAMMARLUND SP-600 SUPER-PRO RCVR
Reviews: 12MSRP: 895 - 1140
Description:
Commercial/military grade tube general coverage receiver
Product is not in production
More Info: http://
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
00124.8
W9LBB Rating: 2002-04-13
An Oldie but a Goodie... Time Owned: more than 12 months.
In the past 25 years I've owned four of these beasts. I still have two of them, and still regret giving up the other two. THAT in itself should tell you SOMETHING.

Hammarlund designed and built a warhorse that really fits the (much overused and abused) title "Classic". Even in these days of digital readout, ten tons of bells and whistles, do everything for you receivers, the old Super Pro has a definite place in the ham shack. But, it's a receiver that requires a good operator to bring out the best in it.

I've got a TON of different receivers here, of all vintages and qualities, but the SP-600 and Collins R-390 are the ONLY ones I even consider using (or for that matter, even consider hooking to an antenna!) in a transmitting environment. My Drake R8 or JRC NRD-525 may be great performers on the ham bands, but I really don't want to put them in situations where stray RF is gonna take out front end devices if something goes wrong. About the only way you're gonna damage the front end of an SP-600 is run coax from the transmitter output to the receiver input, and drop a book on the key! <>

There's a LOT of different versions of the SP-600 out there.

The most common ones (both civilian and military manufacture) cover 540 KHz - 54 MHz in six bands. Most of these have a (seldom used) crystal oscillator for fixed frequency operation. A few are military variants that are modifications of the basic design which allow them to be used as either a MASTER or SLAVE receiver in a diversity system.

I have a civilian SP-600LF. No fixed frequency crystal oscillator, and a frequency coverage of 100 - 400 KHz and 1500 - 30,000 KHz in six bands. Other than the different range, it's pretty much identical to the other SP-600 versions.

I also have an SP-600VLF, ex- Royal Canadian Navy. THIS is altogether a horse of a different color! While the design philosophies, physical construction, and high quality are pretty much the same as the rest of the series, virtually NOTHING in the SP-600VLF is interchangable with the rest of them. This was necessitated by the unusual frequency coverage; 10 - 600 KHz!

As far as using the receiver is concerned... double conversion makes for MUCH better than average image rejection for a receiver of early 1950's design vintage. It makes a great "cruising" receiver for checking out a lot of spectrum in a hurry. If the rig has been aligned right and kept in good shape (ie, a decent set of tubes in it), sensitivity is MORE than adequate for most uses up to perhaps 25 MHz. The noise figure starts to deteriorate a bit above that when compared to more modern designs, but it's STILL quite useful all the way up. Considering the state of the art at the time they designed this rig, the engineers at Hammarlund did an EXCELLENT job. In fact, in terms of resistance to front end overload from TV and FM broadcasters when listening above 30 MHz, the SP-600 beats out a WHOLE LOT of much newer designs!

Below maybe 15 MHz, frequency stability is MORE than adequate for hobbyist purposes. I use mine for RTTY and FAX reception quite frequently, and the rig really delivers. This is the kind of service it was designed for.

Selectivity is quite good, using the stepped bandpass positions (tapped IF transformers) and crystal filter. Bear in mind that shape factors are NOT going to be as steep as with modern mechanical or crystal lattice filters... skirts are wider than we've become accustomed to with modern receivers.

I've made some mods to my SP-600LF to improve audio response; my big thing is 160 metre AM. Even UNmodified tho, the audio response and distortion figures make ANY of my fancy, modern solid state receivers look sick by comparison!

The front end is virtually overload-proof as compared to even the BEST current designs. That's what tube rigs are all about! Intermod is virtually nonexistent, no matter HOW many high power stations are blasting away on the 31 metre international broadcast band! <>

The SP-600 really shines as a BCB DX receiver... at least the common version that covers the entire AM broadcast band does. When I still had one that did, it was ALWAYS my weapon of choice!

The proliferation of SSB in the 1950s is what eventually killed the SP-600 design, like MANY receivers of the period. The detector is a simple diode, NOT a product detector, which is obviously necessary for easy, low distortion SSB reception. Likewise, the AGC isn't suited for SSB. That's not to say that you CAN'T receive SSB with a Super Pro 600... you just have to work at it harder, sans AGC.

As a CW receiver, it's STILL quite good, tho I personally have always felt the tuning rate is a bit fast for the ham bands.


The downsides of this rig...

For those who aren't old enough to be accustomed to analog dials, the frequency readout seems crude, and it IS... but remember, we're talking state of the art in the 1950s. Collins had digital readouts in this period in the R-390 / R-390A / R-389 / R-391 / R-392 series, but it's accomplished by means of a mechanical design nightmare of gears, clutches and other gadgets, and what's essentially a modified automobile odometer!

For "close" frequency readout with an SP-600, you have to learn to use a "logging scale" on the dial (simple for those of us who once learned to use a slide rule! <>), and for anything closer you need an accurate signal generator next to the radio (in my case, a trusty WW2 BC-221 frequency meter). Awkward, but once again we're talking 1950s state of the art.

One thing I've had trouble with on EVERY SP-600 I've owned... the main tuning dial.

While lubricating things, invariably somebody manages to get a drop of oil on the smooth, brass pulley just behind the front panel that is turned by the heavy dial flywheel. As a result, the whole business slips.

The first thing I do with a "new" SP-600 is take a hunk of rag, saturated with wood alcohol, and clean the friction drive pulleys.

Next, there is an S - shaped spring that takes up slack in the dial drive, forcing the pulleys tight together by means of an intermediate "idler" pulley. Usually, over the years the spring has taken a "set", and is too compressed to apply the required force to make the drive turn smoothly. I take the spring out, stretch it slightly, and put it back in.

The result of this simple cleanup / adjustment is that the wonderous, fast, and silky smooth Hammarlund flywheel drive works BEAUTIFULLY!

All in all, I have to reccomend the old timer as STILL being an excellent rig, if you can find one at a decent price... it really is one of the finest tube receivers ever designed.

73's,

Tom, W9LBB

WB6MYL Rating: 2002-02-05
A sleeper and a keeper Time Owned: more than 12 months.
Wow, this thing is heavy, but what a great receiver. This 20 tube Hammarlund receiver came out in 1951 and was used (and probably still is somewhere)by the military, FAA, and the CIA; compares favorably to my R-390A (which it was designed to compete with);sensitivity similar to my R-9000. Unique because of continuous coverage from .54 to 54 mh and Art and his boys could of learned a lot from Hammarlund on tuning mechanisms; the SP-600 flywheel tuning is a joy and an ease to use as one "swoop" can send you from one end of the band to the other. If you have one of these, consider a outboard SSB adapter; I use a TMC 591A but the PD-1 designed by Ron Hankins will work as it has the same IF as the 390A. Highly recommended; Try to get one with a cabinet and a truss