Drake SPR4 value?

[KK4MSA]

Hello all,

  I have a friend that has ran across a Drake SPR4 rx'er and has offered it to me.
i have seen pics of the unit and it looks great inside and out, and works as i have seen videos.
He said something about it not working correctly when he got it,  there was a bad transistor and he jumped it out and it worked, but that transistor would need to be replaced. so anyway, with all that, what would be a fair price to offer him? hes not looking to get loads as im sure it was probably given to him, but i don’t want ot pass it up if its a fair price, and i hate to use ebay as a guide.

thanks
KK4MSA

[K6IC]

We do use a Drake SPR-4 here,  at times.

They are still in demand,  and seem to sell easily on the lists from $250 - $375-ish,  when they work well,  look nice,   and have the desired Crystals.  The Crystals are the only slight downside of these radios,  as crystals appropriate for these radios can be a bit hard to find.

They were sold as SWL RXes,  most often,  as I recall,  so may not have all of the Hammie bands covered.

Depending on cosmetics and the desireabality of the band coverage,  $150,  or so may not be a bad deal.  The transistor replacement should not be too difficult,  or expensive ... and so on.

To me,  the SPR-4 is essentially an R-4 in transistor drag.  It DOES have a built-in speaker,  an advantage IMHO.  GL,  Vic

[WA3VJB]

I thought about getting one of these when we got our first boat, years ago, because it runs off 12VDC.

I'm a little fuzzy on recollection, but I think I passed it by because the selectivity is too narrow, even at its widest.

You might want to test drive it with a good pair of headphones, not only to check function with the "bypassed" transistor, but also to see if it sounds too pinched on a representative AM station.

Otherwise that's a nice looking radio and I bet you will like the smooth, no-backlash tuning on the thing.  Our club station W3EAX bought a brand new set of R4C/T4XC from the factory in the late 1970s and they made a nice impression on me.

[KK4MSA]

thanks guys, that’s what i was looking for, that’s enough info for me to make a decision. that’s about what the guy was wanting, 150$ or so (well i have some old CB stuff laying around and he wants to trade, so i make out either way)
thanks for the help..

KK4MSA

[WQ9E]

The SPR-4 is a good performer.  Selectivity is roughly equivalent to the tube type R-4B but the SPR-4 doesn't have pass band tuning.  Filtering is via L/C circuits so there are no filters to buy and it has suitable bandwidth choices for CW, SSB, and AM.  You can tell it was designed in the CB era because the crystal switch clearly has ties to an old 23 channel CB set.  The FCC bought quite a few of these that have the CB channels on the main tuning dial so they apparently liked them as monitor receivers, probably for mobile use.

I think you might still be able to get the kit of parts for the full range synthesizer described several years ago in QST.  Of course the genuine Drake FS-4 synthesizer will work well with it (requires mod kit and 9.59 Mhz. master xtal) but probably would cost 3 to 4 times what you paid for the receiver.  Otherwise range crystals for various bands show up on ebay.  You can use R-4 series crystals if you can live with a 10 Khz. calibration error.  The R-4/T-4 series crystals are equal to (lower end of desired range + 12.1 Mhz), for example 12.6 Mhz. provides coverage of the 1.5-2.0 Mhz. range.  For the SPR-4 the crystal formula is (lower end of desired range + 12.09) or 12.59 for the 1.5-2.0 Mhz. range.  So a "regular" Drake crystal would result in a 10 Khz. error.

A noise blanker and crystal calibrator were sold as accessories, the noise blanker is very expensive when found so if your receiver has one count yourself lucky.  One of my two SPR-4 receivers came with the noise blanker and calibrator.  This one looked great but was sold as non-working and was cheap.  When I finally got around to putting it on the bench I found it had the NB and calibrator and the reason it didn't work was the shorting plug for the mute line was not installed.

[W3RSW]

I have one and use it mostly bedside for those late laughs on 3843, etc. It has good sensitivity, was an early all transistor model and has a dust proof cabinet.

It was fine in earlier days but I had to replace the tuning/calibrator dial coupling, a rubber sleeve that dries out and slips calib. over the years. The replacement is so soft that there is some squirmy backlash. I think a reset after it ages some will help.

[Steve - K4HX]

One of the more recent DDS units/kits would be a less expensive alternative.

I think you might still be able to get the kit of parts for the full range synthesizer described several years ago in QST.  Of course the genuine Drake FS-4 synthesizer will work well with it (requires mod kit and 9.59 Mhz. master xtal) but probably would cost 3 to 4 times what you paid for the receiver.  Otherwise range crystals for various bands show up on ebay.  You can use R-4 series crystals if you can live with a 10 Khz. calibration error.  The R-4/T-4 series crystals are equal to (lower end of desired range + 12.1 Mhz), for example 12.6 Mhz. provides coverage of the 1.5-2.0 Mhz. range.  For the SPR-4 the crystal formula is (lower end of desired range + 12.09) or 12.59 for the 1.5-2.0 Mhz. range.  So a "regular" Drake crystal would result in a 10 Khz. error.

[gerry_w1id]

I just recently sold my SPR-4 which I had owned for several years. It behaves pretty much like an R-4 except it doesn't have tunable passband. Very stable, sensitive. But you say your friend's radio has a blown transistor. Unfortunately the SPR-4 uses several dual gate mosfets which are difficult to find and once found turn out to be very expensive. The ones in the SPR-4 are not available, even in the surplus market. They use MFE3007/SFC4982 in the RF/IF stages. If I were in a pinch, I would try a generic 40673 as you may reasonably expect to find one, eventually and are very unlikely to find the original type at all. Of course I don't know which transistor is blown. Those in the power supply and audio section are bipolar jucntion transistors and should be easier to find or should I say, easier to substitute. As someone mentioned, this receiver requires a crystal for each 500kHz range desired which could be a very expensive proposition if you need to change frequency coverage. I believe they came with only the 40m band with the rest dedicated to SWL coverage for a total of 10 ranges out of a possible 23. Incidentally, standard Drake twins crystals cannot be used due to size and frequency offset which I believe is 10kHz compared to the twins. For example the twins require a 12.6mHz crystal for 1.5 to 2.0 mHz coverage while the SPR-4 requires 12.59 mHz. As for the price, that would depend largely on the cosmetics and functionality. The top and bottom covers are not painted but vinyl clad steel, just like the Drake W-4 wattmeters. Refinishing such a case is more work than it's probably worth. Since I haven't seen it and it does have an problem, I might be tempted to offer $150 maximum.

[W3FJJ]

I love my Drake SPR-4, it was dream receiver, I drooled over as teenager
and couldn't afford.. I got one a few years ago, and been very impressed,
very stable, sensitive, and selective, with good freq readout for analog rx..
Only Draw back on AM its a little too narrow.. But maybe if can be modified?

Mine came with all the xtals slots filled and most of the ham bands...pre warc..
I think around 250 is good price with all xtals, 150 a steal... To me, mine is worth at least 350

GL  CHuck-W3FJJ