With a forecast high today of 104 it is too hot to think about tubes even with the AC running full speed ahead. So I decided to check out a couple of vintage solid state receivers.

First was a Marconi Nebula (rebadged Eddystone EC-958/5) from 1973. This one didn't lock up reliably in high stability mode and the simple solution was a plug in card that wasn't making good contact. I touched up the alignment slightly and it is working well. It covers from 10 Khz. to 30 Mhz. in 10 bands and the range from 1.6-30 Mhz. can be used in high stability mode where the range is split into 100 Khz. bands which are tuned at 4 Khz. per knob revolution. Long term drift is specified at less than 20 hertz using an AFC system locked to a temperature controlled master oscillator. There is a crystal filter for SSB and the other bandwidths are provided by L/C filters at 100 Khz. Styling is pretty utilitarian but performance is quite good.

The second patient was a newly received Drake DSR-2 that just got a quick check out and it is performing as it should. I pulled the cover to check inside and it is quite clean so this one will soon be paired with a transmitter. Frequency coverage is also 10 Khz. to 30 Mhz. with the 10 Mhz, 1 Mhz, and 100 Khz. range switch selected with continuous tuning within the 100 Khz. range. Filtering is provided by Tyco crystal filters and the 6 Khz. AM filter sounds very nice. I guess this one does qualify as partially tube type with its Nixie readout system.

This is one time I would love to have to ground the antennas because of a storm. There hasn't been significant rainfall in two months.

Rodger WQ9E

Rodger

How did that Anritsu marine RX turn out?

Pete

Pete,

The Anritsu turned out fine. I found a power connector and tried it out and it works as it should. The synthesizer tunes in 100 hz steps with a fine tuning control to interpolate between steps so the tuning on CW/SSB feels a little coarse compared to an analog or more modern synthesized rig with 10 hz or smaller steps. But performance is good, it has a nice sound on AM and does well on CW and SSB also. A Japanese user published a modification to change the FAX BFO crystal to the proper frequency for LSB and I may do this at some point. But the receiver will receive LSB fine by placing the receiver in the CW mode with the BFO offset and the 3 Khz. filter selected. I don't think this receiver saw a lot of use before I bought it. Out of the group of 3 pictured below the SRT CR-91 remains my favorite with its smooth 1 hertz step synthesizer and easy keyboard entry and the Telefunken E-1501 is a close runner up, both have a good selection of excellent mechanical filters. The Anritsu RG-52A is nice but it is not up to the performance of the SRT and Telefunken.

The Kyoritsu RA-003B needed a little more work and through the help of a very good Japanese friend I received a translated copy of the manual. The main problem was a failed BCD to Binary decoder IC. The front end and variable first IF are tuned by separate servo motor systems and the RF servo was not receiving the proper presets from the band switch because of the failed IC. It was a bit of a comedy of errors acquiring the TI chip needed. I found one at a good price on ebay but the Italian seller required my social security number to ship internationally and that wasn't going to happen. I then found one on Amazon, a bit more money, but it kept my private data private and the new chip restored the receiver to normal operation. It has an analog VFO system which can be stabilized via an AFC locking system which provides near zero drift. It has a nice tuning feel and a good selection of filters. It obviously saw a bit more service than the Kyoritsu.

I still don't fully understand the design of the RA-003B because it uses a Wadley loop system but it also has a separate local oscillator crystal for each of 1 Mhz. ranges from 1 to 29 Mhz. I am heading to the Smoky mountains for a vacation in a few weeks and I will take this manual along to look at in more detail on one of those days when it is sure to be raining too much for hiking

Rodger WQ9E

I think I am feeling a little jealous. I am not only envious of your receiver collection but also of your apparent

technical expertise. Oh well I will get over it.

I'm jealous of all those great radios. The most modern Marconi Marine receiver I had on a ship was the "Atalanta" - I don't know how that would stack up against today's "synthesised-down-to-1Hz plus DSP" rigs. Sometimes it was pretty hard to find the Portishead Radio traffic lists amongst all the clatter at the start of the watch.

It's a pity that there are very few such radios available down here - used, gov't surplus or whatever. I did toy with sending off to Helmut Singer for a Telefunken 1500 but by the time I summoned up the funds they were all gone! I guess I'll just have to be content with my JRC NRD 515 and Kenwood R2000 - both of which go pretty well, I must admit!

That's a cool lookin' Drake. I remember seeing them advertised somewhere, maybe the local (now long gone) ham supply store.

Reminds me a bit of the McKay Dymek radio that came out during the same part of the 70's, where you sort of dial in each digit.

The McKay DR-33C is a cool receiver to play with. I've had mine since the 90's. Also have a DR-22C. The DR-33C has 56 Integrated circuits, 31 FETs, 20 transistors and 66 diodes and uses Collins filters.



Pete

Pete,

I have the less advanced McKay version, the DR-22C. The 5 Khz. step tuning makes it a little awkward for ham use but perfect for shortwave broadcast listening. I think the 22 and 33 both share the same very low distortion AM detector. The McKay looks right at home in the same cabinet as my vintage Marantz 3200 and 140 hifi gear. I don't think it is as mechanically robust as the Drake but it sure looks nice.

I have never seen a Marconi Atalanta receiver in person but the pictures sure make it look nice. It has a nicely laid out front panel and looks to be built to stand up to heavy use.

There is a lot of interesting marine gear out there and more of it is showing up as the Chinese buy older vessels for scrap metal. I have a Skanti R-5000 receiver and matching exciter that I will get to at some point.

Rodger WQ9E

This belongs over on the Transistor Radio forum

Somehow I could never get enthused over the SS commercial gear, no spirit or warmth to them at all.

Carl

Not even a HRO-500?

Someone didn't have any love for that National model, there was one on ebay several years ago with a bullet hole in it. I have become frustrated with some restoration work but never to the point of pulling a weapon.

Rodger WQ9E

The 500 is fine since it still looks like a real radio, OTOH the HRO-600 doesnt interest me at all.

Carl