Scott SLRM and the sdr-iq

[N2DTS]

Tonight I got around to working on the Scott SLRM I got dirt cheap off ebay.
I am always shocked when something from the 1930/1940 time frame still works, with all the original parts.
Boy, did they make those things well!
2 bands were off in calibration, so I did the complete alignment.
I have some old cheap signal generators, so the sdr-iq helped make sure the signal I was injecting was on the right frequencys.
After getting the tracking done, I did the IF, I set the sdr-iq to 455 KHz and put the antenna feed close to the last IF can and got a nice picture of the IF response.
It was all tuned up on 451 KHz.
Not sure that makes much difference, but I tuned the IF cans to center on 455 KHz.
Its really cool to be able to SEE the IF response.
The SLRM can go broad as a barn door in the HIFI position, but it goes fairly narrow in the narrow position.
 

[Opcom]

Did you use the special matching coupler as stated in the manual? First time around I did not make and use this item, and the sensitivity was off from one end of the band to the other.

They sound great but the little speaker in the big metal cabinet can cause rattles. Mine has a definite resonance.

It is really a good SWL set. The heaviest ac-dc shortwave receiver ever made.
 
The 'nut' on the trimmers underneath can split and come loose, resulting in a plate to plate short and a dead band. It's odd but they seem to be brass and press fit. A picture of this kind of failure is here: http://bunkerofdoom.com/cap/fix1/03.jpg

[KA2DZT]

I've seen that failure in that type cap too.  The nut I think is a press fit.

[N2DTS]

I did not make the 'fake antenna" thing in the manual because I did not mess with the antenna input coils.
I did the tracking (band 3 was way out, 50 KHz off at 3880 and I did the IF cans and bfo.
The antenna caps did not want to turn so I left them alone, I was picking up signals with no antenna hooked up, if anything, it seems to have too much gain, the magic eye tube is closed all the way with most signals.
I should test the tubes at some point.

I should replace the speaker, but it sounds ok.
I have a bit of hum, and its not the filter caps.
I am missing the side strips and knobs that hold the radio in its cabinet, and the jackass who sold it just put it in a box with no padding and it has a dent on the front panel right on the Scott plate.

I may give it to my nephew who likes old stuff and has his own sail boat.

[WD8BIL]

Good deal Brett.

I love my Scott RCH receiver. I tweeked the L.O. in the appropriate band to cover 160 meters. As supplied it stopped at 550kHz and started the next band at 1.9MHz. A little tweek to the L.O. and I brought that down to 1.8MHz. Yes the dial on that band is off 100kHz but I use the 0 to 1000 log scale anyway and have the 80/75M band settings written and posted on the frequency chart provided.

[N2DTS]

Looks like the same dial type as the slrm.
I guess they will never make things like the Scott stuff anymore, the stuff was really built well to still work like a top 75 years after it was built.
Good designs also, push pull AB1 audio, very stable for octal tubes.

If caps and resistors have changed value it has not made any difference in the way things work.