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This peaked my interest so I looked up my lab data for the SSB noise floor and sensitivity of the TR-4C and IC-705. I don’t measure AM sensitivity so I cannot comment on that. A legacy radio like a

I was just talking to my Elmer about that globe scout yesterday, as a matter of fact. QTH must be monitoring my 2m rag chews.

Saw this on QTH. No affiliation with the seller. Good thing I don't live in that area or I would have even more things in my shop! https://swap.qth.com/view_ad.php?counter=1670778 Thanks, Barry -

Epilogue ? Yesterday I hooked up my TR-4C to my R&S RF signal generator, and it turned out that the sensitivity in AM is not bad at all. ?It is even better that the sensitivity of my IC-705! Case

And then you have SSB with carrier, H3E, which many modern transceivers call AM. That's a horse of a different color. There was a guy on Youtube not long ago who thought his newly acquired TR7 was

The end of my previous message got deleted. I was going to say ,"many Audiophiles think no semiconductor can replace a big tube glowing in the dark." [email protected]> wrote:

Richard your AM Analysis was very good. I would add AM distortion is in the ears of the beholder. Many wrote:

You have yet another issue with the L4B / L7. The oem 3pdt mech relay in both amps takes 17 msecs to operate.? Unless the xcvr has a delay circuit, it will hot switch the TR relay in the L4B/L7, like

Great. All 4 Line receivers should have hiss that can be peaked with the preselector. All of them. RF gain should be fully CW. AF gain should be midrange. Sometimes, the bandswitch is dirty. Try

Ya, I unplugged that thing early on. Mostly because I didn’t want to whack it and break it. I only had it in the picture to show y’all what it looked like.

Two comments here. Rule #1 of vintage radios: Never leave them running unattended, ever for "just a minute". That's all it takes to smoke an unobtanium part if something goes sideways. I'm not

Ryan, upon reviewing the schematic, I'm going to recommend that you unplug the 4-LF from the accessory socket. Whilst the socket seems to provide mostly power and ground to the accessory, it also has

Be sure to keep track of which tubes go where. It can make a difference with the alignment. Your transmitter seems to already be working fine. Steve Wedge, W1ES/4 Time flies like an arrow.? Fruit

You are correct, Steve, I have already put power to it. I’ve ran it a few days, mostly letting it just sit there under power. I had to box it up today because I had two welding jobs holding, waiting

Which brings up best practices. Always check the amplifier keying voltages/currents against the ratings of your exciter. As shown here, even within a brand with two models that are still in production

I believe that Ryan has already fired everything up, so no variacs are needed at this point. A view of the top and bottom of the chassis will be helpful. There are few mods done to the earlier Twins.

It is surprising to me (shouldn't be) how much confusion there is about AM. For one thing the term "distortion" means different things to different people. In almost prehistoric times, like the 1930s,

Rob, don't put too much effort measuring the sensitivity of your TR-4C and R-4C . If you hear an obvious increase in the noise level when connecting the antenna to the TR-4C in the AM position, while

Thanks folks, Indeed, the TR-4C doesn't seem to be the ideal rig for AM. Luckily I also have the 4C twins, and the R-4C does AM very well. ?I could accept the 'distortion' caused by squeezing AM

There's one thing that maybe should be kept in mind about what people may be using to drive their L-7 or L-4 /L-4B when it comes to ICOM transceivers. I'm not sure that everyone who uses ICOM radios