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The TR-4 manual states the receive sensitivity should be "less than 1/2 microvolt for 10 db S+N/N." The manual also states that each S unit on the S-Meter corresponds to approximately 5 DB. If I establish a reference point on the S-Meter for just noise, then feeding a 0.5 uV voltage into the antenna jack should, at a minimum, increase the S-Meter by two units. Is that an oversimplification? If so, what is a better way to measure S+N/N. I seem to recall that when I was doing that for the Collins R390As I had, I was using an audio level meter (TS-585) and using AM detection to measure the increase so maybe that's a better way (although, sadly, I no longer have that TS-585). Thanks, Barry - N4BUQ

You just saw it in a previous post. This one came in with a mid-late C Line, with a cut cord. Since I had to replace the cord and test it, I tried my “new” (to me) use of a gland strain relief. All voltages good, tested with a TR-4 after verifying voltages. Supply hums a little (the supply itself — not the audio). This is an original supply that has not been rebuilt. I can rebuild for an extra $150, including parts. $120 plus shipping from central NC (27253). Also have an MS-4 that is decent for $50 plus shipping. Shipped separately from AC-4, of course. The rest of the C Line will be available but not for awhile. The transmitter needs to be revived and receiver is pretty grotty. Receiver is mid-Late with a full deck of CW filters, Sherwood mixer and power supply upgrades. 73, Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana. Sent from Proton Mail for iOS

Okay, this one is strange. I may have bodged something and may need “second sight”. I had to replace V1 socket because I ruined one pin whilst removing resistors. Rebuilt using a socket from a parts rig and reconnected everything, as far as I know. Xtal oscillator adjustment went fine. Peaked 40, 15 and 10. Receive is great on all bands. 10 doesn’t elicit S meter response but receive is strong. For an early set, receive is fine. Transmit is the opposite of what most people see: 15 and 10 are pretty good. 20 and lower are almost nothing. It was providing plenty of power before the repair. Now — it’s QRP. Counter sees correct frequency but power out is nearly nil. Reading the rotary switch diagrams is torture. Anything jump out at any of you? Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana. Sent from Proton Mail for iOS

I'm working on a TR-3 with the dreaded "bouncy meter". I have one plate amperes meter. These can't be swapped because they're mirror image of each other but noticed that the deflection is different in each. Does anyone know what these meters are calibrated to (i.e., what is FS current for each)? Also, if anyone has a spare S meter, please let me know if you're interested in selling it. 73, Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana. Sent with Proton Mail secure email.

I was trying to re-seat the LSB bulb to the chassis because the bulb was intermittent. In doing so I think the positive side of the bulb housing touched ground some how because when I turned the TR-4CW back on and the amp meter light, frequency light, LSB, and USB lights were not lit. Then the filament fuse blew! I replaced the wire with #26 AWG and pulled both LSB and USB out and re-seated them and made sure nothing was shorting to ground. I quickly turned on the rig but still those lights would not light. The only light that I get is the round red light on the right side of the frequency read out. I connected my power supply to my other TR-4CW and that rig works OK so the power supply is still good. Not sure what is going on? Mark

I have a 1A, Serial #331, an early one, and another later one with WWV. I didn't realize that the original version did not have a crystal calibrator (I knew it didnt have WWV) until I opened them both up for recapping. The "newer" one also has a couple of sub boards, the original does not, though the components seem to be there. I don't have and cannot find the manual or a schematic for the older unit, just for the newer one from BAMA. My question is does anyone know what the WWV mod, (which could be performed by Drake) consisted of? I assume it was not a difficult mod, and that the bandswitch has another contact for WWV. I have replaced the tuning dial with another I had, which has the WWV marking. Was thinking of adding the calibrator and WWV mod, but since no schematic of original old version its not obvious what was added. I have a third unit Which works but missing knobs and face place, its a shame to use it as spare parts. Thanks, Ed W1FU

i have seen pictures of a matching speaker for the 1A in advertising, but have never actually heard of one. Did they actually produce it? It looked like it used (or would use) the same 1A cabinet. Was thinking of making one as I have another cabinet, but did they actually exist? I use a 2A speaker, which looks good. Thanks, Ed W1FU

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For sale: Drake L4B and power supply. Very good condition. Eimac 3-500 tubes. 1200 watts output with 100 watts drive. $1,000 shipping extra. W3RJ -- This email has been checked for viruses by Avast antivirus software. www.avast.com

Gentleman: For a TR-4C, is there any difference between 6JB6A brands? I'm buying 3 of them and there's some well known brands available such as Sylvania, GE and RCA. RCA a bit cheaper. All NIB/NOS. Any recommendations? 73 Marcus PY2PLL + PY3CRX GG66rf

When tuning up my second TR-4CW the current meter goes to 0 when I push in the load control to tune it. I can see the load control working on my external power meter just nicely. I figured it was the switch. I measured all 3 terminals on this switch compared to my other TR-4CW (that doesn't have this issue) and my ohm measurements are pretty close so I believe the switch is OK. Not sure what to do next? Mark

There is an IO group devoted to Leo Myerson's equipment. Leo made a huge impact on amateur radio. If you have an interest, please join us at: /g/WRL-Galaxy-Radios Tnx, Dale W4OP

Hello all, I am selling one of my Drake C Lines: R-4C, T-4XC with manual AC4, MS-4 and fresh cables. All stock, very good condition, and regularly on the air. For the time being, pickup only in Arlington, VA. $550. tks, Burt W3IO

The following items have been added to the Files area of the [email protected] group. /RCA_CA3053.pdf By: Jim Shorney <jimNU0C@...> Description: RCA CA3053 differential amp IC data sheet