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Re: Can't get SWR sweeps to be 1:1 with dummy load
Back on the air :)
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I chose in the end to just replace ic 402 and 403, and everything seems to be working fine now.
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I'm still not sure what exactly killed the chips. The limiting diode and the receive switching fet seem to be functioning correctly, but it's certainly fixed for now.
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Thanks all!
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Greg,
N1TR? |
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I used two different wires - The one that Hans provided and this one: . I did that in order to maintain color coding for the P and S wires. The P wire is the Amazon wire. At the very least, I seem to have cleared enough enamel to establish continuity between the center tap and the P on the other side. I'm going to try some more when I get home. Here is what I have:
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On Tue, Mar 25, 2025 at 09:10 AM, Stan Dye wrote:
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K used a lighter and tried scraping as well. I'm going to try with some hot solder. Thanks!?
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On Tue, Mar 25, 2025 at 08:57 AM, Chuck Harris wrote:
Unless you are using some exotic insulated wire, a few |
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You're referring to the leads on the right (primary center tap), correct? If so, I did that, which I believe is how I'm getting continuity from left to right. However, I'm going to apply some solder to the twist in order to make sure that I'm not getting a false positive by touching one lead or the other. Thanks!
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On Tue, Mar 25, 2025 at 08:04 AM, <john.runchey@...> wrote:
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Re: Leaving 50-watt amplifier in-line but off
Hi Nate.
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Transmitting and receiving.? I'd like to put a switch on the PTT going to the amplifier so that if I want the amplifier in the circuit, all I do is flip the PTT switch so that the amplifier will see 5V when the QDX transmits.
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I don't mind keeping the amplifier on all the time as the current used is nil.
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Jim
K8DDV |
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On Tue, Mar 25, 2025 at 08:57 AM, Chuck Harris wrote:
Unless you are using some exotic insulated wire, a few My experience is different, Chuck.? A simple roll of wire (certainly not exotic) I bought on Amazon from a quality manufacturer happens to have a high-temperature enamel.? So yes, I can burn it off, but only with with a high-temperature butane torch, but not a simple butane lighter flame nor any soldering temperatures.
Other wire types do have enamel that is specially formulated to burn off with solder or at low temperatures - you can often see it in their specs.
The .6 wire that Hans originally provided is somewhere between the two - if I didn't scrape it at least some amount, to significantly fracture its surface, it wouldn't burn off for me with soldering nor a simple lighter flame.? And I don't like to use a high-temperature torch.
Stan KC7XE. |
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Unless you are using some exotic insulated wire, a few
seconds of exposure to the flame of a butane lighter will easily burn off the enamel. After you have done that, there will be a little oxide and smutz on the wires, so a gentle pull through a folded piece of sand paper will clean that right off. Way easier than scraping, or sanding the insulation off. -Chuck Harris, WA3UQV On Tue, 25 Mar 2025 08:31:25 -0700 "Stan Dye via groups.io" <standye@...> wrote: If you didn't scrape the enamel off the newly-twisted 'A' center tap |
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On Tue, Mar 25, 2025 at 06:57 AM, Joel W9JFK wrote:
trying hard not to do a second transistor transplant. Not sure the patient would surviveJoel, when replacing the transistors 'next time' if there is one: just cut off the body of the bad transistors, leaving most of their lead-length in place and soldered to the board.? Then lay the new transistor in place, on top of the still-soldered leads, and solder the new transitor to the old leads.? Much easier, in my opinion, that cleaning out those vias. Stan. |
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If you didn't scrape the enamel off the newly-twisted 'A' center tap on the right side, those two wires won't contact each other, and you won't have continuity between the two left 'A' points - even if you scraped the enamel off the outside of the twist.
If you have the finer-gauge wire, you can burn the rest of the enamel off with solder and a hot soldering iron, if you have the thicker .6 wire, you need to un-twist the A center tap and scrape the wires first, then twist.
Stan |
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Re: Qmx Ssb intermittent transmit.
The same with me. Smtm you need to press PTT twice to start tx.
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16:35, 25 March 2025, "Howard Lamhut via groups.io" <howardlam@...>:
--
Sent from Yandex?Mail for mobile |
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Re: Qmx Single versus double click volume.
Purely a firmware thing, I believe. When/if the BASIC comes, I want to customize the UI so that a single click of the left encoder puts the QMX into band select mode and you choose the band by rotating the encoder. And, put the mode change behind a double-click.
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Another problem, I experience while operating is that I’ll tap the right button to end Message playback, but will get a little bounce and end up swapping the A and B VFO, which is annoying when you don’t notice and sit there wondering why the station calling you just disappeared! In fact, I might go so far as to have the multi VFO features enabled by a menu item so I don’t hit them inadvertently. |
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Hi. You are logically inconsistent.? If I have 3 points A,B,C and A connects to C, and B connects to C, then A and B MUST show continuity to each other. I suggest you check your measurements.
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Roger
8P6RX
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On 25 Mar 2025, at 11:00, "avinoam83 via " <gmail.com@groups.io target=_blank>[email protected]> wrote:
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No point to clean out the holes when replacing the BS170's, about all that does is damage the board with all the heat.
Just clip the new leads short and lay them flat across the top of the holes, solder them down.
Makes it easier to remove them next time you blow the finals.
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Jerry, KE7ER
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Those are plated through holes full of solder, and there is no chance the new BS170's are going to fall off the board.
What's the point of pushing the new leads through the holes?
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On Tue, Mar 25, 2025 at 07:35 AM, Chuck Harris wrote:
While waiting on my |
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I managed to get through the steps to build the RWTST version of the transformer. I'm getting caught up on Step 14:
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I have continuity between the secondaries. I also have continuity between the primary center tap and each of the two primary points on the left side. I do not have continuity between the two P points on the left side (i.e., the wires that were part of the hairpin loop before I cut it). Am I supposed to? Based on the wording in the instructions ("points P (P is for primary) should all show continuity to each other"), I assumed that I should have continuity between the two P points on the left side.
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Separately, do I understand correctly that the tighter the wire is twisted, the closer I will get to optimum power? I was able to twist them quite tightly, but it made them brittle for completing the coil. I tried again with fresh wire but I'm concerned that it's not tight enough.
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Thanks!
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Thank you for kindly answering my question... I truly appreciate it. I suppose I could have known that Hans already addressed this, but I admit that I have been unable to keep up with messages.
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I will run the calibration at the operating voltage. Might steal a few tenths though LOL...
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But I truly appreciate the information, fellowship, and helpfulness on this forum.
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73 & God bless,
Joel W9JFK |
Howard Lamhut
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