Yes, all terminals of T507 are at DC ground.? The inductors allow the RF signal to pass, and generate the FWD and RVS signal detection for power and SWR calculations.

I redid my windings as you suggested and they came out better.? Not perfect but better.

After soldering in place, when I checked the connections with a DC meter on ohms everything seemed to be very low resistance and very close to the same readings.? I've looked at the circuit diagram and can see that it is basically a few short lengths of wire more or less connected to one another and ground so I want to convince myself everything is OK.? But ....

Is this normal?

Good idea to have spare 74ACT08's if you plan to blow the BS170's.

When the BS170's fuse up internally I'd guess the 74ACT08 gate drivers might see 12v, at least for a moment.

?

Look on Mouser or Digikey for anything that claims to be a 74ACT08D, and then get the cheapest one.

The D means it's in an SOIC8 form factor, anything else won't fit on the board.

Any additional stuff after the D says how it gets packaged at the factory, and what kind of metal the leads are plated with.

You can verify this on page 11 of the datasheet where part markings are decoded for you:

This is the one I'd get off of Digikey: ?

In small quantities it arrives as "Cut Tape", because Digikey cuts a bit of tape off of a reel of 2500 parts.

?

The TI32A35SM that codeleaf reports is probably something like a lot number.

?

Jerry, KE7ER

?

?

?

On Wed, May 21, 2025 at 08:02 PM, <codeleaf@...> wrote:

New to the group - wanted to say Hi and since this thread is about observations and best QSO - I wanted to share my recent experience with the QMX+.? I am very fortunate to have an awesome? brother (K7MWD) who put together and sent me a QMX+ as I am just getting back into HAM radio.? I am working on the General so limited to 6M and 10M.? I have been having such a blast with this QMX+.? With a very simple QRP setup and a 6M Maxon, I have made some incredible contacts. Yesterday (5/20) in marginal conditions I was able to work all over the US on 6M running about 4 watts.? This little rig is amazing.? Here is a pic from the E opening yesterday.? Still trying to count the grids and contacts but this awesome radio worked the US, Canada and Mexico from DN81.? In this case less was more!? ?

?

?

I love this radio!

?

73s?

Chris K0CAO

?

?

I threw a few condenser mic elements into my last order, the one Hans recommends for the QMX.

?

My whole order had a 10% tariff fee added on, which didn't thrill me.

?

?

?

The IC503 likes to fail along with the BS170's. No part numbers unfortunately.

?

Schematic shows IC 503 is a 74ACT08D but chip is marked TI32A35SM ACT08 which I cannot find a spec sheet on.

I need to order some parts from Digikey. I though it would be good to order some backup parts for the QMX+.? Besides BS170's what are the components that fail most frequently? Also if you have specific digikey part numbers or names that would be great, ss some of the part names match multiple items.?

I say do them all, they're super cheap. Make sure you get them from Mouser or Digikey. There are a ton of fake bs170 out there.

?

To Da Wiz; thank you, and a request, to make it better.

?

Personally, I would appreciate the choice to use AGC, with my QMX+, or not, for all modes.

I have used fast or slow AGC with my FT-990 and TS-790A for years, for different modes,

and have found no noticeable performance penalty, except that the sound from no AGC

was harsh and undesirable, and the S meter unusable.

?

Some folks will not RTFMs to turn off the AGC, or properly tweak other software or

hardware, and complain about imagined "bugs" - but for this ol' geezer,

the choice would be appreciated, and I promise I will not whine about the consequences ;-)

?

Thanks for a hearing,

????????????????????????????????? DA Ol' Dog, wa4hei

Hi all,

I learned from the operating manual that the SWR measurement is from the center of the band. I had forgotten this trying to squeeze a POTA activation while on a business trip this week. My SWR reading was 2.00, on 20m . Not great but I was too lazy to pull my antenna out of the tree and use the shorter segment which usually gets me 1.4. (EFRW 71’ with 41’ segment) I have a EFHW which will work better but haven’t put it together yet.

?

To test propagation, I decided to hook up the iPad and do a little FT8. I think the SWR was much worse down at that frequency because halfway through my first transmit cycle.. snap! I knew what happened right away. ?I did have SWR protection on and set at 3 but it didn’t stop the pop. Radio still received but I shut it down. ?I ordered some BS170’s from Digikey for a whopping 24 cents a piece and they’ll be here tomorrow.

?

I think I should replace all four but thought I’d ask from those who know if it is likely the others are damaged too. Hopefully nothing else is damaged and I’ll recalibrate as well. Love this radio and pack it in my bag when I travel.

?

?

yep sorry the talet cell operates as you specified. the one i have can either charge with a 12.6v charger, or a usbc cable.? i have a couple other regulated batteries that i can choose 12v out.? and thanks for the schematic.? i haven't dived into the schematic or troubleshooting yet, just waiting to hear back from my ticket i submitted before i open the case.? and not a lot of free time lately.

My QMX arrived last week. Since I operate primarily digital, ( but seriously working on honing my CW skills) I was able to get several 'DIGI' mode programs to work. Not so easy with the SSB-required modes. I cannot believe the lack of YT videos on setting up this radio on digital modes. That will probably come with time. I now have Winlink, VARAC, FLdigi, etc. running. Some observations so far:

?

1. When I switched between two antennas I was testing last night, the QMX display suddenly shows only all horizontal lines, and the software loses contact with the rig. I have to re-start them. And NO, the rig is NOT transmitting when I remove the BNC connector.

?

2. I hope we will eventually have access to narrow filters in SSB digital modes. I have found that a weak DIGI signal becomes much stronger and copy improves when filtering to even 200Hz with my other rigs.

?

3. Finally, I must report my longest-ever ham radio QSO occurred last night on 40 meters. It was a QMX-to-QMX, JS8 contact with Cal, AD8Q in northern Idaho, 725 miles NW of my Colorado QTH, which lasted 2hrs, 17 minutes! I am very impressed with both the QMX and the INIU 10,000mAh PD power bank as recommended by the 'Ham Radio Duo' channel. On full charge, I am getting up to 22 hours of operating with moderate transmissions, and will probably see 14-16 hours of long QSOs like last evening. Not bad for $20 (on sale).

Here's the complete thread:

?

You can see all recent messages to the forum with a web browser here:

To see an entire thread for one of the posts, first click on the post number on the upper right.

For example, here is your post, and the post number is 145840

Then click on "View All Messages" at the bottom of that post.

?

Jerry, KE7ER

?

On Wed, May 21, 2025 at 02:40 PM, KK4ITX John wrote:

Randy, you would find some of this information when reading Hans papers. And did you check the Wiki? I think there is such a document already, but not complete now.

73 Ludwig

?

John

KK4ITX?

Stan, your two posts here and Jerry Gaffke's would make an excellent QMX* SSB Setup and Troubleshooting Wiki entry for the group!

Might save you having to restate it at some point. :-)

--

Randy, N4OPI

On Wed, May 21, 2025 at 01:20 PM, SA6ZGM Arne wrote:

At this point I'm worried that the solder will short if it flows too much between the PCB layers

It won't,, not to worry about that.

73,Don N2VGU

It's not designed for this kind of environment. If you want to do mobile HF you'd be better off using a rig purpose-built for mobile HF.

?

It's noisy on the road, so you will need a good audio amp. Also, you tend to bounce around a lot, at least on my town's potholed roads, so you should think of ways to ruggedize the rig, or give it a little shock protection.??

--

73, Dan - W2DLC