Keyboard Shortcuts
ctrl + shift + ? :
Show all keyboard shortcuts
ctrl + g :
Navigate to a group
ctrl + shift + f :
Find
ctrl + / :
Quick actions
esc to dismiss
Likes
- QRPLabs
- Messages
Search
Re: T507 Winding Direction/Handedness
#building
#QMXplus
#transformer
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. |
Re: T507 Winding Direction/Handedness
#building
#QMXplus
#transformer
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? |
Re: Digikey order
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.
My QMX+ also has IC503 marked as "ACT08", that other gibberish says "TI43A5SRM".
?
Jerry, KE7ER
?
?
?
On Wed, May 21, 2025 at 08:02 PM, <codeleaf@...> wrote:
|
Re: New QMX - observations and best QSO
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
?
? |
Hi Mark,
?
How did things go with your setup?
?
I¡¯m in exactly the same situation! I¡¯ve run all the tests, and from what I understand, the MAX3221IPWR chip used in the IC-9700 should be able to distinguish between TTL and standard RS232 signals.
?
The only thing I haven¡¯t tried yet is using a standard RS232 converter. I¡¯ve tested with TTL signals at 3.3V and 5V, but there¡¯s absolutely no way to get the IC-9700 to update its GPS data.
?
To give you more context: my goal was to extract GPS data from a GPSDO, send it to a Raspberry Pi, and then use a small Python script to forward the data to the radio.
?
Everything works ¡ª except the radio receiving the data!
Everything has been checked: protocols, pinout, etc... ?
Have you figured anything out on your side? Or could it be that my radio has a hardware issue?
|
Digikey order
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.? |
Why no AGC for digital modes, as other modes?
?
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 |
Pop! Oops, blew a BS170 in my QMX, my fault. Lesson learned
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.
?
? |
Re: QMX died before i got a chance to transmit.
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. |
New QMX - observations and best QSO
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). |
Re: Introducing QMX CARROT
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:
I guess that I missed the start of this thread¡¡ where is the carrot info? |
Re: Introducing QMX CARROT
¿ªÔÆÌåÓýI guess that I missed the start of this thread¡¡ where is the carrot info?John KK4ITX? ?Each mistake is a learning opportunity.? On May 21, 2025, at 10:38 AM, Chris via groups.io <chmuenzer@...> wrote:
|
to navigate to use esc to dismiss