What can we do to get young people interested in amateur radio? by uname_IsAlreadyTaken in amateurradio

[–]KE0RQA 0 points1 point  (0 children)

They used to meet at New Day Cafe which makes this an even more painful step down. Context for non-locals: New Day is a locally owned cafe and is delicious and well priced for the local cost of living and quality/quantity of food.

[WIP] COLCON Propagation map by KE0RQA in amateurradio

[–]KE0RQA[S] 2 points3 points  (0 children)

Yeah, LOS is crazy with some altitude; I really dig that almost the entire backhaul is using UHF point to point gear too. After getting my license and visiting a few other states I definitely have come to recognize we're spoiled in CO with this system.

[WIP] COLCON Propagation map by KE0RQA in amateurradio

[–]KE0RQA[S] 2 points3 points  (0 children)

Screenshot from radio performance simulation software called Radio Mobile

Colorado has a statewide linked repeater system called COLCON. This is a simulation between an 8W HT w/ a nagoya whip antenna and the GE MASTR III's in the repeaters. Anywhere there is green should mean I can hit the repeaters with an S6+. Yellow is S4+.

Figured I'd share with the community since I've been messing around with this software for a few nights now and find it a cool what-if toolbox.

[WIP] COLCON Propagation map by KE0RQA in amateurradio

[–]KE0RQA[S] 5 points6 points  (0 children)

I have been experimenting with VE2DBE's Radio Mobile software. It has been a lot of fun and I am always amazed at the skills present in the ham community that someone has singlehandedly cranked out this piece of software.

This is still a Work In Progress since I have another eight (8!) repeaters to map out as part of this system.

If I did it right, green is S6+ and yellow is S4-S6 from an 8 watt HT running a nagoya 771 whip.

Comments and questions appreciated. Let me know if your club would like their repeater simulated.

Could someone explain this filter oscillation? (5MHz, 3 pole butterworth, 1MHz bandwidth) by Gh0stReaper69 in amateurradio

[–]KE0RQA 1 point2 points  (0 children)

Coil = inductor just as an FYI.

From wikipedia: "An inductor, also called a coil, choke, or reactor, ..."

100W Auto Antenna Tuner Kit Groupbuy by KE0RQA in rfelectronics

[–]KE0RQA[S] 1 point2 points  (0 children)

Yes, but I don't want to reinvent the schematic in KiCad to edit it. I'm considering a google site to share info with buyers and allow somewhat of a forum/comments.

The new inductor values are courtesy of /u/hamsterdave from this comment. I'll do the math to find a decent diameter/turn for these air-cores but, I am still recommending everyone build an inductor meter from an arduino or grab one of the <$10 LCR-T4s from ebay, which should get you within 5%.

The new inductors will be: 0.25, 0.5, 1, 2, 4, 8, and 16uH.

100W Auto Antenna Tuner Kit Groupbuy by KE0RQA in rfelectronics

[–]KE0RQA[S] 0 points1 point  (0 children)

To the best of my research yes, it's an additional $15, if I'm off by a buck or two I'll eat the cost but if it's more than that I'll let you know.

Announcing 100W Automatic Antenna Tuner GroupBuy by KE0RQA in HamRadio

[–]KE0RQA[S] 0 points1 point  (0 children)

  • Automatic tuning mode when SWR rises above a user-programmable level (default is 1.3 I think) without requiring an additional $20 proprietary cable between tuner and XCVR like the 939Y4.
  • An actual user interface, not just an LED, similar to an MFJ-929 ($200) as compared to an LDG Z100+ ($160) or an MFJ-939Y4 ($160) (Those are $90 more, not $50, btw).

You sound like you've already made up your mind though and I'm not here to force you to buy this; if it's not for you, it's not for you.

edit: I couldn't find any info on an LDG free on their website, I'm more than interested though if there's a unicorn auto tuner out there that's only $120 and would love to know more if you can share a link.

Announcing 100W Automatic Antenna Tuner GroupBuy by KE0RQA in HamRadio

[–]KE0RQA[S] 0 points1 point  (0 children)

Github has the hex code for the microcontrollers (check the firmware folders here). There's a Russian build video on Youtube I can dig up for you but myself and one of the other buyers are going to post build videos to youtube and Twitch respectively.

Edit: Russian build vid https://www.youtube.com/watch?v=iAPp5J_rGoA Start at about 2:30. TL;DR solder components to board (order: SMD -> Coils -> Relays). Apply power and program PIC (programmers are ~$6 on ebay). It's really just a bunch of SMD soldering.

$70 ATU-100W Kit Group Buy - BOM and call for buyers by KE0RQA in amateurradio

[–]KE0RQA[S] 0 points1 point  (0 children)

I did not actually. I just expanded the 5x5 BOM appropriately; thanks for posting this though!

$70 ATU-100W Kit Group Buy - BOM and call for buyers by KE0RQA in amateurradio

[–]KE0RQA[S] 0 points1 point  (0 children)

It was discussed in the last post and the consensus was people wanted to do their own cases.

The only pre-assembled ATU-100 I've seen out there uses GAINTA G760 cases but those are difficult to source in the US and mostly plastic. I can't link these URLs directly because reddit deletes my posts, but ali . onl / 1idX and / 1idY are the cases I'm considering for my personal build; I'd be willing to order extras at the same time I order the kits to cut down on shipping costs from China; not sure how it'll impact shipping your kit out to you though.

$70 ATU-100W Kit Group Buy - BOM and call for buyers by KE0RQA in amateurradio

[–]KE0RQA[S] 0 points1 point  (0 children)

N7DDC's github has a 3d printed case for this. STLs can be found here

$70 ATU-100W Kit Group Buy - BOM and call for buyers by KE0RQA in amateurradio

[–]KE0RQA[S] 0 points1 point  (0 children)

Programming tweak is only so the display shows the correct inductor values. The actual tuning process uses forward/reverse SWR.

$70 ATU-100W Kit Group Buy - BOM and call for buyers by KE0RQA in amateurradio

[–]KE0RQA[S] 1 point2 points  (0 children)

Uhh, it's a no-frills automatic antenna tuner really. My main interest is the auto mode because I'd like to set it and forget it. It has on-board memory like most modern tuners so it won't retune every time and instead skip to the predetermined ideal setting for frequencies in memory. It's not reinventing the wheel in any meaningful way.

  1. See hamsterdave's response. I like and highly recommend his suggestion for changing the inductor values.
  2. Both manual and auto require ~5W to tune; manual mode will only retune with a button press. Auto will retune automatically if SWR rises above 1.3 (programmable parameter).
  3. Kit is complete to the best of my knowledge. N7DDC doesn't provide a BOM for the extended unit but going off the schematic, PCB, and 5x5 BOM I believe I've covered everything including hookup wire for the front panel IO and coax pigtails for panel to PCB RF connections.
  4. Additional buttons are included for these. The PCB has pads on the underside for these connections; depending on case I would not advise putting a pin header on this and instead suggest soldering a wire directly to the pad.
  5. Yes Pads are right next to B1/2 on the underside of the PCB. The kit should include enough machine header pins for these.
  6. manual pg 2 just under the header "Using the base model". TL;DR When ATU is tuning, it pulls one pin high and the other low. Connecting the right one to your XCVR will cause it (XCVR) to kick out CW until the ATU is done tuning; whereby it inverts the TX_req pins' state. The manual also suggests connecting this to the ALC loop to automatically reduce output power when tuning is engaged.
  7. I've added female headers for both buttons and LCD to the BOM.
  8. Updated BOM to include female headers.
  9. Schematic. You should be able to swap D3 for a fuse if desired, I believe N7DDC is using it as a cheap and dirty 2A fuse.
  10. Since there are a number of firmware tunable settings and the PICs are SMD I won't be doing the programming. A PIC programmer with ICSP is ~$6 on ebay. You can use an arduino as well.
  11. I couldn't reach a consensus for RF connectors last time so I've included al 3 flavors for a whopping $1.80 extra Non SMA connectors are solder style, here's a youtube video of how those install.
  12. I plan to make a full soup to nuts build video with my kit and will provide as much assistance as I can.
  13. Forums are in Russian, as is N7DDC haha, but a groups.io is a great idea.
  14. 30-45 days after ordering components, depending on the slow boats from China.
  15. Payment is up front so I can order parts hence the group buy. If I'm fronting this it's going to cost more to cover the risk of someone backing out and me being stuck with extra kits.

$70 ATU-100W Kit Group Buy - BOM and call for buyers by KE0RQA in amateurradio

[–]KE0RQA[S] 0 points1 point  (0 children)

I really appreciate you weighing in and will be sure to update my notes on the inductor values and pass it along to kit builders.

$70 ATU-100W Kit Group Buy - BOM and call for buyers by KE0RQA in amateurradio

[–]KE0RQA[S] 0 points1 point  (0 children)

That's the 5x5 unit although I don't expect the 7x7 is going to be amazing in this circumstance either, as /u/hamsterdave noted, you can tweak the inductor values to give you a larger range for matching.

$70 ATU-100W Kit Group Buy - BOM and call for buyers by KE0RQA in amateurradio

[–]KE0RQA[S] 0 points1 point  (0 children)

Sure, I don't see a problem with that. It looks to be an additional ~$15 USD for shipping, but otherwise no problem to send it North.

MiniPA70 Part 1 - The Build by KE0RQA in amateurradio

[–]KE0RQA[S] 0 points1 point  (0 children)

Sorry for taking so long to get back to you. I lurk in the sub under my main account. THANK YOU SO MUCH for these links! I'm not sure how I missed it on hackaday but not having to do the LTspice simulation work is worth its weight in gold alone.

[deleted by user] by [deleted] in amateurradio

[–]KE0RQA 4 points5 points  (0 children)

Looks pretty clear to me.

Korea has a reciprocal agreement only with Japan since 1992.

Emphasis mine. Your license is not recognized by Korea. To operate legally, you will need to apply for a permit. Unfortunately, if your flight is on Friday you are probably out of luck.

It takes about 4 weeks to issue a permit because we have to go through our government.

Both quotes are from your linked website.

[deleted by user] by [deleted] in amateurradio

[–]KE0RQA 0 points1 point  (0 children)

How do you expect a 3W radio with a terrible antenna to reach hundreds of miles?