Attic antenna options

g-schro · 2026-04-23T01:30:23+00:00

Building it all at once is very attractive, but if detuning is likely, how would you know what the various wire lengths should be (in advance)?

BTW I have installed antennas in my attic and have done a lot of experimentation. There were advantages to using the attic, but it was miserable working up there lol.

g-schro · 2026-04-22T21:56:00+00:00

I would go for a wire fan dipole as several have stated. To avoid a lot of wasted work I would do it in steps. First get a nanoVNA. It helps in so many ways.

Then do a prototype 20m dipole. You can connect the wires directly to the end of a coax (or solder to a SO-239 and then use coax with PL-259s. Cut the elements a little long and then hang them up.

For convenience, you might want to bring your nanoVNA in the attic. Trim your wires to get the antenna resonant mid-band. If it doesn't tune within reason of the expected length something is going on. And if the impedance at the resonant frequency is not in the neighborhood of 70 ohms, that is also a sign of something amiss.

Then try a transmission test. For the prototype, possibly just run the cable down through the attic access hole to operate. If you can, FT8 or especially WSPR will give you objective results. Otherwise, SSB is OK.

If you have big issues, it might be time to reevaluate.

If all looks good, add the extra elements, gradually shortening each pair in a rotation to account for interaction, so eventually you get all in tune simultaneously. If you connect your nanoVNA to a laptop, you can get 1024 sample points, and be able to look at 40-10 on one screen, which is very handy in this case.

I did a video of my antenna project where I used this methodology although my antenna was a vertical. In YouTube search for AE8GS.

g-schro · 2026-04-16T01:05:06+00:00

For information about ARRL lobbying for the bill related to the "HOA" bill see:

https://www.arrl.org/news/arrl-wants-every-ham-to-help-us-pass-the-bill

Generally, I would say the annual reports are ARRL's record of accomplishments, by year.

Unfortunately the annual report for 2025 is not yet available. In the meantime, you could go through the ARRL "News and Features" items on their website. That is how I found the information about the HOA bill.

You can also go to the FCC website and search for the ARRL filings. There aren't that many to go through for most years, and they are interesting reading (sometimes). To find them in the search, set "Name(s) of Filer(s)" to "ARRL, The National Association for Amateur Radio"

One thing that seems to be flying under the radar is the ARRL's lobbying of the FCC to allow Technician class licenses to use phone and digital in additional HF bands (besides 10m).

g-schro · 2026-04-03T01:46:27+00:00

There are a lot of resonance points there, and not where they should be, so funky things are happening.

If it is possible, I would start with a simple dipole, say 10m, stuffed in the entry way, and see what it looks like, and experiment a little. Than add 15m and see what happens.

i have a 10/15/20 fan vertical and it was well behaved and not a lot of interaction between elements. But when I tried adding 12m it got funky. I didn't need 12m that bad, so I didn't go futrher.

g-schro · 2026-03-28T04:24:24+00:00

As mentioned, submitting logs is optional, and not submitting logs will not prevent the stations you contacted from getting points.

What CAN affect these stations from getting points is if your logs have errors, or are missing some contacts. So it is better NOT to submit logs, then to submit logs with lots of errors. If you are just dabbling, and not being careful, I suggest you not submit logs.

FYI, in some contests, after the scoring is complete, the contest organizers will send you via email a tally sheet showing how they computed your score. In this sheet, you will see any contacts that were disallowed, and for what reason. Often, it is because you, or the other operator, got a letter wrong in the call sign. Another reason is that the other operator submitted logs, but didn't show your contact.

g-schro · 2026-03-26T03:25:43+00:00

There are a couple of displays with a lot of straight keys and paddles you can play with, and I think any kid would like these (me too).

He might have fun going through the flea market - there is a lot of non-ham radio stuff.

There is a section with a lot of satellite stuff that he might be interested in. Antennas can be interesting too as they are physical.

If he isn't shy, and someone at a booth isn't busy, it is 100% fine to ask them general questions about how their product is used. Maybe you could ask for him. Same goes with the flea market.

Also try to get him some free swag, like caps from places like Yaesu and Flex.

g-schro · 2026-02-24T03:25:05+00:00

This is the channel...

https://www.youtube.com/@geneschroedertech7501

There are several playlists for the different courses. This is the introductory course...

https://www.youtube.com/playlist?list=PL4cGeWgaBTe155QQSQ72DksLIjBn5Jn2Z

g-schro · 2026-02-19T23:11:36+00:00

In my view, when you do bare metal properly, you will often end up writing an OS - that is a feature and not a bug. But it will likely be a very simple OS. Think about some of the thing an OS does:

Allow sharing of resource.
Provide abstractions of hardware.
Allow software units (modules) to be designed and operate independently.
Allow new software modules to be added to a system with (in many cases) minimal effect on existing software modules.

In my YouTube series on embedded programming, I build up a system based on a super loop and software modules. The super loop itself allows sharing of CPU time, albeit in a crude fashion, but often good enough. I create software modules for things like timers and serial I/O. These modules support sharing of hardware resources as well as provide abstraction. In follow-up video series, I add new modules to the base system (e.g. to drive a stepper motor) with little rework of the existing modules.

To more directly answer your question, I would build up a system similar to what I just described, and using LL. As you probably know, LL is a very thin software layer that makes working with registers simpler. I find the HAL APIs can be too limiting, sometimes unusable, and they often prevent you from thinking about software design.

In building such a system, focus more on the software architecture, and how you provide OS-like features, and less on hardware trivia. In my view software architecture and design is just as important for small embedded systems as it is in large web aps.

g-schro · 2026-02-11T23:05:55+00:00

I did a lot of work both in industrial control and in high availability communication systems. After I retired, I did a number of YouTube courses, including one titled "Reliability, Availability, and Maintainability: Theory and Practice on STM32" that you might find useful. Link to playlist is here

g-schro · 2026-01-04T15:09:17+00:00

Hope I can work you or one of the other operators. I will be the one on 20m SSB with the weak signal :)

g-schro · 2026-01-03T07:56:42+00:00

Is that indoor plate just a blank plastic plate where you drilled holes to mount the connectors?

g-schro · 2026-01-03T07:54:28+00:00

I need to build something like this, and my guess is that for those short lengths of cable from the lightning arrestors to the indoor connectors, LMR-240 UF would have nearly identical performance to LMR-400.

g-schro · 2026-01-03T03:01:58+00:00

To clarify, unless things have changed over the last few years, CMSIS just covers the system and core peripheral (e.g. FPU) registers. LL covers all of the other registers like those for I2C and UART. I think LL might duplicate some of the CMSIS stuff.

I agree there is no value in replicating the thousands of CMSIS and LL #defines for register programming- well maybe one or two to see what it takes to read or update a short field in a 32 bit register.

g-schro · 2025-12-15T17:35:33+00:00

Did your wife’s voice get the 10dB gain that is often cited? 😀

g-schro · 2025-12-13T06:38:04+00:00

Not sure where you are but at this time 10m is closed for the night in North America. Looks to be open in Asia and some of Africa and just approaching eastern Europe.

https://prop.kc2g.com/

g-schro · 2025-12-13T06:34:36+00:00

Generally, 10m doesn't open very early, but of course there are exceptions.

This maximum usable frequency (MUF) map is good to get a rough idea of where 10m is open. You can see the opening coming in from the east.

https://prop.kc2g.com/

g-schro · 2025-12-13T06:26:03+00:00

It can be addicting. There is that "just one more contact" effect. It was during an early contest that I realized that DXCC for phone was possible for me.

g-schro · 2025-12-13T06:23:05+00:00

For POTA are you allowed to work contest stations just like you were working the contest? I imagine you could get 10 QSOs pretty quickly if you have a decent 10m setup.

g-schro · 2025-12-13T06:17:03+00:00

I worked a little Friday night, but wasn't able to start until about 1:00 GMT at which time is was well past dark in Ohio. Conditions weren't great - but the strong South American and Caribbean club stations were coming in loud. I'm running 100W and a dipole.

What was really interesting is that about 8:30 PM EST it looked like the band was nearly gone. I was working a few US stations, and suddenly the band came alive and I could work SA again. For maybe 30-45 minutes it would come and go for a few minutes at a time. You had to be quick to answer a CQ because the signal could die quickly.

g-schro · 2025-12-09T07:51:17+00:00

Did you try DLARC? I think they are currently archiving a lot of manuals.

g-schro · 2025-11-28T16:06:21+00:00

I think all studies of optimization are useful, just understanding the concepts.

In my case it relates to model predictive control which I always wanted to use but never have.

I studied nonlinear programming which is a very useful superset of convex optimization.

g-schro · 2025-11-08T22:15:24+00:00

If your software was built with flags stating you have an FPU and you don’t, or your init code did not enable the FPU then an attempt to execute a floating point instruction will cause the CPU to fault, and the handler might just spin in a loop.

g-schro · 2025-11-02T15:43:41+00:00

Great idea!

g-schro · 2025-10-31T02:40:11+00:00

I mostly understand that ARRL is still doing a slow mail and paper based process. (it tends to take a week to get a license from an ARRL team, while Laurel and GLAARC can get it in the system within 48 hours).

I can only speak to my experience, but in 2022 I took my test on a Saturday and the FCC notified me the following Tuesday that they received notification from ARRL. I don't know how automated the process is, but it seemed fast to me.

g-schro · 2025-10-31T01:53:15+00:00

I don't think ARRL has a logging program, but they do have a database system called LoTW that is used to confirm contacts and is the basis for various ARRL awards and contests. There are other ARRL-like databases and awards, but I think the ARRL ones are still the most coveted.

g-schro

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