How to upgrade the GPS module in a Meade LX200GPS telescope for much faster GPS fixes

The 25 year old GPS module in my LX200GPS telescope has great difficulty getting a GPS fix. (My telescope is on a wedge, so the antenna is facing north instead of “up”, plus the backup battery died and is extremely difficult to replace without removing the telescope from the wedge. The biggest reason is that it is 25 years old.)

So I bought a modern BN-280 GPS module ($25) and a $10 USB->Serial TTL programmer, and replaced it. There are some technical details you need to get right to make it work (4800 baud, sending only $GPRMC messages, getting the wires hooked up right) but the overall process is relatively straightforward. Above is my howto video, and below is my big text dump:

Continue reading

Flashing the One Time Programmable (OTP) eFlash fuses on an u-Blox M8Q GPS to default 4800 baud and GPS only mode

To issue an One-Time Programmable (OTP) eFlash message in u-blox u-center use the “Messages View” to send specific binary commands to configure or flash the device.
This is done by opening the message view, selecting the CUSTOM type, pasting the command string, and sending it.

WARNING: This is a one time only, non-reversible procedure. After you blow the eFuses with these commands, the M8Q device will ALWAYS default to 4800 baud and GPS only mode on startup. (You can connect to it at 4800 baud and issue configuration messages to change this, but the next time the device is powered down without backup memory power, it will revert to the 4800 / GPS mode only defaults.)

To program 4800 baud default:
B5 62 06 41 09 00 01 01 30 81 00 00 00 00 FC FF 20

To program GPS only mode (disables GSV messages about individual satellites, reducing the total amount of data sent each second):
B5 62 06 41 09 00 01 01 31 81 00 00 00 00 01 05 2C

The above eFlash commands are not published by uBlox (they probably don’t want random people permanently changing the startup default behavior of their GPS units without understanding the irreversible nature of the command) but were provided by u-Blox technical support upon request.

WARNING to LX200GPS users: The uBlox M8Q can ONLY handle 3.3 volt TTL signaling. The Meade LX-200 holds the GPS TX pin high to 5 volts (but uses a level shifter to 3.3v for the GPS RX pin???), which has killed my TX pin (latch up) on a SAM-M8Q unit. So I’m switching over to using a Beitian BN-220 module.

Easy Setup for RTL-SDR (v3) on Ubuntu Linux


Quick HOWTO on how to configure Ubuntu / Lubuntu (24.04 or later) to work with the RTL-SDL Blog $50  hardware kit (that includes a dipole antenna)

The RTL2832U chip in the v3 dongle is designed for DVB-T (European digital TV standard) and not for the ATSC standard used in North America. While these dongles are excellent for general-purpose software-defined radio, they lack the necessary bandwidth to capture the 6 MHz ATSC channel width, as they are limited to approximately 2.4–2.8 MHz of bandwidth.


If you want to go more in depth and download / install some more software, I highly recommend the “Intercept” package which makes it relatively easy to switch between a LOT of cool things to receive:  https://github.com/smittix/intercept


The following commands were used to get the hardware up and running using only “repository” sources, no downloading software from github and compiling and installing anything yourself.   (If you are willing to go that route, look at Intercept linked above, as its install script makes things as painless as possible.)
Continue reading

Vespera 1 (VE50) vs Seestar S50


This test is both very unfair, and also fair:
First, I just placed the two telescopes outside and set them to image the same three objects for the same amount of time, and I didn’t try super hard to keep the imaging area the same. Both telescopes have mosaic modes, and if I used them, I used the android app for each telescope to “eyeball” them to be about the same general size around the target.

Continue reading

HOWTO: Identify optional components (UI-7 AM/FM Unit, FL-100 / FL 101 Narrow CW Filter) in an Icom IC-725 from the outside

The Icom IC-725 radio has three optional expansion units that may or may not be installed.

The UI-7 AM/FM Unit allows it to operate in AM and FM modes (in addition to SSB and CW) and plugs into the bottom of the main circuit board near the rear of the unit. When it is installed, the air flow grill openings on the rear right side of the bottom of the radio will be blocked. (Looking at the radio upside down from the front/knob side)

(Empty) Location where the UI-7 AM/FM unit would be installed (also the UT-30 tone unit would go under it.

[All IC-725 radios have the FM/AM and CW/Narrow buttons on the front panel, so the existence of these buttons, or even the AM/FM icons lighting up on the LCD panel doesn’t mean anything.]

The FL-100 or FL-101 (500Hz or 250Hz) Narrow CW Filter units plug into the front middle of the bottom main board. You can faintly see a rectangle in white with the text “CW Filter” inside it on the green circuit board to the left of a silver crystal if the optional CW narrow filter is not installed. [If it IS installed, it will look like a larger rectangular prism that covers the “CW Filter” writing, usually silver in color with a black sticker on top.]

Empty location for the narrow CW filter outlined in white with “CW FILTER” on the main circuit board

The UT-30 Programmable Tone Generation unit plugs into the UI-7 unit but is invisible from the outside of the radio as it is sandwiched between the main board and the UI-7 board when installed.

 

 

The $650 budget HF Ham Radio setup for Voice & Digital Modes

Ham Radio can be a very inexpensive hobby if you are using a $30 Baofeng handy talky on the 2m or 70cm bands. But when you get into the lower HF bands (160-10m) costs start to mount (in both the core radio as well as the larger antennas and mounting hardware).  I was able to put together a budget ham radio setup for $650, and I don’t see a lot of room to go lower than that without getting parts donated or using a much lower quality radio.

I have a listing of the model/part numbers and links to sources below.

With this IC-725 radio and a 20m Dipole (mounted only 20′ up in the air) I’m able to easily make good voice contacts 1000-1,500 miles away (New York & Colombia).

Using FT8 digital mode at 100 watts, I can reliably reach most of North and South America and parts of Africa. (If I re-oriented my antenna to face Europe, I’m sure I could also easily make contacts there).

My longest contact to date (at a -19 reception level) was to Chongqing, China, but this was during exceptionally good atmospheric conditions (lots of bouncing through the F layer of the ionosphere) and it’s not something that happens regularly.

PSK reporter shows all of the remote stations have have heard my callsign (just because the can hear me, doesn’t necessarily mean I can hear/work them, as my IC-725 probably isn’t as sensitive as many newer transceivers).

Note that I’m using my “fair weather” radio outdoors on the patio, so I don’t have any lightning suppressors, grounding rods or wall penetration hardware/boxes, which will probably eventually add another $100-200 to make a permanent “ham shack” install.

I’m also planning on upgrading to a RadioWavz 40m DX off center fed (OFC) Windom dipole that will be resonate at 40m, 20m, and 10m, allowing me to try out two other bands without buying a separate antenna tuner (I’ll probably upgrade to a newer radio with a built in tuner before buying an external antenna tuner).

Parts list with costs and source links:

Icom IC-725 Ham Radio – 30 years old, 100 watt transmitter that covers 160-10m bands (but only if your antenna is resonate at the frequency, as it doesn’t include a built in Antenna tuner). $300 used  (The Icom IC-7300 (not Mk2) can be purchased new for $1,000 right now on discount because ICom released the IC-7300Mk2, and is a direct replacement for this radio that is better in every way except price.)

Icom HM-36 hand mic (with Up/Down buttons) $40 used (+$10 s/h)
(I really appreciate the up/down buttons on the hand mic for searching the band at 1kHz increments….)

RadioWavz 20M “Double Bazooka” Dipole antenna ($40 used, $80 new w/ shipping)

DigiRig Mobile (CI-V configured) with ICOM CI-V Din 8 cables: $87.93 shipped
(I also recommend their shielded USB cables to prevent any RF/EMI from messing with your computer.)

Surplus LiIon “12 volt” (really 13.5 volts) 28 Ah battery: $60
(You could also buy an AC 13.8 volt 30 amp power adapter for under $100)

~ $100 of rope, pulleys, and coax to hang and connect the antenna (Note that I’m using my “fair weather” radio outdoors on the patio, so I don’t have any lightning suppressors, grounding rods or wall penetration hardware/boxes, which will probably add another $100-200 to make a permanent “ham shack” install).

50′ RG58 coax with PL259 connectors: $30

500′ 3/16 inch Black Dacron Polyester Rope $40
(I had some left over…)

2x U-Type Swivel Pulley 304 Stainless Steel $20

40 lb Neon Fire fishing line – 370 Yds (used to pull ropes and pulleys into trees) $13

I also used my son’s 20lb draw bow and arrow (for free!) but you’ll need something to launch the monofilament fishing line over tree limbs. I’d recommend a “Tree throw weight” thrown by hand as your least expensive option at $15 You can also buy a complete kit that includes 3mm rope instead of fishing line and a bag for $22.

Copilot vs ChatGTP for Meme Image remixing


Finding this meme on the internet, I decided to use AI to re-mix it to feature a family dogs’ face instead.

I gave the above two images to both CoPilot and ChatGPT with the following prompt:
“I have uploaded a picture that has words at the top and a picture of a red glass reflective Christmas ornament that has a reflection of a black cat looking out of it. I will next upload a photo of the face of a dog and I want you to replace the reflection of the cat with a reflection of the dogs face. Make the output image as high resolution as you can without modifying the text.”

Here are the results:

Generated by CoPilot

Generated by ChatGPT

Both AI tools performed well in this simple image merging task. I feel like CoPilot ingested the details of both images and generated a new image using a “generic” version of the dog photo, while ChatGPT generated a much closer match to the second source image (However, this gives a bit of a two images photoshopped together vibe, probably because the dog face isn’t tinted quite red enough.)

FT8 and CAT rig control with the Icom IC-725 using a DigiRig Mobile (CI-V)

The DIN8 (audio in/out) plugs into the Acc 1 port (the right most 8 pin port on the back of the rig) and the serial control plugs into the “remote” jack which is directly above the two 8 pin ACC ports.


I was able to successfully make digital FT8 contacts using my vintage Icom IC-725 transceiver, a DigiRig (with the correct cables) and the WSJTX software.  
You need a DigiRig mobile that is configured for CI-V cat control (not the default) and the “Icom DIN8” cables.  [Plus a USB-C cable.]

With the above hardware, you can control your rig via the “remote” jack (tuning to frequencies and turning the transmitter on) while using audio in/out via the built in USB Soundcard.  Many things can be done with the right software, but for now I’m just using WSJTX for FT-8.

For my IC-725 (which I suspect has the default diode settings inside) I needed to change the Baud Rate to 1200, and the PTT method to “RTS” (this is specific to the Digirig).  [I also had to pick the DigiRig USB soundcard under the “Audio” tab.]

This combo lets WSJTX tune the radio (although I mostly just work in the 20 meter band because that’s the antenna I have up right now) as well as transmit and receive audio for FT8 and other digital modes.

 

Excellent Books

Fantasy:
The Abhorsen Trilogy by Garth Nix
Sabriel, Lirael & Abhorsen

Hood, Scarlet, Huck – Steven Lawhead

The Night Circus by Erin Morgenstern

Karen Memory – Elizabeth Bear (fast summer read)

The Tainted Cup – Robert Jackson Bennett

Science Fiction:
Debatable Space by Philip Palmer

The Icarus Hunt Timothy Zahn

Falling Free by Lois McMaster Bujold

The Changeling Plague by Syne Mitchell

Novel
The Amazing Adventures of Kavalier & Clay by Michael Chabon

A Heroine of the World by Tanith Lee

SanDisk 512GB Ultra Luxe USB 3.2 Gen 1 Flash Drive – SDCZ74-512G-GAM46 – Extremely Slow Write Speeds

I purchased a SanDisk 512GB Ultra Luxe USB 3.2 Gen 1 Flash Drive with the markings: “SDCZ74-512G-GAM46” on it about a year ago, and it worked “fine” but the write speed was much slower than it should be (around 4 MB/s in sustained writes) so backups to the drive were taking 4-8 times longer than they should.

I eventually got tired of this, and sent it back to SanDisk for a warranty replacement, and I’m happy to report that the replacement Ultra Luxe drive [USB 3.1 Flash Drive] with markings “512GB  BR200357930W SDCZ74 Made in Malaysia” works much better. [27 MB/s sustained writes on a 252 GB file system, 90+ MB/s reads on a 2.8 GB file.]

There are two remaining downsides that keep this from being the perfect “keyring” backup drive. 1) It gets very hot to the touch (I’ve measured temps as high as 124 F when writing for multiple hours….).  2) I wish that the hole on the back of the drive was just slightly larger. If you orient it correctly on a keyring, it will fit snugly against other keys, but the hole isn’t large enough to let it “rotate” on the keyring so the ring can rotate and fold flat in your pocket.

So, if you have a SanDisk flash drive that isn’t working as fast as it should, try the warranty replacement process. Here is a photo of the back of the good drive: