Monday, July 27, 2020

Black Powder Shotgun Go Boom!

A few years ago I loaded up some black powder 12 gauge shotshells in Magtech all-brass hulls, that I bought from Ballistic Products. This exercise was inspired by a video on the Survival Russia YouTube channel, which has since been taken down in accordance with their rule prohibiting videos that show how to load ammunition.



(The picture is a frame grab from an iPhone video.)

I did a few variants:

1-1/4 oz. of #7.5 shot on top of a compressed column of sawdust (in lieu of a cushion wad)
1-1/4 oz. of #5 shot on top of sawdust.

Also, some of the same payloads on top of lubricated wool felt wads. (I have a supply of such homemade wads for use in my Euroarms Magnum Cape Gun percussion 12 bore.)

And a patched .690 round ball on top a couple lubricated felt wads. All were loaded on top of 80 grains of 3Fg.

I tested one each of the #7.5 and #5s, and 3 of the PRB loads.

From 10 yards the #7.5 penetrated one wall of an empty soup can. The #5s went through both sides. Patterning seemed OK for a cylinder bore gun.

Accuracy with the PRB would be good enough to take a deer out to 40 - 50 yards or so.

Because these shells were loaded with black powder, I ran a couple patches wet with a Ballistol/water emulsion through the bore when we finished shooting. I repeated this at home and left the bore with a good coat of Ballistol.

The empty shells got put into a soapy water bath overnight. I found that a 12 gauge tornado brush was perfect for brushing out the inside of the cases to remove residue left from the glue I used to hold the over-shot cards in place.

Tomorrow I'll punch the primers out of the spent shells and clean the primer pockets. I'll also use some acetone to remove the load info I'd written on the side of the shells with a Sharpie marker.

Shooting these BP shells was a lot of fun and the cases should be reusable more or less indefinitely.

One thing I like about the Magtech brass shells is that they use large pistol primers rather than 209 shotshell primers. I use LPPs for .38 WCF and .44 WCF, so that's one less component I need to stock. Also, in normal times, pistol primers are less expensive than 209 primers. (All bets are off in this election/pandemic/civil unrest year, however.)

Saturday, July 18, 2020

NanoVNA Vector Network Analyzer

The NanoVNA vector network analyzer is a handheld device that came out a few years ago. It's based on open source software and among other things, can be used to measure the standing wave ration (SWR) on antennas. There are several versions of the NanoVNA, this is the one I bought (Amazon affiliate link.)

Wikipedia has a good explanation of SWR and why it's important.

I finally got around to trying it out today. I used it to take SWR measurements of the Ultimax 100 end-fed antenna that's on my roof.

On 80 meters, SWR hovered around 2.5:1.




On 40M, SWR was around 1.7 - 1.8:1.



On 20M, SWR was around 2.5:1.




And finally, on 6M, it ranged from about 1.25 to 1.28:1.



The NanoVNA was connected as the antenna presents to my LDG IT-100 tuner: antenna-feedline-passthrough panel-patch cord.

When I checked the Radiowaz 40M dipole that I strung recently, SWR was much higher on 40M. It should be better when I get it elevated more.

The NanoVNA is a very cool and potentially useful device. However, like a lot of things that rely on open source, documentation can be spotty. The unit came with some calibration info, but nothing on how to use it. Some documentation sources to check out:

The NanoVNA is a good addition to your toolbox if you're a ham radio operator who builds antennas. If your "the commo guy" for a group of preppers, you should give it a hard look.

Monday, July 13, 2020

RTL-SDR Blog Dongle v3

Today I received the RTL-SDR Blog v3 dongle that I ordered last week from Amazon. It came in a kit with a couple different antennas, a cable, a suction cup mount for the antennas, and a small, flexible tripod for them.

This is a replacement for an older SDR dongle that I've had for several years. The thing that attracted me to this one is that you can use it to monitor HF in direct sampling mode, without an upconverter. My older dongle could only do VHF and UHF.

One nice feature of this dongle is an aluminum case. These things get hot and the metal case acts as a heatsink. That said, I may fab something to increase the surface area to improve heat dissipation. (I have a mini-mill that may come in handy for this project.)

I installed the SDR# Community Package on my HP laptop running Windows 10, and started playing with it.

This screenshot shows it tuned to KYW 1060 AM, the Philadelphia AM news station. For this I connected it to an Ultimax 100 40M - 6M end fed antenna that's on my roof.




The second screenshot shows the dongle monitoring the 2M ham band, tuned to the W3OI repeater in Allentown, PA during their Monday night net. I am located outside Philadephia in SE PA, about 42 miles away from the Allentown repeater. The terrain isn't flat between here and there, plenty of rolling hills between my home at the repeater.





The antenna for this exercise was my Comet GP-3, which is attached to a five foot mast strapped to my chimney. The tip is probably around 30' to 35' up. It's been up there for about 15 years and I cannot recommend it highly enough.

Future plans for this SDR include trying DSDPlus to try decoding digital modes, and possibly connecting it to a Raspberry Pi and accessing it over my LAN.

Saturday, July 11, 2020

Jungle Antenna from CAT5 and Cardboard

Brett from the SurvivalComms YouTube channel has a nice series going on building field-expedient antennas. This one is a 2M ground plane antenna built from CAT5, a length of coax for the feed line, and some cardboard to spread the radials apart. The basic idea is the same as the "jungle antenna."

Check it out.



BTW, the link to the jungle antenna will take you to Brushbeater's blog, which has a ton of good info and links.

Friday, July 10, 2020

How to Use a Digital Multimeter

A digital multimeter (DMM) is a handy tool to have around the house for troubleshooting circuits. Sparkfun put out this nice video on how to use a DMM to measure voltage, current, resistance, and test for continuity.



RT Systems Programming Software for the Icom 7200

With my getting back into ham radio I wanted to update the memory settings on my Icom 7200. You can do so via the front panel, and it's good to know how, but it's tedious.

The popular open source program CHIRP will talk to the IC7200. However, functionality is pretty minimal with this radio. For example, it works with the rig in live mode with changes you make in the application immediately written to the radio. It also misconfigured some fields in the memories, as I discovered later.

Years ago, shortly after buying the rig, I'd purchased  RT Systems' WCS-7200 programming software on CD from the New Castle, DE Ham Radio Outlet store. That CD disappeared, along with the product registration info. So, I decided to drop $25 for a new digital download of the program. (What the heck, it's good to support small businesses anyway.)

Unlike CHIRP, it runs only on Windows, but it can use the same USB A-B cable used for digital mode operations.

The WCS-7200 software is more mature and full-featured than CHIRP. For example, I entered in a bunch of frequencies into the spreadsheet-like UI, and it then allowed me to select a group of them and move them up or down for organization. It also has a Comment field, which I used to identify which frequency is for, for example "20M PSK31" or "WWV."




Unlike CHIRP, it doesn't operate in live mode, so I could tinker with memory organization, save the file locally, and then upload it to the rig.

Before closing the app I exported the memory to a .csv file in the Ham Radio folder I keep on Dropbox, opened it in Numbers on my Mac, and printed out a copy for reference.

I still like CHIRP for programming my Baofengs and it seems to work fine with my Yaesu FT-7800R, but in this case, it was worth $25 for the commercial software.

Incidentally, a good source of frequencies to input into your radio for making contacts or just monitoring is Bandplans.com. Also check out Repeaterbook.com and RadioReference.com.




Tuesday, July 07, 2020

Radiowavz 40M Dipole Antenna

Today's vacation day activity was to put up a Radiowavz 40M dipole. I got it in trade several years ago for an AR15 lower receiver. :)

Hams know that antennas offer better performance when erected in crappy weather, ideally a New England winter day. Not having one of those handy, hopefully a hot-as-balls SE Pennsylvania day will suffice.

It's currently supported on both end but not the middle, which as you can see, sags a bit. The end supports are 5 foot lengths of schedule 40 PVC pipe with an eye bolt on the end. Braided dacron cord is strung through each eye bolt and then secured to the end insulators of the antenna with a bowline knot. The halyards are then attached to a large plastic landscaping stake in the ground.

The feedline is a 25 foot piece of RG-8X coaxial cable running to an MFJ-4602 window pass-through panel.

After it was up and connected I texted a couple friends and we tried it on 80M phone using NVIS propagation. I was able to hear them but they could not hear me, which wasn't surprising.

I'd like to get the middle up higher so I'm going to look into a military surplus fiberglass mast. If I get the center elevated the resulting antenna will be an inverted-V, which will give me better performance.

I haven't made any QSOs on this antenna yet, but this screenshot from pskreporter.info shows the results of calling CQ with 50W on JS8.




And this one from WSPRnet.org shows the results of transmitting 50W on WSPR.


Friday, June 19, 2020

Open Source Intelligence (OSINT) Resources

I ran across this first link yesterday and thought it's worth sharing with the current State of the Union.

Bellingcat's Online Investigation Toolkit - Links to a variety of OSINT tools. If you have a Google account, you can go to File > Make a Copy and save it to your own Google Drive.

And this video is interesting:

Using Skiptracer to Gather License Plate OSINT Data.

(That channel, Null Byte, has a number of interesting videos.)


Scanner stuff:

Radio Reference - Site with information on frequencies, licenses, and discussion.

Broadcastify - Site to stream scanner feeds on your computer or mobile device.

Police Scanner and Radio on Apple App Store.

Police Scanner and Radio on Google Play.

Freescan - Free software to program and control many police scanners. Can also be used to record. I use this with my Uniden Trunktracker IV.

ProScan - Another piece of scanner software.

Chirp - Free software for programming primarily ham radios, but you can use it to easily add other common frequencies like FRS, GMRS, MURS, and NOAA weather to hand held radios like the ever-popular Baofengs.