Measuring SWR on an Ed Fong J-Pole with a NanoVNA

I have an Ed Fong roll up J-Pole antenna for use with 2M/70cm HTs. It's currently hanging from a thumb tack pushed into the wall of my shack up near the ceiling. I thought it would be interesting to measure the SWR (Standing Wave Ratio) on it for 144 Mhz through 446 Mhz, using a NanoVNA. 

After getting the reading I uploaded the picture to Google Gemini, ChatGPT, and Grok for analysis. Here's what Grok had to say:

This is a classic NanoVNA SWR (Standing Wave Ratio) plot of an Ed Fong-style dual-band J-pole antenna (2 m / 70 cm).

What the Graph Shows

• X-axis (horizontal): Frequency sweep from 144.000 MHz (START) to 460.000 MHz (STOP).
  This covers the entire 2-meter band (144–148 MHz) and most of the 70 cm band (430–450 MHz), plus the frequencies in between.
• Y-axis (vertical): SWR, scaled from 1.00 (bottom of the screen) to 1.75 (top of the screen).
  The labels at the top (“CH0 SWR 1.00/ 1.75”) confirm this narrow scale, which zooms in on the good-performance region.
• Blue trace: Measured SWR at each frequency (derived from the reflection measurement on CH0 / S11).

Key rule for reading SWR plots on a NanoVNA:
Lower on the screen = better match (lower SWR).
Higher on the screen = worse match (higher SWR).

The trace shows clear downward dips at the resonant frequencies — these are the “good” spots.

Interpretation of the Dips (Resonances)

J-pole antennas (especially dual-band designs like Ed Fong’s) are not simple dipoles. They consist of a radiating element + a matching stub, so they naturally exhibit multiple resonant modes, including harmonics. This is exactly what you see:

• Left side of the plot (near 144 MHz marker): One or more dips in/near the 2 m band. The marker is placed right at 144.000 MHz (lower edge of the band). The trace near the marker is on the shoulder of a dip, indicating usable (but not necessarily the absolute best) SWR at the very bottom of the band. The main 2 m resonance is likely slightly higher (typical center ~146 MHz).
• Middle of the plot: Several additional dips. These are intermediate/harmonic modes that are normal for this antenna type but usually not used for transmitting.
• Right side of the plot (toward 430–460 MHz): Prominent dip(s) corresponding to the 70 cm band. One of the deeper dips is in this region, showing excellent match where it matters. The trace also trends low again near the right edge (~460 MHz), consistent with another higher-order response.

Between the dips the trace rises high (often off the top of the 1.75 scale) — this is completely normal and expected. You only care about SWR in the actual amateur bands you use.

Overall Performance Assessment

This is a very good result for a dual-band J-pole:

• Multiple deep dips reaching close to the bottom of the scale → SWR very close to 1.0 at the resonant frequencies (excellent match).
• The scale only goes up to 1.75, and the dips are well below that → the antenna is well-tuned for both 2 m and 70 cm.
• Typical real-world Ed Fong J-poles show SWR in the 1.2–1.8 range on both bands when properly built; your scan is right in that ballpark or better.

Quick Summary Table

Frequency Region	Expected Behavior	What You See in the Plot	Quality
144–148 MHz (2 m)	Main resonance	Clear dip(s) near left side	Good to excellent
~200–400 MHz (in between)	High SWR (unused)	Trace high between dips	Normal
430–450 MHz (70 cm)	3rd-harmonic resonance	Prominent dip(s) toward right	Excellent
>450 MHz	Higher-order modes	Trace trending low again	Normal for J-pole

Bottom Line

Your Ed Fong J-pole is performing as designed — it has solid low-SWR resonances in both the 2 m and 70 cm bands. The multiple dips are characteristic of this antenna style and are not a problem.

If you want the exact SWR number at 144 MHz (or any other specific frequency), just move the marker on the NanoVNA and read the value at the top of the screen. You can also narrow the sweep (e.g., 140–150 MHz or 420–450 MHz) for a more detailed view of each band.

~~~

Afterwards, I ran scans but limited the range to 140 - 150 MHz and 450 - 460 MHz, to get more granular views of the 2M and 70cm bands. But this shows how you can use AI to help you understand raw data.

Building a 2M Jungle Antenna

Brett from the Survivalcomms YouTube channel has this nice video on how to build a 2M jungle antenna. The only tool he used to build it was a Leatherman multitool. After he built and hoisted it he measured scanned it with a spectrum analyzer.

This is the same antenna design described by NC Scout on the Brushbeater blog, here. It's a 1/4 wave vertical with three counterpoise elements that create the ground plane.

You might wonder whether a jungle antenna or a roll-up J-pole works better on VHF. Realistically they are very similar but the J-pole is more portable. This archived thread from the Arfcom ham forum goes into some details.

One advantage to the jungle antenna is that some folks (i.e., me) may find it easier to build. When I've tried to strip 300 Ohm TV twinlead to make a J-pole I always mangled the conductors because the wire inside the insulation is so thin. In contrast I find it easier to strip insulation from other slightly thicker wire, like lamp cord. So, for me, if I needed to make an expedient antenna, I'd go with the jungle antenna, assuming I had the BNC-to-banna plug adapter.

Yaesu FT-7800R Programming

Today I found out the hard way not to use CHIRP* to program my Yaesu FT-7800R radio. IIRC, this worked OK for me in the past but not on my current M4 MacBook Air, with a Cable Matters USB-C to RS-232 adapter. I was able to download the pre-existing memory channels fine but when I made some changes and uploaded them to the rig, only the first two memory channels worked.

I wound up doing a factory reset on the radio and trying again with the same result.

So, I bit the bullet and ordered the RT Systems ADMS-2K software plus their USB-29 programming cable. 

The cable will be shipped to me but RT Systems provided me with a download link for the Mac software. I grabbed that and tried it with the aforementioned Cable Matters adapter and the Yaesu RS-232 programming cable, and it worked fine. Once I receive the RT Systems cable I use that, since it'll be a more elegant setup.

My radio is at least 20 years old and while futzing with it I noticed that the microphone cable is fraying on both ends, although it still worked for me to get into a local 2M net this morning. I checked for replacement mics and found a replacement cable only at Amazon, which I should get tomorrow.

*In contrast to the Yaesu rig, CHIRP has never given me a lick of trouble with my Baofeng UV-5Rs or UV-25PRO.

One-Handed Racking of the Ruger Security-380

This shows just how easy it is to rack the slide on the Security-380 by hooking the rear sight on your pants pocket.

The front edge of the rear sight is undercut a bit probably just for this purpose.

Ruger Security-380 Lite Rack

Being in my late 50s and having spent about 26 years in IT using a keyboard a lot, my hands no longer take well to heavy recoiling guns. I recently got a CZ-82 in 9mm Makarov but being a straight blowback, I'm limited to about 50 rounds per session with that gun.

A couple days ago I traded off my SIG P365X, which had gotten unpleasant to shoot, in favor of a Ruger Security-380 Lite Rack. It's based on the Security-9 Compact but chambered for .380 ACP. Size-wise it's comparable to a Beretta 81 or 84 Cheetah .32 or a SIG P365 AXG Legion. Unlike the blowback Berettas, the Ruger is a locked-breech gun so my hope was that it would have mild recoil.

Shown between a 3" S&W Model 10-8 K-Frame and a S&W Model 432UC J-Frame (my EDC):

I tried a few holsters that I have on hand for other guns and found that it fits my El Paso Saddlery M-1942 Tanker made for the S&W M&P M2.0 Compact 9mm:

It's large trigger guard kept it from seating in a Tanker holster for 1911s.

The Ruger came with two 15-round mags (for this RSR-exclusive SKU), a mag loader, chamber flag, owner's manual, and gun lock.

The front sight is a green fiber optic while the rear is blacked out with a U-notch that gives just the right amount of space on the sides of the front when aiming. Sight visibility is excellent.

My hands are medium-sized and I'm able to grip the gun and reach the trigger comfortably.

There is a thumb safety on the left side, but not on the right for us lefties. The safety lever is small and might not be easy to work with gloves on. I plan to ignore it.

One caution I saw in a video review by Honest Outlaw on YouTube is that if you eject magazines and let them fall onto a concrete floor, they may shed their floorplates and possibly break. So, don't do that.

Today was a good day to test my theory that a locked-breech large .380 pistol would be good for folks with hand issues, because they were acting up.

While .380 ACP may not be as powerful as 9mm, the ballistics are similar to those of the Colt 1851 Navy .36 percussion revolver, which put a lot of men in the ground in the late 19th Century. Think of the Ruger as a 15-shot Colt Navy.

I put 137 rounds of .380 FMJ through it (38 Federal American Eagle, 49 CCI Blazer w/aluminum cases, and 50 rounds of PMC). The gun ran perfectly.

The trigger pull is consistent and my SWAG is that it breaks at about 4 - 4.5 lbs. There is zero overtravel due to a stop molded into the trigger guard. There is a little takeup in the pull before you encounter resistance, similar to a two-stage military rifle trigger.

The two 15-round mags that were included with the gun definitely need a magazine loader to fill, especially for the final round. I used my Maglula UpLULA instead of the one included with the gun. The magazines have the same bodies as those for the Security-9, but with a spacer in the back to work with the shorter .380 rounds. Any mag loader meant for double-column 9mm pistol mags will work.

Seating a fully loaded magazine with the slide forward requires you to give it a good whack on the bottom to ensure it's latched in place.

I shot it on paper at 10 yards and on steel at 25 yards. The point of impact is a little to the right at 10, more so at 25. Looking down at the top of the slide it looks like Ruger didn't get the rear sight perfectly centered. It's a hair off to the right. I'm going to center it before I shoot it the next time.

Field stripping is easy but may require a small flat head screwdriver to pull out the takedown pin, if it's dirty or dry. A good accessory for this gun would be a Czech surplus CZ-82 cleaning rod, which has a flat head screwdriver on the tip.

Despite Ruger not getting the rear sight properly centered on my sample, overall I'm very impressed with the Security-380.

The recoil is very soft, similar to the Beretta .32. However, the slide is much easier to rack than the Beretta's, more like a .22 autoloader's. Even after 137 rounds my hands weren't feeling much worse than when I started. If you have hand strength or pain issues, or are just recoil-sensitive, this is a gun to seriously check out.

Ballistol Gun Cleaning Wipes

Last weekend I placed an order with the Ballistol online store for a couple bottles of their oil, along with some of their cleaning wipes. In my experience, Ballistol is a pretty good CLP, and when made into a water/Ballistol emulsion, is good for cleaning black powder or corrosive primer fouling. I've been using it more lately because it's non-toxic.

My order arrived today and I used one of the wipes for cleaning my S&W Model 64-3 and my EDC, Model 432UC.

The wipe is made from is some kind of synthetic cloth. It reminds me of the Hoppe's No.9 synthetic cleaning patches. It was large enough that I cut two rectangular patches from it and used one each to clean the bores of my guns, after first running a brush wet with Ballistol through them. The remaining wipe was large enough for me to do a quick external wipe down of both guns. I.e., cleaning fouling off the outside of each cylinder and getting rid of most of the fouling inside the cylinder window on each gun's frame.

Ballistol is often criticized for its smell, which reminds many people of dirty gym socks. I noticed that the smell of the wipes wasn't nearly as pungent as when you use a spray bottle, whether aerosol or pump. I don't like Ballistol's odor so this was welcome.

I'm planning to add a couple wipes to each field cleaning kit I have for my guns. They'll be good for external wipe downs and if necessary, oiling the bore. 

Jewish Armed Self Defense Case

Here's another recent example of why Jewish Americans must embrace and exercise their right to keep and bear arms as protected by the Second Amendment. Being a defenseless victim is NOT a Jewish virtue. In fact, it is against Jewish law.

https://www.nbcmiami.com/news/local/man-charged-antisemitic-hate-crime-miami-beach/3790877/

My book "Guns for Jews" discusses why being armed for self defense is in accordance with Jewish law, and provides resources for those new to owning and carrying a firearm. The link goes to the free PDF on my Google Drive.

https://drive.google.com/file/d/18GXFERy8nH1iM6ERtLs-PXX3qXDo5C0K/view?usp=drive_link

Home Defense Shotgun Setup

As antisemitism continues to rise I want to remind my fellow Jewish Americans that if you aren't armed for self defense, you need to be. See my free book, "Guns for Jews," which is a free book I wrote to help Jewish Americans arm themselves. It's a PDF hosted on my Google Drive.

Ideally, your first gun should be a handgun to along with a concealed carry permit. However, many jurisdictions where Jewish Americans live make it difficult and time consuming to get a handgun and a carry permit. Something you can probably get with less paperwork and delay is a shotgun for home defense.

I've had this Mossberg 500 Mariner 12 gauge shotgun for close to 20 years. It's pretty much a dedicated home defense gun, although I did use it in one or two action matches over 10 years ago. Recently, I've done a few mods to make it more useful for me.

When choosing these modifications, I kept Greg Ellifritz's comments in these posts in mind:

• https://www.activeresponsetraining.net/shotguns-for-home-protection
• https://www.activeresponsetraining.net/home-defense-shotgun-questions-answered

So, after a couple different configurations over the years, I think I've settled on my final set up:

1. Magpul SGA stock, set to my length of pull using spacers. Five extra rounds are kept in a Hill People Gear stock cuff. I also added a QD sling swivel stud to the stock.
2. A Hi Viz clamp on fiber optic front sight, which much more visible and taller than the factory bead. This corrected the high point of impact with the factory bead.
3. Defender Tactical Mini-Pro Lifer and Cartridge Arrestor System, so I can shoot the 1.75" mini shells.
4. CVLIFE 1.25" quickly adjustable rifle sling.
5. CDM Gear ROC-12 accessory rail.
6. Inforce WML 400 lumen weapon light mounted so I can activate it using my right thumb (I'm left handed).

I've been wanting to try out 1.75" mini shells due to their reduced recoil and because you can load more in the tube magazine. Mossberg shotguns are easily modified to run with the mini shells with adapters from either Op Sol or Defender Tactical. The Mossberg 590S comes from the factory already setup to handle mini-shells.

Even if I keep the gun loaded with Federal 2.75" 00 Flitecontrol for now, the mini shell adaptor gives me the ability to use reduced recoil loads when I'm older.

Since I no longer have any small children in the house, the gun is kept in a closet "cruiser ready," i.e., full magazine, empty chamber, bolt locked forward.

Set up this way, the Mossberg will handle any home defense situation I can reasonably think of in my suburban location.

Links:

(Some of these are affiliate links.)

• Inforce weaponlight: https://amzn.to/4unaiN7
• CGM gear light mount rail: https://www.amazon.com/dp/B081NTW9TM?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_3
• HiViz fiber optic sight: https://www.amazon.com/dp/B0002INN3G?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_3
• CVLife sling: https://www.amazon.com/dp/B07WRB433Q?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1&th=1
• QD sling swivels: https://amzn.to/4loI8gF
• Sling swivel studs: https://www.amazon.com/dp/B0CMTXBT1R?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_3&th=1
• Magpul SGA stock for Mossberg 500/590: https://magpul.com/sgastock-mossberg500-590-590a1.html?mp_global_color=118
• Defender Tactical Mini-Pro Lifter and Cartridge Arrestor System: https://defendertactical.com/products/mini-pro
• Hill People Gear Stock Cuff: https://hillpeoplegear.com/Products/By-Activity/Hunting/CategoryID/37/ProductID/43