I know several members have purchased one of those cute little nanoVNAs. They are a powerful design and diagnosis tool. I found an article which describes practical techniques for using a VNA for various tasks, like measuring inductors & capacitors, characterizing filters & chokes, etc.
The article is based on using a different VNA (MiniVNA) and its PC software, but the techniques apply equally to the nanoVNA & its NanoSaver PC software.
In my first post I had attached the original article. That violated the author's copyright, which we should not do. The copyright gives permission for personal use only, not re-publication.
Posted by: Tom VA3TS - 2022-04-07, 10:05:38 - Forum: Antennas
- No Replies
The following suggestions will reduce the difficulty in matching an antenna with a tuner:
1. Never center feed a half-wave multi-band antenna with a high impedance feedline that is close to an odd multiple of a quarter-wave long.
2. Never center feed a full-wave antenna with any feedline close to a multiple of a half-wave long.
3. If a tuner will not tune a multi-band antenna, add or subtract 1/8 wave of feedline (for the band that won't tune) and try again.
4. Never try to load a G5RV or cente fed dipole on a band below the half-wave design frequency. If you want to operate an 80 meter antenna on 160 meters, feed either or both conductors as a longwire against the station ground.
To avoid problems matching or feeding any dipole antenna with high impedance lines, keep the lines around these lengths
[ The worst possible line lengths are shown in brackets ]:
160 meter dipole:
35-60, 170-195 or 210-235 feet.
[ Avoid 130, 260 ft]
80 meter dipole:
34-40, 90-102 or 160-172 feet.
[ Avoid 66, 135, 190 ft ]
40 meter dipole:
42-52, 73-83, 112-123 or 145-155 feet.
[ Avoid 32, 64, 96, 128 ft ]
NOTE:
Some trimming or adding of line may be necessary to accommodate higher bands.
WARNING:
To avoid problems, a dipole antenna should be a full half-wave on the lowest band.
On 160 meters, an 80 or 40 meter antenna fed the normal way will be extremely reactive with only
a few ohms of feedpoint resistance. Trying to load an 80 meter (or higher frequency) antenna on
160 meters can be a disaster for both your signal and the tuner. The best way to operate 160 with
an 80 or 40 meter antenna is to load either or both feedline wires (in parallel) as a longwire. The
antenna will act like a "T" antenna worked against the station ground
Taking the antenna tuner approach is not a good idea when you are using coaxial cable under high (greater than 3:1) SWR conditions. The tuner may provide the 50 ohm match to your radio, but the mismatch and high SWR still exists between the antenna tuner and the antenna! This translates to high losses in the coaxial cable.
Topic for discussion -
1. APRS - Automatic Packet Reporting System
- What do you know about it? Have you used it? What are your experiences OR open mic.
- Bonus question - Look up www.aprs.fi and see if you can identify a local digipeater or igate.
- For more info, look up www.aprs.org
VHF/Echolink
VE3VVE Colin
KO4DXQ Bob
VE3GIO Larry
VE3MIO Maureen
VA3MFO Jim
VE3FGG James
VE3VCG Marvin
VA3EAC Janet
VE3RQY Greg
VE3RWY Rob
VE3BQM Bernie
VE3FP Adam
VA3KOT John
9Z4DX Bertrand
HF – 3.779 MHz
VE3GIO Larry
VE3IJD Gene
VA3MFO Jim
VE3VCG Marvin
VE3BQM Bernie
VE3FJN Colin
VE3FGG James
VE3RQY Greg
You can use SD or SDHC cards up to 32 GB (this is in the manual). Larger cards come formatted exFAT which won't work in the 7300.
If you're having trouble with a card, try the free SD card formatter that's downloadable from the SD Card Association (available for Win & Mac only, no Linux version ). https://www.sdcard.org/downloads/formatter/
NCS VA3TS Tom 16 Mar 2022
What projects do you have for this summer
KO4DXQ – Bob / Tennessee...via Echolink
K4CWK-Richard / South Carolina...via Echolink
VE3GIO Larry
VE3PQ Paul
VA3MFO Jim
VE3BQM, Bernie / Georgian Bluffs
VE3RWY, Rob / Owen Sound
VE3RQY Greg
VE3MIO Maureen checked in via landline to Bernie BQM. Maureen reports her ic7300 will not power up. The radio will be checked the next day as Maureen is close to va3ts's qth. Paul PQ reported that Service, if needed for the 7300, could be obtained at
Service Dept.
ICOM CANADA
Glenwood Centre 150-6165 Hwy 17A
Delta, BC V4K 5B8
GBARC Net Report 19:00 EST March 9, 2022 Net Controller Marvin VE3VCG, QTH Paisley, Ontario, Canada EN94ih
Topics (1) Reestablishing Emergency Communications in Bruce County (2) Open mic, for any topic
Log: 2 meters Ko4DXQ – Bob / Tennessee...via Echolink V K4CWK-Richard / South Carolina...via Echolink VE3KOT, John / Owen Sound VE3WI, Dave / Port Elgin VE3BQM, Bernie / Georgian Bluffs
VA3EAC, Jan / Paisley VE3RWY, Rob / Owen Sound VE3DGY Doug
80 Meters
Ve3IJD, Jean/ Honey Harbour VE3FJN, Collin, Hamilton VE3BQM, Bernie, Georgian Bluffs VE3KOT, John / Owen Sound VE3WI, Dave / Port Elgin VE3RWY, Rob / Owen Sound VE3DGY, Doug
VHF:
VE3FAS Philip John
VE3VVE Colin
VE3GIO LARRY
VA3MFO James
ve3/IN3IJO Reberto : Born Canadian, lived in Italy, moved back to Canada
VA3KOT John
VE3RQY Greg
VE3WI Dave
VE3RWY Rob
VE3OZW Richard
HF:
VE3IJD Gene
IN3IJO Reberto
VA3KOT John
VE3RWY Rob
VA3MFO James
VE3WI Dave
VE3OZW Richard
VE3GIO LARRY
This morning, Russian President Putin declared war on Ukraine.
As Hitler once did, the Russian attack took place early in the morning, when Ukraine was resting peacefully before the working day.
Explosions erupted in many cities, including military units, warehouses, infrastructure and air defense. The occupiers used planes, helicopters, drones and cruise missiles that flew from Russia, Belarus, Crimea and Transnistria. At the same time, a ground operation began.
Fighting is currently underway, and the Armed Forces of Ukraine are repelling the aggressor.
The LRU informed international amateur radio organizations about Russia's military invasion of Ukraine. To date, there have been many reports from radio amateurs around the world in support of Ukraine.
Follow the news from news agencies.
Please be informed that due to the imposition of martial law, the use of amateur radio stations is prohibited for 30 days. (Decree of the President of Ukraine № 63/2022 of February 23, 2022)
The LRU Executive Committee is working out and agreeing on the possibility of exchanging operational information. Radio frequencies will be reported additionally.
). 
