This is a journey that started a number of years back when I moved from one city to the next one over. Keeping what I was normal scanning and adding to my Favorites List the results were not the best.
In hopes of improving the reception I built what you see “In the Beginning”. Bulkhead female BNC connector on a piece of Prototype Perf board with copper on both sides. Added some 4 inch “spike” radials from stripped Romex. High ceiling room so assembly was placed on top of a piece of PVC with Radio Shack 800MHz scanner antenna and about 8 feet of coax to a 536 scanner. Not much improvement and I think the coax was the issue. Sold the scanner and got a SDS100 and just used the 800MHz with BNC adaptor on scanner. Spike assembly placed on shelf until recently.
Along comes the VNA-Nano analyzer. I got one, played with it and was impressed with what it was for the money and the results. I followed many of the discussions and whole heartedly agree that testing HT/Scanner antenna can be an exercise in futility.
What follows in the pictures is my attempt to create a test stand that meets no known standard of acceptance or certification. Hopefully it does give me something repeatable which is mechanically and electrically stable that allows easy swapping of antennas I have to gage how they perform against each other. The cardboard disk is 12 inches in diameter covered with heavy duty aluminum foil both sides overlapping in the center and outside edge. It only sits on the spike assembly. Spikes have been shortened and looped on the ends to keep from damaging the foil.
I’ve just finished the fabrication and using it with the SDS100 for now. What has happened so far with the SDS100 is the reception has markedly improved for items in my Favorites List I normal scan and I’m familiar with reception. RSSI and NOISE display on the SDS100 are the only measurable indication other than subjective listening to the various agencies in the FLs.
Changes in NOISE are typically lower and fluctuate less. RSSI are a couple of dBm lower. None of the changes significant, but the reception for distant or weak stations “seems” to be improved out of proportion to NOISE and RSSI changes. I have had to reassess my thinking about receiving antennas in this frequency range and the impact they can have on the SDS100.
Future activities will include collecting data using ProScan for distant agencies and comparing with and without the “ground plane” disk. Also using VNA Saver to scan various HT/scanner antennas again with and without the disk.
The journey continues…
In hopes of improving the reception I built what you see “In the Beginning”. Bulkhead female BNC connector on a piece of Prototype Perf board with copper on both sides. Added some 4 inch “spike” radials from stripped Romex. High ceiling room so assembly was placed on top of a piece of PVC with Radio Shack 800MHz scanner antenna and about 8 feet of coax to a 536 scanner. Not much improvement and I think the coax was the issue. Sold the scanner and got a SDS100 and just used the 800MHz with BNC adaptor on scanner. Spike assembly placed on shelf until recently.
Along comes the VNA-Nano analyzer. I got one, played with it and was impressed with what it was for the money and the results. I followed many of the discussions and whole heartedly agree that testing HT/Scanner antenna can be an exercise in futility.
What follows in the pictures is my attempt to create a test stand that meets no known standard of acceptance or certification. Hopefully it does give me something repeatable which is mechanically and electrically stable that allows easy swapping of antennas I have to gage how they perform against each other. The cardboard disk is 12 inches in diameter covered with heavy duty aluminum foil both sides overlapping in the center and outside edge. It only sits on the spike assembly. Spikes have been shortened and looped on the ends to keep from damaging the foil.
I’ve just finished the fabrication and using it with the SDS100 for now. What has happened so far with the SDS100 is the reception has markedly improved for items in my Favorites List I normal scan and I’m familiar with reception. RSSI and NOISE display on the SDS100 are the only measurable indication other than subjective listening to the various agencies in the FLs.
Changes in NOISE are typically lower and fluctuate less. RSSI are a couple of dBm lower. None of the changes significant, but the reception for distant or weak stations “seems” to be improved out of proportion to NOISE and RSSI changes. I have had to reassess my thinking about receiving antennas in this frequency range and the impact they can have on the SDS100.
Future activities will include collecting data using ProScan for distant agencies and comparing with and without the “ground plane” disk. Also using VNA Saver to scan various HT/scanner antennas again with and without the disk.
The journey continues…