Hopefully you all have some small handheld transmitter (HT) units like the Baofeng UV-5R+. This is a common rig in the self-reliance community for both UHF (430 MHz) and VHF (145 MHz)1. The antenna is external through an RF screw connector.
But since good antennas are tuned for their operating frequency how can one single unit work well for both different frequencies? The answer is it can’t as a simple geometry whip type so compromises must be made.2 The impact is on transmit efficiency which for a HT is an important factor since the power is limited and you’re running on batteries.
You do receive a “rubber ducky” antenna with the radio but there are a number of other models also commercially available. Are they worth buying? Let’s go find out.
The Yardstick
In radio, the measurement of transmit efficiency is named standing wave ratio or SWR. It measures how much of the power sent out to the antenna actually goes by how much gets reflected back. The reflected power is wasted as heat. Think of it like yelling through a closed window. Someone on the other side can hear you but very loudly. Open the window and the same yell can be received much better.
You can have a powerful transmitter but if it is driving a poorly tuned antenna, much of that transmit power just warms the inside your rig instead of radio waves propagating outward. Good (matched) antennas are like open windows.
n.b. I am not a ham so I’m not going to bore you with their cat lady-grade stuff but I am a physicist with plenty of practical radio experience so you can make good decisions on how to spend your resources to be successful.
Testing Setup
I used the Surecom SW-33 PLUS power meter, which you can learn about here. I bought it on eBay and it came with a slew of RF adapters. It is a laboratory grade device? No. But since I’m using it to compare the relative performance between antennas it is suitable.
Above you can see the SWR meter in place of the antenna and what is called a dummy load attached to the other end. The load is a perfect antenna in the sense that it absorbs all RF power without any reflection. I used this to test the transmit power of the HT just to get an idea of its performance.
On most VHF and UHF channels it can transmit at both low power (1 watt) or high (4 watts). My testing into the dummy load showed the following into Family Radio Service (FRS) which is UHF and Multi-Use Radio Service (MURS) which is VHF:
Name/Band/Freq. Power Setting Measured
FRS/UHF/463MHz Low (1W) 1.6W
High (4W) 4.3W
MURS/VHF/152MHz Low (1W) 1.2W
High (4W) 4.7WSurecom claims an accuracy of 5% but even if its measurements are high, the power into the dummy load is more than what Baofeng advertises. Which is great. OK now that we can see the HT can put out some RF power let’s talk about SWR and measure the antennas.
Interpreting SWR
There is some “real” math involved here so smarter people than I (like Pat Haggerty at Right Channel Radios) have explained it in clear terms:
SWR Value Meaning
1.0 - 1.5 Ideal!
1.5 - 1.9 Adequate
2.0 - 2.4 Not exactly good
2.5 - 2.9 Poor
3.0 + Possibly damagingOn to the victims.
The Short Antennas
These are semi-flexible, the type you’d tend to use if the radio was on your belt or a vest. Here is the data:
Notes:
(1) is stubby and expected to perform poorly but useful when you’re doing a field training exercise and you don’t want your radio comms to splash all over the place.
(2) is the standard that comes with the radio and it obviously performed better on the UHF band than VHF.
(3) looks like the standard antenna but is a bit longer and really knocked it out of the park. I don’t even remember where I got these; maybe Baofeng changed what they included in later models? It doesn’t have any manufacturer markings.
The Long Antennas
These are very flexible and designed for sticking out of your backpack or in the case of (6), the Tactenna, threading it through the loops of the gear you are wearing.
Notes:
(4) acted so strangely that I tested 3 of them and they were all useless on UHF, though slightly better on VHF. No idea but I’ll mark them and probably never use them in the field. The sort of thing you’d save to barter to a future enemy.
(5) is a lot like (4) but the radiating element is a rubber coated length of steel measuring tape so it is stiff when extended but can be folded up like in the photo. Still, it did better and though not shown here, radiated 1/3rd more power than (4).
(6) was a disaster on UHF but OK on VHF. It is certainly a novel design but manufacturer is not linked here because the website is dead. I find that too bad because both the idea is novel and construction is really nice.
Conclusion
The 14cm (3) was clearly the winner with the 11cm (2) unit coming in right behind. If you think you need a longer antenna, then the “tape measure” unit (5) would be the choice.
I’d be happy to repeat this with another HT (like a high quality Kenwood or Yaesu) or again on the Baofeng but with a different SWR and forward power meter. It took me a long time to collect and present this data but I think it is worth it for you to know: you’re likely fine by just sticking with the antenna that comes with your Baofeng radio. I would never have guessed that! (So you know this data countered any biases I may have held.)
Final Words
The myth is that there isn’t enough time. There is plenty of time. There isn’t enough focus with the time you have. You win by directing your attention toward better things.
– James Clear
Typically you want a radio that will transcieve (transmit and receive) on both frequency bands because sometimes one work better than the other.
This is an example of an engineered antenna with two parts, one radiates ideally at UHF and the other at VHF.
©2024 – Current Year by Dan D. All rights reserved.
No part of this can be reproduced without the author’s permission.