2m handheld antenna tests

Posted November 12, 2003
Updated November 14, 2003

Introduction

I purchased an Icom W32a earlier this year, and bought a Diamond RH77CA antenna with it, for use as a daily antenna. However, the Diamond antenna didn't perform as well as I had expected. Because of this experience, I decided to perform some rudimentary, semi-scientific tests on the Diamond antenna, as compared to the stock Icom antenna. I also decided to include a few other antennas I had around, as long as I was performing tests. (Note: I'd like to add pictures of my test setup in the next few days, so check back occasionally.)

Test Procedure

The test consisted of two parts. The first test procedure was as follows:

  1. Set the W32a to high power (5W output) on 146.88 MHz
  2. Establish a location with a good path to the 146.88 MHz repeater
  3. Attach each antenna in turn to the W32a, and transmit a request for a received signal report from the repeater
  4. Ensure that the antenna position is as similar as possible every time
  5. Record the reported signal
  6. Repeat for each antenna

Note: the distance between my test location and the repeater is approximately 38.25 km, or around 24 miles, with a fairly clear line-of-sight. However, the important part of this test is the relative signal result between each antenna.

The second test procedure was:

  1. Set a frequency of approximately 144 MHz on an MFJ-259 SWR Analyzer
  2. Attach each antenna in turn via a UHF to BNC adapter and record the SWR
  3. Maintain antenna and body position as similar as possible for each test
  4. Set the MFJ-259 to approximately 146.28* MHz
  5. Repeat steps 2 and 3
  6. Set the MFJ-259 to approximately 148 MHz
  7. Repeat steps 2 and 3

* 146.28 was chosen as an intermediate test frequency because that's the transmit frequency used for the 146.88 MHz repeater.

Antennas tested were:

  • the stock Icom W32a antenna (7.5" long)
  • Larsen Hi-Q Kulduckie 2m model (11" long)
  • Diamond RH77CA (14.75" long)
  • Pryme RL-800 (33.75" long, fully extended, 9.5" collapsed)

I refer to them by brand name, since that's easier to read than a bunch of model numbers.

Expectations

I know that the Diamond is working either about the same as the stock Icom antenna, or slightly worse. The Larsen seems to work better than the Icom, although not by a whole lot. The Pryme comes highly recommended, and I've used it to contact AO-27, an FM satellite in low earth orbit. I expect that the performance of the antennas will rank, from best to worst, like this: Pryme, Diamond, Larsen, Icom. Rather, that's the expectation based on manufacturer claims. I think the performance is more likely to be: Pryme, Larsen, Icom, Diamond.

Test Results

Signal report (dBm) SWR readings
Antenna # 1 # 2 144 MHz 146.28 MHz 148 MHz
Icom -78 -79 2.4:1 1.2:1 1.3:1
Larsen -79 -79 2.5:1 2.4:1 2.5:1
Diamond -79 -79 3.1:1 3.0:1 3.0:1
Pryme -71 -72 3.0:1 1.6:1 1.4:1
[Received signal strength graph]
Received signal strength graph
[SWR graph]
SWR graph

Notes:

"Smaller" numbers in the received signal reports are better.

An SWR ratio of 2:1 is considered marginal, and 3:1 is considered bad. However, testing the SWR as outlined is not a good test, and antenna performance is not necessarily accurately reflected in the SWR numbers. SWR numbers are therefore of secondary importance, in this test suite.

Discussion

I was surprised by the results. I had expected, first of all, to see a difference in received signal power between each of the antennas. Instead, all of the antennas except the Pryme has pretty much identical received signal strength at the repeater. I expected the Pryme to be better than the other antennas, but not that much better.

The other big shocker for me was the fact that two of the antennas never broke 2:1 SWR. I had expected for sure that any antenna sold for 2m use would get better than 2:1 SWR at least somewhere within the 2m band. That high SWR on the Diamond and Larsen antennas may explain why those antennas, which should theoretically be capable of higher gain, failed to actually put out measurably more power than the short Icom antenna.

In a way, it's not fair to include the Pryme antenna in this test, since it's not a rubber-duck style antenna, but rather a fancy center-loaded half-wave whip. However, I was interested in seeing what its performance was like in comparison to the other antennas I was using (which you can think of as the "is it worth carrying around this fancy, breakable antenna for marginal conditions?" test). The answer to that question is that it definitely works better, and is worth pulling out when the signals are weak.

I guess the conclusion I can draw from this test is that, as I had already found in practice, the Icom antenna is the best choice for daily use. The Pryme performs quite well, but in its tested configuration (nearly a yard long), it's unwieldy, and not really practical for everyday use, particularly when clipped to a belt. Although the Pryme is built pretty well, it's also quite fragile for daily use.

Created by Ian Johnston. Questions? Please mail me.