Saturday, March 13, 2021

HAM Radio Geekery

 So I decided to do a little antenna testing on HT Antennas as there are lots of different opinions and a whole bunch of conflicting data out concerning portable antenna performance. I didn't bother with fox tails as that is not practical on an HT that you carry around and it is even more impractical to be switching back and forth between a short tail for 70cm and a long tail for 2m.

The Antenna's


From top to bottom: Factory Yaesu VX-2R, Factory Yaesu FT-60R, Factory Yaesu FT-3DR, Comet SMA-24, a 2nd Comet SMA-24, HYS NA-772, Diamond SRH77CA, and ABBREE 42.5" "Tactical" antenna. (Yes I am a Yaesu FanBoi)

The Test Equipment

I Used an ANYSECU SF-103 Frequency Counter with field strength meter and an MFJ-266B Antenna Analyzer. No calibration data needed as I am comparing antennas to each other and the two instruments agreed within about 10Hz on frequency. So, I am happy to call the equipment adequate for this test.

The Test

I setup the MFJ-266B and the SF-103 so that the antenna base was at the same level and they were 12" apart. With the SF-103 sporting its supplied antenna, I mounted each antenna on the MFJ-266B and set the frequency to 146MHz (center of the 2m HAM band) and recorded readings of SWR and receive field strength. I then tuned the MFJ-266B until I reached the lowest SWR reading in the VHF range and recorded at what frequency the antenna was resonant and what that lowest SWR was. Lather, Rinse, Repeat for 435MHz and tuning through UHF range. Next, I setup the MFJ-266B with an SMA male adapter and a Nagoya 771 antenna as a "transmitter" and installed a BNC to SMA Female adapter on the SF-103 to measure each antennas relative ability to receive a weak signal. Mounting the 42.5" antenna on the tiny SF-103 was an interesting exercise in balance and not bumping the table. I tested signal capture ability at both 146MHz and 435MHz.

The Data

THIS IS SCIENCE because I wrote it all down!

Just looking over the data raised a few thoughts. The factory antennas, the Diamond and the ABBREE are really tuned for 2m while everyone is roughly tuned for both 2m and 70cm although the SWRs at 435MHz are higher than I would like. I was surprised at the high SWR of the factory antennas from my FT-60R and FT-3DR. I expected better tuning from the factory.

Plotting out the data for 2m band

showed the ABBREE unfolded topped 2m performance but it is huge so the SMA-24's pretty much are the right balance of size and performance with the NA-772 and the SRH77CA following closely.

While the plot for 70cm

showed the NA-772 being the peak performer with the SRH77CA second and the ABBREE third, then the SMA-24's following while performing differently from each other but close to the factory antennas.

On the receiving end

the monster ABBREE pretty much blows everyone away at 2m but I would expect that from an antenna that is three times the size. At 70cm it was the worst and performed the same straight out as well as folded in thirds. At 2m the NA-772 leads the 16" antennas with the SMA-24's second followed by the SRH77CA. While at 70cm the SRH77CA "wins" with the factory and the NA-772 following and the SMA-24's all performing pretty much the same and the ABBREE worst.

The Final Thoughts

When all is said and done it would appear the best antenna tested overall and certainly the best for the money is the HYS NA-772. Best $8 spent on radio gear. I will likely buy another and test it to see if it performs consistent with the one I already have or if their QC is lacking. The Diamond SRH77CA and the Comet SMA-24's are a wash compared to each other at 2m and the Diamond has the edge at 70cm while all cost about the same but significantly more than the HYS. Although I would give the edge to the SRH77CA over the SMA-24's slightly and I am curious about the difference between the 2 Comets. I wonder about the QC of the Diamond but I'm not $28 curious.

Biggest surprise is the receive performance of the factory FT-60R and FT-3DR antennas. The transmit performance I pretty much expected to be better at 2m with the larger antennas but at 70cm they did pretty well despite having high SWR. I was surprised at the Comet antennas performing worse than factory stubbys on 70cm transmit and all the 16" antennas lesser performance across the board on receive.

That's enough science for me today. Tune back in a couple years and I'll likely have another post up. Hopefully sooner but you never know.

No comments:

Post a Comment