On some SOTA summits that are established radio sites, there can be significant RFI on 2 meters. I recently wrote about that here: RFI on SOTA Summits. There have also been discussions from time to time among VHF SOTA activators on which handheld transceiver (HT) has the most robust receiver for use in high RF environments. (Hint: a Baofeng is not going to be your best choice.)
This led me to an excellent web page by Razvan/YO9IRF that tabulates the receiver performance of HTs as measured in the ARRL lab. This is arguably the most objective look at HT performance out there. You can do a sort on a particular parameter and see which models are best.
Probably the parameter to start with is wide 3rd-order intermodulation on the 2-meter band. (I am going to ignore the 70 cm performance because most VHF SOTA contacts are on 2 meters.) The wide 3rd-order intermod performance relates to interference rejection from outside the amateur band.
Here are the best performing HTs for this parameter. (Go to the website directly to see other models listed.)
Interestingly, the Icom IC-V8 jumps to the top of the list. This is an older single-band 2m radio…and I happen to have one hiding somewhere in the basement. I am a bit surprised there are two Wouxun radios near the top of the list but they performed well. No surprise that the Yaesu FT-60 shows up…it seems to be well-regarded by SOTA activators.
The narrow 3rd-order intermod performance relates to the receiver performance inside the amateur band. Sorting based on that parameter shows these radios at the top:
The Kenwood TH-22AT takes the top position, followed by the Yaesu FT-10R, both older single-band radios. The general trend here is that some of the older radios, especially single-band rigs, have better front end filtering. Newer radios tend to include reception of a wider range of frequencies outside the ham band and have receiver front ends that are correspondingly more open. The Radio Shack HTX-202 gets a lot of positive comments from the SOTA crowd and is on the shortlist. Again, the well-regarded FT-60 makes the list.
Let’s check a few of my favorite HTs to see how they rate.
My usual SOTA handheld is the Yaesu FT-1DR. The wide 3rd-order intermod is 73 dB, or 12 dB worse than the FT-60 (85 dB). For narrow 3rd-order intermod, the FT-1DR is 58 dB vs 67 dB for the FT-60. This matches my impression that the FT-1DR does OK for most summits but is not the best radio for high RF environments.
Another radio to consider is the Yaesu FT-4XR. I often have this radio on at the house but I don’t use it for SOTA. This radio uses the same receiver IC as the Baofeng UV-5R but has better input filtering. The wide 3rd-order intermod is only 63 dB and the narrow 3rd-order is 61 dB (about the same as the FT-1DR). The table does not list any Baofeng radios but I would expect them to perform worse than the FT-4XR.
Regular readers of this blog know that I use a Yaesu FT-90 mini-mobile transceiver for most SOTA activations. I looked up the ARRL tests on it. The wide and narrow 3rd-order intermod are 85 dB and 65 dB respectively, not better than the best handhelds but near the top. My experience is that the FT-90 receiver is better than my FT-60 and FT-1DR, consistent with the ARRL lab measurements.
Another radio of interest is the Yaesu FT-818, which the ARRL measured as 96 dB (wide 3rd-order intermod) and 72 dB (narrow 3rd-order intermod) on the 2m band. This puts the FT-818 at the top of the list with the best handhelds. Actually, I would have expected it to be even better, far superior to an HT, but apparently not.
So I need to dig out that old Icom IC-V8 that is hiding in the basement. It may be a good piece of equipment to have along on SOTA activations.
73 Bob K0NR
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