I would like to practice in CW on 2m/70cm bands when and if there will be a tropospheric or sporadic-E propagation. However I don't have mush space for the antenna. There is a possibility to install 3+5 el Uda-Yagi antenna on the balcony (the height is ~20 meters), which has 9.5 dBi gain on 2m and 11.15 dBi gain on 70cm in free space according to the manufacturer. Previously I successfully used this antenna to make SAT QSOs in FM. My QTH is Russia, Moscow, the balcony looks southwest (i.e. to Europe), the horizon is quite clear.

Assuming that I'm going to use 50W of power (e.g. Yaesu FT-991A), will the antenna be adequate for making CW QSOs? If not, what gain approximately is required? Would it help to use a 200W power amplifier on 2m?

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    $\begingroup$ My dad once calculated that if you had line-of-sight, you could communicate from New York to Los Angeles on 1W. The point being VHF/UHF it's as much about height (and 20m is pretty darned good IMHO) and obstacles as it is about power. $\endgroup$ – Duston Feb 4 '20 at 15:00
  • $\begingroup$ How are you planning on stacking those 3 Yagis? $\endgroup$ – Mike Waters Feb 4 '20 at 18:53
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    $\begingroup$ @MikeWaters this is a single antenna, 3 elements for 2m band and 5 elements for 70cm band $\endgroup$ – Aleksander Alekseev - R2AUK Feb 4 '20 at 20:33
  • $\begingroup$ @Duston True, except the question about DX, which on VHF+ is arguably defined as paths where there isn't line of sight, using modes like troposcatter, meteor scatter, or EME. $\endgroup$ – Phil Frost - W8II Feb 4 '20 at 22:06

I will talk about my experiences with 2m here - 70cm is similar, except (and anybody who knows better than me please correct me) there is no sporadic-E at all ever on 70cm.

It all depends on conditions.

When I was living in the UK, I used to have a 9-element Yagi for 2m, and was into SSB DXing. I used 2.5W because that was all the power I had from my FT-290.

I was in the south of England, and in winter when there were temperature inversions and tropospheric propagation I would easily work into GM, F, ON, PA, EI, GD, GJ, GU ...

I loved 2m SSB - the only problem is that the 2m band only gets sporadic-E extremely rarely during absolute solar maximum, and tropospheric propagation only happens in winter under exceptional circumstances. For anything else, you are waiting for meteor showers, or you are doing line-of-sight contacts.

So for the most part if you want to work DX on 2m, you would be waiting for winter and keeping your fingers crossed. We are currently at the absolute bottom of the solar cycle, with the new one having just started - so don't expect any sporadic E for another 5 years.

There was a recent extremely deep occurrence of tropospheric propagation, where a GM station was able to make an FT8 contact with a D4 station on 70cms - a new world record [link here].


My experienses on 2 meters when I was living in southern Finland (near Helsinki). My Finnisf call sign was (and still is) OH2AXE. I did not have 70 cm equipment.

Antenna: 2 x 2 stack of double hybrid quads, gain about +12 dBd, about 10 m above ground. 50 W homemade linear amplifier.

Most of the time the TX power is not so critical, even 5 or 10 W is enough to work DX. The limiting factor is your ability to hear the DX stations and for that a higher gain antenna helps a lot. I seems to me that +10 dBd (over dipole) is the minimum for DX. At the same time it increases your ERP (Effective Radiated Power) for TX by the gain (in dB) given for the antenna.

FM contacts up to about 250 km away were always possible in more or less any direction.

SSB contacts via sporadic E to Yugoslavia (as it was then), England, Poland, Germany, Italy and other parts of Central Europe. To my experience sporadic E is specifically a summer phenomenon, between abou April and September. I have never experienced it during winter. It is somewhat rare on 2 meters, though. But if you start hearing strange stations from your FM (89 - 108 MHz) radio, check the 2 meter situation immediately, the sporadic E may reach even up to 145 MHz.

CW contacts via aurora to Russia (longest to Archangel, Moscow and the Ural mountains), the Baltic states, Sweden, Norway, Denmark, Poland, North Germany. Via aurora only CW is intelligible and it sounds like hiss-hiss-hisssss-hiss ---. There is no tone and the report is given for instance as 59A (A for aurora tone). To my experience radio aurora is mostly a winter phenomenon and in Southern Finland the antenna had to be pointed more or less to North (say from NW to NE) for contacts. Note that most of the time there is no visible aurora, but the radio aurora may still be quite strong.

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    $\begingroup$ When were you active on 2m? Are conditions different now, or about the same? $\endgroup$ – rclocher3 Feb 8 at 19:25

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