23cm & 13cm Antenna height above ground

Hello All
Having more than little time on my hands just now, decided to set up the 23cm and 13cm kit at last.
I have SG xverts for both bands, with a 13ele light yagi for 23cm, and currently a way over long 55 ele for 13cm (This will be ok to test in the garden, next job, building something more manageable).
Intention is to mount the x vert as close as I can to the antenna, but with the battery remaining at ground level to reduce weight.
What are the optimum heights above ground for SOTA 23cm and 13cm activations?
The 23cm is 144Mhz in, and the 13cm 432Mhz in, so losses and long cables may be a factor too.
I have various poles from 5 to 10m, but only the thicker sections are usable with the current 23cm antenna. I have seen that some activators use photographic tripods, are there issues with RF proximity at 23 and 13cm when sitting so close to gain antennas?
Thanks all

1 Like

Modelling will give you answers

1 Like

A few wavelengths, same rule of thumb as HF. But at microwaves, that’s only a meter or two! After that, as high as possible so balance mechanical design vs feedline loss.


1 Like

Hi Tim,
I have SG transverters for 13 and 23, and use an aluminium photographic tripod for support. The Yagi antennas that I use are rear mounted eg the whole antenna is clear of the tripod, and I haven’t noticed any interaction.
The SWR connector (accessible inside the transverters) is very useful - I mention it because it is not obvious, apologies if you are already an avid user - not only will it give you an indication of SWR when antenna building, but it will also show a variation as you move the antenna, if it is interacting significantly with surrounding objects…

The battery and FT817 are slung on a shelf under the tripod, which makes for a pleasant operating position and adds a bit of stability.
Transverters are mounted on the back end of the antenna booms, which again adds stability by balancing the weight distribution and wind resistance to some extent.

Have fun!


Thanks Adrian,
I have had both transverters for about a year, this is the first chance I have had to spend some time with them. The SWR connection is useful, and something that I need to make visible on the box. Just mocked up the connections and footprint, and now searching through the catalogues to find something lightweight and suitable for SOTA and using from the van for UKAC. The tripod idea looks good, and would make easy steering of the system. My photographic tripod weighs the same as a small aircraft carrier, so would need to source a different one for this activity.
Thanks for the input.

I bought mine from a charity shop, they seem to have become less desireable for their original purpose now that most folks use a smartphone camera…good hunting!

There is an exisiting tread Getting started on 23cm that has some useful info.

The 2nd part of the 23cm and 13cm equation is someone to have a QSO with ! Based on experiance you need to cultivate a number of chasers who will listen out for you.This means you need to beam in their direction. It also helps to announce when making 2m QSOs that you will be moving to 23cm and 13cm to pick up who may be able to work you for a 2nd time on annother band.

73 de

Andrew G4VFL

1 Like

Same as for HF. After a few wavelengths the ground effect is less. The only reason to go higher is to clear local obstructions.

I mount my 13cms antenna at about 1.5m on the pole used for HF wires. That is about 11 wavelengths at 13cms. So this equivalent to mounting your 7ele 20m monoband Yagi at about 220m AGL. :slight_smile:

I prefer having the transverter at ground level and using a 1m RG223 cable on 70cms to connect to the transverter and either 2m RG400 or 3m RF400UF feeder for the antenna. I believe the loss at 2250MHz is about 0.6db in the RF400 feeder.

Hi Tim,

I have the 1296 tvtr from SGLAB. when setting it up i use a light camera tripod and i have a 4 el yagi that a [SK] friend made. The transverter would ideally be mounted on the tripod too, to reduce cable losses on 1296 to reduce cable loss. For the IF, cable loss can be compensated when setting the rx gain and rf sensing trigger level on tx. Use the same cable you intend to use in the field when making those settings. So the loss in the IF cable, though small, is immaterial.

My setup still has a metre of RG58 on 1296 and that is the main loss in my setup. The use of a longer yagi with the transverter mounted on the rear end of the boom is a better system.

Increasing antenna size from 4 el to 8el is only 3db more gain at most.

Re the proximity of the operator to the antenna, see Enter parameters - RF Exposure Calculator - VP9KF/Hintlink. Note the correction factor for average power. Recalculate for 25w if you use the add-on amplifier.

That site is linked to by the arrl site.

There is another EMR calculator for windows computers which can be downloaded from the WIA website. The software was developed by Doug VK3UM (SK).

73 Andrew VK1DA/VK2UH

1 Like

2 wavelenths. And I also use a tripod. I did have a S2S on 23cm with the tripod blown over and on the ground and yagi pointing where ever it wanted. I think the distance was around 65KM.
Amazing how this 23cm stuff works!


1 Like

Thanks All for the information.
I have only used my Alinco DJ-G7 up to now with various patch antennas, so the input from this thread is really useful.
The transverters will be boxed up this week, and a trial garden run attempted from IO84 before lugging it all up the LDs. Let you know how it gos.
Thanks again for all the advice.

Hi Tim

I’ve done the occasional 23cm activation, with a home-built 13el Yagi and transverter/amplifier combination, usually when I know there are other activators out.

I’ve either used a tripod or a couple of sections of a 7m pole. It has just depended on the summit and what I want to carry. If you have line-of-sight height is not really an issue. I also keep my losses down by having a feeder of a reasonable length.

Kudos points for anyone who can identify the summits.


1 Like

First one - no idea.
Second one - Snaefell , GD/GD-001?

1 Like

The first one based on the filename to give date and time, looking in the database it would appear to be GW/NW-040 Tal y Fan

73 de

Andrew G4VFL

1 Like

Cheat! :smile:

Tom was likewise incensed that I used some photo manipulation to recover the BM number from a trig point on one of his photos. From the BM number, getting the summit was simplicity. His next picture had no such clues.

1 Like

I’ll remember for another time that the file name carries over :slight_smile:

Some filenames are more useful than others… :wink: