Arecibo radio telescope KP4AO - EME

Maybe a little off topic, but I know a few here have quite decent 70cms stations.

I read about this several days ago & hope to listen for them with my meagre 9 element Tonna. I doubt I could work them with 20 Watts TX power, but I know a few of you here have much more capable stations :slight_smile:

Relevant details taken from the Sunday 18th April GB2RS news script:

" The Arecibo Observatory Amateur Radio Club will put the 1000-foot radio telescope on the air for three days for 432MHz EME. The scheduled times of operation for the final day today, 18 April, are 1840 - 2125UTC. Using the callsign KP4AO and 400W the transmit frequency is 432.045MHz and receive frequency is 432.050 to 432.060MHz. KP4AO can be heard with a small hand-held Yagi pointed at the moon and a good receiver. A 15dBi antenna and 100 watts will be enough to work them on CW. "

The Arecibo radio telescope will be familar to many, as it appeared in a James Bond film.

My neighbours were quite impressed several months ago watching me wave a couple of Yagi’s around in the garden simply to listen to a couple of satellites. Imagine how impressive listening to the worlds largest single radio telescope bouncing signals off the Moon would be!

I can only dream of firing enough RF back to be heard in Puerto Rico on 70cms, but I know a few SOTA people have very decent UHF gear. For anyone who thinks EME looks easy, only 7% - 12% at best, of your RF signal that actually reaches the Moon will be reflected back towards Earth.

If you were not aware of the above activity then maybe you could take a listen, & if you do have a capable station, give them a call.

It certainly will be a nice QSL card to have in your collection :slight_smile:

Good luck, & Best 73,

Mark G0VOF

In reply to G0VOF:

Hi Mark!

HÁROS RÁDIOKLB ( HA5SOTA ) was watching the activity.
Here visible the pictures:

The operators: HA5OB, HA5PT and HA5TI!

We heard it well through long time the KP4AO SSB signs.

Our equipment: FT-847, 23 el. Yagi Manfrotto Video Tripod!

73 DX Pista HA5TI

In reply to G0VOF:

I heard KP4AO last night sat in the garden using my 6ele SOTABeam (SB270), a small length of RG58(60cm), and my FT817! I heard CW from KP4AO on 432.044.14 MHz.

I imagine with a pre amp and a proper antenna aiming device, the signals would be very strong. I wish I’d have rescued some parts from the scrap bin at work and knocked up a suitable preamp!

Good luck to any guys having a go this evening, I believe the mode of choice tonight is going to be JT65. I imagine it will be very easy to work KP4AO on this mode.

73 Colin

For those interested the moonbounce starts at 1840 UTC this evening on around 432.045MHz.

There is live video stream at

In reply to M0CGH:
We heard KP4AO from W2/GC-055 on Sunday using a homebrew yagi by KC2UHB. Unfortunately we could not get the netbook to decode the signal correctly…but we heard it quite loudly on 432.044.77 with an IC-7000

We also heard some earth based stations answering (higher in frequency), but we could not decode those either.

We had a couple of curious onlookers. When the gawkers asked what were doing I think a few did not know whether to believe us or think we were insane…

You can see the beam here:


Tom, N2YTF