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Antenna tests on NW-051


#1

On Sunday I plan on doing some tests on Foel Fenlli with my Clansman PRC-320 hf manpack radio. This covers 2 to 30Mhz with an output of 3 or 30W.

There are various antenna combinations to use with it but on this occasion I want to try out the least efficient of them which is the 2.4m whip. This is not loaded in any way and simply plugs into the body of the radio and is tuned using a manual built-in ATU.

To quote from the user manual ‘As a manpack radio with a whip antanna, the PRC-320 provides reliable ground wave SSB communication for distances up to 35km, day or night, over the kind of country found in Western Europe.’

When set up on the ground four 9m long counterpoises are used.

I am interested in seeing if there is any appreciable NVIS from this set up so hopefully some of you will hear me if you listen carefully!I tried it out in the garden in April and Alistair GW0VMZ gave me a report of 33, so don’t expect a big signal!

The angle of the whip can be set anywhere between vertical and horizontal although in the latter position it is only about six inches above the ground.
Anyone any theories as to which angle should work best?
I seem to remember reading an article on NVIS experiments from a valley using vehicles with whip antennas and the best results were obtained with the antenna sticking out horizontally from the vehicle roof.

I can use other bands besides 5MHz if anyone wants to try a contact but only on USB, there is no LSB on the radio.

Will have the 2m handy with me as well.

Best wishes,

Ron.


#2

In reply to GW4EVX:

I saw you’d been spotted too late to see if I could hear you up here. How did your tests go? All reports on the performance eagerly awaited!

Andy
MM0FMF


#3

I spent a very interesting and enjoyable couple of hours on the summit in glorious sunshine and am very happy with the results.

I got set up by 1100 and heard Rob 'RQJ working through a pile up on FE from LD-049 so waited for things to quieten down before calling him. Much to my surprise he was able to copy me so a S2S made a good start to the operation.

Unexpectedly the ground wave was virtually non-existent as illustated by the contact with Mike 'DSP who was just a few miles away but had the most trouble copying my signal. Best sky wave contacts were with Don G0RQL in Devon, George GI4SRQ and Robin GM7PKT.

A lot of stations reported problems with severe QSB on my signal and as expected signal strength was way down compared to a dipole although I had no problems receiving the incoming signals.

A breakdown of the contacts made with my report received:

Rob G4RQJ/P 53
Alistair GW0VMZ 33
Ian GW8OGI 53
John GW4BVE 42
Don G0RQL 47
Pete M0COP 43
Mike GW0DSP 31
Martyn M1MAJ 33
George GI4SRQ 44
Phil G4OBK 56
Steve G1INK/P 52
Robin GM7PKT 56
Steve GW7AAV 53 (ground wave probably?)
Dave G0AOD/P 51 (I think you were /P Dave but I may have mis-logged!)
John M0JDK 51
Roger M1CBO/P 51

Thanks for the spots from Alistair and Robin and the report of 43 from Peter ON3WAB.

So, what have I learnt?
Well the antenna was easy to carry up the hill (it’s in 8 short pieces which slot together) and easy to set up but as expected from such a short antenna at 5MHz the efficiency was not good. Nevertheless it worked in a fashion and showed that communication around the UK is possible on 5MHz if it were not possible to erect a dipole or end fed antenna.

Next tests will be with an end fed wire with the far end connected to the top of a 5.4m fibreglass mast (if I can carry all the gear up the hill!)

Best wishes,

Ron.