Antennas for MSARS

G4UDU Phil


Most of you know the problems we have with the antennas at Cypress Hall primarily with a G5RV which has failed and to which we have intentions to replace it with an end fit halfwave

There are also plans to install a web SDR to provide a remote receiving station useful for those both locally and more distant and picking up our local HF schedules plus general receiving, this in addition to the fact that most of the equipment in the shack is now very outdated and would benefit from being modernised both for existing members use and to encourage new club members to join us operate with new technologies.

Friday the 22nd I did a test on the existing antennas to see what their state was after taking some pictures the week before realising that the antennas on the roofarer in need of some considerable care and restoration, for halyards for the HF wire are in a very poor state and need replacing together with new pulleys but on inspection of the photographs the VHF devices were certainly showing the fact they have been installed for 20 years and corrosion has had its effect  

First the position for the antennas to operate on the web SDR would probably be best placed by changing the rear guying pole and adding a bit more height plus a cross mounting pole and putting a loop on one side and a vertical on the other both of these are active receive aerials only 

6m 3Ele Beam

The driven element is slightly askew and on checking its performance it is interesting to see that it is far from ideal with respect to the primary operating frequencies of 50.000 up to 50.300

2m 9 ele beam

Now on this one we should be operating centred around 144.300 - again not in the correct part of the band

Triband vertical

First the situation on 6 m - certainly a bit high here.

Now 2m - now this should be on 145.500

And 70cms - its up and down everywhere, but not that bad on the TX input frequency for HY which is possibly the only frequency it will be used on.

Another observation I made is the rotator currently swings from south through to south which is the opposite that is required for operation with VHF antennas - it should stop at North - this is an error at the time of installation - if you think about it all signals are going to come in on bearing headings between 30° and 220° so making it stop in the middle is a total inconvenience because you have to wind it full circle to get round to the place you want to go - the rotator is correct if you are using it on HF which allows you to swing through north .

Nothing is completely broken (apart from the HF G5RV) but its not all as it should be.

So what do we get from this ?  Is it time to get a contractor in on a "day rate" and get all of the work done in one go ?   Taking into account how much the shack is ever used is it worthwhile actually doing this ?

It's the memberships decision to decide what they want and the committee's responsibility to make it happen - so over to you ………..

Phil G4UDU