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Posts : 7 Times Thanked : 0 Join date : 2019-11-09 QTH or Location : West Sussex. Equipment Used : Alinco DX10, CRT 9900, Jaws Mk 11 and HW Gainmaster Age : 63
Subject: HW Gainmaster Fri Feb 21, 2020 10:39 pm
Hi Guys.
Just got a new Antenna, decided on a new HW Gainmaster. Took it out the box and put it together. On the tuning section it gives the lengths for the tubes so i set it at 27.5 which i thought was be nearest for the UK 27/81 Band. Going by these measurements i am left with about 5" of the radiator cable out the top, too much to push down in the tube without bending it. Decided to ring the shop where it came from and they said just extend the tubes to take up the excess cable and not to bother with the chart. Done that and got it on the mast and got my ladder down. When i checked the SWR i was getting just under 1.5 on the uk 21. Now i know that is an acceptable SWR to use but on all my previous antennas it has been nearer to 1.1. What i would like to know is if i take it down and set the tubes to the length given in the tuning chart , will that SWR reading come down, also if i do, how do i solve the issue with the excess cable on the top, or shall i just use it as it is and use a tuner/matcher in line.
Has any one else had that issue with a Gainmaster, and help would be appreciated.
Thanks Guys.
GaryWilson CT Directors
Call Sign : 26-CT-1836 Amateur Radio Call Sign 2E0GGQ Posts : 4505 Times Thanked : 388 Join date : 2019-06-27 QTH or Location : Redcar, North Yorkshire. Equipment Used : Radios & Wires & Stuff! Age : 60
Subject: Re: HW Gainmaster Sat Feb 22, 2020 6:20 am
Hi Steve,
What is it reading at 27.5? Channel 21 on the Muppets is 27.8 so 300k up from there, I would expect the SWR to be rising a bit. The plastic tubes are only there to support the radiating element so just changing their length alone won't change the SWR.
To be honest 1.5 is a more than acceptable reading so if you spend most of your time on the U.K 40 and it's not high on any other part of that block I'd leave it there.
Best 73's Gary.
stephen Gunrunner Major contributor
Call Sign : 26CT526/MR021/M6XXX. Posts : 277 Times Thanked : 11 Join date : 2019-06-27 QTH or Location : wooler north northumberland or some were near it Equipment Used : mobile 4000hp base A99 radio base magnum257hp mobile magnum 257 standed power Age : 67
Subject: Re: HW Gainmaster Sat Feb 22, 2020 1:39 pm
if you have allot of spare cable just remember that when its up in the air and the big winds come ,it will bend every were and the extra long cable will be good, as if its short and tight then when its bends puts pressure on the cable,, and with a little slack will not affect how the antenna works lots up my way do this and its saves the coax been stretched and it will give up after a while,
woodworm New Member
Posts : 7 Times Thanked : 0 Join date : 2019-11-09 QTH or Location : West Sussex. Equipment Used : Alinco DX10, CRT 9900, Jaws Mk 11 and HW Gainmaster Age : 63
Subject: Re: HW Gainmaster Sat Feb 22, 2020 11:06 pm
Firstly, thanks for replays, you got me thinking now.
Now relying to Gary, yes, 1.5 is perfectly workable, so with the time it takes to get the ladder up, getting the Antenna down, then put it back up, its fine left as it is so probably going to leave it as it is.
Moving on to the reply from Stephen, i can see why the cable needs the slack especially with the winds we have had recently but where does the cable go. Going by the chart that Sirio give i had about 3 to 4 inches of cable out the top. The brass top will still go on with the cable coming through and the grub screw can be tightened, no issue there. Only thing is that the rubber top wont go on, other option keeping it in the tube is a no no, because there is to much cable to get back in the tube without having to bend it and risk damaging it.