G1WHP Repairs Diamond X300

Diamond x300 repair

[@radiofhi]

Thanks for showing the disassembled L/C assembly. SWR on my Diamond has shot up and all points to an open or bad cap. Your video really helps understanding the construction of the trap. Thanks!

[@buddhistsympathizer1136]

I'd expect to see a little better build quality for a £100+ antenna!

[@mike-M0MSN]

Nice.

[@G1WHP]

Well tested the antenna and it’s way off tune. Going to change the capacitors to see if it makes any difference. Update will follow.....

[@ianxfs]

Looks good. Fingers crossed for your testing! How old is that one Paul? I’ve just put up a new X300 a few months back. I sealed it well, so I’m hoping for a decent life span.... Ian.

[@G1WHP]

Hi Ian. The antenna a quite old I reckon 10yrs +. It had only one fixing screw that holds it to the short fixing stub the new ones come with two. The white pole somehow overtime the white pole worked loose and managed to come completely out of the base and I found it hanging from the pole one morning 30’ in the air. But once on the ground I was able to put it back together but did not realise the capacitors had become detached. It was only when we came to use it that there was a fault. Hope this fix works testing later today... cheers Paul

[@ianxfs]

Good one Paul. Yes mine had two fixing screws.

[@Surjon003]

what capacitor did you used?

[@user-pu3sx4rv7s]

💯💯💯💯👍👍👍👍 ☝

[@ruivalentect2ggx918]

Hello Can you tell me the capacity off the two capacitors? 73 from CT2GGX

[@BASSLINEPFP]

Hello. I also repaired my x300 antenna. When i bought it the swr response was ok. After 2 years or so I had high swr response. I dont know why. When I opened it there was one 5pF capacitor inside. In fact it turned out that the cap was ok. (It had exactly 5pF). I tried to make my own 5pF cap with RG174 cable. I soldered it exactly where the previous one was. But unfortunately it did not help. I started to trim the cable until the swr response was ok. So the cable capacitor has now 3-4cm in length.(around 3 pF) The antenna works perfectly now. 1:28 at 144mhz 1.08 at 145mhz and 1.28mhz at 146. At 70cm it is also fine, around 1:2 or 1:3. So if anyone has this problem with antena, do what I did and it will be fine 😊

[@G1WHP]

Nice work, it can be very time consuming but rewarding when it works thanks to adding to the comments Best Regards Paul

[@BASSLINEPFP]

@@G1WHP yeah it is time consuming. but this method with triming the coax cable capacitor is very good. And those cable caps are easy and cheap to make.

[@andrewgordon642]

How did you get the base off? I have an X-30 with a damaged N type plug I'd like to replace if it's possible.

[@G1WHP]

Hi Andrew, the vertical white stick will with a little effort pull out of the base then the element can be removed by loosing a grub screw. You can then remove the inner part including the coax female connector by removing grub screws equally spaced around the base. Hope this helps Paul

[@andrewgordon642]

@@G1WHP Thank you, sorry I didn't replt sooner, it didn't notify me. I need to replace the N type and didn't want to destroy the antenna. I tried looking to see if anyone else had made a clip of it but couldn't find anything.

[@isrowfr25]

Hello , what is the blue capacitor ??? Thank you mine on my antenna is unsoldered, and I can't read its value... THANK YOU YOU VERY MUCH 73 from F0FDZ , in JN37AG

[@G1WHP]

Mine had 6.5 pF but I was never able to get the tuna right the winding is critical especially the tapping point. In the end I gave up and purchased a new one. Hope this helps Paul

[@isrowfr25]

@@G1WHP Oh.. Thank you Paul for your quick response... ok, I'm going to dig into my junk, to change this capacitor... And above all to prevent water from seeping into the antenna and depositing limestone... Thank you a lot, really ... Friendship 73 ... Maybe this little modification will allow us to establish a qso between our 2 stations ... a day of good propagation ... I hope so anyway ... bye bye

[@osopaul]

And, ah and ah and ah ah ah and ah ah ah