24GHz Transverter

Post a reply


This question is a means of preventing automated form submissions by spambots.
Smilies
:D :) ;) :( :o :shock: :? 8-) :lol: :x :P :oops: :cry: :evil: :twisted: :roll: :!: :?: :idea: :arrow: :| :mrgreen: :geek: :ugeek:

BBCode is ON
[img] is ON
[flash] is OFF
[url] is ON
Smilies are ON

Topic review
   

Expand view Topic review: 24GHz Transverter

Re: 24GHz Transverter

by G0DJA » Tue Sep 17, 2019 4:17 pm

I've removed the 'penny' feed and I think that whoever made the feed up miscalculated slightly.

The usual way to calculate the feed point is to measure the diameter (D) in cm and the depth (d), again in cm, of the dish then use the formula

Feed point (f) cm = D x D/16 x d

Since the diameter of the dish is 25cm and its depth is 6cm the focal point should be at 6.51cm (incidentally, this makes the f/D ratio of the dish 0.26 which isn't great but will have to do for now) but the waveguide only reaches to 6cm from the centre of the dish. So, when I unsolder the dodgy end I'll cut back the block behind the big flange and drill and tap a hole for a screw to hold it in place.

Unfortunately, all of the 24GHz beacons are a bit far away unless there is a really good opening, so I'll have to ask to see if one of the people with a lot more power available than I have with this set up can put up a signal for me to look for.
IMG_0057[1].JPG
IMG_0059[1].JPG

Re: 24GHz Transverter

by G0DJA » Tue Sep 17, 2019 1:18 pm

Just realized that I'd not taken a photo of the dish that's attached to the front.
IMG_0055[1].JPG

24GHz Transverter

by G0DJA » Tue Sep 17, 2019 1:15 pm

I've taken a couple of pictures of the 24GHz transverter. It's been checked out and realigned on the current narrowband section of the band.
IMG_0054[1].JPG
IMG_0053[1].JPG
I need to remove the dish and re-solder the waveguide to the flange on the box.

Top