It is currently Thu Oct 24, 2019 5:25 am

Click the link below to visit the site sponsor

The Ham Radio Shop




Post new topic Reply to topic  [ 4 posts ] 
 VHF Antenna Switch? 
Contributor 2019
User avatar

Joined: Tue Oct 09, 2012 1:09 pm
Posts: 10313
Location: West Midlands
Feedback: 99 (100%)
Reply with quote
Post VHF Antenna Switch?
The question will be whether it will work on 2m.

It seems to be reasonable going through two of the relays on the bench, but that may be totally different at 2m when mounted on a board with other relays and grounds around it.
I do not have space to make the tracks exactly 50 Ohms and space things correctly, so I thought I would just build it and see, if it is no good I can use it on HF :)

The idea is to have two antennas, four rigs, and be able to switch any rig to either antenna, at the same time connecting the other antenna to one of the other rigs.
Obviously it must not be possible to have two rigs connected to each other, nor to have both antennas connected to one rig at the same time.

What it will be able to do is to switch a rig between two antennas with one switch action, or one antenna between two rigs with one switch action.

Hope to get it in the box tomorrow.
Attachment:
sw1.jpg
sw1.jpg [ 117.69 KiB | Viewed 321 times ]




Notice the depth of the cut is not constant, I either have an issue with the controller or the Z axis stepper motor, I had to stand and watch it and be ready to manually wind it out when it didn't lift while it was running.
Attachment:
sw2.jpg
sw2.jpg [ 110.67 KiB | Viewed 321 times ]

_________________
===================
Gee Three Eee Jay Ess - RSGB, SARL, G-QRP, EPC
===================


Sat Jun 29, 2019 7:32 am
Profile Send private message

 VHF Antenna Switch? 
Contributor 2018
User avatar

Joined: Wed Oct 30, 2013 2:47 pm
Posts: 1691
Location: Llanwrtyd Wells
Feedback: 20 (100%)
Reply with quote
Post Re: VHF Antenna Switch?
I'd be inclined to sub one of the radios for a power meter, and see if there is leakage when transmitting.

_________________
The Devil take your stereo and record collection.


Sat Jun 29, 2019 8:51 am
Profile Send private message WWW

 VHF Antenna Switch? 
Contributor 2019
User avatar

Joined: Tue Oct 09, 2012 1:09 pm
Posts: 10313
Location: West Midlands
Feedback: 99 (100%)
Reply with quote
Post Re: VHF Antenna Switch?
GW6RRL wrote:
I'd be inclined to sub one of the radios for a power meter, and see if there is leakage when transmitting.



Yes, I normally check all ports with the SA, transmitting into all one at a time,and checking all the rest, terminated and open.

It does take quite a while to go through all the combinations, but it is worth it.

The worst I have on the HF one I built a few years ago is 50dB isolation, but that one has a better designed board, and it can be improved with shielding.

Just have to try this one to see :)

_________________
===================
Gee Three Eee Jay Ess - RSGB, SARL, G-QRP, EPC
===================


Sat Jun 29, 2019 9:23 am
Profile Send private message

 VHF Antenna Switch? 
Contributor 2019
User avatar

Joined: Tue Oct 09, 2012 1:09 pm
Posts: 10313
Location: West Midlands
Feedback: 99 (100%)
Reply with quote
Post Re: VHF Antenna Switch?
Well, it works!

In practical terms, if I transmit 45W through the first port on 145.0, and connect another radio to the second (adjacent) port, that is not switched through to an antenna, I get an S3 signal if it is tuned t 145.5, and an S7 signal on 145.00125.

The change to SWR measured at the rig is 1.05:1 going to just under 1.1:1


Much better than I had expected, there is a lot of wire in it :)

Attachment:
vsw1.jpg
vsw1.jpg [ 93.97 KiB | Viewed 232 times ]

Attachment:
vsw2.jpg
vsw2.jpg [ 130.6 KiB | Viewed 232 times ]

Attachment:
vsw3.jpg
vsw3.jpg [ 134.7 KiB | Viewed 232 times ]

_________________
===================
Gee Three Eee Jay Ess - RSGB, SARL, G-QRP, EPC
===================


Thu Jul 04, 2019 2:13 pm
Profile Send private message
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 4 posts ] 


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
Powered by phpBB © phpBB Group.
Designed by Vjacheslav Trushkin for Free Forums/DivisionCore.