Vertex VXR-7000 UHF

[WRVD377]

I read all the current posts in a search for the above title.

1.) Does anyone know where and what to buy to link this repeater to mygrms as a node?

2.) Has anyone used a less expensive VNA to retune a notch duplexer in the gmrs range?

3.) Has anyone seen the reasons not to use LMR400 outside and if yes what is the alternative?

Thank you for any help,

Royce

 

 

[OffRoaderX]

#3 - I have been using about 60ft of LMR400 with my VXR7000 for over a year with no issues.

[WRVD377]

Thank you. A friendly ham pointed out an issue.  At the time I looked for that issue I found a cable site that confirmed it.  What was said was that the outer aluminum shield if it gets wet tends to cause an issue with the copper main line due to the different metals. Which I know from other industries, AL on steel is an issue also.

I am not saying I completely believe them over anyone else only asking if anyone "really!" has seen it.

But I thank you for your reply.

Royce

[tcp2525]

5 hours ago, WRVD377 said:

Thank you. A friendly ham pointed out an issue.  At the time I looked for that issue I found a cable site that confirmed it.  What was said was that the outer aluminum shield if it gets wet tends to cause an issue with the copper main line due to the different metals. Which I know from other industries, AL on steel is an issue also.

I am not saying I completely believe them over anyone else only asking if anyone "really!" has seen it.

But I thank you for your reply.

Royce

That should never be an issue if one observes proper weather sealing of all connections. Moisture  in ANY connection is a no-no, so  do it properly with any cable and  never worry.

[SteveShannon]

5 hours ago, WRVD377 said:

Thank you. A friendly ham pointed out an issue.  At the time I looked for that issue I found a cable site that confirmed it.  What was said was that the outer aluminum shield if it gets wet tends to cause an issue with the copper main line due to the different metals. Which I know from other industries, AL on steel is an issue also.

I am not saying I completely believe them over anyone else only asking if anyone "really!" has seen it.

But I thank you for your reply.

Royce

If you get moisture inside any coax you’ll have an issue, whether the shield and core are dissimilar metals or not.  That has happened to people here on the forums and they end up lopping off the last couple feet or completely replacing the cable. But that’s not strictly the fault of LMR400 and I wouldn’t avoid LMR400 for that reason, especially if you already have it.  I would take great care to waterproof the connections.  In answer to your question about what to use, professional radio people would specify “hardline” and N connectors.  If you have access to it, it’s measurably better in terms of losses and resistance to the elements, but it’s also more costly and less flexible. 

The link kits, as I’m sure you are aware, are unobtainable right now, but if you don’t mind paying a scalper high prices for a Raspberry Pi (or if you’re fortunate enough to already have a Raspberry Pi) you can assemble one yourself. [Edited to add: in other posts/threads of yours, it appears you have got all the parts, but were looking for help, so I’m confused.  Did that not pan out?] I haven’t done it, but there are some threads on the forum.  Take heart; Raspberry Pi models are reportedly expected this summer.  We will see. Rpilocator.com is a good website to use to learn about availability. Here’s a link to a website that discusses building nodes: http://pascogmrs.us/video/how-to/

I have seen a video on YouTube that shows using a NanoVNA, using both port set up to measure insertion loss, to tune each side of a duplexer.  I’ll see if I can find it.  If I do, this is where I’ll place the link: 

The same person has another similar video:

 

 

[tweiss3]

Yes, I used a NanoVNA H3 to tune duplexers. I did bypass the internal screen and use my computer with the NanoVNA-APP and increased the number of data points (and took my time). Afterwards, I took the whole repeater over to a friend who had real equipment, and ended up not changing a thing. The real challenge is to go slow, take your time and move in small increments. Also, make sure you have the correct jumpers, adapters and dummy loads before starting.

[WRVD377]

Thanks.  Sounds like a "normal" issue for all cables then.

[WRVD377]

Sshannon,

Thanks, I have seen those videos "VNA", good ones to watch.  I will go look at the gmrs ones to see if I can follow any of them to a solution for me for the Vertex repeater node building.