Thoughts on building a portable base station, antenna mount on enclosure

[KR4GVA]

I'm a new ham and need some help! I am wanting to purchase one of the Powerwerx MBLCOVR base station enclosures to use both at home and away (vacation, emergency coms, POTA, etc). Someone mentioned that once your radio is installed in the enclosure that it is difficult to get to the antenna connection. That got me to thinking about using a short jumper cable (6" or so) so that it was easier to disconnect. I also thought about using a bulkhead connector (BNC or SMA) and drilling a hole in the top rear corner of the enclosure to give me a spot for a solid connection for an antenna. I could use a permanent antenna at home and attach something like a Signal Stick when I go portable and maybe one day invest in a better portable antenna. My question is whether or not this is a good idea.

• Would using a bulkhead mount affect the ground and/or ground plane of the antennas?
• Would I need to isolate the bulkhead mount?
• Is is safe to have an antenna that close in proximity to the operator? I'm guessing that 50 watts is not enough to do any real damage and in reality my mobile antenna is not much farther away than this would be.
• Would this use case benefit from the "Tiger Tail" for the Signal Stick?
• Is there a better antenna that would be still be "portable" and inexpensive?

Wow, that's a lot. Thanks in advance for sharing your knowledge and wisdom!

Ken KR4GVA

PS I would be using the Anytone 578UV, and would need a dual band antenna. Repeaters in my area are a mix of VHF and UHF.

 

[AK9R]

The back of that enclosure appears to be wide open, so there should be no problem routing an antenna cable to the antenna connector on the radio. The problem may be getting your fingers in there to tighten a threaded RF connector. A simple solution would be to adapt the radio to a BNC connector and use a BNC on your antenna cable.

You should separate the antenna from the operator. There's an RF exposure calculator on the ARRL website: RF Exposure Calculator

 

[mmckenna]

Yeah, you want some separation, especially at 50 watts. Not good for long term exposure.

The chassis isn't going to supply a suitable ground plane, so performance of an antenna directly mounted to it is going to suck.
High RF in direct proximity to the mic cord and power supply may cause issues.

You'd do better with a proper antenna mounted away from the operator/other humans.

If you are going to run an extension to make connections easier, use decent coax, like RG-142, RG-58, or similar. Avoid the temptation to use something like RG-174.

 

[prcguy]

I have the same enclosure and radio pictured in the link. I would not run more than 5w on an antenna connected to the enclosure. You can make a bracket to mount an SMA or BNC antenna then use a long 2m/440 HT antenna like the Nagoya NA771.

I would rather see you use something like an Ed Fong dual band roll up J-pole with some coax to get the radio away from you. Otherwise I am not a fan of J-poles.

 

[KR4GVA]

Wow, thanks for the quick responses. Looks like I was correct to be a little concerned about my ideas! Based on your suggestions I will not mount an antenna to the chassis, I will get it away from me. I will take a look at some of the Ed Fong antennas since what I have seen about them seems to be pretty good and the price is right!

However, one question is left unanswered. Is it ok to use a chassis mount or bulkhead mount connector on the side or top of the chassis? How would this affect things? I am thinking of doing this to clean things up and protect the antenna connection on the back of the antenna versus just adding a short extension. It just seems a little cleaner in my mind.

 

[AK9R]

Another source of quality roll-up J-pole antennas is N9TAX: Dual band 2M / 70CM Slim Jim Antenna with integrated 10' or 16' Cable.

Assuming the radio has an SO-239 ("UHF") connector, I would get a UHF to BNC adapter (see below) and leave the adapter on the radio all the time. Make sure your antenna cable has a BNC male connector. You should be able to get your fingers in far enough to connect-disconnect a BNC (1/4 turn).

This may seem pricey, but I think the quality is suitable for what you are doing. They are priced as a quantity of 2. DX Engineering DXE-170321315-2 DX Engineering Coaxial RF Connector Adapters | DX Engineering

Looking down the road, this collection from Chatt Radio has just about every adapter you'll need for amateur radio work. Yes, the connectors are Chinesium, but you probably won't be using them on space rockets. 10 Pc Adapter Kit + Jumper

 

[prcguy]

Wow, thanks for the quick responses. Looks like I was correct to be a little concerned about my ideas! Based on your suggestions I will not mount an antenna to the chassis, I will get it away from me. I will take a look at some of the Ed Fong antennas since what I have seen about them seems to be pretty good and the price is right!

However, one question is left unanswered. Is it ok to use a chassis mount or bulkhead mount connector on the side or top of the chassis? How would this affect things? I am thinking of doing this to clean things up and protect the antenna connection on the back of the antenna versus just adding a short extension. It just seems a little cleaner in my mind.

It is a PIA to reach the antenna connector on the Anytone DMR radio used in the chassis. I use a PL-259 to female BNC adapter which puts the connection a little further in the open and a BNC is an easy 1/4 turn compared to fumbling with many threads by your finger tips. I've standardized BNC for most of my radios and antennas for interop and quick on/off.

Not sure if there is anywhere on the chassis to mount a bulk head connector, you need space behind it and most of the space is used up. A male/female jumper cable would also make for easier antenna connection.