Base Antenna for Home

[tweiss3]

As seen before, I don't have a clue with antennas. I did get the cars figured out, but there isn't nearly as much option with the NMO antennas.

 

I'm looking to bite the bullet and just get a base station for my office at home. I definitely need to keep GMRS, but want to add the Ham stuff, and listening to public works 800MHz. That being said, I may have an easy time with zoning, because I think they wrote an exception in the code for amateur radio (email response waiting). I'm starting my window shopping in hopes for a good Christmas.

 

My house is a split level with dual peak. I want to install the antenna off the higher peak, and pass into the attic under the eave.

 

Challenge 1:

I'm confused on what type of antenna. I know I don't want a yagi. Do I want a fiberglass amateur base station antenna, or a discone base station? I'd like the VHF/UHF and GMRS bands at a minimum, and good radiation pattern. This will be "roof" mounted, on the side at the peak, on a pole (probably 10'+-).

 

https://www.theantennafarm.com/catalog/diamond-x6000a-4879

vs

https://www.theantennafarm.com/catalog/comet-cx-333-1076

vs

https://www.theantennafarm.com/catalog/diamond-d3000n-5695

 

 

Challenge 2:

What else do I need to look into?

I was thinking grounding the support pole all the way to the ground and using a 10 grounding rod. I was also going to connect it (antenna)-(cable)-(multi strike under eave)-(cable through attic to office).

 

https://www.theantennafarm.com/catalog/coax-cable-accessories-627/lightning-protection-628/multi-strike-50-ohm-629/20-1990-mhz-with-n-connector-635/

 

I'm looking for just 1 antenna at this time as I ease my way into this and DMR.

 

Thanks for all the help.

[UHFJim]

The discone has zero gain, a waste of time unless you are monitoring only.  The other antennas you listed are ham antennas, they will be inefficient with high SWR on GMRS.  I just installed https://www.theantennafarm.com/catalog/comet-ca-712efc-1085.

The antenna is very easy to install, tuned for GMRS, 10 feet tall, and weighs 3 lbs.  I pounded an 11 foot grounding rod into the ground and used #6 copper ground wire.  50 feet of LMR-400 with N connectors.  The results have been fantastic on GMRS.  My ham VHF/UHF antenna setup is a Diamond CR-8900A mag mounted in the attic on a metal plate.  It works OK for local repeaters but like I said I prefer GMRS over ham.  Your proposed mounting and grounding specs look fine. What kind of support pole and wall mounts are you going to use?

[tweiss3]

The plan is to buy a CS800D which will do all Ham and GMRS in one, so I'm trying to few away with a single antenna.

 

Mount is probably going to be this: https://www.theantennafarm.com/catalog/rohn-heavy-duty-wall-mount-kits-8449

 

800MHz will be monitor only, so I'm sure any antenna will be better than nothing in that aspect.

[UHFJim]

The plan is to buy a CS800D which will do all Ham and GMRS in one, so I'm trying to few away with a single antenna.

 

Mount is probably going to be this: https://www.theantennafarm.com/catalog/rohn-heavy-duty-wall-mount-kits-8449

 

800MHz will be monitor only, so I'm sure any antenna will be better than nothing in that aspect.

 

Not a radio cop but if you "do" ham and GMRS in one radio, You are asking for trouble.  Good luck with your setup.

[tweiss3]

@marcspaz, don't you have a bunch of attic antennas? What's the lightening risk for an antenna in the attic? I apparently are beyond deficient electrically in my house (60+ years old, original panel and no grounding).

[Lscott]

Not a radio cop but if you "do" ham and GMRS in one radio, You are asking for trouble.  Good luck with your setup.

Were would the problem be for example in my case out of curiosity since I’m doing exactly the above? I’m licensed for both services and use a Kenwood TK-370G-1 which is Part 95 certified, unmodified and has a full front panel keypad. The radio is not enabled, through hardware and software, for front panel programming. However it is programed for both GMRS simplex channels, a couple of GMRS repeaters and various local UHF Ham repeaters.

[tweiss3]

Not a radio cop but if you "do" ham and GMRS in one radio, You are asking for trouble.  Good luck with your setup.

 

You are right that part 90 radios are technically not listed specifically approved for GMRS. I was talking about a Part 90 certified radio, not an off the shelf ham that isn't certified.

 

Were would the problem be for example in my case out of curiosity since I’m doing exactly the above? I’m licensed for both services and use a Kenwood TK-370G-1 which is Part 95 certified, unmodified and has a full front panel keypad. The radio is not enabled, through hardware and software, for front panel programming. However it is programed for both GMRS simplex channels, a couple of GMRS repeaters and various local UHF Ham repeaters.

 

Your's is Part 95, and 100% acceptable for GMRS: https://fccid.io/ALH29473110

 

There is not a restriction, that im aware of, on using Part 90/95 equipment in the ham bands.

[kidphc]

@marcspaz, don't you have a bunch of attic antennas? What's the lightening risk for an antenna in the attic? I apparently are beyond deficient electrically in my house (60+ years old, original panel and no grounding).

 

Not marc. I have one mounted in the attic, I still grounded it like it was an outside antenna, since my LMR400 is going down the side of the house. Plus I'll be set up for an outside antenna (wishful thinking). The biggest problems are, coupling with wiring (metallic) objects in the attic, potentially irradiating family members below, copper granular shingles, radiant barriers and some losses associated with going through the lumber and shingles.

 

X200a mounted in the attic.

 

[tweiss3]

The only wiring in my attic is shielded CAT6 for my POE camera system.

 

Roof is new asphalt shingle (replaced 2 years ago). All wire would be kept inside the house, as this antenna would be going almost right above my office.

 

Wouldn't a proper ground plane/radial set keep the radiation from a downward trajectory and impacting the house?

[kidphc]

Wouldn't a proper ground plane/radial set keep the radiation from a downward trajectory and impacting the house?

Yes, theoretically.  Even continuous chicken wire, not the braided should provide a ground plane. The x200a has 3 long radials, however RF is going to do what RF wants to. So depending on wattage, you might want to do a field exposure study. Especially, if you are directly below it. My antenna is above a closet, an unused bathroom and a hall way.

 

I was told not to put the HF dipole in the attic because even at 50 watts the exposure was iffy.

[tweiss3]

I was thinking a mobile conversion like such: https://www.theantennafarm.com/catalog/laird-technologies-mbc-1649. Maybe get a dual band, or just stick with a 1/4 wave whip. I'll have to pull out the VNA again and do some seaching.

 

I'm not going to touch HF, in fact, if it weren't for more nets being on the VHF repeaters than the UHF, I'd stick with UHF only. Still at 50W max.

 

Another quick question will having oversized ground radials hurt overall performance? It doesn't seem to on a car when the whole car is the ground plane/radial.

[kidphc]

.Another quick question will having over-sized ground radials hurt overall performance? It doesn't seem to on a car when the whole car is the ground plane/radial.

Probably won't help on a car. As far as at home, you should check/experiment with the vna. Although, what I have read, long radials or simply addding more have severally diminishing returns.

 

Something anecdotal on ground radials mostly for HF but you'll get the idea.

[Lscott]

You are right that part 90 radios are technically not listed specifically approved for GMRS. I was talking about a Part 90 certified radio, not an off the shelf ham that isn't certified.

 

 

Your's is Part 95, and 100% acceptable for GMRS: https://fccid.io/ALH29473110

 

There is not a restriction, that im aware of, on using Part 90/95 equipment in the ham bands.

Thanks for the info. I was fairly sure there wasn't a problem. I was interested in tweiss's opinion since he seems to think it's an issue based on a rather broad comment in his post. I used myself as an example where I was sure it wasn't doing exactly what he said likely was. Maybe there is something that he's seen, read or whatever where it could be. The FCC's rules are not always that clear cut about what's permitted and prohibited. No harm in trying to find out.

[tweiss3]

Probably won't help on a car. As far as at home, you should check/experiment with the vna. Although, what I have read, long radials or simply addding more have severally diminishing returns.

 

Something anecdotal on ground radials mostly for HF but you'll get the idea.

 

I'm not so much worried about diminishing returns, I just want to make sure if I don't trim, that it doesn't affect performance.

[UHFJim]

Were would the problem be for example in my case out of curiosity since I’m doing exactly the above? I’m licensed for both services and use a Kenwood TK-370G-1 which is Part 95 certified, unmodified and has a full front panel keypad. The radio is not enabled, through hardware and software, for front panel programming. However it is programed for both GMRS simplex channels, a couple of GMRS repeaters and various local UHF Ham repeaters.

No problem at all. TK-370G is a nice rig. Enjoy.  What antenna are you using?

[Lscott]

No problem at all. TK-370G is a nice rig. Enjoy.  What antenna are you using?

I have 4 of the TK-370G-1’s and 2 of the TK-370-1’s. The later are just 32 channel regular FM only. Both are Part 95 certified I believe. The TK-3170-1 are nice, Part 95 certified, if you can find any at a reasonable price.

 

The antennas are either the ones they came with, eBay or local Ham swap, the rest are from a cheap 5 pack I purchased from an eBay seller. I did do an SWR scan of the cheap 5 pack ones and was surprised the SWR was comfortably below 2:1. I was hoping I didn’t get a “50 ohm resister in a rubber stick”. Yea there are a few like that around.

 

When mobile I use a high gain dual band antenna. It has low enough SWR across the Ham bands and the GMRS frequencies. The antenna is almost 60 inches tall. Comet no longer makes this model. I wish they did. I’ve had two for nearly 20 years. One is on the Jeep’s roof rack the other is used inside when I lived in an apartment. That one has never been out doors. Still looks new.

 

CA-2x4MB, 4.5 dBi on VHF, and 7.4 dBi on UHF

[kidphc]

I'm not so much worried about diminishing returns, I just want to make sure if I don't trim, that it doesn't affect performance.

If you trim them THEN you will affect performance. Leave them as is and you should be good to go. You may get more performance by adding radials or lengthen the ones you have.

[n4gix]

I've been using a pair of CS800 (UHF) for four years and a CS800D for the past six months for both ham and GMRS services.