Antenna Recommendation for 420MHz

[KickinCans]

I am tying to improve my reception of a few CAP+, COM+ DMR systems locally. I feel the antenna is the prominent factor affecting my poor reception. The frequencies for the systems are in the 420-425 MHz range. I have Googled for antennae that are suitable for range, but I seem to not find anything in this frequency range. There are a few at Antena Farm, but well beyond my budget for casual monitoring. Commander 420-430Mhz is $2k, Commander 406-426MHz is $720, RFS has a 406-470MHz model for $1.4k. From what I have seen, many reasonably priced models are maxed at 420MHz.

Can anyone suggest a good omnidirectional base antenna to cover 420-425, suitable for DMR, for attic mount, reasonably priced (<$250), keeping in mind about 50' of coax, likely some adapters, a (broadband?) multicoupler. I would consider a decent broadband omnidirectional if I can find one that would perform similar to a dedicated band in this range.

I was looking at the Browning BR6157? Would this be a recommended performer?

 

[mmckenna]

If this is going to be in the attic, easy solution is to use a mobile antenna with a base adapter.

Laird TE Connectivity B4065C UHF 406-430MHz 5dB 5/8 Wave Mobile Antenna

Laird TE Connectivity B4065C UHF 406-430 MHz Base Loaded 5/8 Wave Stacked 5dB Gain Mobile Antenna

theantennafarm.com

Base adapter will provide the necessary ground plane:

PCTEL Maxrad MBSUHF Converts Mobile UHF Antennas into a Base Station Antenna

PCTEL Maxrad MBSUHF Converts Mobile UHF Antennas into a Base Station Antenna

theantennafarm.com

 

[kayn1n32008]

Buy a 5/8 over 5/8 NMO colinear from Larsen, PCTel or EMWave and put it on a BSA kit. Buy a N connector version and feed it with LMR400 or LMR600(depending on feed like length). It's going to be under a meter tall on the BSA kit, and it's easily mounted in an attic.

Avoid Browning, Comet, Diamond and other garbage hammy manufacturers.

 

[kayn1n32008]

If this is going to be in the attic, easy solution is to use a mobile antenna with a base adapter.

Lol you beat me to it.

 

[KickinCans]

Thank you!
Just a general question if I may. Is there a significant signal loss with an antenna being in the attic (woodframe construction) vs. outside. If I were to take the configuration suggested by @mmckenna, would results be better in the attic which would provide height vs outside (not as high but not enclosed?

 

[ultrajv]

You didn't say what antenna or coax youre currently using. Any advantage you get with another antenna will be made worse by attic mounting. You'll get more noise etc. Don't spend much on it, round 100 or less is ok. You'll get better results mounting outside. Also you won't get much difference from dedicated 420 MHz antenna Vs standard VHF/UHF antenna. Your coax quality has a huge impact on signal strength also. RG213 is good coax. Adaptors, multicouplers etc will affect signal strength also

 

[mmckenna]

Thank you!
Just a general question if I may. Is there a significant signal loss with an antenna being in the attic (woodframe construction) vs. outside. If I were to take the configuration suggested by @mmckenna, would results be better in the attic which would provide height vs outside (not as high but not enclosed?

RF attenuation in your attic will depend entirely on the construction materials used. All materials introduce some about of RF loss, even dry wood. Primary concern would any metal materials. Some insulation has a foil backing for moisture barrier. HVAC ducts, wiring, plumbing can all be issues. Actual roof skin should be considered, is it a wood shake roof, composite or metal?

Height can be important if range is your concern. Since these frequencies tend to be line of sight, the higher antenna will give you more range. But if the system is nearby and you can pick it up outside the home with a stock antenna, height may not be a requirement.

Since this antenna seems to be aimed at listening to a very specific system, I'd choose your mounting location based on whatever gets you an acceptable signal.

 

[KickinCans]

Thank you. I think I will try outdoors first at a lower elevation, but that won't be much higher than the simple telescopic antenna I'm using now inside my room. It will eliminate the need to be putting holes in the ceiling to run the coax. The components you recommended mmckenna in post #2, I assume they are appropriate to be outdoors with proper sealing of connections etc. The way your worded it made it sound that being in the attic was important in selecting this combination.

 

[mmckenna]

Thank you. I think I will try outdoors first at a lower elevation, but that won't be much higher than the simple telescopic antenna

Right, difference is that this is a tuned antenna and has some amount of gain compared to the stock telescopic antenna.

Also, getting the antenna outside will help.

I'm using now inside my room. It will eliminate the need to be putting holes in the ceiling to run the coax. The components you recommended mmckenna in post #2, I assume they are appropriate to be outdoors with proper sealing of connections etc. The way your worded it made it sound that being in the attic was important in selecting this combination.

Long term these mobile antenna/base station adapters are not as durable as a well built base station antenna.
But a mobile antenna will last decades on top of a vehicle if properly maintained.

I think you'll be fine. Important part is to properly seal ALL outdoor coax connections.
Get yourself some of this stuff:

https://www.amazon.com/Proxicast-Pro-Grade-Weatherproof-Self-Fusing-Electrical/dp/B00K5GW67O/?th=1

Connect the coax to the bottom of the antenna. Torque appropriately (your knuckles should NOT turn white, but make sure it's snug). Then wrap this around the connector so no metal is showing.