My portable GMRS repeater using BF-888s radios

[cdesigns]

This is my portable GMRS Repeater for camping, traveling or emergencies. I tested this repeater setup this past weekend using a big duplexer and it worked great. I sold the big duplexer and ordered a smaller one to put everything inside a small waterproof case with a big lipo battery and solar charger.

This is a test of the repeater without the duplexer, IT WILL NOT WORK without a duplexer, desentitation is a big problem without the duplexer.

Im using a ID-O-MATIC II as my repeater controller, it will ID my GMRS call sign and works great.
The only catch is that the repeater will activate on any incoming transmition with out without PLcode.
The ID-O-MATIC II requires a COR input to activate but on the BF-888s radio the only COR output Inwas able to find was the GREEN LED but it turns out it will turn on everytime is detects a transmition on that frequency. For what I need works great.

Portable Repeater (ID-O-MATIC II) Baofeng BF-888s - YouTube

 

[Rt169Radio]

Interesting idea.

 

[cdesigns]

I should ad that the setup works around 50ft-100ft without a duplexer, after that desentitation "kicks in"

 

[popnokick]

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Cdesigns- Trying to understand what you wrote re: after 50-100 feet desense kicks in. Do you mean that the setup shown in the video only has a range of 50-100 feet? If so, then you are already experiencing receiver desense... It's just not severe enough within 50-100 feet to completely desense the receiver. Out past 50-100 feet the full effect of desense kicks in. This setup- with a proper duplexer and antennas- should be good for a couple of miles... More if rooftop antennas are used.

 

[cdesigns]

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Cdesigns- Trying to understand what you wrote re: after 50-100 feet desense kicks in. Do you mean that the setup shown in the video only has a range of 50-100 feet? If so, then you are already experiencing receiver desense... It's just not severe enough within 50-100 feet to completely desense the receiver. Out past 50-100 feet the full effect of desense kicks in. This setup- with a proper duplexer and antennas- should be good for a couple of miles... More if rooftop antennas are used.

Yeah what I meant is that without a duplexer this system will not work if you are 50ft-100ft away from it. i tested a big duplexer and it worked fine 3 miles out using the stock whip antenna, I sold the duplexer and ordered a mini 20w duplexer small enough to fit inside a small pelican case. The video is showing the the ID O MATIC do work as a repeater controller. but to get it work 100% you need a duplexer. I paid $83 shipped and tunned from hong kong, but it hasnt arrive yet.

 

[popnokick]

Ahhh...makes sense now. FYI I have same type of mobile duplexer on my repeater feeding a single antenna on my garage. Works well out to about 15-20 miles.... but having the duplexer properly tuned was the key.

 

[kd2goe]

Where did u order the duplexer from?

 

[popnokick]

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eBay.... usually multiple sellers there. Many offer tuning but had mine tuned after purchase.

 

[cdesigns]

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eBay.... usually multiple sellers there. Many offer tuning but had mine tuned after purchase.

Yeah like popnokick said, ebay sellers will tune them for you.

 

[kayn1n32008]

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Once you get the duplexer, I recommend having the tuning, reject, and losses verified before you use the duplexer. Some people I know that have bought the Chinese duplexers have had to get them retuned before putting them into service. Best case poor receive due to improper tuning, worst case burning out a PA due to high SWR on the transmitter side.