When it comes to cross-band HT repeaters there is very few choices and none as reliable at such an economical price point as the TYT.  The UV8000D's cross-band repeater function allows you to extend your HT range by taking input traffic on one band (like VHF) and repeating it out immediately on another band (like UHF) so that radios with "Dual Watch" (90%+ of all HTs) can talk to others like they were standing next to each other via it's repeater function. It allows users to communicate when they are not LOS (Line Of Sight) to each other but are LOS to the repeater, most commonly placed on high ground. # Sample Of Two This is my second  [TYT TH-UV8000D](https://amzn.to/48UQxE3) that I have owned as the first was stolen by hunters a few years ago. The stolen one was an older model before they went to USB rechargeable batteries and required the use of a "battery eliminator" to extend the RX time past that of one OEM battery, this made the total package larger than it needed to be and pretty clumsy. With the new USB battery model, I can easily extend the RX time by a factor of over (x2) using my favorite power bank the [Talentcell Rechargeable 12V 3000mAh Lithium ion Battery Pack](https://amzn.to/4b6laYq) and a USB cable, without the hassle of using a battery eliminator. # Be Your Own Infrastructure While the grid is up, everyone has access to repeaters on the HAM Freqs, Oregon has a state wide repeater chain that allows me to talk across the state even in the wilderness, but relying on someone else infrastructure in a crisis is poor planning. Most repeaters are on very limited backup power plans and placed so high up on mountains for area coverage that just getting to them for maintenance in a grid-down scenario is not likely to be easy. >Long story short, if you can't put you hands on it in 15 minutes, it doesn't belong to you. Don't rely on other people's gear for your comms plan. # Cross-Band Repeater Besides being a nice "normal" HT, this radio has the ability to extend your HT (Handi-Talkie) range past LOS (Line Of Sight) while in repeater mode and is a force multiplier when the grid is down. Think of patrolling outside of your AO and being able to communicate instantly back to "base" what you see, or the potential to add a solar panel to a more permanent location to allow comms with those just outside your AO. While that is not my "use case" it has the potential.  Put this radio at a high point between your "base" and where you are going to be and you can talk to each other through the repeater where you would not be able to talk directly to each other without it, due to terrain and/or distance. Add in [[Analog TX Encoding]] and you have a secure transmission potential for feeding SITREPS back to "base" on the other side of a ridge and/or extended distances WITHOUT the need for someone to monitor the radio 24/7! # Initial Runtime Test My initial run test inside the house of the OEM battery with the radio on RX mode only, was 135 hours (5.6) days inside a 72 DegF house. OEM Battery - 28.12Wh @ 7.4V = 3800mAh - ==135 hour (5.6 days) runtime \*\*\*== = 3800mAh / 135h = 28.15mA on RX - ==\*\*\* 6.6v @ 135h battery empty display, low warning light on, still transmitting== ELXJAR Aftermarket Battery - 21.6Wh @ 7.2V = 3000mAh - 3000mAh / 28.15mA = ~==106h== (4.4 days) on RX TalentCell Power Bank - 33.3Wh @ 11.1v = 3000mAh - 33.3Wh @ 7.2v = 4625mAh / 28.15mA = ~==164h== (6.8 days) on RX Using the smaller after market battery and the TalentCell charging it should equate to roughly 270h (11.3 days) of RX in optimal 72 deg weather. # Worst Case Runtime Test Actual runtime testing with the aftermarket battery and TalentCell combo was done in outside in December with recorded lows/highs of 34/54 DegF and radio on RX. |  |  | | ------------------------------------------------------------------- | --------------------------------------------------------------------- | >The OEM/TalentCell combo was still going 10 days later! That's a pretty respectful standby time for a worst case scenario of Winter. The more you transmit on the repeater, the less battery life you can expect, but knowing it will transmit xxx hours after setting it is going to extend your comms greatly. # Use Case The use case is not to have a dedicated repeater per say on a hillside, but a mid-point extension of comms while on patrol, patrol that would be less than 72 hours 99% of the time. This "non-dedicated" setup allows me to throw it in the pack and drop it off as I traversed over the surrounding hills of my AO where SIMPLEX will not make the trip back to base on VHF/UHF. # My Comms Extension Kit  The radio alone fits in the radio pouch, but a 5L-9L dry bag as shown below is a better option with more versatility if using a USB power bank to supplement the OEM battery.  The whole setup consists of: 1. [TYT TH-UV8000D](https://amzn.to/48UQxE3) 2. [Waterproof Radio Case PVC Carry Case](https://amzn.to/49big1Y) to hoist it into a tree 3. [USMC SEAL-LINE WATERPROOF DRY BAG 9L](https://www.ebay.com/itm/125005500890) for hoisting extra power pack also. 4. [Talentcell Rechargeable 12V 3000mAh Lithium ion Battery Pack](https://amzn.to/4b6laYq) 5. [Multi Charging Cable 1FT](https://amzn.to/4992GE9) 6. 50ft of 550 cord