Hi folks -- I want to try my hand at setting up a simplex repeater on GMRS because... well... why not? While I could drop a few bucks on a Baofeng, I'd prefer something a little more robust (although the BF-888s would probably work for testing/initial build). I've recently been made aware of the Bendix/King VHF/UHF portable units which look like they'd fit the bill -- not too fancy, readily available used, and built like a Mack truck. I've been looking on ebay for BK handhelds and they seem to be there, but a lot of them look kind of rough. I'd like to avoid this turning into a "buy enough junk radios to get enough parts to get one good working one" type of project (for now, anyway), so I'm wondering what else might be available used that would be similar to this type of radio? I know there are a lot of the big-name handhelds out there (Kenwood, Motorola, etc...) but they tend to command a higher asking price used than I want to spend. I'm hoping to tap into the collective intelligence here to see what less-well-known brands (at least, to someone not in the industry, such as myself) might also show up and be a good fit for this type of project. So... any ideas or advice is welcome.
Here is a thred on my site about building using HTs http://www.preparedham.com/forums/index.php?topic=1302.msg10641#msg10641
I question your "Simplex Repeater" designation for what you are planning to build.... In Comms Language, Simplex means that you are Transmitting and Receiving on the SAME Frequency, but NOT at the same time.... Half Duplex means you are Transmitting and Receiving on Different Frequencies, again NOT at the same time.... Duplex means you are Transmitting and Receiving on different Frequencies, Simultaneously, or AT the SAME Time.... Repeating means that what the Receiver Audio is hearing, is also what the Transmit Audio, is Transmitting. So a Simplex Repeater would be a Device that Transmits and Receives on the Same Frequency, simultaneously, or At the Same Time, Which is REALLY REALLY HARD to Do... SO describe what you are trying to do.... I suspect what you really want to do is make a Duplex Repeater out of Two cheap Chinese HandHelds, and put them on one of the GMRS Duplex Frequencies. If that is the case there are a few things you have to understand about these Radios, in General, and designing Repeaters in specific... It isn't Rocket Science, but for the unInitiated it can be a challenging Learning Experience. Also NOTE, that such an Operation is a Licensed, and Regulated Operation, by the FCC in the USA... and if you build one of these Systems, and put it on the Air, without FCC Frequency Coordination, and stomp on someone else's Licensed Operation, They will turn you in to the local FCC Field Office, and the Field Agents will come looking for you, and if the catch up with you, plan on a BIG Monetary Forfeiture, as well as a Cease and Diciest Order...
I intend to get a single UHF handheld and attach it to a simplex repeater controller, such as one of these: https://www.amazon.com/dp/B014H2D2TM/?tag=survivalmonke-20 ADS-SR1 Simplex Repeater, Argent Data Systems (And yep... I do understand the difference between a half duplex repeater and a simplex "parrot" repeater.) Repeater operation is permitted on the GMRS frequencies, though there is some ambiguity as to how exactly they should be configured for pure simplex operation. I was intending to take one of the repeater pair frequencies and have it work in "split" -- have the repeater rig listen on the 467 side and transmit on the 462. The radio wishing to activate the repeater would have the split reversed (TX 467, RX 462). This seems to be the best "fit" for the intended use of the repeater pair frequencies. Prefer to avoid the cheapie HTs if possible since I'm not sure how well they'd hold up. For the record I am both ham and GMRS licensed.
Been running a pair of UV-5Rs for several years, no probs. BKs are cost prohibitive and battery eaters. Also Ham and GMRS licensed. Oh, GMRTS as well.
Ok, you have the bases covered, looks like... Maybe post pictures, when the project gets up and running....
(Emphasis added) <nitpick> Using two frequencies instead of one means that it's not simplex. If you use a simplex controller, you'd be running half-duplex. </nitpick> Parrot repeaters are very confusing for untrained users, and the retransmission will often frustrate and confuse the users, because some users will be able to hear the original transmission and some will not. You have a good idea - running half duplex so that other users will only hear the retransmission, not the original - but don't forget that every transmission takes twice as long, and since the controller will be recording until whomever is speaking releases their PTT button, you'll often have users stomping on the input with question like "Are you still there?" or "Are you hearing me at all?", etc. I suggest you check out some other ideas, and consider putting together a full-duplex, real-time repeater. See http://www.repeater-builder.com/johnson/pdfs/updated-ppl-to-repeater.pdf . FWIW. YMMV. William Warren
I have built repeaters using BKing radios and they work very well. Relm has a repeater box that works very well and is used by several organizations as a portable repeater. Setup and modified one that's still outll there somewhere. Have the bones of one that was used on Sentinel Dome in Yosemite, somewhat worse for wear after it was rolled down the side of hill during a deployment. Lots of stuff out there that's use able. I like the Kenwood TK3160 for simplicity and stoutness. Easy to program with laptop and includes a simple inversion scrambler (legal on GMRS). We used a lot of them..... If you like bricks the MT series was solid as well... Even if Motorola software is a pain. Cavities are a must for true repeater but hard to tune without a service monitor. Check out batlabs online for a ton of great info. William Warren in post above gave you a great link. Happy tinkering!
