Dual band 2m 70cm simplex MMDVM hat

[G6ZKC]

My first Post !

Please excuse my ignorance, Can the MMDVM (Pi-Star) hats, the ones with two 7201's, be used with a dual band 2m/70cm DMR handheld to have a choice between the two bands, i.e. use 2m simplex OR 70cm simplex ?

[M1DNS]

Only if the manufacturer supports it.

I've not see any duplex hotspot boards
(Boards with 2x 7021 transceiver chips) that run dual band. Near all ive seen are listed as 70cms.

Often with many of the cheaper copy simplex boards, their chineese sales sites say they do dual band when in fact they don't. So trusting their sales sites will be an issue for you also.

There is a ki6(ZUM) simplex board that states its dual band, and it is def. capable of running dual band, but of corse that is only 70cms OR 2m depending on what you set in pistar.

Although ive never tried it, afaik it wont do eg. 2m TX 70cms RX. or vis-versa.

Sent via smoke signals from my SM-G935F M1DNS (Admin)

[AF6VN]

There is a ki6(ZUM) simplex board that states its dual band, and it is def. capable of running dual band, but of corse that is only 70cms OR 2m depending on what you set in pistar.

There is/was a dual-band DVMEGA board (I'm running one), but again -- it is simplex and only operates one one band at a time, as configured in Pi-Star. Given the limited 2m band range and crowding by repeaters, I'll probably never use the 2m band on that board.

[G6ZKC]

Thanks for all the replies.

It's all a bit confusing dualband, simplex, duplex naming conventions with different boards abilities depending on supplier. My idea was is to have a dual band handheld 2/70 and have the hotspot listening on both and being able to change bands on the H/H to whichever is the best signal, when I'm wandering about outside - it would probably be 2m but not necessarily given trees, power etc.

Even so I'm not sure if Pi-Star is able to listen to two bands at once and give priority to one given a signal on it. Failing all that it's down to just a case a choosing a band 2 or 70. The area here is very quiet RF wise no repeaters FM or digital I can receive - being in a rural area and in a valley !

[AF6VN]

Thanks for all the replies.

It's all a bit confusing dualband, simplex, duplex naming conventions with different boards abilities depending on supplier. My idea was is to have a dual band handheld 2/70 and have the hotspot listening on both and being able to change bands on the H/H to whichever is the best signal, when I'm wandering about outside - it would probably be 2m but not necessarily given trees, power etc.

Even so I'm not sure if Pi-Star is able to listen to two bands at once and give priority to one given a signal on it. Failing all that it's down to just a case a choosing a band 2 or 70. The area here is very quiet RF wise no repeaters FM or digital I can receive - being in a rural area and in a valley !

DualBAND is a unit that can be tuned for EITHER VHF(2m) OR UHF(70cm), but operates on only one of the two bands per the configured frequency.

Duplex (the other "Dual") boards are low-powered repeaters -- they will have two stubby antennas. Whether any of these boards are also dualband I don't know. As repeaters, they do use two frequencies, but those frequencies are typically within the same band, with normal repeater offsets for the band.

Simplex boards are the common Hotspot -- using just one frequency during operation (dualband or not). It is either transmitting network traffic OR receiving local radio traffic, but can not do both at the same time.

Given the typical range and sensitivity (or lack thereof -- my HTs can hear my hotspot from down the block, but it can't hear them even on high power more than one or two houses away), which band you pick probably doesn't matter. VHF is reputed to have somewhat better range in woods, but UHF manages to pass through doorways and windows better (hence the selection of UHF and up by many big city departments).

Pi-Star software doesn't "listen" to bands. It merely sends the configuration frequency to the RF board. The RF board then does the listening and transfers digitized audio packets between it and the R-Pi. The R-Pi wraps those packets with network headers and transfers between the R-Pi and network.

[G6ZKC]

Thanks Dennis and thanks for the concise reply.

It's pretty much as I assumed, I wouldn't expect much from a few milliwatts away - maybe a watt or two. I like the idea of DMR but the audio quality is well, not always the best.. I've listened on Brandmeister so far. I don't own any DMR or digital at all I just like to fully understand something before I leap.

Dave.

[AF6VN]

It's pretty much as I assumed, I wouldn't expect much from a few milliwatts away - maybe a watt or two. I like the idea of DMR but the audio quality is well, not always the best.. I've listened on Brandmeister so far. I don't own any DMR or digital at all I just like to fully understand something before I leap.

I'm of the opinion that no one bothers to check microphone gain on DMR (for those radios that /have/ an adjustable gain), or to compare with the parrot talkgroup (configure volume on busy channel to what one considers reasonable, then switch to parrot, speak something, and compare how it returns; adjust gain so one sounds similar to the [average?] traffic).

I have some DMR radios where I never go above volume level 1 -- my best guess is they were meant for noisy construction zones where one needs a LOUD radio to even know there is traffic.

More expensive alternatives are D-STAR (while an "open" standard, currently only Icom produces units -- Kenwood had some for a few years but dropped out of the market) or Yaesu's proprietary C4FM/System Fusion [YSF]. I don't have any YSF gear. I find modern D-STAR rigs fairly easy to program. Check the manual first, before buying -- "modern" rigs will have a separate "repeater list" which can be accessed via push button/menu, and a "near repeater" function if the rig has a GPS lock to allow selecting the nearest D-STAR repeater; they also have a button/menu to access a reflector selection menu, making it easy to specify the reflector link/unlink/info commands, along with "use reflector" to set the proper CQCQCQ target. Older models require one to manually select the repeater from "regular" channels, then configure the target and gateway entries (gateway is needed to have traffic routed from the repeater over the internet to other linked repeaters or to the servers that handle reflectors). All such done directly on the modern units (select nearest repeater, select local or gateway call , etc.)

[M1DNS]

Couple o things to answer you both in one reply.

The board doesnt listen to both bands. In the config you set it to the freq you want to use. Be it UHF or VHF (if the board supports it.)

-----------------------------------------

Yaesus (system fusion being their choosen marketing name) offering isnt proprietary anymore than any other digital mode DSTAR DMR P25 NXDN etc. making use of AMBE vocoding.

C4FM is an over the air protocol that any manufacturer can employ in their radios should they choose. Many prob. wont because...

What is proprietary though is their wires X networking offering, closed source and restricted to use.

it demands you run yaesu hardware as the only way to ingest into their network (imho this has no place in an amateur radio usecase. Ham radio being a hobby open to all, beginner or experimentor alike and this requirement to run only yaesu hardware to access their network goes againt that ideology) even if another manufacturer were to release a C4FM capable radio it will do fine for over the air comms, but most prob. not connect directly with their network. As that side of Yaesu's operation remains closed spurce.

wires x follows a buisness model where you can only use it if you buy into yaesu hardware and run their own (agn. closed source) windows software offering.

Luckily we have YSF networking (not yaesu system fusion) an open source networking alternative to make use of.

Sent via smoke signals from my SM-G935F M1DNS (Admin)

[G6ZKC]

Thanks both for the replies.

I feel DMR is the way to go not being tied to a brand and possibly more used. Being a 99.99999% listener I'm in no rush to buy anything just like reading about things radio PDF manuals etc. PI-star looks very straight forward - being into Linux helps with PI servers etc already doing stuff here for years.

[AF6VN]

Thanks both for the replies.

I feel DMR is the way to go not being tied to a brand and possibly more used. Being a 99.99999% listener I'm in no rush to buy anything just like reading about things radio PDF manuals etc. PI-star looks very straight forward - being into Linux helps with PI servers etc already doing stuff here for years.

Unless you pay for upper-end DMR rigs you won't find front-panel programming on most -- being based on land-mobile (business band) radios, where the end-user is not allowed to program the radios means learning to use (often confusing, given translations from Chinese) computer programming software. For DMR that then means defining which talk-groups you may want to access, then (typically) creating a "channel" for each talk group (all having the same frequencies, color code, etc. -- differing only in contact/TG name and the name you give the channel itself; this odd split is to allow using the same talk groups on different repeaters, where everything is the same except frequency and channel name). Then you get to add them to a "zone" (group of channels -- depending on use case you might have multiple repeaters all on one talk group in a zone, or one repeater with channels for multiple talk groups, or any combination in between. Some older radios may only allow 16 channels per zone as they use a 16-position rotary switch rather than a rotary encoder with "up/down" signals).