VHF issues on MMDVM hotspot

[AB5WX]

I recently purchased this hotspot to use on VHF with a VHF motorola XTS 5000 p25 radio.

I have tried several methods to get it to receive or transmit RF on my chosen frequency: 145.400

I've done all of the radio configurations to the radio and can confirm that it works on the 70 cm band using other modes like YSF and DMR.

However, I can not get it to do anything on VHF. Am I missing something in the hotspot configuration to allow this to happen? The hotspot came with 2m and 70cm antennas.

Any help is much appreciated.

Nick,
AB5WX

Here's the link to the hotspot on Amazon.

https://www.amazon.com/gp/product/B08JG ... _qh_dp_hza

[AF6VN]

Rather confusing

Suit for Raspberry Pi Zero W. Support:DMR,D-STAR, P25 and work with UHF in duplex mode. In Simplex mode support both Uhf and Vhf

I have no idea how to interpret that "Simplex mode support both" clause. Could mean cross-band.

Note that, at least the UHF band, is defined as duplex -- that implies setting up a repeater split (separate Tx/Rx frequencies). Hence my confusion about Simplex mode (from stuff I've read on the forum, I get the impression duplex boards don't support simplex operations since the receive antenna would be picking up the transmit antenna).

This board is NOT the same as a dual-band hotspot (one antenna, but can operate in either VHF or UHF -- but not both at the same time).

[AB5WX]

I know that's what I didn't understand either.

It says on the amazon page:

"Suit for Raspberry Pi Zero W. Support:DMR,D-STAR, P25 and work with UHF in duplex mode. In Simplex mode support both Uhf and Vhf"

It allows me to put in 2 meter frequencies, and I can see activity on the hotspot dashboard, but it doesn't pick up any local RF in any direction.

I am puzzled because why include 2 VHF antennas if it doesn't support VHF simplex?

Starting to think I've been scammed, unless someone knows some kind of magic I can do in the expert settings to get this to work.

[M1DNS]

Many chineese clone boards SAY they run vhf as well as uhf but generally we've found they dont. its being made by a company with finacial gain in mind, to supply a popular product with little or no understanding how its actually used.

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

[G4AON]

My Chinese copy MMDVM board definitely doesn’t work on 2m. It also only had micro Watts output due to faulty filter components (I removed them and it now outputs 10 mW and the harmonics are still quite low, around -30 dBc). Buyer beware.

Another one to be aware of are those cheap Chinese copies of Diamond SRH805 compact antennas for hand held radios, that can also be used on an MMDVM board.

They claim to cover 2m, 70cm and 23cm, they are just single band for 70cms

73 Dave