KD7RJC
Member
- Joined
- Jun 22, 2023
- Messages
- 97
I ended up using the term "echoing" to refer to my own equipment in order to attempt to keep it more clear versus a hilltop-repeater hosting the net. I'll continue to do so for the purposes of clarity, even though obviously my FTM-500 is acting as a cross-band repeater. From here forward "repeater" in my post will only refer to that hilltop-repeater, not to the crossband repeat function, which I'll refer-to as echoing.
The trouble I encountered was that if I configured the mobile with just the normal memory for communicating with that hilltop-repeater on the 70cm side in crossband echoing mode, the mobile was not only echoing my 2m Tx from my HT to the 70cm repeater-input frequency, but was then taking the 70cm repeater-output frequency Rx and retransmitting it on 2m back toward my HT. For a net this was a problem.
The crossband echoing function works both ways, what it receives on its listening frequency on 2m is echoed-out 70cm, and whatever is recevied on 70cm is echoed-out 2m. If either the 2m side or the 70cm side is either on a particular frequency that's part of ARS or is on a memory slot configured for ARS then that shift will occur when the traffic is cross-banded. so if my 2m side is simplex on 144.590, and my 70cm side is tuned to listen to 440.375 and ARS in the radio is enabled then when the mobile hears 440.475 with the right tone it will echo that out 144.590, and if it hears 144.590 with tone it will echo it out 445.375. With Crossband Repeat enabled It's not only echoing 2m to 70cm, it's echoing 70cm to 2m. And this is the problem.
I had then revised to where the 70cm mobile-output Tx was just simplex on the hilltop repeater-input frequency, so the mobile wasn't tuned to receive the repeater-output (the HT itself with split-memory is Tx on 2m 144.590 for the benefit of the mobile picking it up, and is Rx on the hilltop repeater's output frequency 70cm 445.375), but the problem eventually encountered was that the mobile picked up other amateurs participating in the same net if they were close by, so other stations' Tx on 70cm toward the repeater-input could be received by the mobile.
At this stage, the mobile would echo 2m 144.590 out to 70cm 445.375, but since everyone else on the net is also transmitting to the hilltop repeater on 445.375, the mobile was then echoing their transmissions heard on 70cm 445.375 out 2m 144.590. Since I'm in an urban area this meant this happened several times on the net. One shouldn't retransmit other stations, only one's own in this scenario since the mobile isn't identifying itself. So this was a problem.
So when I reconfigured the split-memory on the mobile to a basically bogus receive frequency on 70cm that has nothing to do with the repeater and sent tone-squelch, someone would have to transmit on that bogus frequency with that tone in order for the mobile to turn around and echo that 70cm transmission out the 2m-side. Since the memory programmed for the 70cm-side on the mobile was programmed using split-memory (aka custom offset) it meant that while set up to receive effectively nothing on 70cm, when it received on 2m, it would transmit out on the 70cm frequency programmed in that split-memory, aka the repeater input on 445.375.
The biggest headache is having to program split-memory on both the HT and the mobile, basically in tandem with each other, for it to work. On the Yaesu FT5D one has to select the repeater output frequency in VFO mode, then turn off repeater shift, set the tone that one wishes to use to Tx from the HT to the mobile as tone-only (ie NOT Tone Squelch, NOT the same tone that the hilltop repeater uses), then write to memory, then go back to VFO mode to program the Tx-frequency to the same memory number.
For this example that's memory # 398 or something like that. So on the HT, memory #398 is Rx 445.375, CTCSS Tone (no squelch) 67.0, and Tx 144.590.
On the mobile there are two memory slots used. #400 is simplex 144.590, CTCSS Tone Squelch 67.0. The other is #398 (keeping consistent with the HT) with Rx 440.975, CTCSS Tone Squelch of 100.0, Tx 445.375.
HT Tx on 144.590 CTCSS 67.0 -> Mobile in Crossband Repeat Rx on 144.590 and opens-up due to CTCSS 67.0, mobile then keys-up Tx on 445.375 CTCSS 100.0.
When hilltop repeater Tx on 440.375, the mobile doesn't receive it. The HT receives it directly on 440.375.
When another ham Tx on 445.375, the mobile doesn't receive it.
If another ham or some kind of interference Tx on 440.975, if it doesn't have CTCSS tone 100.0 set, then the mobile doesn't come off-squelch so it doesn't receive it to then echo it out 144.590.
If I want to use this for any other repeater, I 1) need to confirm that the repeater owner is okay with this, and 2) need to program the repeater's relevant frequencies into new memory slots on both the HT and the mobile. This is not especially convenient. Additionally I have to go out to the truck in order to change frequencies by changing which memory slot is used.
Subsequent to this it has been suggested that I use DCS rather than CTCSS between the HT and the mobile, since DCS is not especially popular, and it's even more unlikely that someone would interfere, accidentally or otherwise, due to DCS. But that's another matter.
