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--- public:radio:2024:hf-vhf_xgate [29/03/24 09:28 GMT] – [Mobile Cross-band repeat access] john
+++ public:radio:2024:hf-vhf_xgate [06/03/25 06:49 GMT] (current) – external edit 127.0.0.1
@@ Line 206: / Line 206: @@
 I've updated the ''mercurial repository'' - added new files, committed recent changes and made a clone of it on the shack laptop - in Dropbox (which might be a bad idea?)
-There's another page about [[public:linux:mercurial| simple Mercurial]] , as an aid to remembering how to do it each time.
+There's another page about [[public:computers:mercurial| simple Mercurial]] , as an aid to remembering how to do it each time.
 |24/3/24 |{{ :public:radio:2024:xgate_m710.zip |}} |Xgate scripts |
@@ Line 216: / Line 216: @@
 === 29/3/24 ===
-If the X-gate is set to ''simplex'' mode (single band for both in and out) on ''VHF'' it should be possible to access the system via a mobile cross-band repeater from a low power UHF handheld.
+If the X-gate is set to ''simplex'' mode (single band control) on ''VHF'' it should be possible to access the system via a mobile cross-band repeater from a low power UHF handheld.
 This extends the range of the ''local VHF network''.
-If you are within UHF simplex range of the V/UHF cross-band repeater (vehicle mounted?) and the vehicle is located within VHF range of the X-Gate (eg on a distant hill-top) it //should// be possible to access the X-Gate and log in/change frequency and operate through it on HF from the UHF side of the vehicle's Cross-BAnd repeater.
+If you are within UHF simplex range of the V/UHF cross-band repeater (usually vehicle mounted) and the vehicle is located within VHF range of the X-Gate (e.g. on a suitable distant hill-top) it //should// be possible to access the X-Gate and log in/change frequency  etc. and to operate through it on HF, from the UHF side of the vehicle's Cross-Band repeater.
 I am beginning tests on this using a [[public:radio:radio_database:tm-d710| TM-D710 mobile]] and [[public:radio:radio_database:th-d72|TH-D72 handheld]].
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 From the RSGB Band Plan
-  * 144.9750, 144.9875 MHz   Low power / Adhoc repeater inputs (Note 11)
+  * 144.500 MHz   Image Modes (SSTV, Fax etc)
+  * 144.600 MHz   Data Centre of Activity (MGM, RTTY etc)
   * 433.8000-434.2500 MHz   Digital communications & Experiments
-I'm choosing to use 144.975MHz for the X-Gate VHF uplink frequency - as there's little chance of a clash with any "ad hoc repeater" and to sue 433.825MHz for the UHF side of the system (either the mobile cross-band repeater or when the X-gate itself is using split/duplex uplink). These frequencies are totally clear here in remote Shetland!
+On 2m an appropriate place seems to be between 144.500 and 144.600, where there don't seem to be any prior ''centre-of-activity'' channels carved out.
+I'll use 144.575MHz.
+On 70cm an appropriate place seems to be between 433.800 and 434.250 - //experiments//
+I'll use 433.825MHz
+  * X-Gate uplink changed to ''Simplex'' : 144.575MHz
+===== Talkthrough Watchdog Timer =====
+I found an old piece of the python code I'd written that adds a **Talkthrough Timeout** to the X-Gate. It detects the commencement of a //Talkthrough// period and starts a timer. The timeout of this watchdog is set in the code, as is a //pre-timeout// warning time.
+At the end of the //warning// time the VHF port sends "di-dit" every 20 seconds superimposed over the talkthrough (HF Receive) audio, to warn the VHF user(s) that the talkthrough will terminate soon.
+At the end of the //timeout// period the //Talkthrough// is turned off and the system returns to it's quiescent state.
+The Barrett 2062 Crossgate has a 10 minute inactivity timeout, which closes the cross-connection (talkthrough) after 10 minutes with no user activity.
+My X-Gate doesn't take into consideration user activity, as the VHF->HF PTT does not get monitored by the X-Gate, so it is not currently possible to quantify "user inactivity", by observing if there's any traffic on the VHF port. The Watchdog as it stands is a safety precaution against talkthrough getting locked up in transmit (in either direction).
+After a timeout it's a simple matter of logging in again via VHF DTMF and re-starting talkthrough if it's still required. The "warning pips" give notice that this action is soon to be needed. If talkthrough is no longer needed then no further action is required.
+=== Ideas ===
+Make the Watchdog timer user switchable - be able to disable it if required.
+  * Added new DTMF Commands "Timeout on" = ''* 3 1 #'', "Timeout off" = ''* 3 0 #''
+  * Use these to write to the "status" file
+  * The watchdog process can check the status file to decide whether to take action or not
+  * Tested and it works as expected
+=== Problems ===
+/3/24
+  * Found that the IC-M710 HF radio has poor receive sensitivity - well below spec. 12dB SINAD should be at 0.5uV but it needs more like 3uV (or more) which is quite poor
+  * X-Gate taken out of use until I can either repair the ''IC-M710'' or make up connections to use the ''IC-7200''. The latter needs a 13-pin DIN plug for the rear panel ACC socket.
-  * Uplink changed to ''Simplex'' : 144.975MHz
 ===== Further Information =====