Rather Odd HT1000 Programming Issue

[Jatla]

Hello All,
I've encountered an odd issue while programming an HT1000 (H01KDC9AA3DN). The radio when programmed with a particular repeater pair, straight 25kHz split transmits on 126.1800 MHz. Definitely out of band! It transmits the input freq fine, it transmits on the output fine, but when combined on a single channel it reverts to the 126MHz on transmit. There are other pairs in the radio which function fine.
I have tried moving the transmit around a little (~50kc or so) thinking it was some kind of birdy and all that happens it the 126MHz freq moves slightly.

Any Ideas???



Edited one time to correct model number in the heading.
W2NJS

[Jim202]

It has been a long time since I have programmed an HT1000. My bet is that the simplex TX frequency was fat fingered in the software. I believe that there is
a separate block to enter the talk around frequency. Have you looked at the programming to make sure the simplex TX channel is where you think it is?

Jim

Hello All,
I've encountered an odd issue while programming an HT1000 (H01KDC9AA3DN). The radio when programmed with a particular repeater pair, straight 25kHz split transmits on 126.1800 MHz. Definitely out of band! It transmits the input freq fine, it transmits on the output fine, but when combined on a single channel it reverts to the 126MHz on transmit. There are other pairs in the radio which function fine.
I have tried moving the transmit around a little (~50kc or so) thinking it was some kind of birdy and all that happens it the 126MHz freq moves slightly.

Any Ideas???



Edited one time to correct model number in the heading.
W2NJS

[MTS2000des]

not possible to enter a 126.xxx frequency in HT1000 RSS.
Give it a good realignment. Otherwise replace the RF board, today it's probably cheaper to replace the radio.

[Jatla]

Thanks for the replies...I manually entered the freqs several times on different channels so I don't think that it is an issue with fat fingers. (The VHF HT1000 capabilities are from 138-176MHz I don't even know how this is possible.) Every time it goes to 126MHz. I looked at the waveform on a spectrum analyzer and it looks and tastes like FM and definitely is at 126MHz. The radio will transmit other repeater pairs fine, but just doesn't seem to like this pair. I will look at reversing the split and see what happens. The split is 5.260MHz.
If it didn't work at all, or was throwing off all kinds of spurs I would agree with an alignment issue. On other repeater splits it woks fine. That is what is maddening...

Thanks Again.

[Jatla]

Update: I checked the alignment as much as possible with the instruments at hand and it looks good.

The further issue seems to be that for some reason the radio will not tolerate 5.26MHz+/- 50kHz splits in repeater offsets. When other frequencies are programmed in with the same 5.26 meg offset the radio will go down to a 12x.xxMHz output. Unfortunately this is what the particular repeater is requiring.

Yes the price of radios would probably preclude fixing this, but just for illumination purposes this is what I've found. That is why I initially posted this in the general forum.

If anyone had any ideas I'll still be interested. I hate to relegate this portable to simplex only...

Thanks Again.

[Will]

Hello All,
The radio when programmed with a particular repeater pair, straight 25kHz split transmits on 126.1800 MHz. Definitely out of band!

Where did you get these frequencies? Are they not in the aircraft band, which is AM?

[Jatla]

That is correct, it shouldn't even work there(airband); and that is what is so maddening. Just when the Tx/Rx split is ~5.26MHz or ~6.26, or ~3.26 for that matter all result in a transmission around ~126MHz FM. (Yes, I know its Airband, but its really there!)

5.7MHz or 3.7MHz or 3.2 or 5.2MHz Tx/Rx splits all operate correctly. No problems at all. Just that slice of x.2xx to x.6xxMHz split.

It looks like splits that are x.2xxMHz to x.6xxMHz will result in airband transmit. Somewhat lower power than where it is supposed to be, but well above 1Watt.

I am assuming that it is something wrong with the controller, maybe some kind of address line error that is commanding the PLL when the controller gets around to the calculation for the offset. Think of a Binary Coded Decimal switch when a single broken wire results in a repeating error that is much like this.

With the price of HT1000's where they are its not the cost, but the principle of it now. I don't want this to beat me.

Thanks Again
Jatla

[wavetar]

Just for kicks & to eliminate a "DN" controller firmware issue, I programmed an identical model # unit here & tried various combinations using an offset of 5.26MHz with RX high, then TX high, then using talkaround. All tests were fine, no 126MHz TX with this unit.

[N4KVE]

Sometimes it's not worth the time, money, & hassle to fix a radio that can be purchased for $100. Since it only does this with this particular split, clean it up & sell it to a ham for amateur use. The split there is .600. Funny, but 5.26 was the split used way back when for the old IMTS mobile phones. Did that years ago with a HT 220. LOL. GARY N4KVE

[Jatla]

Thanks to all for the replies (and the attempts to duplicate the problem in the simulator). I know that is is not worth the time to fix a $100 radio, but if this can happen here where else may it crop up??? That was my only concern. I was not aware that this radio could go here (airband) beyond a spur.

I'll go back to my spider hole now. /Rant off.

Thank You All for the Replies,
jatla.