Handheld Transeiver Linton LT9100 on 23cm?

 A few weeks ago, in a weekly microwave video chat someone mentioned  getting the Linton LT9100 handheld transceiver. It claims to work up to 1300MHz with 5W (Chinese watts?)

A few of us ordered one, and I got mine today, and made a quick check.

When I use it in the house with the IC-9700, it actually does transmit and receive.

Here is the catch. When connected to an antenna normally used for running the local repeater with 1W, this happened:

In TX no signal through the repeater.

In RX, transmitting with the IC-9700, no reception whatsoever.

In other words, transmit power is certainly below 1W, and the receiver is deaf.

Given that the chip in this transceiver is not specified, and filters may be off, I am not so surprised.

Okay, let's try with a 30dB attenuator between radio and a spectrum analyzer, just to be safe.

Oops! Hardly any visible output on 1296. Let's just say that some amplification is needed. A lot of amplification, the output is in the uW (yes, microwatts) range. 

I still need to check receiver sensitivity, I do have a signal generator for the frequency, I need to check if I can modulate it with FM.

That is for another day.

The radio can be easily programmed for the repeater (and other 23cm) frequencies, so the question is, can it be used as a separate transceiver, with a bit of filtering and a good deal of amplification in both transmit and receive mode?

Possibly. There is no connector for external microphone (or speaker) so it will have to be dismantled and modified, so the PTT can be controlled externally.

I will also wait to see the results from other people in the group, and what they think about it.

So, first impressions, maybe not good for 1296. We shall see.

A Bit More on the IC X02s and Propagation Monitoring.

 I have made some tests of the two IC202s, the IC402 and the IC502.

These are the preliminary results, essentially my notes after testing:

1) Ancient (my first) IC 202 #1 (2m):

Some modifications were made:

- Antenna connector changed to BNC and moved. PL connector disconnected.

- Telescopic antenna removed.

- Audio CW filter added with switch at the top. In working order.

- unknown veroboard with ??? circuitry connected to main board main connector.. Detective work needed.

- Some relay circuitry and ???. Detective work needed.

Most of the mods are in the original battery compartment, replaced with a copper clad PCB

- This one looks like it has a connector for an external VFO. Could be useful making a more stable LO. Need to find the appropriate info if I want to build/connect one.

- TX out CW: 30mW Detective work needed.

Use as back end for transverter ot down converter?, or just 2m monitor (144.300)?

2) Also a quite ancient IC 202 #2 (2m):

- PL connector replaced with N connector (good move).

- Some Veroboard modification at the mainboard main (long) connector. Detective work needed. Looks like RF output power control circuit. 

- This one also looks like it has a connector for an external VFO. Could be useful making a more stable LO. Need to find the appropriate info if I want to build/connect one.

- Zero out put in CW. Detective work needed.

- Still needs a check.

Use as back end for transverter?

3) IC 402 (70cm):

- quick check, and seems to be in working order.

- Need to change power connector (I do not have any "male" 3-pin-plus ground connectors for power cables, so will likely let a filtered cable out through the power connector opening.

- TX out CW: just under 3W @ 12.5V Looks OK.

Build external VFO? (e.g. in the battery compartment)

4) IC 502:

- Checked the IC502. VFO looks rather unstable. Contact spray helped with RIT and a bit with the fine tuning. Still not quite good, but could be used for "fixed" frequency monitoring, e.g. +/-50.100.

Should probably (long term) be replaced by a Si5351 synthesizer w/Arduino control (e.g. in the battery compartment) 

- Need to change power connector (I do not have any "male" 3-pin-plus ground connectors for power cables, so will likely let a filtered cable out through the power connector opening.

- TX out CW: 2W @ 12.5V Looks OK

Final result: 

All radios seem to work fine in receive mode (a bit more testing, and maybe alignment, will be in order.

The '402 and the '502 appear to work nicely overall.

The two '202s need some work to get TX working properly again. Those could still be used as monitor receivers without problems.

Epilogue:

I do have some FT817s. One with a blown PA, the three others okay. Here is the thing:

I want to do as much general monitoring as possible on solar power. This means minimizing power consumption.

The IC-X02s use about 100mA @ 12.5VDC

The FT817s use 3-400mA. 

So for monitoring, I could power 3 or 4 IC-X02s for the power that the FT817 draws. Yes, I want those up and running.

The IC-X02s will not be suitable if I want to monitor digital modes like FT8. for that I need to use the FT-817, maybe later build some simple crystal or PLL controlled receivers.

Yes, still far too many things to try out.