Using Community CPS to program for 220Mhz receive.

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VITULLI_1
Posts: 2
Joined: Sun Nov 24, 2019 8:01 pm

Using Community CPS to program for 220Mhz receive.

Post by VITULLI_1 » Sun Nov 24, 2019 8:25 pm

Hello Everyone,

A question regarding the suggestions made in the GD77mods page to use the GD-77 for reception on the 1.25m band. It mentions to use the UHF channel range settings in the CPS, to lower the frequency to include the 220 Mhz channels. Since 1.25m band is closer to VHF and I believe considered as High-VHF, would it make sense to actually set it as part of the VHF range?

Not really knowing how the decoders/demod circuits are setup in the radio; Does it have two separate decoders (VHF-UHF) or just one that can span the whole range, does it make a difference?

I have tried it both ways and results seem similar.

Anything I should be careful with in the long run? (Other than no Tx on that range.)

Best,

Pardo.

VK3KYY
Posts: 1541
Joined: Sat Nov 16, 2019 3:25 am
Location: Melbourne, Australia
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Re: Using Community CPS to program for 220Mhz receive.

Post by VK3KYY » Sun Nov 24, 2019 9:26 pm

The radio does not have a tuned RF section for that band, however from tests done by other people, the GD-77 may be usable on that band with limited power and reduced RF sensitivity

The main problem is that there is no calibration data for the power settings or more crucially the DMR deviation settings, for that band

So currently if you try to use the radio on that band, DMR would not work.

VITULLI_1
Posts: 2
Joined: Sun Nov 24, 2019 8:01 pm

Re: Using Community CPS to program for 220Mhz receive.

Post by VITULLI_1 » Sun Nov 24, 2019 10:29 pm

Thanks, VK3KYY.

I just wanted to use it as a 1.25m analog receiver. The analog repeaters in my area come in ok. I just wanted to know if there was a difference in making it part of the VHF band vs the UHF band on the GD77.

I had this wanting to listen on 1.25m, as there is a friend who participates on a 1.25m Net, I actually, got the 1.25m bug when I saw his Triband mobile rig. I think it's a Kenwood-A741? Analog only and pretty old but still very nice.

Not too many Triband DMRs out there but I have seen something on the Anytone AT-578xx? Many are waiting for that to start shipping and if it does what it promises, I think they will sell quite a few. Eventually, the hope is there will be more like it soon. I know that squeezing more out something is not ideal... Get the right tool for each job is the better way to go but sometimes you just have to make due with "a vise-grip and duct tape" :).

Thanks again.

Best,
Pardo.

VK3KYY
Posts: 1541
Joined: Sat Nov 16, 2019 3:25 am
Location: Melbourne, Australia
Contact:

Re: Using Community CPS to program for 220Mhz receive.

Post by VK3KYY » Mon Dec 02, 2019 3:52 am

I'll investigate what needs to be done to enable 220Mhz

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