Rx wider frequency range

cmwang
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Re: Rx wider frequency range

Post by cmwang » Sun Apr 19, 2020 6:01 am

I had no opinion for extended UHF frequency range. But I do not recommend to extend VHF frequency down to 12xMHz for following reason.

1:The civilian aeronautics use 118-137MHz in AM. Since the RDA1846 does not support AM at all,it would be meaningless to use RDA1846 to receive 12x-137MHz.

2:Support TX in 12x-137MHz in FM would be meaningless,and might cause harmful interference to civilian aeronautics.

I recommend the author could reserve extended frequency in source code,but restrict to within 136-174MHz in binary F/W to prevent unintentional abuse.

VK3KYY
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Re: Rx wider frequency range

Post by VK3KYY » Sun Apr 19, 2020 7:44 am

cmwang wrote:
Sun Apr 19, 2020 6:01 am
I recommend the author could reserve extended frequency in source code,but restrict to within 136-174MHz in binary F/W to prevent unintentional abuse.
The official firmware already does this range, if you change the band limits in the codeplug. Most people already did this.

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IU4LEG
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Re: Rx wider frequency range

Post by IU4LEG » Sun Apr 19, 2020 8:59 am

F1RMB wrote:
Sat Apr 18, 2020 2:54 pm
IU4LEG wrote:
Sat Apr 18, 2020 2:34 pm
It was also implemented the microphone gain for the FM?
Yes.

Cheers.
---
Daniel
I also tried the microphone gain in FM. works well
thanks

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F1RMB
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Re: Rx wider frequency range

Post by F1RMB » Sun Apr 19, 2020 9:29 am

Hi,
IU4LEG wrote:
Sun Apr 19, 2020 8:59 am
F1RMB wrote:
Sat Apr 18, 2020 2:54 pm
IU4LEG wrote:
Sat Apr 18, 2020 2:34 pm
It was also implemented the microphone gain for the FM?
Yes.

Cheers.
---
Daniel
I also tried the microphone gain in FM. works well
thanks
Cool ;)


Cheers.
---
Daniel
73 de Daniel.

jobdone
Posts: 21
Joined: Mon Dec 30, 2019 8:16 pm

Re: Rx wider frequency range

Post by jobdone » Sun Apr 19, 2020 9:49 am

Both my GD77's with '1709A'xxxx serial numbers work as follows:
no power levels taken
TX on 128 seemed ok
tx on 177 seemed ok
tx on 190 made my freq counter show 380 (second harmonic)
tx on 280 made my freq counter show 560 (second harmonic)
tx on 380 seemed ok
tx on 560 seemed ok

RX is a bit different.
128 both rx ok
177 both rx ok
190 both rx but rx sensitivity is low
280 both rx but sensitivity is low
380 both rx well
560 one doesn't rx and the other the rx sensitivity is low ( the one that doesn't starts at 559 something)
Test equipment used was very basic , just a chinese RF sniffer and rpitx and The FM mic option is greatly received, I know a few ops that will help out

VK3KYY
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Re: Rx wider frequency range

Post by VK3KYY » Sun Apr 19, 2020 10:07 am

jobdone wrote:
Sun Apr 19, 2020 9:49 am
tx on 190 made my freq counter show 380 (second harmonic)
tx on 280 made my freq counter show 560 (second harmonic)
There is no RF stage for the range from 174 - 400Mhz, but I found it was better to enable the UHF PA and the UHF Rx amp, because if I use the VHF RF sections for this range, the Rx sensitivity is low.

Its not possible with the way the firmware is written to use a different RF section for the Rx to the Tx.
And the change to make the best use of the baseband RF chip are intended for Rx.

jobdone
Posts: 21
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Re: Rx wider frequency range

Post by jobdone » Sun Apr 19, 2020 11:00 am

I doubt anyone wants to TX in this range anyway, so not really a problem , just a warning to be honest.

W1CY
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Joined: Sun Jan 12, 2020 6:57 pm

Re: Rx wider frequency range

Post by W1CY » Mon Apr 20, 2020 6:26 am

Radio #1:

127 - 178
190 - 282
380 - 564

CX2JO
Posts: 4
Joined: Mon Apr 20, 2020 1:17 pm

Re: Rx wider frequency range

Post by CX2JO » Mon Apr 20, 2020 1:21 pm

HI.MY BAOFEN DM-1801 IN TX WORK:

136000 to 172000 - vhf
381000 to 500000 - uhf


does not work at 200 mhz, is this so? Can someone make it work in that band correctly? :cry:
73

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F1RMB
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Re: Rx wider frequency range

Post by F1RMB » Mon Apr 20, 2020 1:35 pm

Hi,
CX2JO wrote:
Mon Apr 20, 2020 1:21 pm
HI.MY BAOFEN DM-1801 IN TX WORK:

136000 to 172000 - vhf
381000 to 500000 - uhf


does not work at 200 mhz, is this so? Can someone make it work in that band correctly? :cry:
73
Did you turned "Band Limits" off, in the Options ?

Cheers.
---
Daniel
73 de Daniel.

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