Author Topic: Use that Cable for VHF, UHF stuff?  (Read 2533 times)

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Offline Lord of nothing

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Use that Cable for VHF, UHF stuff?
« on: October 16, 2021, 08:15:19 pm »
Hi
Sry I dont know much about Antenna Cable but can I use that for VHF, UHF Signal Transmission?
https://www.delock.de/produkte/G_88894/merkmale.html

I have a Splitter who should split the Signal into Multiple SDR for that I need a short Cable to reach the SDR.
THX!
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Offline radiolistener

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Re: Use that Cable for VHF, UHF stuff?
« Reply #1 on: October 16, 2021, 08:47:02 pm »
Sry I dont know much about Antenna Cable but can I use that for VHF, UHF Signal Transmission?
https://www.delock.de/produkte/G_88894/merkmale.html

It can works, but note that thin cables have higher loss. Also note that splitter has insertion loss. 2 port splitter has about 3 dB loss, so if you want to receive weak signals you're needs to avoid using splitter and connect your antenna directly.

Also note that this cable has a hard cover and this often leads to separation from the connector. So if you want to connect and disconnect this cable often, then you're needs spare connectors and crimping tool to replace connectors :)
« Last Edit: October 16, 2021, 08:49:43 pm by radiolistener »
 
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Offline 3isenhorn

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Re: Use that Cable for VHF, UHF stuff?
« Reply #2 on: October 17, 2021, 08:42:32 am »
Hello,
Generally you can use the cable, but Delock is quite expensive.
I would recommend getting alternatives, I personally use some cheap cables from China, but you could also use minicircuits if you want known quality, e.g
https://www.minicircuits.com/WebStore/dashboard.html?model=086-10SM%2B

It can works, but note that thin cables have higher loss. Also note that splitter has insertion loss. 2 port splitter has about 3 dB loss, so if you want to receive weak signals you're needs to avoid using splitter and connect your antenna directly.



Very true, but the cable loss is not so large within VHF/UHF. But you should be careful with the power divider.

 
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Offline Wallace Gasiewicz

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Re: Use that Cable for VHF, UHF stuff?
« Reply #3 on: October 17, 2021, 10:01:53 pm »
You said "multiple SDR receivers" If you are also using this for transmit, there are plenty of problems. But for receive, why just not use 75 ohm CATV/UHF TV cable. Then buy a a commercially available multiple output  TV amp for these freq? Cheap 75 ohm cable generally has low loss.
It is a lot cheaper.
A splitter will decrease your Rx by a denominator equal to the number of outputs plus an additional loss.
Or just use any decent small coax for running to the receivers from the amp. With short jumpers loss is not a considerable factor.
Works on my OTA TV system quite well.
Even if your receiver is 50 ohm input, it should not matter much at all.
Besides lots of VHF receiver inputs are not exactly 50 ohms either.

Wally KC9INK
 
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Offline Lord of nothing

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Re: Use that Cable for VHF, UHF stuff?
« Reply #4 on: October 17, 2021, 10:20:20 pm »
 ;D Dont worry I use then only for Reception.
I still got an Splitter used who was build by Mini-Circuits. I dont know which Model exactly its 6/ 8 Port Splitter I dont remember right.
Everything run on SMA so I would just use a SMA Jumper Cable.
I also will use an LNA to Boost the Signal.
Quote
https://www.minicircuits.com/WebStore/dashboard.html?model=086-10SM%2B
Code: [Select]
Subtotal ( 1 )  €134.86
Austria
Estimate Shipping to
€20.0
Estimated Shipping Cost
€154.86
Estimated Total:
Checkout
Well its a little hight since I must pay Import from non EU (UK...). I pay for the Delock  19,32 €*  + 20% Tax.
* Price change per Day
Quote
I personally use some cheap cables from China
Yes me to but are there some Genuine Seller on Aliexpress who offer a good quality?
Made in Japan, destroyed in Sulz im Wienerwald.
 

Offline radiolistener

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Re: Use that Cable for VHF, UHF stuff?
« Reply #5 on: October 18, 2021, 03:28:01 am »
I still got an Splitter used who was build by Mini-Circuits. I dont know which Model exactly its 6/ 8 Port Splitter I dont remember right.

such splitter will add 8-9 dB loss, so it's not a good idea to use it on receiver antenna
 

Offline 3isenhorn

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Re: Use that Cable for VHF, UHF stuff?
« Reply #6 on: October 18, 2021, 06:35:37 am »
Hello,

I still got an Splitter used who was build by Mini-Circuits. I dont know which Model exactly its 6/ 8 Port Splitter I dont remember right.
Everything run on SMA so I would just use a SMA Jumper Cable.
I also will use an LNA to Boost the Signal.

You just have to make sure you have enough signal strength, depending on the requirement you could also think about an RF switch?


Quote
https://www.minicircuits.com/WebStore/dashboard.html?model=086-10SM%2B
Code: [Select]
Subtotal ( 1 )  €134.86
Austria
Estimate Shipping to
€20.0
Estimated Shipping Cost
€154.86
Estimated Total:
Checkout
Well its a little hight since I must pay Import from non EU (UK...). I pay for the Delock  19,32 €*  + 20% Tax.
* Price change per Day
Quote
I personally use some cheap cables from China
Yes me to but are there some Genuine Seller on Aliexpress who offer a good quality?


I don't see where the price comes from, a single cable $11.83 +VAT which is roughly 10.21€ +VAT, they also have sales agents in the EU for example:
https://www.municom.de/de/produkt-filter?mainCategory=175&category=198&subCategory=3853&product=46434

Or is the price from Delock already for several cables?
Unfortunately, I haven't been able to buy any cheap cables for private use lately, so I can't make any recommendations.
 

Offline A.Z.

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Re: Use that Cable for VHF, UHF stuff?
« Reply #7 on: October 18, 2021, 09:40:26 am »
I still got an Splitter used who was build by Mini-Circuits. I dont know which Model exactly its 6/ 8 Port Splitter I dont remember right.

Knowing the model of the splitter would allow to know the approx insertion loss

https://www.minicircuits.com/WebStore/Splitters.html

anyhow, looking at the list of 6 to 8 ports splitters from microcircuits, the declared insertion loss seems to range between 0.2 and 1.2 dB, depending from the splitter model, for example

https://www.minicircuits.com/pdfs/AD6PS-1+.pdf

as for the cable willing to minimize losses you may consider some pigtails built using LMR-100

 

Offline Wallace Gasiewicz

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Re: Use that Cable for VHF, UHF stuff?
« Reply #8 on: October 18, 2021, 11:15:30 am »
I was thinking CHEAP
Like this one with splitter and amp combined:

https://www.lowes.com/pd/RCA-HD-Television-Tuner/3701514

I know this is US price and the ports are 75 ohm TV cable, but it is cheap and works quite well for me.
Unfortunately you need adaptors for SMA...

Wally KC9INK
 

Offline A.Z.

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Re: Use that Cable for VHF, UHF stuff?
« Reply #9 on: October 18, 2021, 12:52:04 pm »
I was thinking CHEAP

Hi Wally, no need to "SHOUT"  :) I was replying to the OP ("Lord of Nothing"), and since he stated he already has (or has ordered) the splitter, my suggestion was about pigtail cables, while the LMR-100 isn't cheap, for short lengths it won't break the bank, and will offer good performances.
 

Offline ConKbot

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Re: Use that Cable for VHF, UHF stuff?
« Reply #10 on: October 18, 2021, 09:59:30 pm »

https://www.minicircuits.com/WebStore/Splitters.html

anyhow, looking at the list of 6 to 8 ports splitters from microcircuits, the declared insertion loss seems to range between 0.2 and 1.2 dB, depending from the splitter model, for example

https://www.minicircuits.com/pdfs/AD6PS-1+.pdf
Note that those are listed as "above 7.8db" as in dB in excess of the 7.8db theoretical minimum "loss" of  6 way splitter. So 8 to 9 dB in practice. I.e. 2-way splitter that loses no power to heat will have 3db reduction of the signal going to each port, as the power is halved. Any extra insertion loss beyond theoretical is either in heat in the device, or mismatch sending it back out the input.
Not really trying to be misleading there in the datasheet, just separating actual loss from the splitter splitting the signal.
 

Offline radiolistener

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Re: Use that Cable for VHF, UHF stuff?
« Reply #11 on: October 19, 2021, 05:56:02 am »
Quote
I personally use some cheap cables from China
Yes me to but are there some Genuine Seller on Aliexpress who offer a good quality?

I bought RG316 from this seller several times, tested it and its parameters well fits with RG316 datasheet:
https://www.aliexpress.com/item/32850357780.html


anyhow, looking at the list of 6 to 8 ports splitters from microcircuits, the declared insertion loss seems to range between 0.2 and 1.2 dB, depending from the splitter model, for example

https://www.minicircuits.com/pdfs/AD6PS-1+.pdf

The value "between 0.2 and 1.2 dB" is relative and shows insertion loss above theoretical splitter loss, so you're needs to add 7.8 dB to that value:

7.8 + 1.2 = 9 dB


According to the datasheet this 6-port splitter has insertion loss 8-9 dB, which is well corresponds with theoretical insertion loss for balanced splitter:

Insertion loss = 10*log(N) = 10*log(6) = 7.8 dB

where
N - is the number of output ports

as for the cable willing to minimize losses you may consider some pigtails built using LMR-100

LMR100 is much worse than RG142, for example 100 meters at 145 MHz:

cable | insertion loss | max voltage | phase delay | average power
RG142 | 16.6 dB | 1900 V | 147.2 ns | 1300 W
RG316 | 34.8 dB | 1200 V | 147.2 ns | 500 W
LMR100A | 31.7 dB | 500 Vdc / 2000 Vrms | 153.9 ns | 100 W

As you can see, LMR100A is the same as RG316, just a little slower...


By the way, I don't recommend to buy LMR series cable from China. I tried to buy LMR195, but two times I got a bad counterfeit. Tested it and it's impedance was about 63 Ω instead of 50 Ω. I'm not even surprised that both times the cables were visually different and made from different material, and both times it was about 63 Ω, but one of them has significantly worse insertion loss.

For comparison, Chinese RG316 is much better and corresponds with branded RG316.
« Last Edit: October 19, 2021, 09:29:43 am by radiolistener »
 

Offline A.Z.

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Re: Use that Cable for VHF, UHF stuff?
« Reply #12 on: October 19, 2021, 08:13:12 am »
LMR100 is much worse than RG142, for example 100 meters at 145 MHz:

First of all, I'm not sure why one should be so crazy to use 100m of LMR100 (or RG142), those cables weren't designed to be used on long runs, then the OP wrote

I have a Splitter who should split the Signal into Multiple SDR for that I need a short Cable to reach the SDR.

so we're talking about a SHORT run of coax (say 1m or less) and in such a case the loss will be negligible, by the way this doesn't mean that one should pick a crap chinese coax, but there's no need to pick a "special" one, either; that said, if you like using thin coax all the way to the antenna, up to you, as for me, willing to feed an antenna with a relatively long run of coax, I'd go for cheap RG6 (if going RX only), cheaper and will offer much lower losses than (say) an RG142 of the same length

« Last Edit: October 19, 2021, 08:16:16 am by A.Z. »
 

Offline radiolistener

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Re: Use that Cable for VHF, UHF stuff?
« Reply #13 on: October 19, 2021, 08:24:56 am »
First of all, I'm not sure why one should be so crazy to use 100m of LMR100 (or RG142), those cables weren't designed to be used on long runs, then the OP wrote

100m is a standard length which is specified in the cable datasheet, so I used it to show values which is easy to compare with other cables. If you want to get insertion loss for 10 meters, just divide it by 10. For 1 meter, just divide it by 100.
« Last Edit: October 19, 2021, 08:27:26 am by radiolistener »
 

Offline A.Z.

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Re: Use that Cable for VHF, UHF stuff?
« Reply #14 on: October 19, 2021, 08:40:19 am »
100m is a standard length which is specified in the cable datasheet, so I used it to show values which is easy to compare with other cables. If you want to get insertion loss for 10 meters, just divide it by 10. For 1 meter, just divide it by 100.

Thank you for posting the obvious; that said, now divide the loss by 100 and tell me if your note about loss difference between LMR100 and RG142 has any meaning for a 1m pigtail cable
 

Offline radiolistener

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Re: Use that Cable for VHF, UHF stuff?
« Reply #15 on: October 19, 2021, 09:18:46 am »
A.Z.
Usually there is 20-50 meters between antenna and transmitter, so such attenuation will be important.
« Last Edit: October 19, 2021, 09:25:57 am by radiolistener »
 

Offline A.Z.

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Re: Use that Cable for VHF, UHF stuff?
« Reply #16 on: October 19, 2021, 09:23:13 am »
A.Z.
Usually there is 20-50 meters between antenna and transmitter, so such attenuation will be important.

DEEP SIGH !!!

This discussion started with a message from "Lord of Nothing" writing:

I have a Splitter who should split the Signal into Multiple SDR for that I need a short Cable to reach the SDR.

so he asked for a short run of cable, not for a cable to go "all the way to the antenna"

 

Offline radiolistener

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Re: Use that Cable for VHF, UHF stuff?
« Reply #17 on: October 19, 2021, 09:30:56 am »
sorry, here is my mistake, I showed insertion loss for 100 ft instead 100 meters. Just fixed it:

cable | insertion loss | max voltage | phase delay | average power
RG142 | 16.6 dB | 1900 V | 147.2 ns | 1300 W
RG316 | 34.8 dB | 1200 V | 147.2 ns | 500 W
LMR100A | 31.7 dB | 500 Vdc / 2000 Vrms | 153.9 ns | 100 W

so he asked for a short run of cable, not for a cable to go "all the way to the antenna"

it also important for a short cable if you place it between antenna and tuner :)
« Last Edit: October 19, 2021, 09:35:21 am by radiolistener »
 

Offline A.Z.

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Re: Use that Cable for VHF, UHF stuff?
« Reply #18 on: October 19, 2021, 09:40:20 am »
sorry, here is my mistake, I showed insertion loss for 100 ft instead 100 meters. Just fixed it:
 ....

it also important for a short cable if you place it between antenna and tuner :)

So, are you saying that the loss difference between those cables, calculated for a 1 meter run of cable, will make any perceivable difference for the signal going from the splitter to the SDR receiver ?
 

Offline radiolistener

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Re: Use that Cable for VHF, UHF stuff?
« Reply #19 on: October 19, 2021, 09:53:01 am »
A.Z.

No, for the feeder-splitter system (with 1 meter coax) the main loss occurs in the splitter, 6 port splitter has 9 dB insertion loss. This is too much.

It will be noticeable on receiver, SNR of all stations will be reduced with about 10 dB. You can no longer hear weak stations (for which SNR is about 10 dB without splitter). And the rest of stations will be 10 dB more noisy.
« Last Edit: October 19, 2021, 10:02:32 am by radiolistener »
 

Online FransW

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Re: Use that Cable for VHF, UHF stuff?
« Reply #20 on: October 19, 2021, 10:09:59 am »
Do not forget the current modern type of 7 & 10 mm cables.

A tuner is a nice word for dummy load.

Instead of splitting I would concentrate on scanning/switching and avoid the huge
insertion loss. Splitting will lead to disappointing results. Even with pre-amps.

LF/MF is distinctly different from VHF, UHF & SHF.
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Offline Lord of nothing

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Re: Use that Cable for VHF, UHF stuff?
« Reply #21 on: October 24, 2021, 04:26:53 pm »
sry for the late replay.
I want analyse 24/7 some freq if a "Buzz Word" is falling.
Long story short its insane to put 10 VHF next to each other and connect them to one receiver.  :-//
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Offline SQ9MT_PL

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Re: Use that Cable for VHF, UHF stuff?
« Reply #22 on: October 30, 2021, 07:48:56 am »
Interesting measurements of SMA connectors and loads.

up to 26,5 GHz

http://f1chf.free.fr/hyper/MESURES/
 

Offline Lord of nothing

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Re: Use that Cable for VHF, UHF stuff?
« Reply #23 on: October 30, 2021, 03:09:21 pm »
On 11.11 there will be some Discount I would like to use.
Maybe someone have an good recommendation from some AliExpress seller who sell different length.
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Offline Lord of nothing

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