Shortening SMA aerial cables

[Hettie's Crew]

I’ve just fitted my Panorama mimo 2x2 LTE/WiFi aerial but the cables it came with are 5 metres long so they are distributed along the back of the three adjacent cupboards and then looped back to where the router is going to be. Somewhat messy.
They need shortening to about 1.5 metres. I’ve looked on good old YouTube and it looks little different to a TV coax, of which I’ve done plenty, the only difference being the need for a particular crimper.
Anyone done it?
Any advice?
? Need for soldering.

 

[daveandsan]

Is this any good, save faffing about with crimpers.
Need a photo of connectors.

https://cpc.farnell.com/rf-solutions/cba-sma-sma18/cable-assy-sma-m-m-rev-pol-1-8m/dp/RF00373?mckv=s_dc%7Cpcrid%7C224681439257%7Ckword%7C%7Cmatch%7C%7Cplid%7C%7Cslid%7C%7Cproduct%7CRF00373%7Cpgrid%7C45804487566%7Cptaid%7Cpla-368608493182%7C&CMP=KNC-GUK-CPC-SHOPPING&s_kwcid=AL!5616!3!224681439257!!!network%7D!368608493182!&gclid=EAIaIQobChMItezvhcLH8wIVQ-7tCh01lwKKEAQYBCABEgLmx_D_BwE

 

[TheBig1]

The principle is the same as with TV aerial coax but at a tiny level. You need the appropriate tools, including specialist crimpers, a decent large magnifier and really nimble steady hands. Not one single thread from the outer braid can be left in contact with the inner core

Then you might get an issue with the shorter wire affecting the SWR of the antennae

If you spread the surplus wire along the length of the required finished length, then tape it into a loom, it would be much easier to conceal

 

[Geo]

I thought excess leads = signal loss
leads should be as short as possible

 

[TheBig1]

I thought excess leads = signal loss
leads should be as short as possible

That can be true, as extra wire adds resistance, but if using to transmit and receive some antennae are very finely tuned, relying on the set length of wire

Maybe a radio expert like Jaws could help explain

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[Mikeco]

I just coiled mine up inside the cupboard and it’s worked okay everywhere I’ve used it.

 

[daveandsan]

Then you might get an issue with the shorter wire affecting the SWR of the antennae

Don’t go down that road, it’s a minefield.

 

[Manic]

I shortened the cables on my old puck antenna using these and it worked ok but you do need the proper crimping tool.

SMA male plug crimp x 2 RG58 RG142 378A | eBay

SMA male plug crimp / solder RG58 RG142 LMR195 RG400 Coaxial rf straight connector.

www.ebay.co.uk

 

[DBK]

It depends on the cable size you need to shorten. The adaptors Manic quotes are for RG58 cable which is around 6.15mm in diameter and if this is what you have it will be easy, it's just like TV antenna wire.

But if its like my Poynting antenna the cables are much thinner, I suspect its RG174 and is less than 3mm in diameter. I would be reluctant to do the job, RG58 will be trivial in comparison.

If you want to give it a go you will need something like this - but the actual connectors you need may be different but SMA male is the commonest.

Amazon product ASIN B08JLG3MWQ
www.amazon.co.uk/Coaxial-crimping-connectors-Antenna-Extension/dp/B08JLG3MWQ

 

[Jaws]

reducing a cable at VHF by 1.5 mtrs is just not worth the effort as far as signal strength goes..

BUT.. I would not coil it up, you are effectively forming a choke at a specific frequency ( Mikeco )
Far better to sort of bunch it up randomly.. One of those times where neatness is not a good idea !

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[Hettie's Crew]

I’m fairly sure it’s RG58 but I’ll have to check next time I’m there, the problem with being in storage.
1.5 metres is about what it needs to be, rather than 5 metres, not shortening by 1.5 metres.
At the moment it is all coiled up in the limited space available.

 

[Mikeco]

reducing a cable at VHF by 1.5 mtrs is just not worth the effort as far as signal strength goes..

BUT.. I would not coil it up, you are effectively forming a choke at a specific frequency ( Mikeco )
Far better to sort of bunch it up randomly.. One of those times where neatness is not a good idea !

Thankyou and a good point but I probably was a bit incorrect to say coiled up as my cables were only 2 m long, I will however check tomorrow.

 

[Lenny HB]

reducing a cable at VHF by 1.5 mtrs is just not worth the effort as far as signal strength goes..

BUT.. I would not coil it up, you are effectively forming a choke at a specific frequency ( Mikeco )
Far better to sort of bunch it up randomly.. One of those times where neatness is not a good idea !

The frequencies are far higher than VHF on the higher bandwidths the loss is around 1db per meter and you only have 6db gain to start with.

Anyone who doesn't know what they are doing shorting the cables is best left alone as you need a good termination to avoid signal loss.

 

[Lenny HB]

I’m fairly sure it’s RG58 but I’ll have to check next time I’m there, the problem with being in storage.
1.5 metres is about what it needs to be, rather than 5 metres, not shortening by 1.5 metres.
At the moment it is all coiled up in the limited space available.

See John's post #9.

 

[TheBig1]

Many years since I worked on anything broadcasting radio frequencies, so that part of mine brain is a little grey now

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[Hettie's Crew]

See John's post #9.

I did, that’s why I clarified they are RG58. I should have quoted him to avoid confusion.

 

[TheBig1]

I did, that’s why I clarified they are RG58. I should have quoted him to avoid confusion.

The antenna is designed to be panel mounted and can be fitted on a conductive or non- conductive panel. Supplied with integrated flame retardant RG174 cables (Compliant to UNECE 118.01 and EN45545-2) and a halogen free flame retardant radome the antenna is suitable for many environments and applications.

from

Panorama Antennas | Panorama Antennas

Established in 1947, Panorama Antennas is a global leader in the design and manufacture of RF antenna solutions for wireless communications.

www.panorama-antennas.com

 

[Hettie's Crew]

The antenna is designed to be panel mounted and can be fitted on a conductive or non- conductive panel. Supplied with integrated flame retardant RG174 cables (Compliant to UNECE 118.01 and EN45545-2) and a halogen free flame retardant radome the antenna is suitable for many environments and applications.

from

Panorama Antennas | Panorama Antennas

Established in 1947, Panorama Antennas is a global leader in the design and manufacture of RF antenna solutions for wireless communications.

www.panorama-antennas.com

I got it from CO-STAR and they say RG58 in their add, I’ll have to confirm tomorrow.

Our Full Product Range | Co-star

www.co-star.co.uk

 

[DBK]

I did, that’s why I clarified they are RG58. I should have quoted him to avoid confusion.

If you are sure it's RG58 (check diameter) then I think the jobs doable. The set I linked to above should do the job but if you want better quality connectors Messi & Paolini might be better. Not cheap though.

MESSI & PAOLONI CRIMP SMA for Hyperflex 5, Airborne 5 and RG58

Crimp SMA Male Connector compatible with: RG58 C/U | AIRBORNE 5 /.200'' Product dimensions: 0,8cm x 2,3cm Code: C.SMA.AC5M-CR

www.hamradio.co.uk

 

[Lenny HB]

I did, that’s why I clarified they are RG58. I should have quoted him to avoid confusion.

That's the same size as TV co-ax.

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[Hettie's Crew]

If you are sure it's RG58 (check diameter) then I think the jobs doable. The set I linked to above should do the job but if you want better quality connectors Messi & Paolini might be better. Not cheap though.

MESSI & PAOLONI CRIMP SMA for Hyperflex 5, Airborne 5 and RG58

Crimp SMA Male Connector compatible with: RG58 C/U | AIRBORNE 5 /.200'' Product dimensions: 0,8cm x 2,3cm Code: C.SMA.AC5M-CR

www.hamradio.co.uk

I’m not 100% sure until I go back and check, just going by the info on CO-STAR’s page.

 

[DBK]

I got it from CO-STAR and they say RG58 in their add, I’ll have to confirm tomorrow.

Our Full Product Range | Co-star

www.co-star.co.uk

Their description is wrong as on the same page it says the cable is C29SP-5SJ which is 5mm in diameter. This makes sense as the RG cables are not particularly good for high frequencies.

This supplier may be able to provide suitable connectors.

Varia-Store

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[Hettie's Crew]

Their description is wrong as on the same page it says the cable is C29SP-5SJ which is 5mm in diameter. This makes sense as the RG cables are not particularly good for high frequencies.

This supplier may be able to provide suitable connectors.

Varia-Store

As a worldwide distributor and IT specialist, Varia-Store offers a large assortment of network technology and embedded systems both for retail customers and resellers. Real-time VAT ID verification with immediate activation of tax-free shopping.B2B features for resellers and systems houses...

www.varia-store.com

Just been to check before it gets dark and they are the 5mm ones you quote.
Co-Star said they’ll shorten them, probably cheaper than me sourcing a crimping tool that I may never use again

 

[Jaws]

The frequencies are far higher than VHF on the higher bandwidths the loss is around 1db per meter and you only have 6db gain to start with.

Anyone who doesn't know what they are doing shorting the cables is best left alone as you need a good termination to avoid signal loss.

Even at microwave the loss over 1.5 mtrs it is very low..
Just pulled up the spec and it is 3dB over 10mtrs.. so loss over 1.5 mtrs about .5dB
Shortening the cable should net REALLY make any difference to the SWR as it it an unbalanced feeder and SWR should be dealt with at the antenna end and looking at the size and shape of the unit I would guess it is going to be shunt fed ( though that is a guess )

 

[Lenny HB]

Even at microwave the loss over 1.5 mtrs it is very low..
Just pulled up the spec and it is 3dB over 10mtrs.. so loss over 1.5 mtrs about .5dB
Shortening the cable should net REALLY make any difference to the SWR as it it an unbalanced feeder and SWR should be dealt with at the antenna end and looking at the size and shape of the unit I would guess it is going to be shunt fed ( though that is a guess )

Rg174 which is what my pointing aerial uses the loss is 0.75db per ft @ 2.4ghz.

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[Jaws]

Rg174 which is what my pointing aerial uses the loss is 0.75db per ft @ 2.4ghz.

Compared to C29SP-5SJ RG174 is a leaky hose It is air gapped double wrapped

 

[Lenny HB]

Compared to C29SP-5SJ RG174 is a leaky hose It is air gapped double wrapped

But that's the the cable these devices are fitted with so best to keep it short.

 

[Jaws]

DBK said is has C29SP-5SJ fitted ?

 

[Lenny HB]

DBK said is has C29SP-5SJ fitted ?

Nope, he has the same Poynting aerial as me, he was talking about another one, but on our ones the cable is only 300mm long.

 

[Jaws]

Nope, he has the same Poynting aerial as me, he was talking about another one, but on our ones the cable is only 300mm long.

Ahhhh

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